WorldWideScience

Sample records for warm regions gaiki

  1. Study on heat collector of the solar system utilizing outdoor air. Experimental results in cases of cold and warm regions; Gaiki donyushiki solar system no shunetsubu ni kansuru kenkyu. Kanreichi to ondanchi ni okeru shunetsu jikken to kosatsu

    Energy Technology Data Exchange (ETDEWEB)

    Komano, S.; Ebara, Y. [OM Solar Association, Shizuoka (Japan); Wada, H. [Wada Building Constructors Co. Ltd., Hokkaido (Japan)

    1996-10-27

    An experiment on heat collection was made in the heat collector of a solar system utilizing outdoor air in cold and warm regions. In this system, outdoor air is heated by the air circulation layer on the roof exposed to solar radiation. The heated air is supplied to the object space for heating and ventilation. In the experiment in a cold region, the heat collection characteristics can be adjusted by putting a baffle plate in the air duct according to the experiment of a glass heat collector. The heat collecting air layer on only the iron roof may leak or freeze in the region subject to coldness or heavy snowfall. Therefore, preheat forms the space of a garret, and the preheat temperature comparatively becomes low. The data in which the heat collection characteristics can be adjusted using only a glass heat collector is required corresponding to the regional situation. In the experiment in a warm region, an experiment was made inclusive of the preheat for which outdoor air is absorbed at the eaves. As a result, the heat collection characteristics of preheat were improved. Moreover, a heat collection temperature of about 60{degree}C was obtained on the heat collection surface including the preheat. 1 ref., 12 figs., 3 tabs.

  2. Regional warming of hot extremes accelerated by surface energy fluxes

    Science.gov (United States)

    Donat, M. G.; Pitman, A. J.; Seneviratne, S. I.

    2017-07-01

    Strong regional differences exist in how hot temperature extremes increase under global warming. Using an ensemble of coupled climate models, we examine the regional warming rates of hot extremes relative to annual average warming rates in the same regions. We identify hot spots of accelerated warming of model-simulated hot extremes in Europe, North America, South America, and Southeast China. These hot spots indicate where the warm tail of a distribution of temperatures increases faster than the average and are robust across most Coupled Model Intercomparison Project Phase 5 models. Exploring the conditions on the specific day when the hot extreme occurs demonstrates that the hot spots are explained by changes in the surface energy fluxes consistent with drying soils. However, the model-simulated accelerated warming of hot extremes appears inconsistent with observations, except over Europe. The simulated acceleration of hot extremes may therefore be unreliable, a result that necessitates a reevaluation of how climate models resolve the relevant terrestrial processes.

  3. Recent Rapid Regional Climate Warming on the Antarctic Peninsula

    Science.gov (United States)

    Vaughan, D. G.; Marshall, G. J.; Connolley, W. M.; Parkinson, C.; Mulvaney, R.; Hodgson, D. A.; King, J. C.; Pudsey, C. J.; Turner, J.

    2002-12-01

    The Intergovernmental Panel on Climate Change (IPCC) confirmed that global warming was 0.6 ñ 0.2 degrees C during the 20th Century and cited increases in greenhouse gases as a likely contributor. But this average conceals the complexity of observed climate change, which is seasonally biased, decadally variable and geographically patchy. In particular, over the last 50 years three high-latitude areas have undergone recent rapid regional (RRR) warming ? substantially more rapid than the global mean. We discuss the spatial and temporal significance of RRR warming in one area, the Antarctic Peninsula. New analyses of station records show no ubiquitous polar amplification of global warming but significant RRR warming on the Antarctic Peninsula. We investigate the likelihood that this could be amplification of a global warming, and use climate-proxy data to indicate that this RRR warming on the Antarctic Peninsula is unprecedented over the last two millennia and unlikely to be a natural mode of variability. We can show a strong connection between RRR warming and reduced sea-ice duration in an area on the west of the Antarctic Peninsula, but here we cannot yet distinguish cause and effect. Thus for the present we cannot determine which process causes the RRR warming, and until the mechanism initiating and sustaining it is understood, and is convincingly reproduced in climate models, we lack a sound basis for predicting climate change in this region over the coming century.

  4. Recent warming trend in the coastal region of Qatar

    Science.gov (United States)

    Cheng, Way Lee; Saleem, Ayman; Sadr, Reza

    2017-04-01

    The objective of this study was to analyze long-term temperature-related phenomena in the eastern portion of the Middle East, focusing on the coastal region of Qatar. Extreme temperature indices were examined, which were defined by the Expert Team on Climate Change Detection and Indices, for Doha, Qatar; these indices were then compared with those from neighboring countries. The trends were calculated for a 30-year period (1983-2012), using hourly data obtained from the National Climatic Data Center. The results showed spatially consistent warming trends throughout the region. For Doha, 11 of the 12 indices studied showed significant warming trends. In particular, the warming trends were represented by an increase in the number of warm days and nights and a decrease in the number of cool nights and days. The high-temperature extremes during the night have risen at more than twice the rate of their corresponding daytime extremes. The intensity and frequency of hot days have increased, and the minimum temperature indices exhibited a higher rate of warming. The climatic changes in Doha are consistent with the region-wide heat-up in recent decades across the Middle East. However, the rapid economic expansion, increase of population since the 1990s, and urban effects in the region are thought to have intensified the rapidly warming climate pattern observed in Doha since the turn of the century.

  5. Can climate-effective land management reduce regional warming?

    Science.gov (United States)

    Hirsch, A. L.; Wilhelm, M.; Davin, E. L.; Thiery, W.; Seneviratne, S. I.

    2017-02-01

    Limiting global warming to well below 2°C is an imminent challenge for humanity. However, even if this global target can be met, some regions are still likely to experience substantial warming relative to others. Using idealized global climate simulations, we examine the potential of land management options in affecting regional climate, with a focus on crop albedo enhancement and irrigation (climate-effective land management). The implementation is performed over all crop regions globally to provide an upper bound. We find that the implementation of both crop albedo enhancement and irrigation can reduce hot temperature extremes by more than 2°C in North America, Eurasia, and India over the 21st century relative to a scenario without management application. The efficacy of crop albedo enhancement scales with the magnitude, where a cooling response exceeding 0.5°C for hot temperature extremes was achieved with a large (i.e., ≥0.08) change in crop albedo. Regional differences were attributed to the surface energy balance response with temperature changes mostly explained by latent heat flux changes for irrigation and net shortwave radiation changes for crop albedo enhancement. However, limitations do exist, where we identify warming over the winter months when climate-effective land management is temporarily suspended. This was associated with persistent cloud cover that enhances longwave warming. It cannot be confirmed if the magnitude of this feedback is reproducible in other climate models. Our results overall demonstrate that regional warming of hot extremes in our climate model can be partially mitigated when using an idealized treatment of climate-effective land management.

  6. Changes in winter warming events in the Nordic Arctic Region

    Science.gov (United States)

    Vikhamar-Schuler, Dagrun; Isaksen, Ketil; Haugen, Jan Erik; Bjerke, Jarle Werner; Tømmervik, Hans

    2015-04-01

    In recent years winter warming events are frequently reported from Arctic areas. Extraordinarily warm weather episodes, occasionally combined with intense rainfall, cause severe ecological disturbance and great challenges for Arctic infrastructure. For example, the formation of ground ice due to winter rain or melting prevents reindeer from grazing, leads to vegetation browning, and impacts soil temperatures. The infrastructure may be affected by avalanches and floods resulting from intense snowmelt. The aim of our analysis is to study changes in warm spells during winter in the Nordic Arctic Region, here defined as the regions in Norway, Sweden and Finland north of the Arctic circle (66.5°N), including the Arctic islands Svalbard and Jan Mayen. Within this study area we have selected the longest available high quality observation series with daily temperature and precipitation. For studying future climate we use available regionally downscaled scenarios. We analyse three time periods: 1) the past 50-100 years, 2) the present (last 15 years, 2000-2014) and 3) the future (next 50-100 years). We define an extended winter season (October-April) and further divide it into three subseasons: 1) Early winter (October and November), 2) Mid-winter (December, January and February) and 3) Late-winter (March and April). We identify warm spells using two different classification criteria: a) days with temperature above 0°C (the melting temperature); and b) days with temperature in excess of the 90th percentile of the 1985-2014 temperature for each subseason. Both wet and dry warm spells are analysed. We compare the results for the mainland stations (maritime and inland stations) with the Arctic islands. All stations have very high frequency of warm weather events in the period 1930-1940s and for the last 15 years (2000-2014). For the most recent period the largest increase in number of warm spells are observed at the northernmost stations. We also find a continuation of this

  7. Urban adaptation can roll back warming of emerging megapolitan regions

    OpenAIRE

    Georgescu, Matei; Morefield, Philip E.; Bierwagen, Britta G.; Weaver, Christopher P.

    2014-01-01

    Conversion to urban landforms has consequences for regional climate and the many inhabitants living within the built environment. The purpose of our investigation was to explore hydroclimatic impacts of 21st century urban expansion across the United States and examine the efficacy of commonly proposed urban adaptation strategies in context of long-term global climate change. We show that, in the absence of any adaptive urban design, urban expansion across the United States imparts warming ove...

  8. Urban adaptation can roll back warming of emerging megapolitan regions.

    Science.gov (United States)

    Georgescu, Matei; Morefield, Philip E; Bierwagen, Britta G; Weaver, Christopher P

    2014-02-25

    Modeling results incorporating several distinct urban expansion futures for the United States in 2100 show that, in the absence of any adaptive urban design, megapolitan expansion, alone and separate from greenhouse gas-induced forcing, can be expected to raise near-surface temperatures 1-2 °C not just at the scale of individual cities but over large regional swaths of the country. This warming is a significant fraction of the 21st century greenhouse gas-induced climate change simulated by global climate models. Using a suite of regional climate simulations, we assessed the efficacy of commonly proposed urban adaptation strategies, such as green, cool roof, and hybrid approaches, to ameliorate the warming. Our results quantify how judicious choices in urban planning and design cannot only counteract the climatological impacts of the urban expansion itself but also, can, in fact, even offset a significant percentage of future greenhouse warming over large scales. Our results also reveal tradeoffs among different adaptation options for some regions, showing the need for geographically appropriate strategies rather than one size fits all solutions.

  9. Enhanced cold-season warming in semi-arid regions

    Directory of Open Access Journals (Sweden)

    J. Huang

    2012-06-01

    Full Text Available This study examined surface air temperature trends over global land from 1901–2009. It is found that the warming trend was particularly enhanced, in the boreal cold season (November to March over semi-arid regions (with precipitation of 200–600 mm yr−1 showing a temperature increase of 1.53 °C as compared to the global annual mean temperature increase of 1.13 °C over land. In mid-latitude semi-arid areas of Europe, Asia, and North America, temperatures in the cold season increased by 1.41, 2.42, and 1.5 °C, respectively. The semi-arid regions contribute 44.46% to global annual-mean land-surface temperature trend. The mid-latitude semi-arid regions in the Northern Hemisphere contribute by 27.0% of the total, with the mid-latitude semi-arid areas in Europe, Asia, and North America accounting for 6.29%, 13.81%, and 6.85%, respectively. Such enhanced semi-arid warming (ESAW imply drier and warmer trend of these regions.

  10. Warming effects on the urban hydrology in cold climate regions.

    Science.gov (United States)

    Järvi, L; Grimmond, C S B; McFadden, J P; Christen, A; Strachan, I B; Taka, M; Warsta, L; Heimann, M

    2017-07-19

    While approximately 338 million people in the Northern hemisphere live in regions that are regularly snow covered in winter, there is little hydro-climatologic knowledge in the cities impacted by snow. Using observations and modelling we have evaluated the energy and water exchanges of four cities that are exposed to wintertime snow. We show that the presence of snow critically changes the impact that city design has on the local-scale hydrology and climate. After snow melt, the cities return to being strongly controlled by the proportion of built and vegetated surfaces. However in winter, the presence of snow masks the influence of the built and vegetated fractions. We show how inter-year variability of wintertime temperature can modify this effect of snow. With increasing temperatures, these cities could be pushed towards very different partitioning between runoff and evapotranspiration. We derive the dependency of wintertime runoff on this warming effect in combination with the effect of urban densification.

  11. Physiological responses of Kobresia pygmaea to warming in Qinghai-Tibetan Plateau permafrost region

    Science.gov (United States)

    Yang, Y.; Wang, G. X.; Yang, L. D.; Guo, J. Y.; Li, N.

    2012-02-01

    Kobresia pygmaea (C. B. Clarke) C. B. Clarke is one dominant herbaceous species in the alpine meadows of the Qinghai-Tibetan Plateau. From 2006 to 2009, a warming experiment was conducted in this permafrost region. Two 2-year warming treatments with an annual average warming of 2.1 °C and 4.4 °C, and one 4-year warming treatment with an annual average warming of 2.3 °C were established to examine physiological responses of K. pygmaea to warming. Our results indicated that 2-years of warming increased malondialdehyde and non-structural carbohydrates in the plants. There was no effect of 2-year warming on electrolyte leakage and free proline content. In the 2-year warming treatment, superoxide dismutase activity and peroxidase activity increased, ascorbate peroxidase activity and ascorbic acid only increased in 2-year high warming treatment, whereas in the 4-year warming treatment, active oxygen species, electrolyte leakage, UV-absorbing compounds and anthocyanins decreased. The 4-year warming treatment also significantly increased non-structural carbonhydrate and free proline accumulation for osmotic adjustment. The results of this study suggest that K. pygmaea could adapt to a warmer environment in the future.

  12. Projection of global warming onto regional precipitation over Mongolia using a regional climate model

    Science.gov (United States)

    Sato, Tomonori; Kimura, Fujio; Kitoh, Akio

    2007-01-01

    SummaryClimate change due to global warming is of concern to the public and may cause significant changes in the hydrological regimes in arid/semi-arid areas including Mongolia, which locates at a boundary between arid and humid regions. However, general circulation models (GCMs) are not sufficient to evaluate climate change on a regional-scale. In this study, two kinds of dynamical downscaling (DDS), referred to as method-G and method-R, using a regional climate model (RCM) are applied to investigate the rainfall change over Mongolia in July due to the global warming. Method-G is a traditional DDS method in which an RCM is directly nested within a GCM, while method-R is newly suggested in this study and aims to improve the reproductivity of a regional climate. For current climate simulation, method-R uses reanalysis data as a boundary forcing of the RCM while a specially created boundary condition, in which projected changes of meteorological variables in a GCM simulation are added on reanalysis data, is used for global warming simulation. Compared with in situ observations, the rainfall amount for July is very well reproduced by the RCM, even in a smaller area of four subregions in Mongolia. Rainfall intensity by method-R is very close to actual observations; on the other hand, method-G fails to simulate heavy rainfall events stronger than 16 mm day -1. The two DDS methods show similar results with respect to the changes of precipitation in July due to the global warming, which are that precipitation decreases over northern and increases over southern Mongolia. In method-R, a decrease of precipitation of middle to heavy rainfall intensity, stronger than 4 mm day -1, contributes largely to the decreased July precipitation in northern Mongolia. Soil moisture over Mongolia also tends to decrease in July because of the combined effect caused by the decrease of precipitation and the increase of potential evaporation due to rising air temperature. This situation

  13. Global warming and mycoflora in the Baltic Region

    Directory of Open Access Journals (Sweden)

    Hanns Kreisel

    2013-12-01

    Full Text Available The author discusses possible effects of global warming on distribution and ecology of larger fungi, and presents examples of suggested indicator species which apparently are spreading from south to north. Only Basidiomycetes are corncerned, while actually no case of non-lichenized Ascomycetes is known. A continued monitoring of the mentioned species is recommended.

  14. Tropical Warm Semi-Arid Regions Expanding Over Temperate Latitudes In The Projected 21st Century

    Science.gov (United States)

    Rajaud, A.; de Noblet, N. I.

    2015-12-01

    Two billion people today live in drylands, where extreme climatic conditions prevail, and natural resources are limited. Drylands are expected to expand under several scenarios of climatic change. However, relevant adaptation strategies need to account for the aridity level: it conditions the equilibrium tree-cover density, ranging from deserts (hyper-arid) to dense savannas (sub-humid). Here we focus on the evolution of climatically defined warm semi-arid areas, where low-tree density covers can be maintained. We study the global repartition of these regions in the future and the bioclimatic shifts involved. We adopted a bioclimatological approach based on the Köppen climate classification. The warm semi-arid class is characterized by mean annual temperatures over 18°C and a rainfall-limitation criterion. A multi-model ensemble of CMIP5 projections for three representative concentration pathways was selected to analyze future conditions. The classification was first applied to the start, middle and end of the 20th and 21st centuries, in order to localize past and future warm semi-arid regions. Then, time-series for the classification were built to characterize trends and variability in the evolution of those regions. According to the CRU datasets, global expansion of the warm semi-arid area has already started (~+13%), following the global warming trend since the 1900s. This will continue according to all projections, most significantly so outside the tropical belt. Under the "business as usual" scenario, the global warm semi-arid area will increase by 30% and expand 12° poleward in the Northern Hemisphere, according to the multi-model mean. Drying drives the conversion from equatorial sub-humid conditions. Beyond 30° of latitude, cold semi-arid conditions become warm semi-arid through warming, and temperate conditions through combined warming and drying processes. Those various transitions may have drastic but also very distinct ecological and sociological

  15. Changes in extreme regional sea level under global warming

    NARCIS (Netherlands)

    Brunnabend, S.-E.; Dijkstra, H. A.; Kliphuis, M. A.; Bal, H. E.; Seinstra, F.; van Werkhoven, B.J.C.; Maassen, J.; van Meersbergen, M.

    2017-01-01

    An important contribution to future changes in regional sea level extremes is due to the changes in intrinsic ocean variability, in particular ocean eddies. Here, we study a scenario of future dynamic sea level (DSL) extremes using a high-resolution version of the Parallel Ocean Program and

  16. Local atmospheric response to warm mesoscale ocean eddies in the Kuroshio-Oyashio Confluence region.

    Science.gov (United States)

    Sugimoto, Shusaku; Aono, Kenji; Fukui, Shin

    2017-09-19

    In the extratropical regions, surface winds enhance upward heat release from the ocean to atmosphere, resulting in cold surface ocean: surface ocean temperature is negatively correlated with upward heat flux. However, in the western boundary currents and eddy-rich regions, the warmer surface waters compared to surrounding waters enhance upward heat release-a positive correlation between upward heat release and surface ocean temperature, implying that the ocean drives the atmosphere. The atmospheric response to warm mesoscale ocean eddies with a horizontal extent of a few hundred kilometers remains unclear because of a lack of observations. By conducting regional atmospheric model experiments, we show that, in the Kuroshio-Oyashio Confluence region, wintertime warm eddies heat the marine atmospheric boundary layer (MABL), and accelerate westerly winds in the near-surface atmosphere via the vertical mixing effect, leading to wind convergence around the eastern edge of eddies. The warm-eddy-induced convergence forms local ascending motion where convective precipitation is enhanced, providing diabatic heating to the atmosphere above MABL. Our results indicate that warm eddies affect not only near-surface atmosphere but also free atmosphere, and possibly synoptic atmospheric variability. A detailed understanding of warm eddy-atmosphere interaction is necessary to improve in weather and climate projections.

  17. Warm and cold complex regional pain syndromes: differences beyond skin temperature?

    Science.gov (United States)

    Eberle, T; Doganci, B; Krämer, H H; Geber, C; Fechir, M; Magerl, W; Birklein, F

    2009-02-10

    To investigate clinical differences in warm and cold complex regional pain syndrome (CRPS) phenotypes. CRPS represents inhomogeneous chronic pain conditions; approximately 70% patients with CRPS have "warm" affected limbs and 30% have "cold" affected limbs. We examined 50 patients with "cold" and "warm" CRPS (n = 25 in each group). Both groups were matched regarding age, sex, affected limb, duration of CRPS, and CRPS I and II to assure comparability. Detailed medical history and neurologic status were assessed. Moreover, quantitative sensory testing (QST) was performed on the affected ipsilateral and clinically unaffected contralateral limbs. Compared with patients who had warm CRPS, patients who had cold CRPS more often reported a history of serious life events (p CRPS, the incidence of CRPS-related dystonia was increased (p CRPS (p CRPS were characterized by mechanical hyperalgesia (p CRPS) are associated with different clinical findings, beyond skin temperature changes. This might have implications for the understanding of CRPS pathophysiology.

  18. Changes in extreme regional sea level under global warming

    OpenAIRE

    Brunnabend, S.-E.; Dijkstra, H.A.; Kliphuis, M. A.; Bal, H.E.; F. Seinstra; Werkhoven, B van.; Maassen, J.; M. van Meersbergen

    2017-01-01

    An important contribution to future changes in regional sea level extremes is due to the changes in intrinsic ocean variability, in particular ocean eddies. Here, we study a scenario of future dynamic sea level (DSL) extremes using a high-resolution version of the Parallel Ocean Program and generalized extreme value theory. This model is forced with atmospheric fluxes from a coupled climate model which has been integrated under the IPCC-SRES-A1B scenario over the period 2000...

  19. Changes in extreme regional sea level under global warming

    Science.gov (United States)

    Brunnabend, S.-E.; Dijkstra, H. A.; Kliphuis, M. A.; Bal, H. E.; Seinstra, F.; van Werkhoven, B.; Maassen, J.; van Meersbergen, M.

    2017-01-01

    An important contribution to future changes in regional sea level extremes is due to the changes in intrinsic ocean variability, in particular ocean eddies. Here, we study a scenario of future dynamic sea level (DSL) extremes using a high-resolution version of the Parallel Ocean Program and generalized extreme value theory. This model is forced with atmospheric fluxes from a coupled climate model which has been integrated under the IPCC-SRES-A1B scenario over the period 2000-2100. Changes in 10-year return time DSL extremes are very inhomogeneous over the globe and are related to changes in ocean currents and corresponding regional shifts in ocean eddy pathways. In this scenario, several regions in the North Atlantic experience an increase in mean DSL of up to 0.4 m over the period 2000-2100. DSL extremes with a 10-year return time increase up to 0.2 m with largest values in the northern and eastern Atlantic.

  20. Enhanced Warming with Atmospheric Blocking over European Region during Winter

    Science.gov (United States)

    Ji, M.; Huang, J.; He, Y.

    2013-12-01

    A 62-yr (1948-2009) atmospheric blocking climatology over European region during winter is presented. The blocking activity in the European region shows a downward long-term trend. The relationship between blocking index and teleconnection patterns (TCPs) are examined. The statistical result shows the SCAND and the EA patterns can significant effect the blocking, approximately 40% of the blocking frequency variation can be explained by these two patterns. The frequency of European blocking is sensitive to the phase of the SCAND and EA. The average number of blocking days is 46 days during the positive phase of the SCAND which is twice higher than during the negative phase (18). During the negative phase of the EA, the average number of blocking days is 32, which is 54% greater during the negative phase of the EA than during the positive phase (21). The duration of the European blocking is also sensitive to the phase of the SCAND, but isn't sensitive for the EA. The 500 hPa geopotential height composite analysis also shows an evidence of a statistical relationship between the TCPs and blocking, showing that the positive (negative) phase of the SCAND (EA) provides the right conditions for the formation and sustenance of blocking activity over the European region. However, the blocking centers are located at Scandinavia and the Urals with positive of the SCAND and Siberia with negative of the EA. Finally, the downstream surface air temperature (SAT) impact associated with European winter blocking is discussed. The result shows that the SAT of Eurasian continent is significant different between high blocking index winters and low blocking index winters.

  1. Differentiated responses of apple tree floral phenology to global warming in contrasting climatic regions

    Directory of Open Access Journals (Sweden)

    Jean-Michel eLegave

    2015-12-01

    Full Text Available The responses of flowering phenology to temperature increases in temperate fruit trees have rarely been investigated in contrasting climatic regions. This is an appropriate framework for highlighting varying responses to diverse warming contexts, which would potentially combine chill accumulation declines and heat accumulation increases. To examine this issue, a data set was constituted in apple tree from flowering dates collected for two phenological stages of three cultivars in seven climate-contrasting temperate regions of Western Europe and in three mild regions, one in Northern Morocco and two in Southern Brazil. Multiple change-point models were applied to flowering date series, as well as to corresponding series of mean temperature during two successive periods, respectively determining for the fulfillment of chill and heat requirements. A new overview in space and time of flowering date changes was provided in apple tree highlighting not only flowering date advances as in previous studies but also stationary flowering date series. At global scale, differentiated flowering time patterns result from varying interactions between contrasting thermal determinisms of flowering dates and contrasting warming contexts. This may explain flowering date advances in most of European regions and in Morocco vs. stationary flowering date series in the Brazilian regions. A notable exception in Europe was found in the French Mediterranean region where the flowering date series was stationary. While the flowering duration series were stationary whatever the region, the flowering durations were far longer in mild regions compared to temperate regions. Our findings suggest a new warming vulnerability in temperate Mediterranean regions, which could shift towards responding more to chill decline and consequently experience late and extended flowering under future warming scenarios.

  2. Differentiated Responses of Apple Tree Floral Phenology to Global Warming in Contrasting Climatic Regions.

    Science.gov (United States)

    Legave, Jean-Michel; Guédon, Yann; Malagi, Gustavo; El Yaacoubi, Adnane; Bonhomme, Marc

    2015-01-01

    The responses of flowering phenology to temperature increases in temperate fruit trees have rarely been investigated in contrasting climatic regions. This is an appropriate framework for highlighting varying responses to diverse warming contexts, which would potentially combine chill accumulation (CA) declines and heat accumulation (HA) increases. To examine this issue, a data set was constituted in apple tree from flowering dates collected for two phenological stages of three cultivars in seven climate-contrasting temperate regions of Western Europe and in three mild regions, one in Northern Morocco and two in Southern Brazil. Multiple change-point models were applied to flowering date series, as well as to corresponding series of mean temperature during two successive periods, respectively determining for the fulfillment of chill and heat requirements. A new overview in space and time of flowering date changes was provided in apple tree highlighting not only flowering date advances as in previous studies but also stationary flowering date series. At global scale, differentiated flowering time patterns result from varying interactions between contrasting thermal determinisms of flowering dates and contrasting warming contexts. This may explain flowering date advances in most of European regions and in Morocco vs. stationary flowering date series in the Brazilian regions. A notable exception in Europe was found in the French Mediterranean region where the flowering date series was stationary. While the flowering duration series were stationary whatever the region, the flowering durations were far longer in mild regions compared to temperate regions. Our findings suggest a new warming vulnerability in temperate Mediterranean regions, which could shift toward responding more to chill decline and consequently experience late and extended flowering under future warming scenarios.

  3. Diurnal warming in shallow coastal seas: Observations from the Caribbean and Great Barrier Reef regions

    Science.gov (United States)

    Zhu, X.; Minnett, P. J.; Berkelmans, R.; Hendee, J.; Manfrino, C.

    2014-07-01

    A good understanding of diurnal warming in the upper ocean is important for the validation of satellite-derived sea surface temperature (SST) against in-situ buoy data and for merging satellite SSTs taken at different times of the same day. For shallow coastal regions, better understanding of diurnal heating could also help improve monitoring and prediction of ecosystem health, such as coral reef bleaching. Compared to its open ocean counterpart which has been studied extensively and modeled with good success, coastal diurnal warming has complicating localized characteristics, including coastline geometry, bathymetry, water types, tidal and wave mixing. Our goal is to characterize coastal diurnal warming using two extensive in-situ temperature and weather datasets from the Caribbean and Great Barrier Reef (GBR), Australia. Results showed clear daily warming patterns in most stations from both datasets. For the three Caribbean stations where solar radiation is the main cause of daily warming, the mean diurnal warming amplitudes were about 0.4 K at depths of 4-7 m and 0.6-0.7 K at shallower depths of 1-2 m; the largest warming value was 2.1 K. For coral top temperatures of the GBR, 20% of days had warming amplitudes >1 K, with the largest >4 K. The bottom warming at shallower sites has higher daily maximum temperatures and lower daily minimum temperatures than deeper sites nearby. The averaged daily warming amplitudes were shown to be closely related to daily average wind speed and maximum insolation, as found in the open ocean. Diurnal heating also depends on local features including water depth, location on different sections of the reef (reef flat vs. reef slope), the relative distance from the barrier reef chain (coast vs. lagoon stations vs. inner barrier reef sites vs. outer rim sites); and the proximity to the tidal inlets. In addition, the influence of tides on daily temperature changes and its relative importance compared to solar radiation was quantified by

  4. Signatures of global warming and regional climate shift in the Arabian Sea

    Digital Repository Service at National Institute of Oceanography (India)

    PrasannaKumar, S.; Roshin, R.P.; Narvekar, J.; DineshKumar, P.K.; Vivekanandan, E.

    The impact of global warming in the recent decade is shown by the disruption in the natural decadal cycle in the sea surface temperature (SST) of the Arabian Sea after 1995. We propose a regional climate shift after 1995, the signature of which...

  5. Dominance of climate warming effects on recent drying trends over wet monsoon regions

    Directory of Open Access Journals (Sweden)

    C.-E. Park

    2017-09-01

    Full Text Available Understanding changes in background dryness over land is key information for adapting to climate change because of its critical socioeconomic consequences. However, causes of continental dryness changes remain uncertain because various climate parameters control dryness. Here, we verify dominant climate variables determining dryness trends over continental eastern Asia, which is characterized by diverse hydroclimate regimes ranging from arid to humid, by quantifying the relative effects of changes in precipitation, solar radiation, wind speed, surface air temperature, and relative humidity on trends in the aridity index based on observed data from 189 weather stations for the period of 1961–2010. Before the early 1980s (1961–1983, change in precipitation is a primary condition for determining aridity trends. In the later period (1984–2010, the dominant climate parameter for aridity trends varies according to the hydroclimate regime. Drying trends in arid regions are mostly explained by reduced precipitation. In contrast, the increase in potential evapotranspiration due to increased atmospheric water-holding capacity, a secondary impact of warming, works to increase aridity over the humid monsoon region despite an enhanced water supply and relatively less warming. Our results show significant drying effects of warming over the humid monsoon region in recent decades; this also supports the drying trends over warm and water-sufficient regions in future climate.

  6. Dominance of climate warming effects on recent drying trends over wet monsoon regions

    Science.gov (United States)

    Park, Chang-Eui; Jeong, Su-Jong; Ho, Chang-Hoi; Park, Hoonyoung; Piao, Shilong; Kim, Jinwon; Feng, Song

    2017-09-01

    Understanding changes in background dryness over land is key information for adapting to climate change because of its critical socioeconomic consequences. However, causes of continental dryness changes remain uncertain because various climate parameters control dryness. Here, we verify dominant climate variables determining dryness trends over continental eastern Asia, which is characterized by diverse hydroclimate regimes ranging from arid to humid, by quantifying the relative effects of changes in precipitation, solar radiation, wind speed, surface air temperature, and relative humidity on trends in the aridity index based on observed data from 189 weather stations for the period of 1961-2010. Before the early 1980s (1961-1983), change in precipitation is a primary condition for determining aridity trends. In the later period (1984-2010), the dominant climate parameter for aridity trends varies according to the hydroclimate regime. Drying trends in arid regions are mostly explained by reduced precipitation. In contrast, the increase in potential evapotranspiration due to increased atmospheric water-holding capacity, a secondary impact of warming, works to increase aridity over the humid monsoon region despite an enhanced water supply and relatively less warming. Our results show significant drying effects of warming over the humid monsoon region in recent decades; this also supports the drying trends over warm and water-sufficient regions in future climate.

  7. Ventimolina stellata gen. et sp. nov. (Haptophyta, Papposphaeraceae) from warm water regions

    DEFF Research Database (Denmark)

    Thomsen, Helge Abildhauge; Østergaard, Jette B.; Cros, Lluïsa

    2015-01-01

    It has been known for some time that the distinctive polar weakly calcified coccolithophores are also present in samples from lower latitudes. While polar species may actually have a geographic range that vastly extends beyond the polar realms, it is often the case that the warm water regions...... contribute species that can be allocated to genera previously described based on polar material. We are currently in the process of formally dealing with the warm water species diversity affiliated with the family Papposphaeraceae. In this paper we describe a new genus and species Ventimolina stellata based...

  8. Regional Contrasts of the Warming Rate over Land Significantly Depend on the Calculation Methods of Mean Air Temperature.

    Science.gov (United States)

    Wang, Kaicun; Zhou, Chunlüe

    2015-07-22

    Global analyses of surface mean air temperature (T(m)) are key datasets for climate change studies and provide fundamental evidences for global warming. However, the causes of regional contrasts in the warming rate revealed by such datasets, i.e., enhanced warming rates over the northern high latitudes and the "warming hole" over the central U.S., are still under debate. Here we show these regional contrasts depend on the calculation methods of T(m). Existing global analyses calculate T(m) from daily minimum and maximum temperatures (T2). We found that T2 has a significant standard deviation error of 0.23 °C/decade in depicting the regional warming rate from 2000 to 2013 but can be reduced by two-thirds using T(m) calculated from observations at four specific times (T4), which samples diurnal cycle of land surface air temperature more often. From 1973 to 1997, compared with T4, T2 significantly underestimated the warming rate over the central U.S. and overestimated the warming rate over the northern high latitudes. The ratio of the warming rate over China to that over the U.S. reduces from 2.3 by T2 to 1.4 by T4. This study shows that the studies of regional warming can be substantially improved by T4 instead of T2.

  9. Regional Contrasts of the Warming Rate over Land Significantly Depend on the Calculation Methods of Mean Air Temperature

    Science.gov (United States)

    Wang, Kaicun; Zhou, Chunlüe

    2015-01-01

    Global analyses of surface mean air temperature (Tm) are key datasets for climate change studies and provide fundamental evidences for global warming. However, the causes of regional contrasts in the warming rate revealed by such datasets, i.e., enhanced warming rates over the northern high latitudes and the “warming hole” over the central U.S., are still under debate. Here we show these regional contrasts depend on the calculation methods of Tm. Existing global analyses calculate Tm from daily minimum and maximum temperatures (T2). We found that T2 has a significant standard deviation error of 0.23 °C/decade in depicting the regional warming rate from 2000 to 2013 but can be reduced by two-thirds using Tm calculated from observations at four specific times (T4), which samples diurnal cycle of land surface air temperature more often. From 1973 to 1997, compared with T4, T2 significantly underestimated the warming rate over the central U.S. and overestimated the warming rate over the northern high latitudes. The ratio of the warming rate over China to that over the U.S. reduces from 2.3 by T2 to 1.4 by T4. This study shows that the studies of regional warming can be substantially improved by T4 instead of T2. PMID:26198976

  10. The predicted circulation response to global warming and implications for regional hydroclimate.

    Science.gov (United States)

    Simpson, Isla; Seager, Richard; Ting, Mingfang; Shaw, Tiffany

    2016-04-01

    A critical aspect of human-induced climate change is how it will affect regional hydroclimate around the world. To leading order, the increased ability of the atmosphere to hold moisture as it warms, intensifies moisture transports, making sub-tropical dry regions drier and mid- to high latitude wet regions wetter. But regional changes in hydroclimate will also depend on how the atmospheric circulation responds to warming. Here, the predictions of the future of the mid-latitude circulation by the current generation of global climate models will be discussed, with a particular focus on circulation changes that impact on regional hydroclimate. In the Northern Hemisphere winter, stationary wave changes are a leading order effect and impact on both North American and European hydroclimate. However, in certain regions, models exhibit considerable diversity in this response, motivating the need for improved understanding of the mechanisms involved and the reasons behind such a model spread. This is particularly true in the Pacific-North American sector during winter and so the mechanisms involved in circulation changes in this region and the reason for the inter-model spread will be discussed in detail.

  11. Morphology of ionospheric F2 region variability associated with sudden stratospheric warmings

    Science.gov (United States)

    Gupta, Sumedha; Upadhayaya, A. K.

    2017-07-01

    The effect of sudden stratospheric warming (SSW) on the F2 region ionosphere has been extensively analyzed for the major event of year 2009, apart from a few reports on other major and minor events. Morphology of ionospheric responses during SSW can be better comprehended by analyzing such warming events under different solar, geomagnetic, and meteorological conditions. We investigate the features of F2 region variability following the SSW events of 2010, 2011, 2012, 2013, 2014, 2015, and 2016, using ionosonde data from the Asian region covering a broad latitudinal range from 26.6°N to 45.1°N. We find perceptible ionospheric variations in electron densities during these warming events which is accompanied by a large variation of 117% within enhancements, as compared to a meagre variation of 11% within depressions, during these events. We also examine 6 months data at these latitudes and longitudes and find that the maximum and minimum variations in F2 layer critical frequency are observed during each SSW period. The influence of quasi-stationary 16 day planetary waves is seen during these SSW events. Further, a recently proposed parameter "SSW integrated strength" by Vieira et al. (2017) to characterize SSW event with respect to ionosphere is also examined. It is seen that it does not fit well for these seven SSW events at these latitudes and longitudes.

  12. Effect of regional climate warming on the phenology of butterflies in boreal forests in Manitoba, Canada.

    Science.gov (United States)

    Westwood, A R; Blair, D

    2010-08-01

    We examined the effect of regional climate warming on the phenology of butterfly species in boreal forest ecosystems in Manitoba, Canada. For the period 1971-2004, the mean monthly temperatures in January, September, and December increased significantly, as did the mean temperatures for several concurrent monthly periods. The mean annual temperature increased ≈ 0.05°C/yr over the study period. The annual number of frost-free days and degree-day accumulations increased as well. We measured the response of 19 common butterfly species to these temperature changes with the date of first appearance, week of peak abundance, and the length of flight period over the 33-yr period of 1972-2004. Although adult butterfly response was variable for spring and summer months, 13 of 19 species showed a significant (P butterfly species significantly affected by the warming trend. The early autumn and winter months warmed significantly, and butterflies seem to be responding to this warming trend with a change in the length of certain life stages. Two species, Junonia coenia and Euphydryas phaeton, increased their northerly ranges by ≈ 150 and 70 km, respectively. Warmer autumns and winters may be providing opportunities for range extensions of more southerly butterfly species held at bay by past climatic conditions.

  13. Radionuclides in ornithogenic sediments as evidence for recent warming in the Ross Sea region, Antarctica

    Energy Technology Data Exchange (ETDEWEB)

    Nie, Yaguang [Institute of Polar Environment, School of Earth and Space Sciences, University of Science and Technology of China, Hefei 230026 (China); Key Laboratory of Ion Beam Bioengineering, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Key Laboratory of Environmental Toxicology and Pollution Control Technology of Anhui Province, Hefei, Anhui 230031 (China); Xu, Liqiang [School of Resources and Environmental Engineering, Hefei University of Technology, Hefei, Anhui 230009 (China); Liu, Xiaodong, E-mail: ycx@ustc.edu.cn [Institute of Polar Environment, School of Earth and Space Sciences, University of Science and Technology of China, Hefei 230026 (China); Emslie, Steven D. [Department of Biology and Marine Biology, University of North Carolina Wilmington, 601 S. College Road, Wilmington, NC 28403 (United States)

    2016-07-01

    Radionuclides including {sup 210}Pb, {sup 226}Ra and {sup 137}Cs were analyzed in eight ornithogenic sediment profiles from McMurdo Sound, Ross Sea region, East Antarctica. Equilibration between {sup 210}Pb and {sup 226}Ra were reached in all eight profiles, enabling the determination of chronology within the past two centuries through the Constant Rate of Supply (CRS) model. Calculated fluxes of both {sup 210}Pb and {sup 137}Cs varied drastically among four of the profiles (MB4, MB6, CC and CL2), probably due to differences in their sedimentary environments. In addition, we found the flux data exhibiting a clear decreasing gradient in accordance with their average deposition rate, which was in turn related to the specific location of the profiles. We believe this phenomenon may correspond to global warming of the last century, since warming-induced surface runoff would bring more inflow water and detritus to the coring sites, thus enhancing the difference among the profiles. To verify this hypothesis, the deposition rate against age of the sediments was calculated based on their determined chronology, which showed ascending trends in all four profiles. The significant increase in deposition rates over the last century is probably attributable to recent warming, implying a potential utilization of radionuclides as environmental indicators in this region. - Highlights: • {sup 210}Pb, {sup 226}Ra and {sup 137}Cs were measured in ornithogenic sediment profiles. • Chronology within 200 years was determined through Constant Rate of Supply model. • Calculated nuclide fluxes decreased with average deposition rate and locations. • Deposition rate over time indicated warming which caused the flux gradient.

  14. Sustained mass loss of the northeast Greenland ice sheet triggered by regional warming

    DEFF Research Database (Denmark)

    Khan, Shfaqat Abbas; Kjaer, Kurt H.; Bevis, Michael

    2014-01-01

    and northwest Greenland. Here, we show that the northeast Greenland ice stream, which extends more than 600 km into the interior of the ice sheet, is now undergoing sustained dynamic thinning, linked to regional warming, after more than a quarter of a century of stability. This sector of the Greenland ice sheet...... is of particular interest, because the drainage basin area covers 16% of the ice sheet (twice that of Jakobshavn Isbrae) and numerical model predictions suggest no significant mass loss for this sector, leading to an under-estimation of future global sea-level rise. The geometry of the bedrock and monotonic trend...... in glacier speed-up and mass loss suggests that dynamic drawdown of ice in this region will continue in the near future....

  15. Inductive analysis about the impact of climate warming on regional geomorphic evolution in arid area

    Science.gov (United States)

    Anayit, Mattohti; Abulizi, Mailiya

    2016-04-01

    Climate change on the surface of earth will produce a chain reaction among so many global natural environmental elements. Namely, all the issues will be affected by the climate change, just like the regional water environment, formation and development of landscape, plants and animals living environment, the survival of microorganisms, the human economic environment and health, and the whole social environment changes at well. But because of slow frequency of climate change and it is volatility change, its influence on other factors and the overall environmental performance is not obvious, and its reflection performs slowly. Using regional weather data, we calculated qualitatively and quantitatively and did analysis the impact of climate warming on Xinjiang (a province of China) geomorphic evolution elements, including the ground weather, erosion rate, collapse change, landslide occurrences changes and impact debris flow, combining the field survey and indoor test methods. Key words: climate change; the geomorphic induction; landscape change in river basin; Xinjiang

  16. Quasar Rain: The Broad Emission Line Region as Condensations in the Warm Accretion Disk Wind

    Science.gov (United States)

    Elvis, Martin

    2017-09-01

    The origin of the broad emission line region (BELR) in quasars and active galactic nuclei is still unclear. I propose that condensations form in the warm, radiation-pressure-driven, accretion disk wind of quasars creating the BEL clouds and uniting them with the other two manifestations of cool (˜104 K) gas in quasars, the low ionization phase of the warm absorbers (WAs) and the clouds causing X-ray eclipses. The cool clouds will condense quickly (days to years), before the WA outflows reach escape velocity (which takes months to centuries). Cool clouds form in equilibrium with the warm phase of the wind because the rapidly varying X-ray quasar continuum changes the force multiplier, causing pressure waves to move gas into stable locations in pressure-temperature space. The narrow range of two-phase equilibrium densities may explain the (luminosity){}1/2 scaling of the BELR size, while the scaling of cloud formation timescales could produce the Baldwin effect. These dense clouds have force multipliers of order unity and so cannot be accelerated to escape velocity. They fall back on a dynamical timescale (months to centuries), producing an inflow that rains down toward the central black hole. As they soon move at Mach ˜10-100 with respect to the WA outflow, these “raindrops” will be rapidly destroyed within months. This rain of clouds may produce the elliptical BELR orbits implied by velocity-resolved reverberation mapping in some objects and can explain the opening angle and destruction timescale of the narrow “cometary” tails of the clouds seen in X-ray eclipse observations. Some consequences and challenges of this “quasar rain” model are presented, along with several avenues for theoretical investigation.

  17. Regional cooling caused recent New Zealand glacier advances in a period of global warming.

    Science.gov (United States)

    Mackintosh, Andrew N; Anderson, Brian M; Lorrey, Andrew M; Renwick, James A; Frei, Prisco; Dean, Sam M

    2017-02-14

    Glaciers experienced worldwide retreat during the twentieth and early twenty first centuries, and the negative trend in global glacier mass balance since the early 1990s is predominantly a response to anthropogenic climate warming. The exceptional terminus advance of some glaciers during recent global warming is thought to relate to locally specific climate conditions, such as increased precipitation. In New Zealand, at least 58 glaciers advanced between 1983 and 2008, and Franz Josef and Fox glaciers advanced nearly continuously during this time. Here we show that the glacier advance phase resulted predominantly from discrete periods of reduced air temperature, rather than increased precipitation. The lower temperatures were associated with anomalous southerly winds and low sea surface temperature in the Tasman Sea region. These conditions result from variability in the structure of the extratropical atmospheric circulation over the South Pacific. While this sequence of climate variability and its effect on New Zealand glaciers is unusual on a global scale, it remains consistent with a climate system that is being modified by humans.

  18. Regional cooling caused recent New Zealand glacier advances in a period of global warming

    Science.gov (United States)

    Mackintosh, Andrew N.; Anderson, Brian M.; Lorrey, Andrew M.; Renwick, James A.; Frei, Prisco; Dean, Sam M.

    2017-01-01

    Glaciers experienced worldwide retreat during the twentieth and early twenty first centuries, and the negative trend in global glacier mass balance since the early 1990s is predominantly a response to anthropogenic climate warming. The exceptional terminus advance of some glaciers during recent global warming is thought to relate to locally specific climate conditions, such as increased precipitation. In New Zealand, at least 58 glaciers advanced between 1983 and 2008, and Franz Josef and Fox glaciers advanced nearly continuously during this time. Here we show that the glacier advance phase resulted predominantly from discrete periods of reduced air temperature, rather than increased precipitation. The lower temperatures were associated with anomalous southerly winds and low sea surface temperature in the Tasman Sea region. These conditions result from variability in the structure of the extratropical atmospheric circulation over the South Pacific. While this sequence of climate variability and its effect on New Zealand glaciers is unusual on a global scale, it remains consistent with a climate system that is being modified by humans. PMID:28195582

  19. Regional cooling caused recent New Zealand glacier advances in a period of global warming

    Science.gov (United States)

    Mackintosh, Andrew N.; Anderson, Brian M.; Lorrey, Andrew M.; Renwick, James A.; Frei, Prisco; Dean, Sam M.

    2017-02-01

    Glaciers experienced worldwide retreat during the twentieth and early twenty first centuries, and the negative trend in global glacier mass balance since the early 1990s is predominantly a response to anthropogenic climate warming. The exceptional terminus advance of some glaciers during recent global warming is thought to relate to locally specific climate conditions, such as increased precipitation. In New Zealand, at least 58 glaciers advanced between 1983 and 2008, and Franz Josef and Fox glaciers advanced nearly continuously during this time. Here we show that the glacier advance phase resulted predominantly from discrete periods of reduced air temperature, rather than increased precipitation. The lower temperatures were associated with anomalous southerly winds and low sea surface temperature in the Tasman Sea region. These conditions result from variability in the structure of the extratropical atmospheric circulation over the South Pacific. While this sequence of climate variability and its effect on New Zealand glaciers is unusual on a global scale, it remains consistent with a climate system that is being modified by humans.

  20. Changing circulation structure and precipitation characteristics in Asian monsoon regions: greenhouse warming vs. aerosol effects

    Science.gov (United States)

    Lau, William K. M.; Kim, Kyu-Myong; Ruby Leung, L.

    2017-12-01

    Using model outputs from CMIP5 historical integrations, we have investigated the relative roles of anthropogenic emissions of greenhouse gases (GHG) and aerosols in changing the characteristics of the large-scale circulation and rainfall in Asian summer monsoon (ASM) regions. Under GHG warming, a strong positive trend in low-level moist static energy (MSE) is found over ASM regions, associated with increasing large-scale land-sea thermal contrast from 1870s to present. During the same period, a mid-tropospheric convective barrier (MCB) due to widespread reduction in relative humidity in the mid- and lower troposphere is strengthening over the ASM regions, in conjunction with expanding areas of anomalous subsidence associated with the Deep Tropical Squeeze (Lau and Kim in Proc Natl Acad Sci 12:3630-3635, 2015). The opposing effects of MSE and MCB lead to enhanced total ASM rainfall, but only a partial strengthening of the southern portion of the monsoon meridional circulation, coupled to anomalous multi-cellular overturning motions over ASM land. Including anthropogenic aerosol emissions strongly masks MSE but enhances MCB via increased stability in the lower troposphere, resulting in an overall weakened ASM circulation with suppressed rainfall. Analyses of rainfall characteristics indicate that under GHG, overall precipitation efficiency over the ASM region is reduced, manifesting in less moderate but more extreme heavy rain events. Under combined effects of GHG and aerosols, precipitation efficiency is unchanged, with more moderate, but less extreme rainfall.

  1. A possible constraint on regional precipitation intensity changes under global warming

    DEFF Research Database (Denmark)

    Gutowski, William J.; Kozak, K. A.; Arritt, R. W.

    2007-01-01

    Changes in daily precipitation versus intensity under a global warming scenario in two regional climate simulations of the United States show a well-recognized feature of more intense precipitation. More important, by resolving the precipitation intensity spectrum, the changes show a relatively...... precipitation rates that contribute relatively more to the total and rates that contribute relatively less. The behavior is roughly the same as the results of the numerical models and is insensitive to characteristics of the baseline climate, such as average precipitation, frequency of rain days, and the shape...... parameter of the precipitation's gamma distribution. Changes in the normalized precipitation distribution give a more consistent constraint on how precipitation intensity may change when climate changes than do changes in the normormalized distribution. The analysis does not apply to extreme precipitation...

  2. Variation of radiative forcings and global warming potentials from regional aviation NOx emissions

    Science.gov (United States)

    Skowron, Agnieszka; Lee, David S.; De León, Ruben R.

    2015-03-01

    The response to hemispherical and regional aircraft NOx emissions is explored by using two climate metrics: radiative forcing (RF) and Global Warming Potential (GWP). The global chemistry transport model, MOZART-3 CTM, is applied in this study for a series of incremental aircraft NOx emission integrations to different regions. It was found that the sensitivity of chemical responses per unit emission rate from regional aircraft NOx emissions varies with size of aircraft NOx emission rate and that climate metric values decrease with increasing aircraft NOx emission rates, except for Southeast Asia. Previous work has recognized that aircraft NOx GWPs may vary regionally. However, the way in which these regional GWPs are calculated are critical. Previous studies have added a fixed amount of NOx to different regions. This approach can heavily bias the results of a regional GWP because of the well-established sensitivity of O3 production to background NOx whereby the Ozone Production Efficiency (OPE) is greater at small background NOx. Thus, even a small addition of NOx in a clean-air area can produce a large O3 response. Using this 'fixed addition' method of 0.035 Tg(N) yr-1, results in the greatest effect observed for North Atlantic and Brazil, ∼10.0 mW m-2/Tg(N) yr-1. An alternative 'proportional approach' is also taken that preserves the subtle balance of local NOx-O3-CH4 systems with the existing emission patterns of aircraft and background NOx, whereby a proportional amount of aircraft NOx, 5% (N) yr-1, is added to each region in order to determine the response. This results in the greatest effect observed for North Pacific that with its net NOx RF of 23.7 mW m-2/Tg(N) yr-1 is in contrast with the 'fixed addition' method. For determining regional NOx GWPs, it is argued that the 'proportional' approach gives more representative results. However, a constraint of both approaches is that the regional GWP determined is dependent on the relative global emission pattern

  3. Modeling and predicting seasonal influenza transmission in warm regions using climatological parameters.

    Directory of Open Access Journals (Sweden)

    Radina P Soebiyanto

    Full Text Available BACKGROUND: Influenza transmission is often associated with climatic factors. As the epidemic pattern varies geographically, the roles of climatic factors may not be unique. Previous in vivo studies revealed the direct effect of winter-like humidity on air-borne influenza transmission that dominates in regions with temperate climate, while influenza in the tropics is more effectively transmitted through direct contact. METHODOLOGY/PRINCIPAL FINDINGS: Using time series model, we analyzed the role of climatic factors on the epidemiology of influenza transmission in two regions characterized by warm climate: Hong Kong (China and Maricopa County (Arizona, USA. These two regions have comparable temperature but distinctly different rainfall. Specifically we employed Autoregressive Integrated Moving Average (ARIMA model along with climatic parameters as measured from ground stations and NASA satellites. Our studies showed that including the climatic variables as input series result in models with better performance than the univariate model where the influenza cases depend only on its past values and error signal. The best model for Hong Kong influenza was obtained when Land Surface Temperature (LST, rainfall and relative humidity were included as input series. Meanwhile for Maricopa County we found that including either maximum atmospheric pressure or mean air temperature gave the most improvement in the model performances. CONCLUSIONS/SIGNIFICANCE: Our results showed that including the environmental variables generally increases the prediction capability. Therefore, for countries without advanced influenza surveillance systems, environmental variables can be used for estimating influenza transmission at present and in the near future.

  4. Regional to global changes in drought and implications for future changes under global warming

    Science.gov (United States)

    Sheffield, J.; Wood, E. F.; Kam, J.

    2012-12-01

    Drought can have large impacts on multiple sectors, including agriculture, water resources, ecosystems, transport, industry and tourism. In extreme cases, regional drought can lead to food insecurity and famine, and in intensive agricultural regions, extend to global economic impacts in a connected world. Recent droughts globally have been severe and costly but whether they are becoming more frequent and severe, and the attribution of this, is a key question. Observational evidence at large scales, such as satellite remote sensing are often subject to short-term records and inhomogeneities, and ground based data are sparse in many regions. Reliance on model output is also subject to error and simplifications in the model physics that can, for example, amplify the impact of global warming on drought. This presentation will show the observational and model evidence for changes in drought, with a focus on the interplay between precipitation and atmospheric evaporative demand and its impact on the terrestrial water cycle and drought. We discuss the fidelity of climate models to reproduce our best estimates of drought variability and its drivers historically, and the implications of this on uncertainties in future projections of drought from CMIP5 models, and how this has changed since CMIP3.

  5. Ionospheric variations during sudden stratospheric warming in the high- and mid-latitude regions

    Science.gov (United States)

    Yasyukevich, Anna; Voeykov, Sergey; Mylnikova, Anna

    2017-04-01

    The ionospheric dynamic in the high- and middle-latitude regions during the periods of sudden stratospheric warmings (SSW) was studied by using the international network of phase dual-frequency GPS/GLONASS receivers and the vertical sounding data. Twelve SSW events that occurred in the Northern Hemisphere 2006 through 2013 were considered. In order to identify the possible response of the ionosphere to SSW events, we carried out the analysis of the total electron (TEC) and the F2-layer maximum electron density (NmF2) deviations from the background level. We have also studied changes of the level of total electron content (TEC) wave-like variations characterized by a special index WTEC. The index reflects the intensity of medium- and large-scale traveling ionospheric disturbances. The dynamics of the high- and middle-latitude ionosphere at the points near the SSW areas was found to differ from the regular. For a large number of events, it is shown that, despite quiet geomagnetic conditions, a noticeable decrease in the NmF2 and TEC values (by 5-10% relative to the background level) is observed during the SSW evolution and maximum stages. On the contrary, for 10-20 days after the SSW maxima, NmF2 and TEC significantly exceed the monthly averaged values. Moreover, these electron density changes are observed for both strong and weak stratospheric warmings, and are recorded mainly during daytime. The observed SSW effects in the polar and mid-latitude ionosphere are assumed to be probably associated with the changes in the neutral composition at the thermospheric heights that affect the F2-layer electron density. The study is supported by the Russian Foundation for Basic Research under Grant No. 16-35-60018, as well as by the RF President Grant of Public Support for RF Leading Scientific Schools (NSh-6894.2016.5).

  6. Effects of warming and nitrogen fertilization on GHG flux in the permafrost region of an alpine meadow

    Science.gov (United States)

    Chen, Xiaopeng; Wang, Genxu; Zhang, Tao; Mao, Tianxu; Wei, Da; Hu, Zhaoyong; Song, Chunlin

    2017-05-01

    The limited number of in situ measurements of greenhouse gas (GHG) flux during soil freeze-thaw cycles in permafrost regions limits our ability to accurately predict how the alpine ecosystem carbon sink or source function will vary under future warming and increased nitrogen (N) deposition. An alpine meadow in the permafrost region of the Qinghai-Tibet Plateau was selected, and a simulated warming with N fertilization experiment was carried out to investigate the key GHG fluxes (ecosystem respiration [Re], CH4 and N2O) in the early (EG), mid (MG) and late (LG) growing seasons. The results showed that: (i) warming (4.5 °C) increased the average seasonal Re, CH4 uptake and N2O emission by 73.5%, 65.9% and 431.6%, respectively. N fertilization (4 g N m-2) alone had no significant effect on GHG flux; the interaction of warming and N fertilization enhanced CH4 uptake by 10.3% and N2O emissions by 27.2% than warming, while there was no significant effect on the Re; (ii) the average seasonal fluxes of Re, CH4 and N2O were MG > LG > EG, and Re and CH4 uptake were most sensitive to the soil freezing process instead of soil thawing process; (iii) surface soil temperature was the main driving factor of the Re and CH4 fluxes, and the N2O flux was mainly affected by daily rainfall; (iv) in the growing season, warming increased greenhouse warming potential (GWP) of the alpine meadow by 74.5%, the N fertilization decreased GWP of the warming plots by 13.9% but it was not statistically significant. These results indicate that (i) relative to future climate warming (or permafrost thawing), there could be a hysteresis of GHG flux in the alpine meadow of permafrost region; (ii) under the scenario of climate warming, increasing N deposition has limited impacts on the feedback of GHG flux of the alpine meadow.

  7. Observations of an atmospheric chemical equator and its implications for the tropical warm pool region

    Science.gov (United States)

    Hamilton, Jacqueline F.; Allen, Grant; Watson, Nicola M.; Lee, James D.; Saxton, Julie E.; Lewis, Alastair C.; Vaughan, Geraint; Bower, Keith N.; Flynn, Michael J.; Crosier, Jonathan; Carver, Glenn D.; Harris, Neil R. P.; Parker, Robert J.; Remedios, John J.; Richards, Nigel A. D.

    2008-10-01

    This paper reports observations of a tropospheric chemical equator in the Western Pacific region during the Austral monsoon season, separating the polluted Northern Hemisphere from the cleaner Southern Hemisphere. Measurements of carbon monoxide, ozone, aerosol size/composition, and non-methane hydrocarbons were made from aircraft, flying north from Darwin, Australia as part of the Aerosol and Chemical Transport In tropical conVEction (ACTIVE) campaign. A chemical equator, defined as a sharp gradient in the chemical background, was found not to be coincident with the Intertropical Convergence Zone during this period. A pronounced interfacial region was identified between 8.5 and 10°S, where tracer mixing ratios increased rapidly within the boundary layer, e.g. CO from 40 ppbv to 160 ppbv within 0.5° latitude (50 km), with inhibited inter-hemispheric mixing. These measurements are discussed in context using a combination of meteorological and Earth-observing satellite imagery, back trajectory analysis and chemical model data with the conclusion that air flowing into and subsequently uplifted by the active convection of the Tropical Warm Pool (TWP) region in the Western Pacific is likely to be highly polluted, and will perturb the composition of the Tropical Tropopause Layer. The main source of CO and other pollutants within the TWP region is expected to be biomass burning, with extensive fires in North Sumatra and Thailand during this period. The sharp gradient in composition at the chemical equator seen here results from extensive burning to the north, contrasting with pristine maritime air advected from the Southern Indian Ocean by a strong land-based cyclone over the Northern Territory of Australia.

  8. Sustainable groundwater management system based on the regional hydrological cycle in the warm humid country, Japan

    Science.gov (United States)

    Shimada, J.; Crest Kumamoto Groundwater Team

    2011-12-01

    The increase of precipitation variability with the global warming and the rapid population growth lead to the shortage of water resources on a global scale. Groundwater bocome attracted as a relatively stable water resource because of its larger reservoir and a longer residence time. As our country belongs to a warm humid climate with much precipitation and a steep topography, the regional hydrological cycle is extremely active. Surface water could be taken easily and was often used to a water supply until now, but recently groundwater is taking the place of surface water because of the stability of water supply. While in our hydro-climatic condition, the sustainable use of groundwater is possible under the appropriative management, that is, groundwater pumping rate does not exceed the recharge rate in a basin. For the sustainable use of groundwater resources, this project aims to develop new technologies relating to the quantity and quality aspects of groundwater resources. For the precise understanding of groundwater flow system, new technologies will be developed, like frequency changeable electric resistivity exploration method to evaluate an aquifer structure. There are many problems about groundwater quality including nitrate-nitrogen contamination and toxic substances from the domestic and industrial waste disposals. It is necessary to understand the production mechanism to prevent groundwater contamination and the degradation process of nitrate-nitrogen contamination to improve the water quality. Therefore this project will develop new technologies including the reduction of NO3=N and natural toxic substances loads before groundwater recharge, the on-site removal of contaminants from aquifers, and simple and effective equipment to improve groundwater quality after pumping. Furthermore, this project will also develop a new biological monitoring technique for local groundwater users to notice the contamination at a glance; change colar fish by specific ion

  9. Analysing regional climate change in Africa in a 1.5 °C global warming world

    Science.gov (United States)

    Weber, Torsten; Haensler, Andreas; Jacob, Daniela

    2017-04-01

    At the 21st session of the UNFCCC Conference of the Parties (COP21) in Paris, a reaffirmation to strengthen the effort to limit the global temperature increase to 1.5 °C was decided. However, even if global warming is limited, some regions might still be substantially affected by climate change, especially for continents like Africa where the socio-economic conditions are strongly linked to the climatic conditions. Hence, providing a detailed analysis of the projected climate changes in a 1.5 °C global warming scenario will allow the African society to undertake measures for adaptation in order to mitigate potential negative consequences. In order to provide such climate change information, the existing CORDEX Africa ensemble for RCP2.6 scenario simulations has systematically been increased by conducting additional REMO simulations using data from various global circulation models (GCMs) as lateral boundary conditions. Based on this ensemble, which now consists of eleven CORDEX Africa RCP2.6 regional climate model simulations from three RCMs (forced with different GCMs), various temperature and precipitation indices such as number of cold/hot days and nights, duration of the rainy season, the amount of rainfall in the rainy seasons and the number of dry spells have been calculated for a 1.5 °C global warming scenario. The applied method to define the 1.5 °C global warming period has been already applied in the IMPACT2C project. In our presentation, we will discuss the analysis of the climate indices in a 1.5 °C global warming world for the CORDEX-Africa region. Amongst presenting the magnitude of projected changes, we will also address the question for selected indices if the changes projected in a 1.5 °C global warming scenario are already larger than the climate variability and we will also draw links to the changes projected under a more extreme scenario.

  10. Sustained mass loss of the northeast Greenland ice sheet triggered by regional warming

    DEFF Research Database (Denmark)

    Khan, Shfaqat Abbas; Kjaer, Kurt H.; Bevis, Michael

    2014-01-01

    The Greenland ice sheet has been one of the largest contributors to global sea-level rise over the past 20 years, accounting for 0.5 mm yr(-1) of a total of 3.2 mm yr(-1). A significant portion of this contribution is associated with the speed-up of an increased number of glaciers in southeast...... and northwest Greenland. Here, we show that the northeast Greenland ice stream, which extends more than 600 km into the interior of the ice sheet, is now undergoing sustained dynamic thinning, linked to regional warming, after more than a quarter of a century of stability. This sector of the Greenland ice sheet...... is of particular interest, because the drainage basin area covers 16% of the ice sheet (twice that of Jakobshavn Isbrae) and numerical model predictions suggest no significant mass loss for this sector, leading to an under-estimation of future global sea-level rise. The geometry of the bedrock and monotonic trend...

  11. Seasonal patterns of SST diurnal variation over the Tropical Warm Pool region

    Science.gov (United States)

    Zhang, Haifeng; Beggs, Helen; Wang, Xiao Hua; Kiss, Andrew E.; Griffin, Christopher

    2016-11-01

    Five year (2010-2014) Advanced Very High Resolution Radiometer (AVHRR) sea surface temperature (SST) data produced by the Australian Bureau of Meteorology have been validated against drifting buoy data and then used to study the seasonal patterns of the SST diurnal variation (DV) events over the Tropical Warm Pool region (TWP, 25°S-15°N, 90°E-170°E). The in situ validation results illustrate the overall good quality of the AVHRR SST data set, although an average 0.19 K underestimation of the daytime measurements has been observed. The nighttime observations are in good agreement with in situ buoys with an average bias of 0.03 and a 0.30 K standard deviation of the biases. This SST data set is then used to characterize the SST DV seasonal patterns, together with wind speeds, daily maximum solar shortwave insolation (SSImax), and latent heat flux (LHF). A double-peak seasonal pattern of SST DV is observed over the study region: the strongest DVs are found in March and October and the weakest in June. Sensitivity tests of DV to wind, SSImax, and LHF are conducted. The results indicate (1) different morning and early afternoon winds (7 A.M. to 2 P.M. local time, LT) affect DV by as much as 0.73 K when the half-daily (defined as 2 A.M. to 2 P.M. LT in this study) average winds are fixed between 2 and 3 m s-1; (2) SSImax levels regulate DV less significantly (<0.68 K) under fixed winds; and (3) LHF effects on DV are relatively weak (<0.35 K).

  12. Multi-century cool- and warm-season rainfall reconstructions for Australia's major climatic regions

    Directory of Open Access Journals (Sweden)

    M. Freund

    2017-11-01

    Full Text Available Australian seasonal rainfall is strongly affected by large-scale ocean–atmosphere climate influences. In this study, we exploit the links between these precipitation influences, regional rainfall variations, and palaeoclimate proxies in the region to reconstruct Australian regional rainfall between four and eight centuries into the past. We use an extensive network of palaeoclimate records from the Southern Hemisphere to reconstruct cool (April–September and warm (October–March season rainfall in eight natural resource management (NRM regions spanning the Australian continent. Our bi-seasonal rainfall reconstruction aligns well with independent early documentary sources and existing reconstructions. Critically, this reconstruction allows us, for the first time, to place recent observations at a bi-seasonal temporal resolution into a pre-instrumental context, across the entire continent of Australia. We find that recent 30- and 50-year trends towards wetter conditions in tropical northern Australia are highly unusual in the multi-century context of our reconstruction. Recent cool-season drying trends in parts of southern Australia are very unusual, although not unprecedented, across the multi-century context. We also use our reconstruction to investigate the spatial and temporal extent of historical drought events. Our reconstruction reveals that the spatial extent and duration of the Millennium Drought (1997–2009 appears either very much below average or unprecedented in southern Australia over at least the last 400 years. Our reconstruction identifies a number of severe droughts over the past several centuries that vary widely in their spatial footprint, highlighting the high degree of diversity in historical droughts across the Australian continent. We document distinct characteristics of major droughts in terms of their spatial extent, duration, intensity, and seasonality. Compared to the three largest droughts in the instrumental

  13. Multi-century cool- and warm-season rainfall reconstructions for Australia's major climatic regions

    Science.gov (United States)

    Freund, Mandy; Henley, Benjamin J.; Karoly, David J.; Allen, Kathryn J.; Baker, Patrick J.

    2017-11-01

    Australian seasonal rainfall is strongly affected by large-scale ocean-atmosphere climate influences. In this study, we exploit the links between these precipitation influences, regional rainfall variations, and palaeoclimate proxies in the region to reconstruct Australian regional rainfall between four and eight centuries into the past. We use an extensive network of palaeoclimate records from the Southern Hemisphere to reconstruct cool (April-September) and warm (October-March) season rainfall in eight natural resource management (NRM) regions spanning the Australian continent. Our bi-seasonal rainfall reconstruction aligns well with independent early documentary sources and existing reconstructions. Critically, this reconstruction allows us, for the first time, to place recent observations at a bi-seasonal temporal resolution into a pre-instrumental context, across the entire continent of Australia. We find that recent 30- and 50-year trends towards wetter conditions in tropical northern Australia are highly unusual in the multi-century context of our reconstruction. Recent cool-season drying trends in parts of southern Australia are very unusual, although not unprecedented, across the multi-century context. We also use our reconstruction to investigate the spatial and temporal extent of historical drought events. Our reconstruction reveals that the spatial extent and duration of the Millennium Drought (1997-2009) appears either very much below average or unprecedented in southern Australia over at least the last 400 years. Our reconstruction identifies a number of severe droughts over the past several centuries that vary widely in their spatial footprint, highlighting the high degree of diversity in historical droughts across the Australian continent. We document distinct characteristics of major droughts in terms of their spatial extent, duration, intensity, and seasonality. Compared to the three largest droughts in the instrumental period (Federation Drought

  14. Development of probability distributions for regional climate change from uncertain global mean warming and an uncertain scaling relationship

    Directory of Open Access Journals (Sweden)

    2007-01-01

    Full Text Available To produce probability distributions for regional climate change in surface temperature and precipitation, a probability distribution for global mean temperature increase has been combined with the probability distributions for the appropriate scaling variables, i.e. the changes in regional temperature/precipitation per degree global mean warming. Each scaling variable is assumed to be normally distributed. The uncertainty of the scaling relationship arises from systematic differences between the regional changes from global and regional climate model simulations and from natural variability. The contributions of these sources of uncertainty to the total variance of the scaling variable are estimated from simulated temperature and precipitation data in a suite of regional climate model experiments conducted within the framework of the EU-funded project PRUDENCE, using an Analysis Of Variance (ANOVA. For the area covered in the 2001–2004 EU-funded project SWURVE, five case study regions (CSRs are considered: NW England, the Rhine basin, Iberia, Jura lakes (Switzerland and Mauvoisin dam (Switzerland. The resulting regional climate changes for 2070–2099 vary quite significantly between CSRs, between seasons and between meteorological variables. For all CSRs, the expected warming in summer is higher than that expected for the other seasons. This summer warming is accompanied by a large decrease in precipitation. The uncertainty of the scaling ratios for temperature and precipitation is relatively large in summer because of the differences between regional climate models. Differences between the spatial climate-change patterns of global climate model simulations make significant contributions to the uncertainty of the scaling ratio for temperature. However, no meaningful contribution could be found for the scaling ratio for precipitation due to the small number of global climate models in the PRUDENCE project and natural variability, which is

  15. Large differences in regional precipitation change between a first and second 2 K of global warming.

    Science.gov (United States)

    Good, Peter; Booth, Ben B B; Chadwick, Robin; Hawkins, Ed; Jonko, Alexandra; Lowe, Jason A

    2016-12-06

    For adaptation and mitigation planning, stakeholders need reliable information about regional precipitation changes under different emissions scenarios and for different time periods. A significant amount of current planning effort assumes that each K of global warming produces roughly the same regional climate change. Here using 25 climate models, we compare precipitation responses with three 2 K intervals of global ensemble mean warming: a fast and a slower route to a first 2 K above pre-industrial levels, and the end-of-century difference between high-emission and mitigation scenarios. We show that, although the two routes to a first 2 K give very similar precipitation changes, a second 2 K produces quite a different response. In particular, the balance of physical mechanisms responsible for climate model uncertainty is different for a first and a second 2 K of warming. The results are consistent with a significant influence from nonlinear physical mechanisms, but aerosol and land-use effects may be important regionally.

  16. Formation of Cool and Warm Jets by Magnetic Flux Emerging from the Solar Chromosphere to Transition Region

    Science.gov (United States)

    Yang, Liping; Peter, Hardi; He, Jiansen; Tu, Chuanyi; Wang, Linghua; Zhang, Lei; Yan, Limei

    2018-01-01

    In the solar atmosphere, jets are ubiquitous at various spatial-temporal scales. They are important for understanding the energy and mass transports in the solar atmosphere. According to recent observational studies, the high-speed network jets are likely to be intermittent but continual sources of mass and energy for the solar wind. Here, we conduct a 2D magnetohydrodynamics simulation to investigate the mechanism of these network jets. A combination of magnetic flux emergence and horizontal advection is used to drive the magnetic reconnection in the transition region between a strong magnetic loop and a background open flux. The simulation results show that not only a fast warm jet, much similar to the network jets, is found, but also an adjacent slow cool jet, mostly like classical spicules, is launched. Differing from the fast warm jet driven by magnetic reconnection, the slow cool jet is mainly accelerated by gradients of both thermal pressure and magnetic pressure near the outer border of the mass-concentrated region compressed by the emerging loop. These results provide a different perspective on our understanding of the formation of both the slow cool jets from the solar chromosphere and the fast warm jets from the solar transition region.

  17. Rapid climate variability during warm and cold periods in polar regions and Europe

    DEFF Research Database (Denmark)

    Masson-Delmotte, V.; Landais, A.; Combourieu-Nebout, N.

    2005-01-01

    rapid cooling recorded during the Holocene in Greenland ice cores and in Ammersee, Germany. The rate of warming during previous warmer interglacial periods is estimated from polar ice cores to 1.5 °C per millennium, without abrupt changes. Climate change expected for the 21st century should however......Typical rapid climate events punctuating the last glacial period in Greenland, Europe and Antarctica are compared to two rapid events occurring under warmer conditions: (i) Dansgaard-Oeschger event 25, the first abrupt warming occurring during last glacial inception; (ii) 8.2 ka BP event, the only...

  18. Dust load and rainfall characteristics and their relationship over the South Asian monsoon region under various warming scenarios

    Science.gov (United States)

    Singh, Charu; Ganguly, Dilip; Dash, S. K.

    2017-08-01

    Present study investigates the similarities and differences in the pattern of dust load and rainfall and their relationship over the South Asian monsoon region under various future warming scenarios with respect to the historical period using multiple coupled climate model runs that participated in Coupled Model Inter-comparison Project Phase 5 (CMIP5). Based on statistically robust significance tests, we unravel several likely changes in the pattern of the dust load and rainfall over the South Asia under different future warming scenarios by the end of 21st century compared to the historical period. Kolmogorov-Smirnov test results reveal a significant change (at 5% significance level) in the amount of dust and rainfall under different warming scenarios over the study region. Northern part of the Indian subcontinent is likely to witness increased dust loading in future, and regions with increase in dust load are also likely to be the regions of increased rainfall over North India. Positive correlation between rainfall over the Indian region and dust over the Arabian region is also likely to strengthen in future. Considerable changes in the spatial correlation pattern between dust and rainfall are noted under different representative concentration pathways; however, no noteworthy changes are recorded in their temporal relationship. Notable intermodel differences in the patterns of dust load and rainfall relationship over South Asia are possibly caused by variations in the dust emission schemes among the CMIP5 models as well as the parameterization of aerosol indirect effect in addition to the differences in the meteorology simulated by various models under identical forcing scenarios.

  19. Formonsella pyramidosa (Haptophyta, Papposphaeraceae): A new weakly calcified coccolithophore genus from warm-water regions

    DEFF Research Database (Denmark)

    Thomsen, Helge Abildhauge; Cros, Lluïsa; Malinverno, Elisa

    2016-01-01

    A new species Formonsella pyramidosa gen. et sp. nov. is described to accommodate a widely distributed warm-water coccolithophore species that has previously been referred to as Pappomonas sp. 2. Formonsella differs from Pappomonas with respect to, in particular, the detailed structure of the rim...

  20. Assessing summertime urban warming and the cooling efficacy of adaptation strategy in the Chengdu-Chongqing metropolitan region of China.

    Science.gov (United States)

    Liu, Xiaojuan; Tian, Guangjin; Feng, Jinming; Wang, Jun; Kong, Lingqiang

    2018-01-01

    Western China has experienced rapid urbanization since the Chinese reform process began in the late 1970s. It is essential to study the spatiotemporal patterns of warming induced by historical and future urban expansion and to evaluate adaptation strategies for the Chengdu-Chongqing metropolitan region (CCMR) in western China. The observed urban heat island intensity was ~1.5K in July 2009-2011. We employed the weather research and forecasting (WRF) model using real and projected urban land-use data to simulate near-surface air temperatures for a crop, urban in 2010 and urban in 2030 scenarios in summer over the CCMR. The difference between urban 2010 and cropland scenarios is 0.93K. Warming induced by urban development in 2010-2030 is in the range of 1-1.5K, but warming induced by future urban development will be less intense than historical warming over eastern China. We increased roof albedo to 0.8 to assess the difference in near-surface air temperature between cool roofs (CR) and urban 2030 scenarios, which represents the maximum potential impact of CR; we also assessed the cooling caused by green roofs (GR) (i.e., the difference between the GR and urban 2030 scenarios). Greater cooling occurs during the day due to reflection of solar radiation by CR and additional water evaporation by GR. We provided an evaluation criterion, cooling efficiency (CE), to measure the local performances of CR and GR. CE represents the local cooling capability based on urban warming rather than absolute cooling over a larger spatial scale. CE reveals a lower nocturnal cooling capability, which poses a significant challenge to the applications of CR and GR at night. CR has a better cooling capability across CCMR than GR, only when roof albedo of CR exceeds 0.68. Measures enacted should be appropriately adjusted to optimize for cost, technology and energy savings. Copyright © 2017 Elsevier B.V. All rights reserved.

  1. Performance and application of a fluidized bed limestone reactor designed for control of alkalinity, hardness and pH at the Warm Springs Regional Fisheries Center

    Science.gov (United States)

    Springs serving the Warm Springs Regional Fisheries Center, Warm Springs, Georgia, have pH, alkalinity, and hardness levels that lie under the range required for successful fish propagation while free CO2 is well above allowable targets. We evaluate a pretreatment process that exploits limestone's (...

  2. Precipitation in a warming world: Assessing projected hydro-climate changes in California and other Mediterranean climate regions.

    Science.gov (United States)

    Polade, Suraj D; Gershunov, Alexander; Cayan, Daniel R; Dettinger, Michael D; Pierce, David W

    2017-09-07

    In most Mediterranean climate (MedClim) regions around the world, global climate models (GCMs) consistently project drier futures. In California, however, projections of changes in annual precipitation are inconsistent. Analysis of daily precipitation in 30 GCMs reveals patterns in projected hydrometeorology over each of the five MedClm regions globally and helps disentangle their causes. MedClim regions, except California, are expected to dry via decreased frequency of winter precipitation. Frequencies of extreme precipitation, however, are projected to increase over the two MedClim regions of the Northern Hemisphere where projected warming is strongest. The increase in heavy and extreme precipitation is particularly robust over California, where it is only partially offset by projected decreases in low-medium intensity precipitation. Over the Mediterranean Basin, however, losses from decreasing frequency of low-medium-intensity precipitation are projected to dominate gains from intensifying projected extreme precipitation. MedClim regions are projected to become more sub-tropical, i.e. made dryer via pole-ward expanding subtropical subsidence. California's more nuanced hydrological future reflects a precarious balance between the expanding subtropical high from the south and the south-eastward extending Aleutian low from the north-west. These dynamical mechanisms and thermodynamic moistening of the warming atmosphere result in increased horizontal water vapor transport, bolstering extreme precipitation events.

  3. Regional climate change over Europe at specific significant warming levels in a range of EURO-CORDEX regional downscalings at 0.11° resolution

    Science.gov (United States)

    Kjellström, Erik; Nikulin, Grigory; Strandberg, Gustav

    2017-04-01

    We investigate European regional climate change for time periods when the global mean temperature has increased by respectively 1.5°C, 2°C, 2.5°C and 3°C compared to preindustrial conditions. Results are based on regional downscaling of transient climate change simulations for the 21st century with global climate models (GCMs) from CMIP5. We use an ensemble of EURO-CORDEX high-resolution regional climate model (RCM) simulations undertaken at a computational grid of 12.5 km horizontal resolution covering Europe. The ensemble consists of a range of RCMs that have been used for downscaling a few GCMs under different forcing scenarios. We also use an ensemble of RCM simulations with one specific RCM, the RCA4 from the Rossby Centre, which has been used for downscaling ten different GCMs. These two ensembles enable us to address questions related to sensitivity of choice of GCM and RCM on the results. Furthermore, we use two different methods of determining the time period when a certain significant warming level is reached. By contrasting these methods we investigate how sensitive the results are to the choice of method. The results indicate considerable climate change signals already at the lower (i.e. 1.5°C and 2°C) warming levels and increasingly high levels of change with increasing global warming.

  4. Potential Regional Impacts of Global Warming on Precipitation in the Western United States

    OpenAIRE

    United States Department of the Interior, Bureau of Reclamation

    1997-01-01

    Snow and melting of the snowpack provide the principal supply of water to much of the Western United States. Whether global warming threatens this water supply is the focus of this research. This study builds upon a previous Global Climate Change Response Program investigation. Charts were generated of four geopotential height parameters for a domain covering the eastern North Pacific Ocean and western North America. Out of 131 total winter months (from 1946-89), 35 were selected as analo...

  5. Unusual Warming in the Coastal Region of Northern South China Sea and Its Impact on the Sudden Intensification of Tropical Cyclone Tembin (2012

    Directory of Open Access Journals (Sweden)

    Zhe-Wen Zheng

    2014-01-01

    Full Text Available Tropical cyclone Tembin (2012 passed twice and made landfall over south tip of Taiwan in August 2012. During its passage, an unusual sea surface warming was generated at 22.5∘N, 117∘E in the coastal region of northern South China Sea. Subsequently, Tembin passed over this extreme warming region and its intensity was enhanced drastically and suddenly from Category 1 to Category 3 within less than 1-day time interval. This unusual warming seems to largely prompt the intensification of Tembin. Next, the relationship between this extreme warming and rapid intensification of Tembin is identified by atmospheric model Weather Research and Forecast (WRF with updated time-varying lower boundary condition. In addition, given the tight relationship between generation of unusual warming in the shore region and following possible TC intensification, a series of numerical experiments based on oceanic model Regional Oceanic Modeling System (ROMS were designed and executed to resolve the possible generated mechanism of the extreme warming. The results indicate that a distinct positive short-wave radiation influx anomaly may dominate the generation of the unusual warming in the shore region during Tembin’s passage. This result is validated by the distributions of free cloudy coverage shown in satellite infrared images.

  6. Consequences of Global Warming of 1.5 °C and 2 °C for Regional Temperature and Precipitation Changes in the Contiguous United States.

    Science.gov (United States)

    Karmalkar, Ambarish V; Bradley, Raymond S

    2017-01-01

    The differential warming of land and ocean leads to many continental regions in the Northern Hemisphere warming at rates higher than the global mean temperature. Adaptation and conservation efforts will, therefore, benefit from understanding regional consequences of limiting the global mean temperature increase to well below 2°C above pre-industrial levels, a limit agreed upon at the United Nations Climate Summit in Paris in December 2015. Here, we analyze climate model simulations from the Coupled Model Intercomparison Project Phase 5 (CMIP5) to determine the timing and magnitude of regional temperature and precipitation changes across the contiguous United States (US) for global warming of 1.5 and 2°C and highlight consensus and uncertainties in model projections and their implications for making decisions. The regional warming rates differ considerably across the contiguous US, but all regions are projected to reach 2°C about 10-20 years before the global mean temperature. Although there is uncertainty in the timing of exactly when the 1.5 and 2°C thresholds will be crossed regionally, over 80% of the models project at least 2°C warming by 2050 for all regions for the high emissions scenario. This threshold-based approach also highlights regional variations in the rate of warming across the US. The fastest warming region in the contiguous US is the Northeast, which is projected to warm by 3°C when global warming reaches 2°C. The signal-to-noise ratio calculations indicate that the regional warming estimates remain outside the envelope of uncertainty throughout the twenty-first century, making them potentially useful to planners. The regional precipitation projections for global warming of 1.5°C and 2°C are uncertain, but the eastern US is projected to experience wetter winters and the Great Plains and the Northwest US are projected to experience drier summers in the future. The impact of different scenarios on regional precipitation projections is

  7. Consequences of Global Warming of 1.5 °C and 2 °C for Regional Temperature and Precipitation Changes in the Contiguous United States.

    Directory of Open Access Journals (Sweden)

    Ambarish V Karmalkar

    Full Text Available The differential warming of land and ocean leads to many continental regions in the Northern Hemisphere warming at rates higher than the global mean temperature. Adaptation and conservation efforts will, therefore, benefit from understanding regional consequences of limiting the global mean temperature increase to well below 2°C above pre-industrial levels, a limit agreed upon at the United Nations Climate Summit in Paris in December 2015. Here, we analyze climate model simulations from the Coupled Model Intercomparison Project Phase 5 (CMIP5 to determine the timing and magnitude of regional temperature and precipitation changes across the contiguous United States (US for global warming of 1.5 and 2°C and highlight consensus and uncertainties in model projections and their implications for making decisions. The regional warming rates differ considerably across the contiguous US, but all regions are projected to reach 2°C about 10-20 years before the global mean temperature. Although there is uncertainty in the timing of exactly when the 1.5 and 2°C thresholds will be crossed regionally, over 80% of the models project at least 2°C warming by 2050 for all regions for the high emissions scenario. This threshold-based approach also highlights regional variations in the rate of warming across the US. The fastest warming region in the contiguous US is the Northeast, which is projected to warm by 3°C when global warming reaches 2°C. The signal-to-noise ratio calculations indicate that the regional warming estimates remain outside the envelope of uncertainty throughout the twenty-first century, making them potentially useful to planners. The regional precipitation projections for global warming of 1.5°C and 2°C are uncertain, but the eastern US is projected to experience wetter winters and the Great Plains and the Northwest US are projected to experience drier summers in the future. The impact of different scenarios on regional precipitation

  8. Consequences of Global Warming of 1.5 °C and 2 °C for Regional Temperature and Precipitation Changes in the Contiguous United States

    Science.gov (United States)

    Bradley, Raymond S.

    2017-01-01

    The differential warming of land and ocean leads to many continental regions in the Northern Hemisphere warming at rates higher than the global mean temperature. Adaptation and conservation efforts will, therefore, benefit from understanding regional consequences of limiting the global mean temperature increase to well below 2°C above pre-industrial levels, a limit agreed upon at the United Nations Climate Summit in Paris in December 2015. Here, we analyze climate model simulations from the Coupled Model Intercomparison Project Phase 5 (CMIP5) to determine the timing and magnitude of regional temperature and precipitation changes across the contiguous United States (US) for global warming of 1.5 and 2°C and highlight consensus and uncertainties in model projections and their implications for making decisions. The regional warming rates differ considerably across the contiguous US, but all regions are projected to reach 2°C about 10-20 years before the global mean temperature. Although there is uncertainty in the timing of exactly when the 1.5 and 2°C thresholds will be crossed regionally, over 80% of the models project at least 2°C warming by 2050 for all regions for the high emissions scenario. This threshold-based approach also highlights regional variations in the rate of warming across the US. The fastest warming region in the contiguous US is the Northeast, which is projected to warm by 3°C when global warming reaches 2°C. The signal-to-noise ratio calculations indicate that the regional warming estimates remain outside the envelope of uncertainty throughout the twenty-first century, making them potentially useful to planners. The regional precipitation projections for global warming of 1.5°C and 2°C are uncertain, but the eastern US is projected to experience wetter winters and the Great Plains and the Northwest US are projected to experience drier summers in the future. The impact of different scenarios on regional precipitation projections is

  9. Consequences of Global Warming of 1.5 ?C and 2 ?C for Regional Temperature and Precipitation Changes in the Contiguous United States

    OpenAIRE

    Karmalkar, Ambarish V.; Bradley, Raymond S.

    2017-01-01

    The differential warming of land and ocean leads to many continental regions in the Northern Hemisphere warming at rates higher than the global mean temperature. Adaptation and conservation efforts will, therefore, benefit from understanding regional consequences of limiting the global mean temperature increase to well below 2°C above pre-industrial levels, a limit agreed upon at the United Nations Climate Summit in Paris in December 2015. Here, we analyze climate model simulations from the C...

  10. Response of the Arabian Sea to global warming and associated regional climate shift

    Digital Repository Service at National Institute of Oceanography (India)

    PrasannaKumar, S.; Roshin, R.P.; Narvekar, J.; DineshKumar, P.K.; Vivekanandan, E.

    , P.J., Hooten, A.J., Steneck, R.S., Greenfield, P., Gomez, E., Harvell, C.D., Sale, P.F., Edwards, A.J., Caldeira, K., Knowlton, N., Eakin, C.M., Lglesias-Prieto, R., Muthiga, N., Bradbury, R.H., Dubi, A., Hatziolos, M.E., 2007. Coral..., Oak Ridge, Tennessee, U.S.A. Meehl, G.A., Washington, W.M., Collins, W.D., Arblaster, J.M., Hu, A., Buja, L.E., Strand, W.G., Teng, H., 2005. How much more global 19 warming and sea level rise? Science 307, 1769-1772. Meyer, J.L., Sale, M...

  11. Impacts on regional climate of an afforestation scenario under a +2°C global warming climate

    Science.gov (United States)

    Strada, Susanna; Noblet-Ducoudré Nathalie, de; Marc, Stéfanon

    2017-04-01

    Through surface-atmosphere interactions (SAI), land-use and land-cover changes (LULCCs) alter atmospheric conditions with effects on climate at different scales, from local/regional (a few ten kilometres) (Pielke et al., 2011) to global scales (a few hundred kilometres) (Mahmood et al., 2014). Focusing on the regional scale, in the context of climate change, LULCCs may either enhance or dampen climate impacts via changes in SAI they may initiate. Those LULCC-driven atmospheric impacts could in turn influence e.g. the functioning of terrestrial ecosystems, with consequences on mitigation and adaptation strategies. Despite LULCC impacts on regional climate are largely discussed in the literature, in Europe information is missing on LULCC impacts under future climate conditions on a country scale (Galos et al., 2015). The latest COPs have urged the scientific community to explore the impacts of reduced global warming (1.5°C to a +2°C) on the Earth system. LULCCs will be one major tool to achieve such targets. In this framework, we investigate impacts on regional climate of a modified landscape under a +2°C climatic scenario. To this purpose, we performed sensitivity studies over western Europe with a fully coupled land-atmosphere regional climate model, WRF-ORCHIDEE (Drobinski et al., 2012, Stefanon et al., 2014). A +2°C scenario was selected among those proposed by the "Impact2C" project (Vautard et al., 2014), and the afforested land-cover scenario proposed in the RCP4.5 is prescribed. We have chosen the maximum extent of forest RCP4.5 simulates for Europe at the end of the 21st century. WRF-ORCHIDEE is fed with boundary atmospheric conditions from the global climate model LMDZ for PD (1971-2000) and the +2°C warming period for the LMDZ model (2028-2057). Preliminary results over the target domain show that, under a +2°C global warming scenario, afforestation contributes by 2% to the total warming due to both climate change and LULCCs. During summer, the

  12. An Analysis of the Energetics of Tropical and Extra-Tropical Regions for Warm ENSO Composite Episodes

    Directory of Open Access Journals (Sweden)

    Zayra Christine Sátyro

    Full Text Available Abstract This study focuses on the quantification and evaluation of the effects of ENSO (El Niño Southern Oscillation warm phases, using a composite of five intense El Niño episodes between 1979 – 2011 on the Energetic Lorenz Cycle for four distinct regions around the globe: 80° S – 5° N (region 1, 50° S – 5° N (region 2, 30° S – 5° N (region 3, and 30° S – 30° N (region 4, using Data from NCEP reanalysis-II. Briefly, the results showed that zonal terms of potential energy and kinetic energy were intensified, except for region 1, where zonal kinetic energy weakened. Through the analysis of the period in which higher energy production is observed, a strong communication between the available zonal potential and the zonal kinetic energy reservoirs can be identified. This communication weakened the modes linked to eddies of potential energy and kinetic energy, as well as in the other two baroclinic conversions terms. Furthermore, the results indicate that for all the regions, the system itself works to regain its stable condition.

  13. Composite analysis of the temporal development of waves in the polar MLT region during stratospheric warmings

    Science.gov (United States)

    Matthias, Vivien; Hoffmann, Peter; Rapp, Markus; Baumgarten, Gerd

    2012-12-01

    During winter the wind field in the mesosphere/lower thermosphere (MLT) at middle and polar latitudes is characterized by a strong variability due to enhanced planetary wave activity and related stratospheric sudden warming (SSW) events. Such events are considered as distinct vertical coupling processes influencing the atmosphere below and above the stratosphere. In the last 12 years, an enhanced number of SSW, compared to the period from 1989 to 1998, has been observed in the northern hemisphere. Every SSW is connected with different effects in the MLT (strength and temporal development of wind reversals, temperature changes, wave activity, longitudinal dependence). To characterize the average behavior of the mesospheric response to strong SSWs, we combine high-resolution wind measurements from MF- and meteor radar at Andenes (69°N, 16°E) with global temperature observations from MLS aboard the Aura satellite for SSW events with a return to the middle atmosphere normal winter condition afterwards. Our aim is to identify characteristic wave patterns which are common to the majority of these events and to define the average characteristics of the SSW-related wave activity in the MLT. These will be compared to the relatively quiet winter 2011 with only a short minor warming without a wind reversal and to the wave activity in 2009 and 2010. The results show clear signatures of enhanced mesospheric planetary wave activity before and during the SSW and an earlier onset of the short term wind reversal in the mesosphere compared to wind and temperature changes in the stratosphere. The strong eastward winds at altitudes below 80 km after SSW are connected with an enhanced gravity wave activity caused by changed filter conditions. This provides evidence for a strong modulation of semidiurnal tidal amplitudes before and during SSW by planetary waves. However, no clear relation has been found in the temporal development of tides relative to the onset of the selected SSW

  14. Evidence for 20th century climate warming and wetland drying in the North American Prairie Pothole Region.

    Science.gov (United States)

    Werner, Brett A; Johnson, W Carter; Guntenspergen, Glenn R

    2013-09-01

    The Prairie Pothole Region (PPR) of North America is a globally important resource that provides abundant and valuable ecosystem goods and services in the form of biodiversity, groundwater recharge, water purification, flood attenuation, and water and forage for agriculture. Numerous studies have found these wetlands, which number in the millions, to be highly sensitive to climate variability. Here, we compare wetland conditions between two 30-year periods (1946-1975; 1976-2005) using a hindcast simulation approach to determine if recent climate warming in the region has already resulted in changes in wetland condition. Simulations using the WETLANDSCAPE model show that 20th century climate change may have been sufficient to have a significant impact on wetland cover cycling. Modeled wetlands in the PPR's western Canadian prairies show the most dramatic effects: a recent trend toward shorter hydroperiods and less dynamic vegetation cycles, which already may have reduced the productivity of hundreds of wetland-dependent species.

  15. Acidification of musts in warm regions with tartaric acid and calcium sulfate at industrial scale

    Directory of Open Access Journals (Sweden)

    Gómez Juan

    2015-01-01

    Full Text Available Acidification of musts is necessary in warm areas where high temperatures during ripening accelerate breathing com- bustion of tartaric acid and, in particular, malic acid in the berries. L(+ tartaric acid, L(- or D,L malic acid and lactic acids are the only chemical acidifiers authorized by the OIV and European Community regulations. The use of calcium sulfate (gypsum: CaSO4·2H2O is also authorized in the European Community as a complementary acidifier in generous and generous liquor 42 wines from Spain (a practice known as plastering, provided that the residual sulfate content in the wine does not exceed 2.5 g/L expressed as potassium sulfate. However, this practice is not yet approved by OIV. To predict the effect on pH of different acidi- fiers, several chemical modeling approaches have been described in the literature, in particular a simplified model where the acidity of wine is considered to be due to a monoprotic acid. The aim of this work is to verify this model at pilot and industrial scale in the acidification of musts with tartaric and calcium sulfate, added either individually and in combination, using doses up to 3 g/L and to study the modifications that these practices produce on the compositions of the resulting wines. This work sup- plies useful information to study this practice in OIV in order to consider its approval.

  16. Frost stress evolution and winter pea ideotype in the context of climate warming at a regional scale

    Directory of Open Access Journals (Sweden)

    Castel Thierry

    2017-01-01

    Full Text Available Pea (Pisum sativum L. is an important crop in temperate regions for its high seed protein concentration that is particularly sensitive to abiotic stresses. The abrupt temperature increase known as the “1987/1988 temperature regime shift” that occurs over Europe is questioning how winter pea will perform in the changing climate. This study assessed the winter frost damage evolution along from 1961 to 2015 in Burgundy-Franche-Comté by using: (1 daily observed and gridded regional temperature data and (2 a validated crop winter frost stress model calibrated for pea. This study shows a global decrease of the frost stress nevertheless resulting from a subtle balance between the decrease in its intensity and the increase of the number of events. The frost stress evolution patterns with warming depend on both plant frost resistance level and acclimation rate and are still sensitive to winter climate fluctuations. This study provides relevant information for breeding performant winter crop ideotypes able to moderate detrimental effects of climate change and offering new cropping opportunities in temperate regions.

  17. Deep scientific drilling results from Koyna and Killari earthquake regions reveal why Indian shield lithosphere is unusual, thin and warm

    Directory of Open Access Journals (Sweden)

    O.P. Pandey

    2016-09-01

    Full Text Available The nature of crustal and lithospheric mantle evolution of the Archean shields as well as their subsequent deformation due to recent plate motions and sustained intraplate geodynamic activity, has been a subject of considerable interest. In view of this, about three decades ago, a new idea was put forward suggesting that out of all shield terrains, the Indian shield has an extremely thin lithosphere (∼100 km, compared to 250–350 km, elsewhere, apart from being warm, non-rigid, sheared and deformed. As expected, it met with scepticism by heat flow and the emerging seismic tomographic study groups, who on the contrary suggested that the Indian shield has a cool crust, besides a coherent and thick lithosphere (as much as 300–400 km like any other shield. However, recently obtained integrated geological and geophysical findings from deep scientific drillings in 1993 Killari (Mw: 6.3 and 1967 Koyna (Mw: 6.3 earthquake zones, as well as newly acquired geophysical data over other parts of Indian shield terrain, have provided a totally new insight to this debate. Beneath Killari, the basement was found consisting of high density, high velocity mid crustal amphibolite to granulite facies rocks due to exhumation of the deeper crustal layers and sustained granitic upper crustal erosion. Similar type of basement appears to be present in Koyna region too, which is characterized by considerably high upper crustal temperatures. Since, such type of crust is depleted in radiogenic elements, it resulted into lowering of heat flow at the surface, increase in heat flow contribution from the mantle, and upwarping of the lithosphere-asthenosphere boundary. Consequently, the Indian shield lithosphere has become unusually thin and warm. This study highlights the need of an integrated geological, geochemical and geophysical approach in order to accurately determine deep crust-mantle thermal regime in continental areas.

  18. A Comprehensive Modeling Study on Regional Climate Model (RCM Application — Regional Warming Projections in Monthly Resolutions under IPCC A1B Scenario

    Directory of Open Access Journals (Sweden)

    Md. Mujibur Rahman

    2012-10-01

    Full Text Available Some of the major dimensions of climate change include increase in surface temperature, longer spells of droughts in significant portions of the world, associated higher evapotranspiration rates, and so on. It is therefore essential to comprehend the future possible scenario of climate change in terms of global warming. A high resolution limited area Regional Climate Model (RCM can produce reasonably appropriate projections to be used for climate-scenario generation in country-scale. This paper features the development of future surface temperature projections for Bangladesh on monthly resolution for each year from 2011 to 2100 applying Providing Regional Climates for Impacts Studies (PRECIS, and it explains in detail the modeling processes including the model features, domain size selection, bias identification as well as construction of change field for the concerned climatic variable, in this case, surface temperature. PRECIS was run on a 50 km horizontal grid-spacing under the Intergovernmental Panel on Climate Change (IPCC A1B scenario and it was found to perform reasonably well in simulating future surface temperature of Bangladesh. The linear regression between observed and model simulated results of monthly average temperatures, within the 30-year period from 1971 to 2000, gives a high correlation of 0.93. The applied change field in average annual temperature shows only 0.5 °C–1 °C deviation from the observed values over the period from 2005 to 2008. Eventually, from the projected average temperature change during the years 1971–2000, it is apparent that warming in Bangladesh prevails invariably every month, which might eventually result in an average annual increase of 4 °C by the year 2100. Calculated anomalies in country-average annual temperature mostly remain on the positive side throughout the period of 2071–2100 indicating an overall up-shift. Apart from these quantitative analyses of temporal changes of temperature

  19. Impacts of climate warming on the frozen ground and eco-hydrology in the Yellow River source region, China.

    Science.gov (United States)

    Qin, Yue; Yang, Dawen; Gao, Bing; Wang, Taihua; Chen, Jinsong; Chen, Yun; Wang, Yuhan; Zheng, Guanheng

    2017-12-15

    The Yellow River source region is located in the transition region between permafrost and seasonally frozen ground on the northeastern Qinghai-Tibet Plateau. The region has experienced severe climate change, especially air temperature increases, in past decades. In this study, we employed a geomorphology-based eco-hydrological model (GBEHM) to assess the impacts of climate change on the frozen ground and eco-hydrological processes in the region. Based on a long-term simulation from 1981 to 2015, we found that the areal mean maximum thickness of seasonally frozen ground ranged from 1.1-1.8m and decreased by 1.2cm per year. Additionally, the ratio of the permafrost area to the total area decreased by 1.1% per year. These decreasing trends are faster than the average in China because the study area is on the sensitive margin of the Qinghai-Tibet Plateau. The annual runoff exhibited variations similar to those of the annual precipitation (R(2)=0.85), although the annual evapotranspiration (ET) exhibited an increasing trend (14.3mm/10a) similar to that of the annual mean air temperature (0.66°C/10a). The runoff coefficient (annual runoff divided by annual precipitation) displayed a decreasing trend because of the increasing ET, and the vegetation responses to climate warming and permafrost degradation were manifested as increases in the leaf area index (LAI) and ET at the start of the growing season. Furthermore, the results showed that changes to the frozen ground depth affected vegetation growth. Notably, a rapid decrease in the frozen ground depth (eco-hydrological processes in the headwater area of the Yellow River have changed because of permafrost degradation, and these changes could further influence the water resources availability in the middle and lower reaches of the basin. Copyright © 2017 Elsevier B.V. All rights reserved.

  20. The relationship of lightning activity and short-duration rainfall events during warm seasons over the Beijing metropolitan region

    Science.gov (United States)

    Wu, Fan; Cui, Xiaopeng; Zhang, Da-Lin; Qiao, Lin

    2017-10-01

    The relationship between lightning activity and rainfall associated with 2925 short-duration rainfall (SDR) events over the Beijing metropolitan region (BMR) is examined during the warm seasons of 2006-2007, using the cloud-to-ground (CG) and intracloud (IC) lightning data from Surveillance et Alerte Foudre par Interférometrie Radioélectrique (SAFIR)-3000 and 5-min rainfall data from automatic weather stations (AWSs). An optimal radius of 10 km around selected AWSs is used to determine the lightning-rainfall relationship. The lightning-rainfall correlations vary significantly, depending upon the intensity of SDR events. That is, correlation coefficient (R 0.7) for the short-duration heavy rainfall (SDHR, i.e., ≥ 20 mm h- 1) events is found higher than that (R 0.4) for the weak SDR (i.e., 5-10 mm h- 1) events, and lower percentage of the SDHR events (SDR events (40-50%) are observed with few flashes. Significant time-lagged correlations between lightning and rainfall are also found. About 80% of the SDR events could reach their highest correlation coefficients when the associated lightning flashes shift at time lags of SDR events. Better lightning-rainfall correlations can be attained when time lags are incorporated, with the use of total (CG and IC) lightning data. These results appear to have important implications for improving the nowcast of SDHR events.

  1. Responses of the photosynthetic apparatus to winter conditions in broadleaved evergreen trees growing in warm temperate regions of Japan.

    Science.gov (United States)

    Tanaka, Chizuru; Nakano, Takashi; Yamazaki, Jun-Ya; Maruta, Emiko

    2015-01-01

    Photosynthetic characteristics of two broadleaved evergreen trees, Quercus myrsinaefolia and Machilus thunbergii, were compared in autumn and winter. The irradiance was similar in both seasons, but the air temperature was lower in winter. Under the winter conditions, net photosynthesis under natural sunlight (Anet) in both species dropped to 4 μmol CO2 m(-2) s(-1), and the quantum yield of photosystem II (PSII) photochemistry in dark-adapted leaves (Fv/Fm) also dropped to 0.60. In both species the maximum carboxylation rates of Rubisco (V(cmax)) decreased, and the amount of Rubisco increased in winter. A decline in chlorophyll (Chl) concentration and an increase in the Chl a/b ratio in winter resulted in a reduction in the size of the light-harvesting antennae. From measurements of Chl a fluorescence parameters, both the relative fraction and the energy flux rates of thermal dissipation through other non-photochemical processes were markedly elevated in winter. The results indicate that the photosynthetic apparatus in broadleaved evergreen species in warm temperate regions responds to winter through regulatory mechanisms involving the downregulation of light-harvesting and photosynthesis coupled with increased photoprotective thermal energy dissipation to minimize photodamage in winter. These mechanisms aid a quick restart of photosynthesis without the development of new leaves in the following spring. Copyright © 2014 Elsevier Masson SAS. All rights reserved.

  2. Variations of Kelvin waves around the TTL region during the stratospheric sudden warming events in the Northern Hemisphere winter

    Directory of Open Access Journals (Sweden)

    Y. Jia

    2016-03-01

    Full Text Available Spatial and temporal variabilities of Kelvin waves during stratospheric sudden warming (SSW events are investigated by the ERA-Interim reanalysis data, and the results are validated by the COSMIC temperature data. A case study on an exceptionally large SSW event in 2009, and a composite analysis comprising 18 events from 1980 to 2013 are presented. During SSW events, the average temperature increases by 20 K in the polar stratosphere, while the temperature in the tropical stratosphere decreases by about 4 K. Kelvin wave with wave numbers 1 and 2, and periods 10–20 days, clearly appear around the tropical tropopause layer (TTL during SSWs. The Kelvin wave activity shows obvious coupling with the convection localized in the India Ocean and western Pacific (Indo-Pacific region. Detailed analysis suggests that the enhanced meridional circulation driven by the extratropical planetary wave forcing during SSW events leads to tropical upwelling, which further produces temperature decrease in the tropical stratosphere. The tropical upwelling and cooling consequently result in enhancement of convection in the equatorial region, which excites the strong Kelvin wave activity. In addition, we investigated the Kelvin wave acceleration to the eastward zonal wind anomalies in the equatorial stratosphere during SSW events. The composite analysis shows that the proportion of Kelvin wave contribution ranges from 5 to 35 % during SSWs, much larger than in the non-SSW mid-winters (less than 5 % in the stratosphere. However, the Kelvin wave alone is insufficient to drive the equatorial eastward zonal wind anomalies during the SSW events, which suggests that the effects of other types of equatorial waves may not be neglected.

  3. Atmospheric forcing intensifies the effects of regional ocean warming on reef-scale temperature anomalies during a coral bleaching event

    Science.gov (United States)

    Zhang, Zhenlin; Falter, James; Lowe, Ryan; Ivey, Greg; McCulloch, Malcolm

    2013-09-01

    We investigate how local atmospheric conditions and hydrodynamic forcing contributed to local variations in water temperature within a fringing coral reef-lagoon system during the peak of a marine heat wave in 2010-2011 that caused mass coral bleaching across Western Australia. A three-dimensional circulation model Regional Ocean Modeling System (ROMS) with a built-in air-sea heat flux exchange module Coupled Ocean Atmosphere Experiment (COARE) was coupled with a spectral wave model Simulating Waves Nearshore (SWAN) to resolve the surface heat exchange and wave-driven reef circulation in Coral Bay, Ningaloo Reef. Using realistic oceanic and atmospheric forcing, the model predictions were in good agreement with measured time series of water temperature at various locations in the coral reef system during the bleaching event. Through a series of sensitivity analyses, we found that the difference in temperature between the reef and surrounding offshore waters (ΔT) was predominantly a function of both the daily mean net heat flux (Qnet>¯) and residence time, whereas diurnal variations in reef water temperature were dependent on the diurnal fluctuation in the net heat flux. We found that reef temperatures were substantially higher than offshore in the inner lagoon under normal weather conditions and over the entire reef domain under more extreme weather conditions (0.7°C-1.5°C). Although these temperature elevations were still less than that caused by the regional ocean warming (2°C-3°C), the arrival of peak seasonal temperatures in the summer of 2010-2011 (when net atmospheric heat fluxes were positive and abnormally high) caused substantially higher thermal stresses than would have otherwise occurred if offshore temperatures had reached their normal seasonal maxima in autumn (when net atmospheric heat fluxes were negative or cooling). Therefore, the degree heating weeks calculated based on offshore temperature substantially underestimated the thermal stresses

  4. Indirect Radiative Warming Effect in the Winter and Spring Arctic Associated with Aerosol Pollution from Mid-latitude Regions

    Science.gov (United States)

    Zhao, Chuanfeng; Garrett, Timothy

    2016-04-01

    Different from global cooling effects of aerosols and aerosol-cloud interactions, anthropogenic aerosols from mid-latitude are found to play an increased warming effect in the Arctic in later winter and early spring. Using four-year (2000-2003) observation of aerosol, cloud and radiation at North Slope of Alaska, it is found that the aerosols can increase cloud droplet effective radius 3 um for fixed liquid water path, and increase cloud thermal emissivity about 0.05-0.08. In other words, aerosols are associated with a warming of 1-1.6 degrees (3-5 W/m2) in the Arctic during late winter and early spring solely due to their first indirect effect. Further analysis indicates that total aerosol climate effects are even more significant (8-10 W/m2), with about 50% contribution from aerosol first indirect effect and another 50% contribution from complicated feedbacks. It also shows strong seasonal distribution of the aerosol indirect radiative effects, with warming effects in seasons other than in summer. However, only the significant warming effect in winter and spring passes through the significance test. The strong warming effect due to aerosol indirect effect could be further strengthened through following feedbacks involving the surface albedo (early ice melting).

  5. From global to regional and back again: common climate stressors of marine ecosystems relevant for adaptation across five ocean warming hotspots.

    Science.gov (United States)

    Popova, Ekaterina; Yool, Andrew; Byfield, Valborg; Cochrane, Kevern; Coward, Andrew C; Salim, Shyam S; Gasalla, Maria A; Henson, Stephanie A; Hobday, Alistair J; Pecl, Gretta T; Sauer, Warwick H; Roberts, Michael J

    2016-06-01

    Ocean warming 'hotspots' are regions characterized by above-average temperature increases over recent years, for which there are significant consequences for both living marine resources and the societies that depend on them. As such, they represent early warning systems for understanding the impacts of marine climate change, and test-beds for developing adaptation options for coping with those impacts. Here, we examine five hotspots off the coasts of eastern Australia, South Africa, Madagascar, India and Brazil. These particular hotspots have underpinned a large international partnership that is working towards improving community adaptation by characterizing, assessing and projecting the likely future of coastal-marine food resources through the provision and sharing of knowledge. To inform this effort, we employ a high-resolution global ocean model forced by Representative Concentration Pathway 8.5 and simulated to year 2099. In addition to the sea surface temperature, we analyse projected stratification, nutrient supply, primary production, anthropogenic CO2 -driven ocean acidification, deoxygenation and ocean circulation. Our simulation finds that the temperature-defined hotspots studied here will continue to experience warming but, with the exception of eastern Australia, may not remain the fastest warming ocean areas over the next century as the strongest warming is projected to occur in the subpolar and polar areas of the Northern Hemisphere. Additionally, we find that recent rapid change in SST is not necessarily an indicator that these areas are also hotspots of the other climatic stressors examined. However, a consistent facet of the hotspots studied here is that they are all strongly influenced by ocean circulation, which has already shown changes in the recent past and is projected to undergo further strong change into the future. In addition to the fast warming, change in local ocean circulation represents a distinct feature of present and future

  6. Vegetation masking effect on future warming and snow albedo feedback in a boreal forest region of northern Eurasia according to MIROC-ESM

    Science.gov (United States)

    Abe, Manabu; Takata, Kumiko; Kawamiya, Michio; Watanabe, Shingo

    2017-09-01

    The Earth system model, Model for Interdisciplinary Research on Climate-Earth system model (MIROC-ESM), in which the leaf area index (LAI) is calculated interactively with an ecological land model, simulated future changes in the snow water equivalent under the scenario of global warming. Using MIROC-ESM, the effects of the snow albedo feedback (SAF) in a boreal forest region of northern Eurasia were examined under the possible climate future scenario RCP8.5. The simulated surface air temperature (SAT) in spring greatly increases across Siberia and the boreal forest region, whereas the snow cover decreases remarkably only in western Eurasia. The large increase in SAT across Siberia is attributed to strong SAF, which is caused by both the reduced snow-covered fraction and the reduced surface albedo of the snow-covered portion due to the vegetation masking effect in those grid cells. A comparison of the future changes with and without interactive LAI changes shows that in Siberia, the vegetation masking effect increases the spring SAF by about two or three times and enhances the spring warming by approximately 1.5 times. This implies that increases in vegetation biomass in the future are a potential contributing factor to warming trends and that further research on the vegetation masking effect is needed for reliable future projection.

  7. Impact of the model resolution on the simulation of elevation-dependent warming in the Tibetan Plateau-Himalayas, Greater Alpine Region, and Rocky mountains

    Science.gov (United States)

    Palazzi, Elisa; Mortarini, Luca; Terzago, Silvia; von Hardenberg, Jost

    2017-04-01

    The enhancement of warming rates with elevation, the so-called elevation-dependent warming (EDW), is one of the clearest regional expressions of global warming. Real sentinels of climate and environmental changes, mountains have experienced more rapid and intense warming rates in the recent decades, leading to serious impacts on mountain ecosystems and downstream societies, some of which are already occurring. In this study we use the historical and scenario simulations of one state-of-the-art global climate model, the EC-Earth GCM, run at five different spatial resolutions, from ˜125 km to ˜16 km, to explore the existence, characteristics and driving mechanisms of EDW in three different mountain regions of the world - the Colorado Rocky Mountains, the Greater Alpine Region and the Tibetan Plateau-Himalayas. The aim of this study is twofold: to investigate the impact (if any) of increasing model resolution on the representation of EDW and to highlight possible differences in this phenomenon and its driving mechanisms in different mountain regions of the northern hemisphere. Preliminary results indicate that autumn (September to November) is the only season in which EDW is simulated by the model in both the maximum and the minimum temperature, in all three regions and across all model resolutions. Regional differences emerge in the other seasons: for example, the Tibetan Plateau-Himalayas is the only area in which EDW is detected in winter. As for the analysis of EDW drivers, we identify albedo and downward longwave radiation as being the most important variables for EDW, in all three areas considered and in all seasons. Further these results are robust to changes in model resolution, even though a clearer signal is associated with finer resolutions. We finally use the highest resolution EC-Earth simulations available (˜16 km) to identify what areas, within the three considered mountain ranges, are expected to undergo a significant reduction of snow or ice cover

  8. Short period airglow temperature and emission rate oscillations in the high Arctic MLT region during stratospheric warming events

    Science.gov (United States)

    Lederman, J. I.

    2015-12-01

    The airglow is a photochemical glow in the upper atmosphere that occurs in thin layers corresponding to different chemical processes. The O2 Atmospheric airglow layer exists at about 94 km altitude and the hydroxyl layer at about 87 km. The intensity of the light gives information about the concentration of atomic oxygen there, while the shape of the spectrum gives accurate values of the temperature. In this investigation, these are measured above Eureka in the Canadian Arctic (80N, 86W) using an instrument called SATI (Spectral Airglow Temperature Imager). The optical data are employed to characterize short period oscillations in rotational temperatures and integral emission rates of OH (6,2) Meinel and O2 (0,1) Atm. bands during a stratospheric warming event from January 2015. In this presentation, SATI observations coupled with wind radiosonde data at Eureka and the ECMWF model are used to compare the January 2015 warming with the major stratospheric warming event of January 2009, thereby providing a window into high frequency atmospheric wave dynamics at play between altitudes of 20 km - 100 km.

  9. Probing the cold and warm molecular gas in the Whirlpool Galaxy: Herschel SPIRE-FTS observations of the central region of M51 (NGC 5194)

    Science.gov (United States)

    Schirm, M. R. P.; Wilson, C. D.; Kamenetzky, J.; Parkin, T. J.; Glenn, J.; Maloney, P.; Rangwala, N.; Spinoglio, L.; Baes, M.; Boselli, A.; Cooray, A.; De Looze, I.; Fernández-Ontiveros, J. A.; Karczewski, O. Ł.; Wu, R.

    2017-10-01

    We present Herschel Spectral and Photometric Imaging Receiver (SPIRE)-Fourier Transform Spectrometer (FTS) intermediate-sampled mapping observations of the central ˜8 kpc (˜150 arcsec) of M51, with a spatial resolution of 40 arcsec. We detect four 12CO transitions (J = 4-3 to J = 7-6) and the [C i] 3P2-3P1 and 3P1-3P0 transitions. We supplement these observations with ground-based observations of 12CO J = 1-0 to J = 3-2 and perform a two-component non-local thermodynamic equilibrium analysis. We find that the molecular gas in the nucleus and centre regions has a cool component (Tkin ˜ 10-20 K) with a moderate but poorly constrained density (n(H2) ˜ 103-106 cm-3), as well as significant molecular gas in a warmer (Tkin ˜ 300-3000 K), lower density (n(H2) ˜ 101.6-102.5 cm-3) component. We compare our CO line ratios and calculated densities along with ratios of CO to total infrared luminosity to a grid of photon-dominated region (PDR) models and find that the cold molecular gas likely resides in PDRs with a field strength of G0 ˜ 102. The warm component likely requires an additional source of mechanical heating, from supernovae and stellar winds or possibly shocks produced in the strong spiral density wave. When compared to similar two-component models of other star-forming galaxies published as part of the Very Nearby Galaxies Survey (Arp 220, M82 and NGC 4038/39), M51 has the lowest density for the warm component, while having a warm gas mass fraction that is comparable to those of Arp 220 and M82, and significantly higher than that of NGC 4038/39.

  10. Climate warming and disease risks in temperate regions--Argulus coregoni and Diplostomum spathaceum as case studies.

    Science.gov (United States)

    Hakalahti, T; Karvonen, A; Valtonen, E T

    2006-06-01

    The link between climate changes and disease risks from various pathogens has been increasingly recognized. The effect of climatic factors on host-parasite population dynamics is particularly evident in northern latitudes where the occurrence and transmission of parasites are strongly regulated by seasonality-driven changes in environmental temperatures. Shortened winter periods would increase growth potential of many parasite populations. The ways in which climate warming could affect life history dynamics of the directly transmitted crustacean ectoparasite Argulus coregoni and complex life cycle trematode Diplostomum spathaceum, which frequently cause problems in northern fish farming, are discussed. Increased problems for fish farming are predicted in terms of increased infection pressure from these parasites in future. This would increase problems associated with infections and increase the use of expensive management protocols with high environmental impact.

  11. Diving of great shearwaters (Puffinus gravis in cold and warm water regions of the South Atlantic Ocean.

    Directory of Open Access Journals (Sweden)

    Robert A Ronconi

    Full Text Available BACKGROUND: Among the most widespread seabirds in the world, shearwaters of the genus Puffinus are also some of the deepest diving members of the Procellariiformes. Maximum diving depths are known for several Puffinus species, but dive depths or diving behaviour have never been recorded for great shearwaters (P. gravis, the largest member of this genus. This study reports the first high sampling rate (2 s of depth and diving behaviour for Puffinus shearwaters. METHODOLOGY/PRINCIPAL FINDINGS: Time-depth recorders (TDRs were deployed on two female great shearwaters nesting on Inaccessible Island in the South Atlantic Ocean, recording 10 consecutive days of diving activity. Remote sensing imagery and movement patterns of 8 males tracked by satellite telemetry over the same period were used to identify probable foraging areas used by TDR-equipped females. The deepest and longest dive was to 18.9 m and lasted 40 s, but most (>50% dives were <2 m deep. Diving was most frequent near dawn and dusk, with <0.5% of dives occurring at night. The two individuals foraged in contrasting oceanographic conditions, one in cold (8 to 10°C water of the Sub-Antarctic Front, likely 1000 km south of the breeding colony, and the other in warmer (10 to 16°C water of the Sub-tropical Frontal Zone, at the same latitude as the colony, possibly on the Patagonian Shelf, 4000 km away. The cold water bird spent fewer days commuting, conducted four times as many dives as the warm water bird, dived deeper on average, and had a greater proportion of bottom time during dives. CONCLUSIONS/SIGNIFICANCE: General patterns of diving activity were consistent with those of other shearwaters foraging in cold and warm water habitats. Great shearwaters are likely adapted to forage in a wide range of oceanographic conditions, foraging mostly with shallow dives but capable of deep diving.

  12. A case study on the formation and evolution of ice supersaturation in the vicinity of a warm conveyor belt's outflow region

    Directory of Open Access Journals (Sweden)

    P. Spichtinger

    2005-01-01

    Full Text Available A case study is presented on the formation and evolution of an ice-supersaturated region (ISSR that was detected by a radiosonde in NE Germany at 06:00 UTC 29 November 2000. The ISSR was situated in the vicinity of the outflow region of a warm conveyor belt associated with an intense event of cyclogenesis in the eastern North Atlantic. Using ECMWF analyses and trajectory calculations it is determined when the air parcels became supersaturated and later subsaturated again. In the case considered, the state of air parcel supersaturation can last for longer than 24h. The ISSR was unusually thick: while the mean vertical extension of ISSRs in NE Germany is about 500m, the one investigated here reached 3km. The ice-supersaturated region investigated was bordered both vertically and horizontally by strongly subsaturated air. Near the path of the radiosonde the ISSR was probably cloud free, as inferred from METEOSAT infrared images. However, at other locations within the ISSR it is probable that there were cirrus clouds. Relative humidity measurements obtained by the Lindenberg radiosonde are used to correct the negative bias of the ECMWF humidity and to construct two-dimensional maps of ice supersaturation over Europe during the considered period. A systematic backward trajectory analysis for the ISSRs on these maps shows that the ISSR air masses themselves experienced only a moderate upward motion during the previous days, whereas parts of the ISSRs were located just above strongly ascending air masses from the boundary layer. This indicates qualitatively that warm conveyor belts associated with mid-latitude cyclogenesis are disturbances that can induce the formation of ISSRs in the upper troposphere. The ISSR maps also lead us to a new perception of ISSRs as large dynamic regions of supersaturated air where cirrus clouds can be embedded at some locations while there is clear air at others.

  13. Projection of actual evapotranspiration using the COSMO-CLM regional climate model under global warming scenarios of 1.5 °C and 2.0 °C in the Tarim River basin, China

    Science.gov (United States)

    Su, Buda; Jian, Dongnan; Li, Xiucang; Wang, Yanjun; Wang, Anqian; Wen, Shanshan; Tao, Hui; Hartmann, Heike

    2017-11-01

    Actual evapotranspiration (ETa) is an important component of the water cycle. The goals for limiting global warming to below 2.0 °C above pre-industrial levels and aspiring to 1.5 °C were negotiated in the Paris Agreement in 2015. In this study, outputs from the regional climate model COSMO-CLM (CCLM) for the Tarim River basin (TRB) were used to calculate ETa with an advection-aridity model, and changes in ETa under global warming scenarios of 1.5 °C (2020 to 2039) and 2.0 °C (2040 to 2059) were analyzed. Comparison of warming at the global and regional scale showed that regional 1.5 °C warming would occur later than the global average, while regional 2.0 °C warming would occur earlier than the global average. For global warming of 1.5 °C, the average ETa in the TRB is about 222.7 mm annually, which represents an increase of 6.9 mm relative to the reference period (1986-2005), with obvious increases projected for spring and summer. The greatest increases in ETa were projected for the northeast and southwest. The increment in the annual ETa across the TRB considering a warming of 1.5 °C was 4.3 mm less than that for a warming of 2.0 °C, and the reduction between the two levels of warming was most pronounced in the summer, when ETa was 3.4 mm smaller. The reduction in the increment of annual ETa for warming of 1.5 °C relative to warming of 2.0 °C was most pronounced in the southwest and northeast, where it was projected to be 8.2 mm and 9.3 mm smaller, respectively. It is suggested that the higher ETa under a warming of 2.0 °C mainly results from an increase in the sunshine duration (net radiation) in the southwestern basin and an increase in precipitation in the northeastern basin. Vapor is removed from the limited surface water supplies by ETa. The results of this study are therefore particularly relevant for water resource planning in the TRB.

  14. Frost stress evolution and winter pea ideotype in the context of climate warming at a regional scale

    OpenAIRE

    Castel Thierry; Lecomte Christophe; Richard Yves; Lejeune-Hénaut Isabelle; Larmure Annabelle

    2017-01-01

    Pea (Pisum sativum L.) is an important crop in temperate regions for its high seed protein concentration that is particularly sensitive to abiotic stresses. The abrupt temperature increase known as the “1987/1988 temperature regime shift” that occurs over Europe is questioning how winter pea will perform in the changing climate. This study assessed the winter frost damage evolution along from 1961 to 2015 in Burgundy-Franche-Comté by using: (1) daily observed and gridded regional temperature ...

  15. Early-Holocene Climate Change in Beringia: Mediation of Global-Warming Impacts by Regional-Scale Boundary-Condition Changes

    Science.gov (United States)

    Edwards, M. E.; Bartlein, P. J.; Hostetler, S. W.; Shafer, S. L.; Anderson, P. M.; Brubaker, L. B.

    2006-12-01

    The early Holocene transition from glacial to interglacial conditions that occurred ca. 13ka to 10ka in Beringia (eastern Siberia, Alaska, and northwestern Canada) was driven by the amplified seasonal cycle of northern hemisphere insolation and the accompanying changes in global ice volume, atmospheric composition, sea- surface temperature, and sea level. The climate of Beringia also was likely influenced by changes in regional- scale controls, including continental-shelf flooding, the development of thaw lakes, and the replacement of shrub tundra by deciduous forest or woodland. We are examining the sensitivity of Beringia's early Holocene climate to these regional-scale controls by applying a regional climate model (RegCM2), with lateral and oceanic boundary conditions provided by global climate simulations conducted with an atmospheric general circulation model (AGCM) with a mixed-layer ocean (Genesis 2.0). In addition to a present day simulation, we performed five 11ka climate simulations with RegCM2, each driven by the same AGCM 11ka global simulation: 1) a "control" simulation that represents conditions just prior to the major transitions (i.e. exposed land bridge, no thaw lakes or wetlands, widespread tundra vegetation); 2) a vegetation-change simulation, with deciduous needleleaf and boreal deciduous broadleaf vegetation types distributed as suggested by the paleoecological record; 3) a sea-level rise simulation, employing present-day continental outlines; 4) a thaw-lake simulation, using the present-day distribution of lakes and wetlands; and 5) a "post-11ka" simulation, incorporating all of the regional-scale boundary conditions changed in experiments 2-4. The experiments indicate that the regional-scale controls strongly mediate the climate responses to changes in the large-scale controls, amplifying them in some cases, damping them in others, and overall, generating considerable spatial heterogeneity in the simulated climate changes. The vegetation

  16. Investigation of Long-Term Impacts of Urbanization when Considering Global Warming for a Coastal Tropical Region

    Science.gov (United States)

    Gonalez, Jorge E.; Comarazamy, Daniel E.; Luvall, Jeffrey C.; Rickman, Douglas L.; Smith, T.

    2010-01-01

    The overachieving goal of this project is to gain a better understanding of the climate impacts caused by the combined effects of land cover and land use (LCLU) changes and increasing global concentrations of green house gases (GHG) in tropical coastal areas, regions where global, regional and local climate phenomena converge, taking as the test case the densely populated northeast region of the Caribbean island of Puerto Rico. The research uses an integrated approach of high-resolution remote sensing information linked to a high resolution Regional Atmospheric Modeling System (RAMS), which was employed to perform ensembles of climate simulations (combining 2-LCLU and 2-GHG concentration scenarios). Reconstructed agricultural maps are used to define past LCLU, and combined with reconstructed sea surface temperatures (SST) for the same period form the PAST climate scenario (1951-1956); while the PRESENT scenario (2000-2004) was additionally supported by high resolution remote sensing data (10-m-res). The climate reconstruction approach is validated with available observed climate data from surface weather stations for both periods of time simulated. The selection of the past and present climate scenarios considers large-scale biases (i.e. ENSO/NAO) as reflected in the region of interest. Direct and cross comparison of the results is allowing quantifying single, combined, and competitive effects. Results indicate that global GHG have dominant effects on minimum temperatures (following regional tendencies), while urban sprawl dominates maximum temperatures. To further investigate impacts of land use the Bowen Ratio and the thermal response number (TRN) are analyzed. The Bowen ratio indicates that forestation of past agricultural high areas have an overwhelmingly mitigation effect on increasing temperatures observed in different LCLU scenarios, but when abandoned agricultural lands are located in plains, the resulting shrub/grass lands produce higher surface

  17. Comparison of the response of Atlantic cod ( Gadus morhua) in the high-latitude regions of the North Atlantic during the warm periods of the 1920s-1960s and the 1990s-2000s

    Science.gov (United States)

    Drinkwater, Ken

    2009-10-01

    Concern about future anthropogenic warming has lead to demands for information on what might happen to fish and fisheries under various climate-change scenarios. One suggestion has been to use past events as a proxy for what will happen in the future. In this paper a comparison between the responses of Atlantic cod ( Gadus morhua) to two major warm periods in the North Atlantic during the 20th century is carried out to determine how reliable the past might be as a predictor of the future. The first warm period began during the 1920s, remained relatively warm through the 1960s, and was limited primarily to the northern regions (>60°N). The second warm period, which again covered the northern regions but also extended farther south (30°N), began in the 1990s and has continued into the present century. During the earlier warm period, the most northern of the cod stocks (West Greenland, Icelandic, and Northeast Arctic cod in the Barents Sea) increased in abundance, individual growth was high, recruitment was strong, and their distribution spread northward. Available plankton data suggest that these cod responses were driven by bottom-up processes. Fishing pressure increased during this period of high cod abundance and the northern cod stocks began to decline, as early as the 1950s in the Barents Sea but during the 1960s elsewhere. Individual growth declined as temperatures cooled and the cod distributions retracted southward. During the warming in the 1990s, the spawning stock biomass of cod in the Barents Sea again increased, recruitment rose, and the stock spread northward, but the individual growth did not improve significantly. Cod off West Greenland also have shown signs of improving recruitment and increasing biomass, albeit they are still very low in comparison to the earlier warming period. The abundance of Icelandic cod, on the other hand, has remained low through the recent warm period and spawning stock biomass and total biomass are at levels near the

  18. The structure of NGC 7538 IRS9: A massive star forming region with spatially constrained warm gas

    Science.gov (United States)

    Doty, Steven; Bowers, Brant

    2015-08-01

    An important question in the study of massive protostars is the physical structure of the star forming region. An extension of the Shu infall model to high masses would suggest the existence of a spherical envelope surrounding a central, massive disk. On the other hand, turbulence, outflows, instabilities, or other forces might disrupt such a disk or prevent one from forming in the first place. Observations of acetylene in ro-vibrational absorption on GEMINI provide spatially constrained observations of high-lying transitions. We model the absorption and compare the model predictions with the observations, in order to constrain the models. The implications for the physical structure are discussed, and future observations to test the results are suggested.

  19. Global and regional estimates of warm cloud droplet number concentration based on 13 years of AQUA-MODIS observations

    Science.gov (United States)

    Bennartz, Ralf; Rausch, John

    2017-08-01

    We present and evaluate a climatology of cloud droplet number concentration (CDNC) based on 13 years of Aqua-MODIS observations. The climatology provides monthly mean 1 × 1° CDNC values plus associated uncertainties over the global ice-free oceans. All values are in-cloud values, i.e. the reported CDNC value will be valid for the cloudy part of the grid box. Here, we provide an overview of how the climatology was generated and assess and quantify potential systematic error sources including effects of broken clouds, and remaining artefacts caused by the retrieval process or related to observation geometry. Retrievals and evaluations were performed at the scale of initial MODIS observations (in contrast to some earlier climatologies, which were created based on already gridded data). This allowed us to implement additional screening criteria, so that observations inconsistent with key assumptions made in the CDNC retrieval could be rejected. Application of these additional screening criteria led to significant changes in the annual cycle of CDNC in terms of both its phase and magnitude. After an optimal screening was established a final CDNC climatology was generated. Resulting CDNC uncertainties are reported as monthly-mean standard deviations of CDNC over each 1 × 1° grid box. These uncertainties are of the order of 30 % in the stratocumulus regions and 60 to 80 % elsewhere.

  20. First recorded loss of an emperor penguin colony in the recent period of Antarctic regional warming: implications for other colonies.

    Directory of Open Access Journals (Sweden)

    Philip N Trathan

    Full Text Available In 1948, a small colony of emperor penguins Aptenodytes forsteri was discovered breeding on Emperor Island (67° 51' 52″ S, 68° 42' 20″ W, in the Dion Islands, close to the West Antarctic Peninsula (Stonehouse 1952. When discovered, the colony comprised approximately 150 breeding pairs; these numbers were maintained until 1970, after which time the colony showed a continuous decline. By 1999 there were fewer than 20 pairs, and in 2009 high-resolution aerial photography revealed no remaining trace of the colony. Here we relate the decline and loss of the Emperor Island colony to a well-documented rise in local mean annual air temperature and coincident decline in seasonal sea ice duration. The loss of this colony provides empirical support for recent studies (Barbraud & Weimerskirch 2001; Jenouvrier et al 2005, 2009; Ainley et al 2010; Barber-Meyer et al 2005 that have highlighted the vulnerability of emperor penguins to changes in sea ice duration and distribution. These studies suggest that continued climate change is likely to impact upon future breeding success and colony viability for this species. Furthermore, a recent circumpolar study by Fretwell & Trathan (2009 highlighted those Antarctic coastal regions where colonies appear most vulnerable to such changes. Here we examine which other colonies might be at risk, discussing various ecological factors, some previously unexplored, that may also contribute to future declines. The implications of this are important for future modelling work and for understanding which colonies actually are most vulnerable.

  1. First recorded loss of an emperor penguin colony in the recent period of Antarctic regional warming: implications for other colonies.

    Science.gov (United States)

    Trathan, Philip N; Fretwell, Peter T; Stonehouse, Bernard

    2011-02-28

    In 1948, a small colony of emperor penguins Aptenodytes forsteri was discovered breeding on Emperor Island (67° 51' 52″ S, 68° 42' 20″ W), in the Dion Islands, close to the West Antarctic Peninsula (Stonehouse 1952). When discovered, the colony comprised approximately 150 breeding pairs; these numbers were maintained until 1970, after which time the colony showed a continuous decline. By 1999 there were fewer than 20 pairs, and in 2009 high-resolution aerial photography revealed no remaining trace of the colony. Here we relate the decline and loss of the Emperor Island colony to a well-documented rise in local mean annual air temperature and coincident decline in seasonal sea ice duration. The loss of this colony provides empirical support for recent studies (Barbraud & Weimerskirch 2001; Jenouvrier et al 2005, 2009; Ainley et al 2010; Barber-Meyer et al 2005) that have highlighted the vulnerability of emperor penguins to changes in sea ice duration and distribution. These studies suggest that continued climate change is likely to impact upon future breeding success and colony viability for this species. Furthermore, a recent circumpolar study by Fretwell & Trathan (2009) highlighted those Antarctic coastal regions where colonies appear most vulnerable to such changes. Here we examine which other colonies might be at risk, discussing various ecological factors, some previously unexplored, that may also contribute to future declines. The implications of this are important for future modelling work and for understanding which colonies actually are most vulnerable.

  2. Regional climate and vegetation response to orbital forcing within the mid-Pliocene Warm Period: A study using HadCM3

    Science.gov (United States)

    Prescott, C. L.; Dolan, A. M.; Haywood, A. M.; Hunter, S. J.; Tindall, J. C.

    2018-02-01

    Regional climate and environmental variability in response to orbital forcing during interglacial events within the mid-Piacenzian (Pliocene) Warm Period (mPWP; 3.264-3.025 Ma) has been rarely studied using climate and vegetation models. Here we use climate and vegetation model simulations to predict changes in regional vegetation patterns in response to orbital forcing for four different interglacial events within the mPWP (Marine Isotope Stages (MIS) G17, K1, KM3 and KM5c). The efficacy of model-predicted changes in regional vegetation is assessed by reference to selected high temporal resolution palaeobotanical studies that are theoretically capable of discerning vegetation patterns for the selected interglacial stages. Annual mean surface air temperatures for the studied interglacials are between 0.4 °C to 0.7 °C higher than a comparable Pliocene experiment using modern orbital parameters. Increased spring/summer and reduced autumn/winter insolation in the Northern Hemisphere during MIS G17, K1 and KM3 enhances seasonality in surface air temperature. The two most robust and notable regional responses to this in vegetation cover occur in North America and continental Eurasia, where forests are replaced by more open-types of vegetation (grasslands and shrubland). In these regions our model results appear to be inconsistent with local palaeobotanical data. The orbitally driven changes in seasonal temperature and precipitation lead to a 30% annual reduction in available deep soil moisture (2.0 m from surface), a critical parameter for forest growth, and subsequent reduction in the geographical coverage of forest-type vegetation; a phenomenon not seen in comparable simulations of Pliocene climate and vegetation run with a modern orbital configuration. Our results demonstrate the importance of examining model performance under a range of realistic orbital forcing scenarios within any defined time interval (e.g. mPWP). Additional orbitally resolved records of

  3. Incorporating global warming risks in power sector planning: A case study of the New England region. Volume 1

    Energy Technology Data Exchange (ETDEWEB)

    Krause, F.; Busch, J.; Koomey, J.

    1992-11-01

    Growing international concern over the threat of global climate change has led to proposals to buy insurance against this threat by reducing emissions of carbon (short for carbon dioxide) and other greenhouse gases below current levels. Concern over these and other, non-climatic environmental effects of electricity generation has led a number of states to adopt or explore new mechanisms for incorporating environmental externalities in utility resource planning. For example, the New York and Massachusetts utility commissions have adopted monetized surcharges (or adders) to induce emission reductions of federally regulated air pollutants (notably, SO{sub 2}, NO{sub x}, and particulates) beyond federally mandated levels. These regulations also include preliminary estimates of the cost of reducing carbon emissions, for which no federal regulations exist at this time. Within New England, regulators and utilities have also held several workshops and meetings to discuss alternative methods of incorporating externalities as well as the feasibility of regional approaches. This study examines the potential for reduced carbon emissions in the New England power sector as well as the cost and rate impacts of two policy approaches: environmental externality surcharges and a target- based approach. We analyze the following questions: Does New England have sufficient low-carbon resources to achieve significant reductions (10% to 20% below current levels) in fossil carbon emissions in its utility sector? What reductions could be achieved at a maximum? What is the expected cost of carbon reductions as a function of the reduction goal? How would carbon reduction strategies affect electricity rates? How effective are environmental externality cost surcharges as an instrument in bringing about carbon reductions? To what extent could the minimization of total electricity costs alone result in carbon reductions relative to conventional resource plans?

  4. Thermal comfort implications of urbanization in a warm-humid city: the Colombo Metropolitan Region (CMR), Sri Lanka

    Energy Technology Data Exchange (ETDEWEB)

    Emmanuel, R. [Moratuwa Univ., Dept. of Architecture, Moratuwa (Sri Lanka)

    2005-12-01

    In this paper we analyze the historic trends in thermal comfort (measured in terms of Temperature-Humidity Index [THI] and Relative Strain Index [RSI]) in the Sri Lankan primate city of Colombo and correlate them with land cover changes in the region. Land cover is calculated from time-series aerial photographs in terms of 'hard' cover (buildings, paved areas and roads) and 'soft' cover (trees, green areas and waterbodies). The period selected for analysis includes pre-rapid (up to 1977) and rapid urban phases (1978 onwards) in the city. Contemporary Sri Lanka's urbanization is peculiar in that mid to late 20th century urban rates (approx. 22% of the population) had remained virtually unchanged till the economy was liberalized in 1977, but have recently intensified (currently at about 35%). This offers a unique window of opportunity to look at the thermal comfort transition consequent to urbanization. Since many tropical cities are at a similar stage of demographic transition, lessons from Colombo may generally be applicable to other tropical developing cities as well. An increasing trend in thermal discomfort-particularly at night-is seen especially at the suburban station and it correlates well with hard land cover changes. The study also brings out the relative importance of land cover in city center vs. rural areas (e.g. hard cover has more effect on thermal discomfort in city center than in rural areas). Based on these findings, we postulate an outline for a climate-sensitive urban design policy for tropical cities. (Author)

  5. [Food habits and hunting patterns of Tibetan brown bear during warm seasons in Kekexili region on Qinghai-Tibetan Plateau].

    Science.gov (United States)

    Xu, Ai-Chun; Jiang, Zhi-Gang; Li, Chun-Wang; Cai, Ping

    2010-12-01

    Tibetan brown bear (Ursus arctos pruinosus) is an endemic subspecies of brown bear on the Qinghai-Tibetan plateau. We once reported a preliminary study on the summer food habit of Tibetan brown bear from July to August, 2005 in the Kekexili (Hoh Xil).. However, the hunting modes of the Tibetan brawn bear have not been reported. From July to August, 2009, we collected additional data on food habits and hunting patterns of Tibetan brown bear in the Kekexili region. We found Tibetan brown bears are more raptatorial than vegetarian, and their basal food was plateau pika (Ochotona curzoniae), relative frequency occurrence of pika in the fecal residual of brawn bear was 37.3%, dry weight of pika residuals was 44.7%, respectively, followed by wild yak (Bos grunniens) , 18.7% and 30.2%, and Tibetan antelope (Pantholops hodgsoni) 15.0% and 16.2%. Both prey actively mode and scavenge mode were used by Tibetan brown bears in Kekexili. Tibetan brawn bears actively dug and hunted for pika and scavenged bodies of wild yak, Tibetan antelope and Tibetan gazelle. We observed that Tibetan brawn bears spent about 10% of their time to dig and to hunt for pika but we had never seen Tibetan brawn bears actively hunted large mammals such as wild yak, Tibetan antelope and Tibetan gazelle. The total amount of Tibetan antelope, Tibetan gazelle and wild yak ingested by Tibetan brown bear through scavenge was about the same amount of Plateau pika and Himalayan marmot (Marmota himalayana) eaten by the bear.

  6. Dynamical Downscaling over the Great Lakes Basin of North America using the WRF Regional Climate Model: The impact of the Great Lakes system on regional greenhouse warming

    Science.gov (United States)

    Gula, J.; Peltier, W. R.

    2011-12-01

    In this study we investigate the regional climate changes to be expected over the Great Lakes Basin of North America during the next century. Large freshwater systems, such as the Great Lakes, play a key role in determining the climate of their basins and adjacent regions by air mass modification through the exchange of heat and moisture with the atmosphere. Even systems as extensive as the Great Lakes are unresolved in coarse resolution global climate simulations but may be accurately captured in finer-mesh regional simulations by dynamical downscaling. Historical (1979-2001) and future (2050-2060 and 2090-2100) conditions are simulated using the Weather Research and Forecasting model (WRF) forced by CCSM3 global simulations. Our analyses are based upon the IPCC SRES A2 and A1B emissions scenarios. A two-step nesting procedure is employed for the purpose of downscaling, in which the first nested WRF model is of North American continental scale at 30 km resolution, whereas the innermost domain at 10 km resolution covers the Great Lakes Basin and the Canadian Province of Ontario. The differences in extreme temperature and precipitation events delivered by the different scales of simulation are discussed. As the WRF model does not currently have an explicit lake component, lake ice and lake surface temperature need to be prescribed in the model. A first set of simulations is performed using climatological 1979-2001) data for lake ice and lake surface temperature. A second set is performed using outputs from the freshwater lake model "FLake" (Mironov, D. V., 2008, COSMO Technical Report, No. 11, Deutscher Wetterdienst, Offenbach am Main, Germany) forced by atmospheric fields from the global simulations. A third set is performed using an interactive coupling of the lake model FLake with the regional model WRF. Changes in surface temperatures and ice cover, and especially ice-out dates, for the Great Lakes under future atmospheric conditions are discussed. The trends in

  7. Anthropogenic organochlorine compounds as potential tracers for regional water masses: A case study of estuarine plume, coastal eddy, wind-driven upwelling and long-range warm current.

    Science.gov (United States)

    Ya, Miaolei; Wu, Yuling; Li, Yongyu; Wang, Xinhong

    2017-03-01

    Water masses are the crucial factor driving the terrigenous anthropogenic organochlorine compounds (OCs) migration from the coast to open sea. Therefore, organochlorine pesticides (OCPs) and polychlorinated biphenyls (PCBs) were investigated in the Northern South China Sea (NSCS), where different types of water masses are generated by the East Asian summer monsoon: Pearl River estuary plume (PREP), Guangdong offshore eddy (GDEC), South China Sea warm current (SCSWC) and wind-driven upwelling current (WDUC). No discrepant distributions of OC concentrations were found in these water masses (p > 0.05). However, compositions and diagnostic ratios of HCHs, DDTs, trans- or cis-chlordane and PCBs could reflect the discrepancies in the input, transport and transformation of OCs caused by the hydrological characteristics of water masses, therefore, this allowing them to serve as potential tracers of regional water masses. In detail, α/γ-HCH and β-HCH percentages could indicate the weathered residue in the GDEC, long-range transport in the SCSWC, rapid photodegradation in the surface WDUC and biodegradation in the deep WDUC, respectively. The predominance of o, p'-DDT and p, p'-DDT could indicate fresh input in the PREP, GDEC and WDUC. DDT/DDTs of ratios erosion in the PREP. Copyright © 2016 Elsevier Ltd. All rights reserved.

  8. Differential response of corals to regional mass-warming events as evident from skeletal Sr/Ca and Mg/Ca ratios

    Science.gov (United States)

    Clarke, Harry; D'Olivo, Juan Pablo; Falter, James; Zinke, Jens; Lowe, Ryan; McCulloch, Malcolm

    2017-05-01

    During the summer of 2010/2011, a regional marine heat wave resulted in coral bleaching of variable severity along much of the western coastline of Australia. At Ningaloo Reef, a 300 km long fringing reef system and World Heritage site, highly contrasting coral bleaching was observed between two morphologically distinct nearshore reef communities located on either side of the Ningaloo Peninsula: Tantabiddi (˜20% bleaching) and Bundegi (˜90% bleaching). For this study, we collected coral cores (Porites sp.) from Tantabiddi and Bundegi reef sites to assess the response of the Sr/Ca temperature proxy and Mg/Ca ratios to the variable levels of thermal stress imposed at these two sites during the 2010/2011 warming event. We found that there was an anomalous increase in Sr/Ca and decrease in Mg/Ca ratios in the Bundegi record that was coincident with the timing of severe coral bleaching at the site, while no significant changes were observed in the Tantabiddi record. We show that the change in the relationship of Sr/Ca and Mg/Ca ratios with temperature at Bundegi during the 2010/2011 event reflects changes in related coral "vital" processes during periods of environmental stress. These changes were found to be consistent with a reduction in active transport of Ca2+ to the site of calcification leading to a reduction in calcification rates and reduced Rayleigh fractionation of incorporated trace elements.

  9. Performance and application of a fluidized bed limestone reactor designed for control of alkalinity, hardness and pH at the Warm Springs Regional Fisheries Center

    Science.gov (United States)

    Watten, Barnaby J.; Mudrak, Vincent A.; Echevarria, Carlos; Sibrell, Philip; Summerfelt, Steven T.; Boyd, Claude E.

    2017-01-01

    Springs serving the Warm Springs Regional Fisheries Center, Warm Springs, Georgia, have pH, alkalinity, and hardness levels thatlie under the range required for successful fish propagation while free CO2 is well above allowable targets. We evaluate a pretreatment process that exploits limestone’s (CaCO3) ability to react away hydrogen ions (H+) and carbon dioxide (CO2) while increasing alkalinity (HCO3−) and calcium (Ca2+) concentrations, i.e. CaCO3 + H+ ↔ HCO3− + Ca2+ CaCO3 + CO2 + H2O ↔ Ca2+ + 2HCO3− Limestone sand was tested in both pilot and full scale fluidized bed reactors (CycloBio®). We first established the bed expansion characteristics of three commercial limestone products then evaluated the effect of hydraulic flux and bed height on dissolution rate of a single selected product (Type A16 × 120). Pilot scale testing at 18C showed limestone dissolution rates were relatively insensitive to flux over the range 1.51–3.03 m3/min/m2 but were sensitive (P 0.05) demonstrating that limestone was present in the reactor effluent primarily in the form of dissolved Ca(HCO3)2. Effluent alkalinity exceeded our target level of 50 mg/L under most operating conditions evaluated with typical pilot scale values falling within the range of 90–100 mg/L despite influent concentrations of about 4 mg/L. Concurrently, CO2 fell from an average of 50.6 mg/L to 8.3 mg/L (90%), providing for an increase in pH from 5.27 to a mean of 7.71. The ability of the test reactor to provide changes in water chemistry variables that exceeded required changes allowed for a dilution ratio of 0.6. Here, alkalinity still exceeded 50 mg/L, the CO2 concentration remained well below our limit of 20 mg/L (15.4 mg/L) and the pH was near neutral (7.17). Applying the dilution ratio of 0.6 in a full scale treatment plant at the site reduced by 40% the volume of spring water that is directed through each of three parallel reactors that combined react away 49,000 kg of limestone/yr.

  10. Global warming

    CERN Document Server

    Hulme, M

    1998-01-01

    Global warming-like deforestation, the ozone hole and the loss of species- has become one of the late 20the century icons of global environmental damage. The threat, is not the reality, of such a global climate change has motivated governments. businesses and environmental organisations, to take serious action ot try and achieve serious control of the future climate. This culminated last December in Kyoto in the agreement for legally-binding climate protocol. In this series of three lectures I will provide a perspective on the phenomenon of global warming that accepts the scientific basis for our concern, but one that also recognises the dynamic interaction between climate and society that has always exited The future will be no different. The challenge of global warning is not to pretend it is not happening (as with some pressure groups), nor to pretend it threatens global civilisation (as with other pressure groups), and it is not even a challenge to try and stop it from happening-we are too far down the ro...

  11. The transforming perception of a regional geohazard between coastal defence and mediated discourse on global warming: Storm surges in Hamburg, Germany

    Science.gov (United States)

    Neverla, I.; Lüthje, C.

    2010-03-01

    The term regional geohazard is used for a major geophysical risk which can lead to a natural disaster. The effects will be strictly located to a specific region. It is expected but still not proven that global warming will intensify weather extremes and thus the number of regional geohazards will increase. Regional geohazards are not dangerous per se, but from the perspective of human being certain weather and nature extremes are considered dangerous as they impose damage on human beings and their belongings. Therefore the media often call them ‘natural disaster’ and as a matter of fact it seems to be a ‘must’ - according to theory and practice of news selections - that media report on any natural disaster that occur in their region. Moreover, media even report on geohazards in any other region as soon as these events seem to have any general impact. The major geophysical risk along the coast of the North Sea is storm surges. A long list of historical disasters has deeply engraved the ubiquity of this hazard into the collective memory and habitus of the local population. Not only coastal region is concerned by this danger but also the megacity of Hamburg. Hamburg is the second-largest city in Germany and the sixth-largest city in the European Union. The Hamburg Metropolitan Region has more than 4.3 million inhabitants. The estuary of the river Elbe extends from Cuxhaven (coast) to Hamburg a distance of about 130 km. Hamburg has often been subject to storm surges with significant damages. But after the storm flood in 1855 for more than 100 years until 1962 no severe storm surge happened. The Big Flood in the night from February 16 to February 17 1962 destroyed the homes of about 60.000 people. The death toll amounted to 315 in the city of Hamburg, where the storm surge had a traumatic impact and was followed by political decisions driven by the believe in technological solutions. After 1962 massive investments into the coastal defence were made and dikes

  12. Paleoclimatic reconstructions for the south of Valdai Hills (European Russia) as paleo-analogs of possible regional vegetation changes under global warming

    Energy Technology Data Exchange (ETDEWEB)

    Novenko, E; Zuganova, I [Institute of Geography of RAS, Staromonetny Lane 29, Moscow 119017 (Russian Federation); Olchev, A [A N Severtsov Institute of Ecology and Evolution of RAS, Leninsky Prospekt 33, Moscow 119071 (Russian Federation); Desherevskaya, O, E-mail: lenanov@mail.r [Faculty of Geography, M V Lomonosov Moscow State University, Moscow 119991 (Russian Federation)

    2009-10-15

    The possible response of forest ecosystems of south taiga at the south of Valdai Hills on projected future global warming was assessed using analysis of pollen, plant macrofossil and radiocarbon data from four profiles of buried organic sediments of the last interglacial and several cores from modern raised bogs and two small forest mires in the Central Forest State Natural Biosphere Reserve (CFSNBR; Twer region, Russia). The future pattern of climatic conditions for the period up to 2100 was derived using the data of A2, B1 and A1B emission scenarios calculated by the global climatic model ECHAM5-MPIOM (Roeckner E et al 2003 The Atmospheric General Circulation Model ECHAM 5. PART I: Model Description, Report 349 (Hamburg: Max-Planck Institute for Meteorology) p 127). The paleoclimatic reconstructions showed that the optimum of the Holocene (the Late Atlantic period, 4500-4800 {sup 14}C yr BP) and the optimal phases of the last interglacial (Mikulino, Eemian, 130 000-115 000 yr BP) can be considered as possible analogs for projected climatic conditions of the middle and the end of the 21st century, respectively. The climate of the CFSNBR during the Holocene climatic optimum was characterized by higher winter (about 3 deg. C higher than at present) and summer temperatures (about 1 deg. C higher than present values). Precipitation was close to present values (about 600-800 mm yr{sup -1}). Vegetation was represented by mixed coniferous and broad-leaved forest. In the warmest phases of the last interglacial the winter temperature was 5-8 deg. C higher than present values. The summer temperatures were also about 2-4 deg. C higher. Broad-leaved and hornbeam trees were the dominant tree species in vegetation cover.

  13. Arctic dimension of global warming

    OpenAIRE

    G. V. Alekseev

    2014-01-01

    A brief assessment of the global warming in the Arctic climate system with the emphasis on sea ice is presented. The Arctic region is coupled to the global climate system by the atmosphere and ocean circulation that providesa major contribution to the Arctic energy budget. On this basis using of special indices it is shown that amplification of warming in the Arctic is associated with the increasing of meridional heat transport from the low latitudes.

  14. Improving conservation of Florida manatees (Trichechus manatus latirostris): conceptualization and contributions toward a regional warm-water network management strategy for sustainable winter habitat.

    Science.gov (United States)

    Flamm, Richard Owen; Reynolds, John Elliot; Harmak, Craig

    2013-01-01

    We used southwestern Florida as a case study to lay the groundwork for an intended and organized decision-making process for managing warm-water habitat needed by endangered manatees to survive winters in Florida. Scientists and managers have prioritized (a) projecting how the network of warm-water sites will change over the next 50 years as warmed industrial discharges may expire and as flows of natural springs are reduced through redirection of water for human uses, and (b) mitigating such changes to prevent undue consequences to manatees. Given the complexities introduced by manatee ecology; agency organizational structure; shifting public demands; fluctuating resource availability; and managing within interacting cultural, social, political, and environmental contexts, it was clear that a structured decision process was needed. To help promote such a process, we collected information relevant to future decisions including maps of known and suspected warm-water sites and prototyped a characterization of sites and networks. We propose steps that would lead to models that might serve as core tools in manatee/warm-water decision-making, and we summarized topics relevant for informed decision-making (e.g., manatee spatial cognition, risk of cold-stress morbidity and mortality, and human dimensions). A major impetus behind this effort is to ensure proactively that robust modeling tools are available well in advance of the anticipated need for a critical management decision.

  15. Improving Conservation of Florida Manatees ( Trichechus manatus latirostris): Conceptualization and Contributions Toward a Regional Warm-Water Network Management Strategy for Sustainable Winter Habitat

    Science.gov (United States)

    Flamm, Richard Owen; Reynolds, John Elliot; Harmak, Craig

    2013-01-01

    We used southwestern Florida as a case study to lay the groundwork for an intended and organized decision-making process for managing warm-water habitat needed by endangered manatees to survive winters in Florida. Scientists and managers have prioritized (a) projecting how the network of warm-water sites will change over the next 50 years as warmed industrial discharges may expire and as flows of natural springs are reduced through redirection of water for human uses, and (b) mitigating such changes to prevent undue consequences to manatees. Given the complexities introduced by manatee ecology; agency organizational structure; shifting public demands; fluctuating resource availability; and managing within interacting cultural, social, political, and environmental contexts, it was clear that a structured decision process was needed. To help promote such a process, we collected information relevant to future decisions including maps of known and suspected warm-water sites and prototyped a characterization of sites and networks. We propose steps that would lead to models that might serve as core tools in manatee/warm-water decision-making, and we summarized topics relevant for informed decision-making (e.g., manatee spatial cognition, risk of cold-stress morbidity and mortality, and human dimensions). A major impetus behind this effort is to ensure proactively that robust modeling tools are available well in advance of the anticipated need for a critical management decision.

  16. Recent warming of lake Kivu.

    Science.gov (United States)

    Katsev, Sergei; Aaberg, Arthur A; Crowe, Sean A; Hecky, Robert E

    2014-01-01

    Lake Kivu in East Africa has gained notoriety for its prodigious amounts of dissolved methane and dangers of limnic eruption. Being meromictic, it is also expected to accumulate heat due to rising regional air temperatures. To investigate the warming trend and distinguish between atmospheric and geothermal heating sources, we compiled historical temperature data, performed measurements with logging instruments, and simulated heat propagation. We also performed isotopic analyses of water from the lake's main basin and isolated Kabuno Bay. The results reveal that the lake surface is warming at the rate of 0.12°C per decade, which matches the warming rates in other East African lakes. Temperatures increase throughout the entire water column. Though warming is strongest near the surface, warming rates in the deep waters cannot be accounted for solely by propagation of atmospheric heat at presently assumed rates of vertical mixing. Unless the transport rates are significantly higher than presently believed, this indicates significant contributions from subterranean heat sources. Temperature time series in the deep monimolimnion suggest evidence of convection. The progressive deepening of the depth of temperature minimum in the water column is expected to accelerate the warming in deeper waters. The warming trend, however, is unlikely to strongly affect the physical stability of the lake, which depends primarily on salinity gradient.

  17. Recent warming of lake Kivu.

    Directory of Open Access Journals (Sweden)

    Sergei Katsev

    Full Text Available Lake Kivu in East Africa has gained notoriety for its prodigious amounts of dissolved methane and dangers of limnic eruption. Being meromictic, it is also expected to accumulate heat due to rising regional air temperatures. To investigate the warming trend and distinguish between atmospheric and geothermal heating sources, we compiled historical temperature data, performed measurements with logging instruments, and simulated heat propagation. We also performed isotopic analyses of water from the lake's main basin and isolated Kabuno Bay. The results reveal that the lake surface is warming at the rate of 0.12°C per decade, which matches the warming rates in other East African lakes. Temperatures increase throughout the entire water column. Though warming is strongest near the surface, warming rates in the deep waters cannot be accounted for solely by propagation of atmospheric heat at presently assumed rates of vertical mixing. Unless the transport rates are significantly higher than presently believed, this indicates significant contributions from subterranean heat sources. Temperature time series in the deep monimolimnion suggest evidence of convection. The progressive deepening of the depth of temperature minimum in the water column is expected to accelerate the warming in deeper waters. The warming trend, however, is unlikely to strongly affect the physical stability of the lake, which depends primarily on salinity gradient.

  18. Effect of moisture availability on wood density and vessel characteristics of Eucalyptus grandis in the warm temperate region of South Africa

    CSIR Research Space (South Africa)

    Naidoo, Sasha

    2006-09-01

    Full Text Available intolerant of adverse conditions, and performs poorly when planted on shallow soils and/or on dry sites. A study was conducted to assess the effect of moisture availability on the wood density and vessel characteristics of E. grandis grown in the warm...

  19. Geologic Map of the Warm Spring Canyon Area, Death Valley National Park, Inyo County, California, With a Discussion of the Regional Significance of the Stratigraphy and Structure

    Science.gov (United States)

    Wrucke, Chester T.; Stone, Paul; Stevens, Calvin H.

    2007-01-01

    Warm Spring Canyon is located in the southeastern part of the Panamint Range in east-central California, 54 km south of Death Valley National Park headquarters at Furnace Creek Ranch. For the relatively small size of the area mapped (57 km2), an unusual variety of Proterozoic and Phanerozoic rocks is present. The outcrop distribution of these rocks largely resulted from movement on the east-west-striking, south-directed Butte Valley Thrust Fault of Jurassic age. The upper plate of the thrust fault comprises a basement of Paleoproterozoic schist and gneiss overlain by a thick sequence of Mesoproterozoic and Neoproterozoic rocks, the latter of which includes diamictite generally considered to be of glacial origin. The lower plate is composed of Devonian to Permian marine formations overlain by Jurassic volcanic and sedimentary rocks. Late Jurassic or Early Cretaceous plutons intrude rocks of the area, and one pluton intrudes the Butte Valley Thrust Fault. Low-angle detachment faults of presumed Tertiary age underlie large masses of Neoproterozoic dolomite in parts of the area. Movement on these faults predated emplacement of middle Miocene volcanic rocks in deep, east-striking paleovalleys. Excellent exposures of all the rocks and structural features in the area result from sparse vegetation in the dry desert climate and from deep erosion along Warm Spring Canyon and its tributaries.

  20. Investigation of the differences between deepening and intensification for 500-hpa cyclones in central and East Mediterranean region during warm season of the year

    Directory of Open Access Journals (Sweden)

    S. Spanos

    2006-01-01

    Full Text Available The maximum deepening rate per cyclone track is determined by the maximum height drop at the center of the cyclone (500-hPa low on the basis of all the 6-h successive steps in its life cycle. The geopotential height gradient is calculated over the entire low area and the calculation continued with the variation of the gradient in the successive steps. The maximum intensification rate per cyclone is then determined as the maximum increase of the gradient in the life cycle. Maximum deepening rate for the 500-hPa cyclones in the area does not exceed, on average, 12 gpm/6 h. Maximum intensification which is 1.4 gpm/100 Km*6 h on average, occurs in the early stages of the cyclone's life cycle. This on the average happens approximately 9 h after the first time the low is detected. At the gulf of Genoa and the Adriatic Sea, cyclones usually show the maximum intensification after the maximum deepening. At Turkey's cyclogenesis area, however, this order is reversed. The spatial distributions of maximum intensification in the three sub-periods, indicate that it mainly occurs over Seas during late warm periods and over land during early and middle warm periods. Such a behavior underlines the role of low-level instability in cyclone development.

  1. Sudden Stratospheric Warming Compendium

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Sudden Stratospheric Warming Compendium (SSWC) data set documents the stratospheric, tropospheric, and surface climate impacts of sudden stratospheric warmings. This...

  2. A consistent structure of phytoplankton communities across the warm-cold regions of the water mass on a meridional transect in the East/Japan Sea

    Science.gov (United States)

    Kwak, Jung Hyun; Han, Eunah; Lee, Sang Heon; Park, Hyun Je; Kim, Kyung-Ryul; Kang, Chang-Keun

    2017-09-01

    Three cruises were undertaken along a meridional transect in the East/Japan Sea (EJS) in spring (May 2007), summer (July 2009), and fall (October 2012) to determine the geographic variations in phytoplankton biomass and community composition. This study revealed a gradient of surface temperature and a fluctuation of hydrographic conditions along the transect. Although a subpolar front (SPF) formed between the warm- and cold-water masses (37-40°N), no significant differences in phytoplankton biomass and community composition were detected between the southern and northern parts of the EJS. These results disprove our initial hypothesis that different water masses may contain differently structured phytoplankton communities. In the present study, isothermal layers (≤ 12 °C) fluctuated over a depth of 50 m in both warm- and cold-water masses, depending on the SPF. In contrast, the nitracline (i.e. 2.5 μM nitrate isopleth) depth was recorded within a limited range of 20-40 m in spring, 30-50 m in summer, and 40-60 m in fall. The chlorophyll a concentrations at the subsurface chlorophyll maxima (SCM) were significantly higher in spring and summer (356 ± 233 and 270 ± 182 ng L-1, respectively) than in fall (117 ± 89 ng L-1). The relative contributions of individual phytoplankton groups to the depth-integrated chlorophyll a concentration conformed to the composition of the phytoplankton community in the SCM layer, showing a dominance of diatoms (58 ± 19% in spring, 48 ± 11% in summer, and 30 ± 20% in fall). Canonical correspondence analysis revealed that the geographic structures of phytoplankton communities were strongly associated with the vertical structures of water temperature and nutrient concentration in the water column rather than with horizontal gradients of hydrographic conditions. Finally, our findings suggest that water column stability and light-nutrient availability in the euphotic zone play a key role in determining geographical consistency of

  3. Study on the impact of sudden stratosphere warming in the upper mesosphere-lower thermosphere regions using satellite and HF radar measurements [Conference paper

    CSIR Research Space (South Africa)

    Mbatha, N

    2009-07-01

    Full Text Available Neutral atmosphere (including the MLT) and ionosphere are linked by energy and momentum transfer. Thus, this whole region forms a coupled system in which influences that originates at one height or in one region can have profound influence elsewhere...

  4. Warming shifts 'worming': effects of experimental warming on invasive earthworms in northern North America.

    Science.gov (United States)

    Eisenhauer, Nico; Stefanski, Artur; Fisichelli, Nicholas A; Rice, Karen; Rich, Roy; Reich, Peter B

    2014-11-03

    Climate change causes species range shifts and potentially alters biological invasions. The invasion of European earthworm species across northern North America has severe impacts on native ecosystems. Given the long and cold winters in that region that to date supposedly have slowed earthworm invasion, future warming is hypothesized to accelerate earthworm invasions into yet non-invaded regions. Alternatively, warming-induced reductions in soil water content (SWC) can also decrease earthworm performance. We tested these hypotheses in a field warming experiment at two sites in Minnesota, USA by sampling earthworms in closed and open canopy in three temperature treatments in 2010 and 2012. Structural equation modeling revealed that detrimental warming effects on earthworm densities and biomass could indeed be partly explained by warming-induced reductions in SWC. The direction of warming effects depended on the current average SWC: warming had neutral to positive effects at high SWC, whereas the opposite was true at low SWC. Our results suggest that warming limits the invasion of earthworms in northern North America by causing less favorable soil abiotic conditions, unless warming is accompanied by increased and temporally even distributions of rainfall sufficient to offset greater water losses from higher evapotranspiration.

  5. Warming shifts `worming': effects of experimental warming on invasive earthworms in northern North America

    Science.gov (United States)

    Eisenhauer, Nico; Stefanski, Artur; Fisichelli, Nicholas A.; Rice, Karen; Rich, Roy; Reich, Peter B.

    2014-11-01

    Climate change causes species range shifts and potentially alters biological invasions. The invasion of European earthworm species across northern North America has severe impacts on native ecosystems. Given the long and cold winters in that region that to date supposedly have slowed earthworm invasion, future warming is hypothesized to accelerate earthworm invasions into yet non-invaded regions. Alternatively, warming-induced reductions in soil water content (SWC) can also decrease earthworm performance. We tested these hypotheses in a field warming experiment at two sites in Minnesota, USA by sampling earthworms in closed and open canopy in three temperature treatments in 2010 and 2012. Structural equation modeling revealed that detrimental warming effects on earthworm densities and biomass could indeed be partly explained by warming-induced reductions in SWC. The direction of warming effects depended on the current average SWC: warming had neutral to positive effects at high SWC, whereas the opposite was true at low SWC. Our results suggest that warming limits the invasion of earthworms in northern North America by causing less favorable soil abiotic conditions, unless warming is accompanied by increased and temporally even distributions of rainfall sufficient to offset greater water losses from higher evapotranspiration.

  6. Global warming - some perspectives

    OpenAIRE

    Erlykin, Anatoly D.; Wolfendale, Arnold W.; Hanna, Edward

    2012-01-01

    Here the authors critically review the IPCC’s claim that global warming is “very likely” caused by human activity: such a description underestimates the likelihood of the warming being due to this mechanism. Next examined are known alternative “natural” mechanisms which could give rise to the warming if, despite many claims, the man-made explanation was false because of compensation effects (greenhouse gases versus aerosol effects). Also, a number of difficulties, as yet unresolved, ...

  7. Regional stratospheric warmings in the Pacific-Western Canada (PWC sector during winter 2004/2005: implications for temperatures, winds, chemical constituents and the characterization of the Polar vortex

    Directory of Open Access Journals (Sweden)

    A. H. Manson

    2008-11-01

    Full Text Available The vortex during winter 2004/2005 was interesting for several reasons. It has been described as "cold" stratospherically, with relatively strong westerly winds. Losses of ozone until the final warming in March were considerable, and comparable to the cold 1999–2000 winter. There were also modest warming events, indicated by peaks in 10 hPa zonal mean temperatures at high latitudes, near 1 January and 1 February. Events associated with a significant regional stratospheric warming in the Pacific-Western Canada (PWC sector then began and peaked toward the end of February, providing strong longitudinal variations in dynamical characteristics (Chshyolkova et al., 2007; hereafter C07. The associated disturbed vortex of 25 February was displaced from the pole and either elongated (upper or split into two cyclonic centres (lower. Observations from Microwave Limb Sounder (MLS on Aura are used here to study the thermal characteristics of the stratosphere in the Canadian-US (253° E and Scandinavian-Europe (16° E sectors. Undisturbed high latitude stratopause (55 km zonal mean temperatures during the mid-winter (December–February reached 270 K, warmer than empirical-models such as CIRA-86, suggesting that seasonal polar warming due to dynamical influences affects the high altitude stratosphere as well as the mesosphere. There were also significant stratopause differences between Scandinavia and Canada during the warming events of 1 January and 1 February, with higher temperatures near 275 K at 16° E. During the 25 February "PWC" event a warming occurred at low and middle stratospheric heights (10–30 km: 220 K at 253° E and the stratopause cooled; while over Scandinavia-Europe the stratosphere below ~30 km was relatively cold at 195 K and the stratopause became even warmer (>295 K and lower (~45 km. The zonal winds followed the associated temperature gradients so that the vertical and latitudinal gradients of the winds differed strongly between

  8. Regional stratospheric warmings in the Pacific-Western Canada (PWC sector during winter 2004/2005: implications for temperatures, winds, chemical constituents and the characterization of the Polar vortex

    Directory of Open Access Journals (Sweden)

    A. H. Manson

    2008-11-01

    Full Text Available The vortex during winter 2004/2005 was interesting for several reasons. It has been described as "cold" stratospherically, with relatively strong westerly winds. Losses of ozone until the final warming in March were considerable, and comparable to the cold 1999–2000 winter. There were also modest warming events, indicated by peaks in 10 hPa zonal mean temperatures at high latitudes, near 1 January and 1 February. Events associated with a significant regional stratospheric warming in the Pacific-Western Canada (PWC sector then began and peaked toward the end of February, providing strong longitudinal variations in dynamical characteristics (Chshyolkova et al., 2007; hereafter C07. The associated disturbed vortex of 25 February was displaced from the pole and either elongated (upper or split into two cyclonic centres (lower.

    Observations from Microwave Limb Sounder (MLS on Aura are used here to study the thermal characteristics of the stratosphere in the Canadian-US (253° E and Scandinavian-Europe (16° E sectors. Undisturbed high latitude stratopause (55 km zonal mean temperatures during the mid-winter (December–February reached 270 K, warmer than empirical-models such as CIRA-86, suggesting that seasonal polar warming due to dynamical influences affects the high altitude stratosphere as well as the mesosphere. There were also significant stratopause differences between Scandinavia and Canada during the warming events of 1 January and 1 February, with higher temperatures near 275 K at 16° E. During the 25 February "PWC" event a warming occurred at low and middle stratospheric heights (10–30 km: 220 K at 253° E and the stratopause cooled; while over Scandinavia-Europe the stratosphere below ~30 km was relatively cold at 195 K and the stratopause became even warmer (>295 K and lower (~45 km. The zonal winds followed the associated temperature gradients so that the vertical and latitudinal gradients of the winds differed strongly

  9. Climatic warming above the Arctic Circle: are there trends in timing and length of the thermal growing season in Murmansk Region (Russia) between 1951 and 2012?

    Science.gov (United States)

    Blinova, Ilona; Chmielewski, Frank-Michael

    2015-06-01

    Anomalies in the timing of the thermal growing season have become obvious in the NE part of Fennoscandia since 2000. They are in accordance with climatic changes reported for Europe and Fennoscandia. The actual length of the growing season reached 120 days on average, onset on 30 May and ending on 27 September (1981-2010). Shifts in the timing of the growing season and its mean prolongation by 18.5 days/62a are demonstrated for Murmansk Region (1951-2012). In this period, the onset of the growing season advanced by 7.1 days/62a, while the end was extended by 11.4 days/62a. The delay in the end of the growing season is similar to the entire Fennoscandian pattern but it has not been detected in the rest of Europe. The regional pattern of climatic regimes in Murmansk Region remained stable in comparison with earlier climatic maps (1971). However, the actual shifts in the timing of the growing season were more pronounced in colder (oceanic and mountainous) parts. Recent climatic trends could influence the retreat of the tundra zone and changes in the forest line. Losses of tundra biodiversity and enrichment of the northern taiga by southern species could be expected from present climatic trends.

  10. Global Warming: A Myth?

    Indian Academy of Sciences (India)

    tropospheric temperature through a 'positive feedback'. And again, as the troposphere warms up, its water holding capacity also increases, amplifying chances of further warming. But satellite data indicate that free troposphere is largely cut-off from the surface and evaporated water may not moisten the free troposphere ...

  11. Warming shifts ‘worming’: effects of experimental warming on invasive earthworms in northern North America

    OpenAIRE

    Nico Eisenhauer; Artur Stefanski; Fisichelli, Nicholas A.; Karen Rice; Roy Rich; Reich, Peter B.

    2014-01-01

    Climate change causes species range shifts and potentially alters biological invasions. The invasion of European earthworm species across northern North America has severe impacts on native ecosystems. Given the long and cold winters in that region that to date supposedly have slowed earthworm invasion, future warming is hypothesized to accelerate earthworm invasions into yet non-invaded regions. Alternatively, warming-induced reductions in soil water content (SWC) can also decrease earthworm...

  12. [Effects of climate warming on oil flax growth and water use efficiency in semi-arid region of Loess Plateau, Northwest China].

    Science.gov (United States)

    Yao, Yu-bi; Wang, Run-yuan; Yang, Jin-hu; Xiao, Guo-ju; Zhang, Xiu-yun; Yue, Ping

    2011-10-01

    By using the site-specific observation data of oil flax growth and related meteorological records in semi-arid region of Loess Plateau, this paper studied the effects of climate change on the oil flax growth, and analyzed the relationships between the oil flax water use efficiency and meteorological condition. In this region, the annual precipitation displayed a decreasing trend, and its climatic trend rate was -15.80 mm (10 a)(-1), with an annual periodic change of 3 a and 6 a, whereas the annual air temperature had an increasing trend, and its climatic trend rate was 0.36 degrees C (10 a)(-1). In crop growth period, the aridity index displayed a marked increasing trend, its climatic trend rate was 0.12 (10 a)(-1), and the aridity tendency was more obvious from the beginning of 1990s to the year 2009. From sowing to maturation, oil flax needed 120-150 d, 1700-2100 degrees C d of > or = 0 degrees C accumulated temperature, 200-250 mm precipitation, and 1000-1300 h sunshine hours. The main meteorological factors affecting the oil flax growth in the region were air temperature and precipitation. The increase of air temperature shortened the prophase vegetative growth stage, whereas the increase of air temperature and the decrease of precipitation extended the reproductive growth stage, causing the extension of the whole growth period of the oil flax. The air temperature in the oil flax whole growth period except at seeding stage and maturing stage had negative effect on the yield formation, being more obvious at squaring stage, whereas the precipitation in the whole growth period except at blooming stage had positive effect on the yield formation, being more obvious at seeding stage. The water use efficiency of the oil flax was significantly positively correlated with the air temperature and sunshine hours at seeding stage as well as the aridity index from squaring stage to maturing stage, and negatively correlated with the precipitation from squaring stage to

  13. The discoveries of WASP-91b, WASP-105b and WASP-107b: Two warm Jupiters and a planet in the transition region between ice giants and gas giants

    Science.gov (United States)

    Anderson, D. R.; Collier Cameron, A.; Delrez, L.; Doyle, A. P.; Gillon, M.; Hellier, C.; Jehin, E.; Lendl, M.; Maxted, P. F. L.; Madhusudhan, N.; Pepe, F.; Pollacco, D.; Queloz, D.; Ségransan, D.; Smalley, B.; Smith, A. M. S.; Triaud, A. H. M. J.; Turner, O. D.; Udry, S.; West, R. G.

    2017-08-01

    We report the discoveries of three transiting exoplanets. WASP-91b is a warm Jupiter (1.34 MJup, 1.03 RJup) in a 2.8-day orbit around a metal-rich K3 star. WASP-105b is a warm Jupiter (1.8 MJup, 0.96 RJup) in a 7.9-day orbit around a metal-rich K2 star. WASP-107b is a warm super-Neptune/sub-Saturn (0.12 MJup, 0.94 RJup) in a 5.7-day orbit around a solar-metallicity K6 star. Considering that giant planets seem to be more common around stars of higher metallicity and stars of higher mass, it is notable that the hosts are all metal-rich, late-type stars. With orbital separations that place both WASP-105b and WASP-107b in the weak-tide regime, measurements of the alignment between the planets' orbital axes and their stars' spin axes may help us to understand the inward migration of short-period, giant planets. The mass of WASP-107b (2.2 MNep, 0.40 MSat) places it in the transition region between the ice giants and gas giants of the Solar System. Its radius of 0.94 RJup suggests that it is a low-mass gas giant with a H/He-dominated composition. The planet thus sets a lower limit of 2.2 MNep on the planetary mass above which large gaseous envelopes can be accreted and retained by proto-planets on their way to becoming gas giants. We may discover whether WASP-107b more closely resembles an ice giant or a gas giant by measuring its atmospheric metallicity via transmission spectroscopy, for which WASP-107b is a very good target. Based on observations made with: the WASP-South photometric survey instrument, the 0.6-m TRAPPIST robotic imager, and the EulerCam camera and the CORALIE spectrograph mounted on the 1.2-m Euler-Swiss telescope.The photometric time-series and radial-velocity data used in this work are only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (http://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/604/A110

  14. Global Warming Threatens National Interests in the Arctic

    Science.gov (United States)

    2009-03-26

    Global warming has impacted the Arctic Ocean by significantly reducing the extent of the summer ice cover allowing greater access to the region...increased operations in the Arctic region, and DoD must continue to research and develop new and alternate energy sources for its forces. Global warming is

  15. Recent Warming, Rather than Industrial Emissions of Bioavailable Nutrients, Is the Dominant Driver of Lake Primary Production Shifts across the Athabasca Oil Sands Region.

    Science.gov (United States)

    Summers, Jamie C; Kurek, Joshua; Kirk, Jane L; Muir, Derek C G; Wang, Xiaowa; Wiklund, Johan A; Cooke, Colin A; Evans, Marlene S; Smol, John P

    2016-01-01

    Freshwaters in the Athabasca Oil Sands Region (AOSR) are vulnerable to the atmospheric emissions and land disturbances caused by the local oil sands industry; however, they are also affected by climate change. Recent observations of increases in aquatic primary production near the main development area have prompted questions about the principal drivers of these limnological changes. Is the enhanced primary production due to deposition of nutrients (nitrogen and phosphorus) from local industry or from recent climatic changes? Here, we use downcore, spectrally-inferred chlorophyll-a (VRS-chla) profiles (including diagenetic products) from 23 limnologically-diverse lakes with undisturbed catchments to characterize the pattern of primary production increases in the AOSR. Our aim is to better understand the relative roles of the local oil sands industry versus climate change in driving aquatic primary production trends. Nutrient deposition maps, generated using geostatistical interpolations of spring-time snowpack measurements from a grid pattern across the AOSR, demonstrate patterns of elevated total phosphorus, total nitrogen, and bioavailable nitrogen deposition around the main area of industrial activity. However, this pattern is not observed for bioavailable phosphorus. Our paleolimnological findings demonstrate consistently greater VRS-chla concentrations compared to pre-oil sands development levels, regardless of morphological and limnological characteristics, landscape position, bioavailable nutrient deposition, and dibenzothiophene (DBT)-inferred industrial impacts. Furthermore, breakpoint analyses on VRS-chla concentrations across a gradient of DBT-inferred industrial impact show limited evidence of a contemporaneous change among lakes. Despite the contribution of bioavailable nitrogen to the landscape from industrial activities, we find no consistency in the spatial pattern and timing of VRS-chla shifts with an industrial fertilizing signal. Instead

  16. Recent Warming, Rather than Industrial Emissions of Bioavailable Nutrients, Is the Dominant Driver of Lake Primary Production Shifts across the Athabasca Oil Sands Region.

    Directory of Open Access Journals (Sweden)

    Jamie C Summers

    Full Text Available Freshwaters in the Athabasca Oil Sands Region (AOSR are vulnerable to the atmospheric emissions and land disturbances caused by the local oil sands industry; however, they are also affected by climate change. Recent observations of increases in aquatic primary production near the main development area have prompted questions about the principal drivers of these limnological changes. Is the enhanced primary production due to deposition of nutrients (nitrogen and phosphorus from local industry or from recent climatic changes? Here, we use downcore, spectrally-inferred chlorophyll-a (VRS-chla profiles (including diagenetic products from 23 limnologically-diverse lakes with undisturbed catchments to characterize the pattern of primary production increases in the AOSR. Our aim is to better understand the relative roles of the local oil sands industry versus climate change in driving aquatic primary production trends. Nutrient deposition maps, generated using geostatistical interpolations of spring-time snowpack measurements from a grid pattern across the AOSR, demonstrate patterns of elevated total phosphorus, total nitrogen, and bioavailable nitrogen deposition around the main area of industrial activity. However, this pattern is not observed for bioavailable phosphorus. Our paleolimnological findings demonstrate consistently greater VRS-chla concentrations compared to pre-oil sands development levels, regardless of morphological and limnological characteristics, landscape position, bioavailable nutrient deposition, and dibenzothiophene (DBT-inferred industrial impacts. Furthermore, breakpoint analyses on VRS-chla concentrations across a gradient of DBT-inferred industrial impact show limited evidence of a contemporaneous change among lakes. Despite the contribution of bioavailable nitrogen to the landscape from industrial activities, we find no consistency in the spatial pattern and timing of VRS-chla shifts with an industrial fertilizing signal

  17. Global Warming: A Myth?

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 6; Issue 7. Global Warming: A Myth? - Credibility of Climate Scenarios Predicted by Systems Simulations. Deepanjan Majumdar. General Article Volume 6 Issue 7 July 2001 pp 13-21 ...

  18. Global Warming: A Myth?

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 6; Issue 6. Global Warming: A Myth? - Anomalous Temperature Trends Recorded from Satellites and Radiosondes. Deepanjan Majumdar. General Article Volume 6 Issue 6 June 2001 pp 43-52 ...

  19. Global Warming on Trial

    National Research Council Canada - National Science Library

    Broecker, Wallace S

    1992-01-01

      The issue of global warming is fraught with controversy, as it pits groups who are concerned with the short-term well-being of society against those who fear for the long-term future of the planet...

  20. Warm and Cool Dinosaurs.

    Science.gov (United States)

    Mannlein, Sally

    2001-01-01

    Presents an art activity in which first grade students draw dinosaurs in order to learn about the concept of warm and cool colors. Explains how the activity also helped the students learn about the concept of distance when drawing. (CMK)

  1. Media Pembelajaran Global Warming

    OpenAIRE

    Tham, Fikri Jufri; Liliana, Liliana; Purba, Kristo Radion

    2016-01-01

    Computer based learning media is one of the media has an important role in learning. Learning media will be attractive when packaged through interactive media , such as interactive media created in paper manufacture " instructional media global warming" . The advantage gained is that it can increase knowledge, generally educate people to be more concerned about the environment , and also can be a means of entertainment. This application is focused to learn about global warming and packaged in...

  2. Global warming yearbook: 1998

    Energy Technology Data Exchange (ETDEWEB)

    Arris, L. [ed.

    1999-02-01

    The report brings together a year`s worth of global warming stories - over 280 in all - in one convenient volume. It provides a one-stop report on the scientific, political and industrial implications of global warming. The report includes: detailed coverage of negotiations on the Kyoto Protocol; scientific findings on carbon sources and sinks, coral bleaching, Antarctic ice shelves, plankton, wildlife and tree growth; new developments on fuel economy, wind power, fuel cells, cogeneration, energy labelling and emissions trading.

  3. Impact of a warm core eddy on near-surface wind at Brazil-Malvinas Confluence region in high resolution simulations

    Science.gov (United States)

    Hackerott, J. A.; Mesquita, M. D. S.; Camargo, R. D.; Pezzi, L. P.

    2014-12-01

    Several studies show that near surface winds acquire anticyclonic (cyclonic) vorticity and accelerate (decelerate) when flow in the same direction as positive (negative) orientation of the Sea Surface Temperature (SST) gradient. Many of them were made over different oceanic thermal fronts in the world analyzing contrasts in SST gradients. However, still remains much uncertainty about how strong is this wind modulation, particularly on areas in need of studies and in-situ data, such as the Brazil-Malvinas Confluence Region (BMC) where intense SST gradients are found. This study brings results of the Weather Research and Forecasting (WRF) model simulations, configured with nested grids, where it is compared the influence of distinct synoptic patterns observed at BMC where three different SST patterns are imposed to WRF. These patterns are: (1) with a typical smoothed SST field, named as Control; (2) Small Eddy, which is the same as Control but adding an eddy of 1° radius and a +2°C amplitude; and (3) Intense Eddy, which is also the same as Control, but where an eddy of 1° radius and +4°C amplitude is added. The artificial imposed eddy is analogous to the SST patterns observed at BMC, with different intensities. The simulations were integrated for 76 hours using initial and lateral boundary conditions from the Global Forecast System (GFS) model with 0.5° resolution. The results showed that the wind at 10m height is influenced by the diurnal cycle of turbulence in the Marine Atmospheric Boundary Layer (MABL) modified by variations in SST. The wind magnitude changes up to 1m.s-1 over a 4/50°C.km-1 SST gradient and 0.6m.s-1 over a 2/50°C.km-1 SST gradient. This effect generates meso-scale disturbances that propagate to larger scales leading to disturbances in remote areas. Thus, the preliminary analyses are suggesting that there is an interaction between the meso and synoptic scale playing a role. Mechanisms such this one might not be captured by atmospheric

  4. Assessment of the Impact of Metropolitan-Scale Urban Planning Scenarios on the Moist Thermal Environment under Global Warming: A Study of the Tokyo Metropolitan Area Using Regional Climate Modeling

    Directory of Open Access Journals (Sweden)

    Asuka Suzuki-Parker

    2015-01-01

    Full Text Available Using a high-resolution regional climate model coupled with urban canopy model, the present study provides the first attempt in quantifying the impact of metropolitan-scale urban planning scenarios on moist thermal environment under global warming. Tokyo metropolitan area is selected as a test case. Three urban planning scenarios are considered: status quo, dispersed city, and compact city. Their impact on the moist thermal environment is assessed using wet-bulb globe temperature (WBGT. Future projections for the 2070s show a 2–4°C increase in daytime mean WBGT relative to the current climate. The urban scenario impacts are shown to be small, with a −0.4 to +0.4°C range. Relative changes in temperature and humidity as the result of a given urban scenario are shown to be critical in determining the sign of the WBGT changes; however, such changes are not necessarily determined by local changes in urban land surface parameters. These findings indicate that urban land surface changes may improve or worsen the local moist thermal environment and that metropolitan-scale urban planning is inefficient in mitigating heat-related health risks for mature cities like Tokyo.

  5. Application of LC-MS and tristimulus colorimetry to assess the ageing aptitude of Syrah wine in the Condado de Huelva D.O. (Spain), a typical warm climate region.

    Science.gov (United States)

    Gordillo, B; Rodríguez-Pulido, F J; Mateus, N; Escudero-Gilete, M L; González-Miret, M L; Heredia, F J; de Freitas, V

    2012-06-30

    The study of the evolutions of different wine pigment families, copigmentation/polymerisation processes and colour characteristics during the first year of ageing in oak barrel has allowed the assessment of the ageing aptitude of Syrah wines from "Condado de Huelva D.O.", a warm climate region. A total of 32 anthocyanic pigments were identified, including 14 major compounds from grape and 18 minor derivatives formed during the vinification. The anthocyanin profile changed towards more chemical complexity, being vitisin-like pyranoanthocyanins the predominant minor pigments during the first month of ageing. As wine became older, a progressive increase on the content of 4-vinylcatechin, 4-vinylphenol and 4-vinylcatechol compounds took place. Results showed that copigmentation occurred during the whole process of ageing inducing visual perceptible colour effects. Simultaneously to the copigmentation decrease, the degree of polymerisation increased during ageing, being maximum at 9 months old wines (77%). The colour of wines evolved progressively in a positive way from 3 to 9 months of ageing, becoming darker and with more vivid colour. However, from 9 to 12 months of ageing, the chemical structure of wines was negatively affected resulting in lighter, with more red-orange hues and less vivid colours. The inclusion of the chemical and colorimetric information on the PCA model allows us to reach very good discriminations among the Syrah wines with different wood contact period. Copyright © 2012 Elsevier B.V. All rights reserved.

  6. Stratospheric warming in Southern Hemisphere high latitudes since 1979

    Directory of Open Access Journals (Sweden)

    Y. Hu

    2009-07-01

    Full Text Available In the present study, we show evidence of significant stratospheric warming over Southern Hemisphere high latitudes and large portions of the Antarctic polar region in winter and spring seasons, with a maximum warming of 7–8°C in September and October, using satellite Microwave Sounding Unit observations for 1979–2006. It is found that this warming is associated with increasing wave activity from the troposphere into the stratosphere, suggesting that the warming is caused by enhanced wave-driven adiabatic heating. We show that the stratospheric warming in Southern Hemisphere high latitudes has close correlations with sea surface temperature (SST increases, and that general circulation model simulations forced with observed time-varying SSTs reproduce similar warming trend patterns in the Antarctic stratosphere. The simulated stratospheric warming is closely related to increasing wave activity in the Southern Hemisphere. These findings suggest that the stratospheric warming is likely induced by SST warming. As SST warming continues as a consequence of greenhouse gas increases due to anthropogenic activity, the stratospheric warming would also continue, which has important implications to the recovery of the Antarctic ozone hole.

  7. Warm Dense Matter: An Overview

    Energy Technology Data Exchange (ETDEWEB)

    Kalantar, D H; Lee, R W; Molitoris, J D

    2004-04-21

    This document provides a summary of the ''LLNL Workshop on Extreme States of Materials: Warm Dense Matter to NIF'' which was held on 20, 21, and 22 February 2002 at the Wente Conference Center in Livermore, CA. The warm dense matter regime, the transitional phase space region between cold material and hot plasma, is presently poorly understood. The drive to understand the nature of matter in this regime is sparking scientific activity worldwide. In addition to pure scientific interest, finite temperature dense matter occurs in the regimes of interest to the SSMP (Stockpile Stewardship Materials Program). So that obtaining a better understanding of WDM is important to performing effective experiments at, e.g., NIF, a primary mission of LLNL. At this workshop we examined current experimental and theoretical work performed at, and in conjunction with, LLNL to focus future activities and define our role in this rapidly emerging research area. On the experimental front LLNL plays a leading role in three of the five relevant areas and has the opportunity to become a major player in the other two. Discussion at the workshop indicated that the path forward for the experimental efforts at LLNL were two fold: First, we are doing reasonable baseline work at SPLs, HE, and High Energy Lasers with more effort encouraged. Second, we need to plan effectively for the next evolution in large scale facilities, both laser (NIF) and Light/Beam sources (LCLS/TESLA and GSI) Theoretically, LLNL has major research advantages in areas as diverse as the thermochemical approach to warm dense matter equations of state to first principles molecular dynamics simulations. However, it was clear that there is much work to be done theoretically to understand warm dense matter. Further, there is a need for a close collaboration between the generation of verifiable experimental data that can provide benchmarks of both the experimental techniques and the theoretical capabilities

  8. Greenhouse Warming Research

    DEFF Research Database (Denmark)

    Sørensen, Bent Erik

    2016-01-01

    The changing greenhouse effect caused by natural and anthropogenic causes is explained and efforts to model the behavior of the near-surface constituents of the Earth's land, ocean and atmosphere are discussed. Emissions of various substances and other aspects of human activity influence...... the greenhouse warming, and the impacts of the warming may again impact the wellbeing of human societies. Thus physical modeling of the near-surface ocean-soil-atmosphere system cannot be carried out without an idea of the development of human activities, which is done by scenario analysis. The interactive...

  9. The effects of different warm stratification periods on the seed ...

    African Journals Online (AJOL)

    In this study, the effects of different warm stratification periods on the seed germination of some Rosa species such as Rosa heckellana ssp. vanheurckiana, Rosa canina, Rosa pulverelanta and Rosa dumalis naturally grown in the Van region were investigated. In 2007, seeds of these species were kept at 25°C warm ...

  10. Impact of global warming on cyclonic disturbances over south Asian ...

    Indian Academy of Sciences (India)

    Keywords. Climate change; regional climate model; global warming; cyclonic disturbances; projections. ... The analysis suggests that the frequency of cyclonic disturbances forming over north Indian Ocean is likely to reduce by 9% towards the end of the present century in response to the global warming. However, the ...

  11. Climate change lessons from a warm world

    Science.gov (United States)

    Dowsett, Harry J.

    2010-01-01

    In the early 1970’s to early 1980’s Soviet climatologists were making comparisons to past intervals of warmth in the geologic record and suggesting that these intervals could be possible analogs for 21st century “greenhouse” conditions. Some saw regional warming as a benefit to the Soviet Union and made comments along the lines of “Set fire to the coal mines!” These sentiments were alarming to some, and the United States Geological Survey (USGS) leadership thought they could provide a more quantitative analysis of the data the Soviets were using for the most recent of these warm intervals, the Early Pliocene.

  12. Synoptic Conditions Generating Heat Waves and Warm Spells in Romania

    Directory of Open Access Journals (Sweden)

    Lucian Sfîcă

    2017-03-01

    Full Text Available Heat waves and warm spells are extreme meteorological events that generate a significant number of casualties in temperate regions, as well as outside of temperate regions. For the purpose of this paper, heat waves and warm spells were identified based on daily maximum temperatures recorded at 27 weather stations located in Romania over a 55-year period (1961–2015. The intensity threshold was the 90th percentile, and the length of an event was of minimum three consecutive days. We analyzed 111 heat wave and warm spell events totaling 423 days. The classification of synoptic conditions was based on daily reanalysis at three geopotential levels and on the online version of a backward trajectories model. The main findings are that there are two major types of genetic conditions. These were identified as: (i radiative heat waves and warm spells (type A generated by warming the air mass due to high amounts of radiation which was found dominant in warm season; and (ii advective heat waves and warm spells (type B generated mainly by warm air mass advection which prevails in winter and transition seasons. These major types consist of two and three sub-types, respectively. The results could become a useful tool for weather forecasters in order to better predict the occurrence of heat waves and warm spells.

  13. Southern Hemisphere and Deep-Sea Warming Led Deglacial Atmospheric CO2 Rise and Tropical Warming

    Science.gov (United States)

    Stott, Lowell; Timmermann, Axel; Thunell, Robert

    2007-10-01

    Establishing what caused Earth’s largest climatic changes in the past requires a precise knowledge of both the forcing and the regional responses. We determined the chronology of high- and low-latitude climate change at the last glacial termination by radiocarbon dating benthic and planktonic foraminiferal stable isotope and magnesium/calcium records from a marine core collected in the western tropical Pacific. Deep-sea temperatures warmed by ~2°C between 19 and 17 thousand years before the present (ky B.P.), leading the rise in atmospheric CO2 and tropical surface-ocean warming by ~1000 years. The cause of this deglacial deep-water warming does not lie within the tropics, nor can its early onset between 19 and 17 ky B.P. be attributed to CO2 forcing. Increasing austral-spring insolation combined with sea-ice albedo feedbacks appear to be the key factors responsible for this warming.

  14. Warm-temperate deciduous forests around the Northern Hemisphere

    National Research Council Canada - National Science Library

    Box E.O; Fujiwara K

    2015-01-01

    Warm-temperate deciduous forests are "southern", mainly oak-dominated deciduous forests, as found over the warmer southern parts of the temperate deciduous forest regions of East Asia, Europe and eastern North America...

  15. EFFECTS OF GLOBAL WARMING

    OpenAIRE

    Dr. Basanti Jain

    2017-01-01

    The abnormal increase in the concentration of the greenhouse gases is resulting in higher temperatures. We call this effect is global warming. The average temperature around the world has increased about 1'c over 140 years, 75% of this has risen just over the past 30 years. The solar radiation, as it reaches the earth, produces "greenhouse effect" in the atmosphere. The thick atmospheric layers over the earth behaves as a glass surface, as it permits short wave radiations from coming in, but ...

  16. Comparison of Fluoride Content in Drinking Water and Prevalence of Dental Fluorosis in 6 - 12-Year-Old Students in Mariwan (a Cold Region and Behbahan (a Warm Region during the 2013 - 2014 Educational Year

    Directory of Open Access Journals (Sweden)

    Rezvan Rafatjou

    2016-07-01

    Full Text Available Background Fluoride plays an important role in preventing dental caries. Low fluoride concentrations cannot prevent dental caries, but ingestion of very high concentrations of fluoride during enamel development and maturation could lead to fluorosis. Fluoridation of drinking water is the most effective and inexpensive method for preventing caries. The mandated concentration of fluoride incorporated into drinking water should consider the mean temperature of each region. Objectives The aim of the present study was to evaluate the prevalence of fluorosis in children aged 6 - 12 in Mariwan and Behbahan and determine the fluoride content of drinking water in these two towns. Materials and Methods In the present descriptive and cross-sectional study, 13 water samples were taken from homes in Behbahan, 1 sample from the town’s water reservoir, 10 samples from homes in Mariwan (5 samples for each reservoir and 1 sample each from the town’s 2 reservoirs. The 26 samples (23 from homes and 3 from reservoirs were taken in polyethylene containers. The SPANDS colorimetric technique was used to determine fluoride content. Homes that used home-based water purification systems were excluded from the study. In addition, 128 students (62 girls and 66 boys in Behbahan and 90 students in Mariwan were randomly selected. Dean’s index was used to determine dental fluorosis. The mean yearly temperatures of the two towns were obtained from the metrological bureaus of the two towns. Results The means fluoride content of water in Behbahan’s reservoir and Mariwan’s reservoirs 1 and 2 were 0.7, 0.24 and 0.036 ppm, respectively. The mean fluoride content of Behbahan’s home waterlines and in the relevant home waterlines of reservoirs 1 and 2 in Mariwan were 0.67, 0.218, and 0.054 ppm, respectively. There were no significant differences between the relevant reservoirs. The prevalence of fluorosis in Behbahan was as follows: 84.4% healthy, 10.9% questionable, 1

  17. Irrigation enhances local warming with greater nocturnal warming effects than daytime cooling effects

    Science.gov (United States)

    Chen, Xing; Jeong, Su-Jong

    2018-02-01

    To meet the growing demand for food, land is being managed to be more productive using agricultural intensification practices, such as the use of irrigation. Understanding the specific environmental impacts of irrigation is a critical part of using it as a sustainable way to provide food security. However, our knowledge of irrigation effects on climate is still limited to daytime effects. This is a critical issue to define the effects of irrigation on warming related to greenhouse gases (GHGs). This study shows that irrigation led to an increasing temperature (0.002 °C year‑1) by enhancing nighttime warming (0.009 °C year‑1) more than daytime cooling (‑0.007 °C year‑1) during the dry season from 1961–2004 over the North China Plain (NCP), which is one of largest irrigated areas in the world. By implementing irrigation processes in regional climate model simulations, the consistent warming effect of irrigation on nighttime temperatures over the NCP was shown to match observations. The intensive nocturnal warming is attributed to energy storage in the wetter soil during the daytime, which contributed to the nighttime surface warming. Our results suggest that irrigation could locally amplify the warming related to GHGs, and this effect should be taken into account in future climate change projections.

  18. The recent warming trend in North Greenland

    Science.gov (United States)

    Orsi, Anais J.; Kawamura, Kenji; Masson-Delmotte, Valerie; Fettweis, Xavier; Box, Jason E.; Dahl-Jensen, Dorthe; Clow, Gary D.; Landais, Amaelle; Severinghaus, Jeffrey P.

    2017-06-01

    The Arctic is among the fastest warming regions on Earth, but it is also one with limited spatial coverage of multidecadal instrumental surface air temperature measurements. Consequently, atmospheric reanalyses are relatively unconstrained in this region, resulting in a large spread of estimated 30 year recent warming trends, which limits their use to investigate the mechanisms responsible for this trend. Here we present a surface temperature reconstruction over 1982-2011 at NEEM (North Greenland Eemian Ice Drilling Project, 51°W, 77°N), in North Greenland, based on the inversion of borehole temperature and inert gas isotope data. We find that NEEM has warmed by 2.7 ± 0.33°C over the past 30 years, from the long-term 1900-1970 average of -28.55 ± 0.29°C. The warming trend is principally caused by an increase in downward longwave heat flux. Atmospheric reanalyses underestimate this trend by 17%, underlining the need for more in situ observations to validate reanalyses.

  19. Humid heat waves at different warming levels.

    Science.gov (United States)

    Russo, Simone; Sillmann, Jana; Sterl, Andreas

    2017-08-07

    The co-occurrence of consecutive hot and humid days during a heat wave can strongly affect human health. Here, we quantify humid heat wave hazard in the recent past and at different levels of global warming. We find that the magnitude and apparent temperature peak of heat waves, such as the ones observed in Chicago in 1995 and China in 2003, have been strongly amplified by humidity. Climate model projections suggest that the percentage of area where heat wave magnitude and peak are amplified by humidity increases with increasing warming levels. Considering the effect of humidity at 1.5° and 2° global warming, highly populated regions, such as the Eastern US and China, could experience heat waves with magnitude greater than the one in Russia in 2010 (the most severe of the present era). The apparent temperature peak during such humid-heat waves can be greater than 55 °C. According to the US Weather Service, at this temperature humans are very likely to suffer from heat strokes. Humid-heat waves with these conditions were never exceeded in the present climate, but are expected to occur every other year at 4° global warming. This calls for respective adaptation measures in some key regions of the world along with international climate change mitigation efforts.

  20. Global Warming And Meltwater

    Science.gov (United States)

    Bratu, S.

    2012-04-01

    In order to find new approaches and new ideas for my students to appreciate the importance of science in their daily life, I proposed a theme for them to debate. They had to search for global warming information and illustrations in the media, and discuss the articles they found in the classroom. This task inspired them to search for new information about this important and timely theme in science. I informed my students that all the best information about global warming and meltwater they found would be used in a poster that would help us to update the knowledge base of the Physics laboratory. I guided them to choose the most eloquent images and significant information. Searching and working to create this poster, the students arrived to better appreciate the importance of science in their daily life and to critically evaluate scientific information transmitted via the media. In the poster we created, one can find images, photos and diagrams and some interesting information: Global warming refers to the rising average temperature of the Earth's atmosphere and oceans and its projected evolution. In the last 100 years, the Earth's average surface temperature increased by about 0.8 °C with about two thirds of the increase occurring over just the last three decades. Warming of the climate system is unequivocal, and scientists are more than 90% certain most of it is caused by increasing concentrations of greenhouse gases produced by human activities such as deforestation and burning fossil fuel. They indicate that during the 21st century the global surface temperature is likely to rise a further 1.1 to 2.9 °C for the lowest emissions scenario and 2.4 to 6.4 °C for the highest predictions. An increase in global temperature will cause sea levels to rise and will change the amount and pattern of precipitation, and potentially result in expansion of subtropical deserts. Warming is expected to be strongest in the Arctic and would be associated with continuing decrease of

  1. Perturbations in warm inflation

    Energy Technology Data Exchange (ETDEWEB)

    de Oliveira, H. P.; Joras, S. E.

    2001-09-15

    Warm inflation is an interesting possibility to describe the early universe, whose basic feature is the absence, at least in principle, of a preheating or reheating phase. Here we analyze the dynamics of warm inflation generalizing the usual slow-roll parameters that are useful for characterizing the inflationary phase. We study the evolution of entropy and adiabatic perturbations, where the main result is that for a very small amount of dissipation the entropy perturbations can be neglected and the purely adiabatic perturbations will be responsible for the primordial spectrum of inhomogeneities. Taking into account the Cosmic Background Explorer Differential Microwave Radiometer data of the cosmic microwave background anisotropy as well as the fact that the interval of inflation for which the scales of astrophysical interest cross outside the Hubble radius is about 50 e-folds before the end of inflation, we could estimate the magnitude of the dissipation term. It is also possible to show that at the end of inflation the universe is hot enough to provide a smooth transition to the radiation era.

  2. Global Energy Demand in a Warming Climate

    OpenAIRE

    De Cian, Enrica; Wing, Ian Sue

    2016-01-01

    This paper combines an econometric analysis of the response of energy demand to temperature and humidity exposure with future scenarios of climate change and socioeconomic development to characterize climate impacts on energy demand at different spatial scales. Globally, future climate change is expected to have a moderate impact on energy demand, in the order of 6-11%, depending on the degree of warming, because of compensating effects across regions, fuels, and sectors. Climate-induced chan...

  3. An aftereffect of global warming on tropical Pacific decadal variability

    Science.gov (United States)

    Zheng, Jian; Liu, Qinyu; Wang, Chuanyang

    2017-05-01

    Studies have shown that global warming over the past six decades can weaken the tropical Pacific Walker circulation and maintain the positive phase of the Interdecadal Pacific Oscillation (IPO). Based on observations and model simulations, another aftereffect of global warming on IPO is found. After removing linear trends (global warming signals) from observations, however, the tropical Pacific climate still exhibited some obvious differences between two IPO negative phases. The boreal winter (DJF) equatorial central-eastern Pacific sea surface temperature (SST) was colder during the 1999-2014 period (P2) than that during 1961-1976 (P1). This difference may have been a result of global warming nonlinear modulation of precipitation; i.e., in the climatological rainy region, the core area of the tropical Indo-western Pacific warm pool receives more precipitation through the "wet-get-wetter" mechanism. Positive precipitation anomalies in the warm pool during P2 are much stronger than those during P1, even after subtracting the linear trend. Corresponding to the differences of precipitation, the Pacific Walker circulation is stronger in P2 than in P1. Consequent easterly winds over the equatorial Pacific led to a colder equatorial eastern-central Pacific during P2. Therefore, tropical Pacific climate differences between the two negative IPO phases are aftereffects of global warming. These aftereffects are supported by the results of coupled climate model experiments, with and without global warming.

  4. Daytime warming has stronger negative effects on soil nematodes than night-time warming

    OpenAIRE

    Xiumin Yan; Kehong Wang; Lihong Song; Xuefeng Wang; Donghui Wu

    2017-01-01

    Warming of the climate system is unequivocal, that is, stronger warming during night-time than during daytime. Here we focus on how soil nematodes respond to the current asymmetric warming. A field infrared heating experiment was performed in the western of the Songnen Plain, Northeast China. Three warming modes, i.e. daytime warming, night-time warming and diurnal warming, were taken to perform the asymmetric warming condition. Our results showed that the daytime and diurnal warming treatmen...

  5. Competent and Warm?

    Science.gov (United States)

    Hansen, Karolina; Rakić, Tamara; Steffens, Melanie C

    2017-01-01

    Most research on ethnicity has focused on visual cues. However, accents are strong social cues that can match or contradict visual cues. We examined understudied reactions to people whose one cue suggests one ethnicity, whereas the other cue contradicts it. In an experiment conducted in Germany, job candidates spoke with an accent either congruent or incongruent with their (German or Turkish) appearance. Based on ethnolinguistic identity theory, we predicted that accents would be strong cues for categorization and evaluation. Based on expectancy violations theory we expected that incongruent targets would be evaluated more extremely than congruent targets. Both predictions were confirmed: accents strongly influenced perceptions and Turkish-looking German-accented targets were perceived as most competent of all targets (and additionally most warm). The findings show that bringing together visual and auditory information yields a more complete picture of the processes underlying impression formation.

  6. Global Warming on Triton

    Science.gov (United States)

    Elliot, J. L.; Hammel, H. B.; Wasserman, L. H.; Franz, O. G.; McDonald, S. W.; Person, M. J.; Olkin, C. B.; Dunham, E. J.; Spencer, J. R.; Stansberry, J. A.; hide

    1998-01-01

    Triton, Neptune's largest moon, has been predicted to undergo significant seasonal changes that would reveal themselves as changes in its mean frost temperature. But whether this temperature should at the present time be increasing, decreasing or constant depends on a number of parameters (such as the thermal properties of the surface, and frost migration patterns) that are unknown. Here we report observations of a recent stellar occultation by Triton which, when combined with earlier results, show that Triton has undergone a period of global warming since 1989. Our most conservative estimates of the rate of temperature and surface-pressure increase during this period imply that the atmosphere is doubling in bulk every 10 years, significantly faster than predicted by any published frost model for Triton. Our result suggests that permanent polar caps on Triton play a c dominant role in regulating seasonal atmospheric changes. Similar processes should also be active on Pluto.

  7. Local warming: daily temperature change influences belief in global warming.

    Science.gov (United States)

    Li, Ye; Johnson, Eric J; Zaval, Lisa

    2011-04-01

    Although people are quite aware of global warming, their beliefs about it may be malleable; specifically, their beliefs may be constructed in response to questions about global warming. Beliefs may reflect irrelevant but salient information, such as the current day's temperature. This replacement of a more complex, less easily accessed judgment with a simple, more accessible one is known as attribute substitution. In three studies, we asked residents of the United States and Australia to report their opinions about global warming and whether the temperature on the day of the study was warmer or cooler than usual. Respondents who thought that day was warmer than usual believed more in and had greater concern about global warming than did respondents who thought that day was colder than usual. They also donated more money to a global-warming charity if they thought that day seemed warmer than usual. We used instrumental variable regression to rule out some alternative explanations.

  8. Physical Mechanisms of Rapid Lake Warming

    Science.gov (United States)

    Lenters, J. D.

    2016-12-01

    Recent studies have shown significant warming of inland water bodies around the world. Many lakes are warming more rapidly than the ambient surface air temperature, and this is counter to what is often expected based on the lake surface energy balance. A host of reasons have been proposed to explain these discrepancies, including changes in the onset of summer stratification, significant loss of ice cover, and concomitant changes in winter air temperature and/or summer cloud cover. A review of the literature suggests that no single physical mechanism is primarily responsible for the majority of these changes, but rather that the large heterogeneity in regional climate trends and lake geomorphometry results in a host of potential physical drivers. In this study, we discuss the variety of mechanisms that have been proposed to explain rapid lake warming and offer an assessment of the physical plausibility for each potential contributor. Lake Superior is presented as a case study to illustrate the "perfect storm" of factors that can cause a deep, dimictic lake to warm at rate that exceeds the rate of global air temperature warming by nearly an order of magnitude. In particular, we use a simple mixed-layer model to show that spatially variable trends in Lake Superior surface water temperature are determined, to first order, by variations in bathymetry and winter air temperature. Summer atmospheric conditions are often of less significance, and winter ice cover may simply be a correlate. The results highlight the importance of considering the full range of factors that can lead to trends in lake surface temperature, and that conventional wisdom may often not be the best guide.

  9. Committed warming inferred from observations

    Science.gov (United States)

    Mauritsen, Thorsten; Pincus, Robert

    2017-09-01

    Due to the lifetime of CO2, the thermal inertia of the oceans, and the temporary impacts of short-lived aerosols and reactive greenhouse gases, the Earth’s climate is not equilibrated with anthropogenic forcing. As a result, even if fossil-fuel emissions were to suddenly cease, some level of committed warming is expected due to past emissions as studied previously using climate models. Here, we provide an observational-based quantification of this committed warming using the instrument record of global-mean warming, recently improved estimates of Earth’s energy imbalance, and estimates of radiative forcing from the Fifth Assessment Report of the Intergovernmental Panel on Climate Change. Compared with pre-industrial levels, we find a committed warming of 1.5 K (0.9-3.6, 5th-95th percentile) at equilibrium, and of 1.3 K (0.9-2.3) within this century. However, when assuming that ocean carbon uptake cancels remnant greenhouse gas-induced warming on centennial timescales, committed warming is reduced to 1.1 K (0.7-1.8). In the latter case there is a 13% risk that committed warming already exceeds the 1.5 K target set in Paris. Regular updates of these observationally constrained committed warming estimates, although simplistic, can provide transparent guidance as uncertainty regarding transient climate sensitivity inevitably narrows and the understanding of the limitations of the framework is advanced.

  10. Winners and losers in a world with global warming: Noncooperation, altruism, and social welfare

    Energy Technology Data Exchange (ETDEWEB)

    Caplan, A.J. [Weber State Univ., Ogden, UT (United States). Dept. of Economics; Ellis, C.J.; Silva, E.C.D. [Univ. of Oregon, Eugene, OR (United States). Dept. of Economics

    1999-05-01

    In this paper, global warming is an asymmetric transboundary externality which benefits some countries or regions and harms others. Few environmental problems have captured the public`s imagination as much and attracted as much scrutiny as global warming. The general perception is that global warming is a net social bad, and that across-the-board abatement of greenhouse gas emissions is therefore desirable. Despite many interesting academic contributions, not all of the basic economics of this phenomenon have been fully worked out. The authors use a simple two-country model to analyze the effects of global warming on resource allocations, the global-warming stock, and national and global welfare.

  11. Continuously amplified warming in the Alaskan Arctic: Implications for estimating global warming hiatus

    Science.gov (United States)

    Wang, Kang; Zhang, Tingjun; Zhang, Xiangdong; Clow, Gary D.; Jafarov, Elchin E.; Overeem, Irina; Romanovsky, Vladimir; Peng, Xiaoqing; Cao, Bin

    2017-09-01

    Historically, in situ measurements have been notoriously sparse over the Arctic. As a consequence, the existing gridded data of surface air temperature (SAT) may have large biases in estimating the warming trend in this region. Using data from an expanded monitoring network with 31 stations in the Alaskan Arctic, we demonstrate that the SAT has increased by 2.19°C in this region, or at a rate of 0.23°C/decade during 1921-2015. Meanwhile, we found that the SAT warmed at 0.71°C/decade over 1998-2015, which is 2 to 3 times faster than the rate established from the gridded data sets. Focusing on the "hiatus" period 1998-2012 as identified by the Intergovernmental Panel on Climate Change (IPCC) report, the SAT has increased at 0.45°C/decade, which captures more than 90% of the regional trend for 1951-2012. We suggest that sparse in situ measurements are responsible for underestimation of the SAT change in the gridded data sets. It is likely that enhanced climate warming may also have happened in the other regions of the Arctic since the late 1990s but left undetected because of incomplete observational coverage.

  12. Continuously amplified warming in the Alaskan Arctic: Implications for estimating global warming hiatus

    Science.gov (United States)

    Wang, Kang; Zhang, Tingjun; Zhang, Xiangdong; Clow, Gary D.; Jafarov, Elchin E.; Overeem, Irina; Romanovsky, Vladimir; Peng, Xiaoqing; Cao, Bin

    2017-01-01

    Historically, in situ measurements have been notoriously sparse over the Arctic. As a consequence, the existing gridded data of surface air temperature (SAT) may have large biases in estimating the warming trend in this region. Using data from an expanded monitoring network with 31 stations in the Alaskan Arctic, we demonstrate that the SAT has increased by 2.19°C in this region, or at a rate of 0.23°C/decade during 1921–2015. Meanwhile, we found that the SAT warmed at 0.71°C/decade over 1998–2015, which is 2 to 3 times faster than the rate established from the gridded data sets. Focusing on the “hiatus” period 1998–2012 as identified by the Intergovernmental Panel on Climate Change (IPCC) report, the SAT has increased at 0.45°C/decade, which captures more than 90% of the regional trend for 1951–2012. We suggest that sparse in situ measurements are responsible for underestimation of the SAT change in the gridded data sets. It is likely that enhanced climate warming may also have happened in the other regions of the Arctic since the late 1990s but left undetected because of incomplete observational coverage.

  13. Trends in the Indian Ocean Climatology due to anthropogenic induced global warming

    CSIR Research Space (South Africa)

    Meyer, AA

    2009-09-01

    Full Text Available clearly show that due to global warming the South West Indian Ocean Climatology has been changing and that this changing trend will continue into the future as global warming continues. The impacts of regional oceanic climate change on the regions coastal...

  14. Increasing frequency and duration of Arctic winter warming events

    Science.gov (United States)

    Graham, Robert M.; Cohen, Lana; Petty, Alek A.; Boisvert, Linette N.; Rinke, Annette; Hudson, Stephen R.; Nicolaus, Marcel; Granskog, Mats A.

    2017-07-01

    Near-surface air temperatures close to 0°C were observed in situ over sea ice in the central Arctic during the last three winter seasons. Here we use in situ winter (December-March) temperature observations, such as those from Soviet North Pole drifting stations and ocean buoys, to determine how common Arctic winter warming events are. Observations of winter warming events exist over most of the Arctic Basin. Temperatures exceeding -5°C were observed during >30% of winters from 1954 to 2010 by North Pole drifting stations or ocean buoys. Using the ERA-Interim record (1979-2016), we show that the North Pole (NP) region typically experiences 10 warming events (T2m > -10°C) per winter, compared with only five in the Pacific Central Arctic (PCA). There is a positive trend in the overall duration of winter warming events for both the NP region (4.25 days/decade) and PCA (1.16 days/decade), due to an increased number of events of longer duration.type="synopsis">type="main">Plain Language SummaryDuring the last three winter seasons, extreme warming events were observed over sea ice in the central Arctic Ocean. Each of these warming events were associated with temperatures close to or above 0°C, which lasted for between 1 and 3 days. Typically temperatures in the Arctic at this time of year are below -30°C. Here we study past temperature observations in the Arctic to investigate how common winter warming events are. We use time temperature observations from expeditions such as Fram (1893-1896) and manned Soviet North Pole drifting ice stations from 1937 to 1991. These historic temperature records show that winter warming events have been observed over most of the Arctic Ocean. Despite a thin network of observation sites, winter time temperatures above -5°C were directly observed approximately once every 3 years in the central Arctic Ocean between 1954 and 2010. Winter warming events are associated with storm systems originating in either the Atlantic or Pacific

  15. Amplified Arctic warming by phytoplankton under greenhouse warming.

    Science.gov (United States)

    Park, Jong-Yeon; Kug, Jong-Seong; Bader, Jürgen; Rolph, Rebecca; Kwon, Minho

    2015-05-12

    Phytoplankton have attracted increasing attention in climate science due to their impacts on climate systems. A new generation of climate models can now provide estimates of future climate change, considering the biological feedbacks through the development of the coupled physical-ecosystem model. Here we present the geophysical impact of phytoplankton, which is often overlooked in future climate projections. A suite of future warming experiments using a fully coupled ocean-atmosphere model that interacts with a marine ecosystem model reveals that the future phytoplankton change influenced by greenhouse warming can amplify Arctic surface warming considerably. The warming-induced sea ice melting and the corresponding increase in shortwave radiation penetrating into the ocean both result in a longer phytoplankton growing season in the Arctic. In turn, the increase in Arctic phytoplankton warms the ocean surface layer through direct biological heating, triggering additional positive feedbacks in the Arctic, and consequently intensifying the Arctic warming further. Our results establish the presence of marine phytoplankton as an important potential driver of the future Arctic climate changes.

  16. Temperature response of soil respiration largely unaltered with experimental warming

    DEFF Research Database (Denmark)

    Carey, Joanna C; Tang, Jianwu; Templer, Pamela H

    2016-01-01

    , spanning nine biomes and over 2 decades of warming. Our analysis reveals no significant differences in the temperature sensitivity of soil respiration between control and warmed plots in all biomes, with the exception of deserts and boreal forests. Thus, our data provide limited evidence of acclimation...... of soil respiration to experimental warming in several major biome types, contrary to the results from multiple single-site studies. Moreover, across all nondesert biomes, respiration rates with and without experimental warming follow a Gaussian response, increasing with soil temperature up to a threshold...... considerably more responsive to increased ambient temperatures compared with warmer regions. Our analysis adds a unique cross-biome perspective on the temperature response of soil respiration, information critical to improving our mechanistic understanding of how soil carbon dynamics change with climatic...

  17. Responses of arthropod populations to warming depend on latitude

    DEFF Research Database (Denmark)

    Youngsteadt, Elsa; Ernst, Andrew F.; Dunn, Robert Roberdeau

    2017-01-01

    Biological effects of climate change are expected to vary geographically, with a strong signature of latitude. For ectothermic animals, there is systematic latitudinal variation in the relationship between climate and thermal performance curves, which describe the relationship between temperature...... in summer average temperature by 1.7 to 3.4 °C within each city. Arthropod responses to warming within each city were characterized as Poisson regression coefficients describing change in abundance per °C for each family. Family responses in the two mid latitude cities were heterogeneous, including...... declined with warming, perhaps due to habitat loss that was correlated with warming in this city. With the exception of Queens, patterns of family responses to warming were consistent with predictions based on known latitudinal patterns in arthropod physiology relative to regional climate. Heterogeneous...

  18. Soil warming opens the nitrogen cycle at the alpine treeline.

    Science.gov (United States)

    Dawes, Melissa A; Schleppi, Patrick; Hättenschwiler, Stephan; Rixen, Christian; Hagedorn, Frank

    2017-01-01

    Climate warming may alter ecosystem nitrogen (N) cycling by accelerating N transformations in the soil, and changes may be especially pronounced in cold regions characterized by N-poor ecosystems. We investigated N dynamics across the plant-soil continuum during 6 years of experimental soil warming (2007-2012; +4 °C) at a Swiss high-elevation treeline site (Stillberg, Davos; 2180 m a.s.l.) featuring Larix decidua and Pinus uncinata. In the soil, we observed considerable increases in the NH4+ pool size in the first years of warming (by >50%), but this effect declined over time. In contrast, dissolved organic nitrogen (DON) concentrations in soil solutions from the organic layer increased under warming, especially in later years (maximum of +45% in 2012), suggesting enhanced DON leaching from the main rooting zone. Throughout the experimental period, foliar N concentrations showed species-specific but small warming effects, whereas δ15 N values showed a sustained increase in warmed plots that was consistent for all species analysed. The estimated total plant N pool size at the end of the study was greater (+17%) in warmed plots with Pinus but not in those containing Larix, with responses driven by trees. Irrespective of plot tree species identity, warming led to an enhanced N pool size of Vaccinium dwarf shrubs, no change in that of Empetrum hermaphroditum (dwarf shrub) and forbs, and a reduction in that of grasses, nonvascular plants, and fine roots. In combination, higher foliar δ15 N values and the transient response in soil inorganic N indicate a persistent increase in plant-available N and greater cumulative plant N uptake in warmer soils. Overall, greater N availability and increased DON concentrations suggest an opening of the N cycle with global warming, which might contribute to growth stimulation of some plant species while simultaneously leading to greater N losses from treeline ecosystems and possibly other cold biomes. © 2016 John Wiley & Sons

  19. Global warming and coral reefs

    Digital Repository Service at National Institute of Oceanography (India)

    Wafar, M.V.M.

    Ever increasing global warming trend is predicted to cause within the next 100 years an accelerated sea level rise, increase in sea surface temparature and enhanced ultraviolet radiation to a significant enough extent to affect drastically...

  20. Activation of Sahelian monsoon under future warming

    Science.gov (United States)

    Schewe, Jacob; Levermann, Anders

    2015-04-01

    Rainfall variability in the Sahel has been affecting the lives of millions through devastating droughts, such as in the 1970s and 80s, but also destructive rain and flood events. Future climate change is likely to alter rainfall patterns, but model projections for the central Sahel diverge significantly, with climate models simulating anything between a slight drying and a substantial wetting trend. Here we analyze 30 coupled global climate model simulations from the CMIP5 archive. We identify seven models where central Sahel rainfall increases by 40% to 300% over the 21st century, under the RCP8.5 concentration pathway. The same models also outperform the rest of the ensemble in reproducing the magnitude of the 1970s/80s drought. The magnitude and seasonality of the projected future rainfall change, together with a concurrent increase in near-surface wind speed, indicate a northward expansion of the West African monsoon domain. We further find that Sahel rainfall does not increase linearly with rising global temperatures; it is insensitive to moderate warming but then abruptly intensifies beyond a certain temperature. This non-linearity is even more pronounced when instead of global warming, sea surface temperature change in the tropical Atlantic moisture source region is considered. We propose an explanation for this behavior based on a self-amplifying dynamic-thermodynamical feedback, and suggest that the gradual increase in oceanic moisture availability under climate change can trigger the sudden activation of a continental monsoon in the Sahel region, which reaches further inland than the present-day, predominantly coastal West African monsoon. Such an abrupt regime change in response to gradual forcing would be consistent with paleoclimatic records from the Sahel region. More detailed comparison between the model simulations that exhibit this sudden rainfall increase under future warming and those that do not may help to verify this hypothesis.

  1. Media narratives of global warming

    Energy Technology Data Exchange (ETDEWEB)

    Meisner, M. [Syracuse Univ., Syracuse, NY (United States)

    2000-06-01

    The way in which the North American print media are representing global warming was the focus of this paper. It was suggested that the way in which the media presents the issue and proposed responses to it, will influence how the public and decision-makers perceive and respond to the problem. This paper also presented examples demonstrating how nature and humanity's relationship to nature are being presented and what types of responses to global warming are being presented. The issue of who is responsible for acting to prevent or mitigate climate change was also discussed. It was shown that media narratives of global warming are not just stories of scientists debating the existence of global warming, but that they now largely accept global warming as a reality. However, the media continue to construct the problem in narrow technical, economic and anthropocentric terms. Mass media interpretation of global warming offer up a limited selection of problem definitions, reasons for acting and ways of addressing the problem. It was cautioned that this approach will likely promote futility, denial and apathy on the part of the public. 21 refs.

  2. Passive warming reduces stress and shifts reproductive effort in the Antarctic moss, Polytrichastrum alpinum.

    Science.gov (United States)

    Shortlidge, Erin E; Eppley, Sarah M; Kohler, Hans; Rosenstiel, Todd N; Zúñiga, Gustavo E; Casanova-Katny, Angélica

    2017-01-01

    The Western Antarctic Peninsula is one of the most rapidly warming regions on Earth, and many biotic communities inhabiting this dynamic region are responding to these well-documented climatic shifts. Yet some of the most prevalent organisms of terrestrial Antarctica, the mosses, and their responses to warming have been relatively overlooked and understudied. In this research, the impacts of 6 years of passive warming were investigated using open top chambers (OTCs), on moss communities of Fildes Peninsula, King George Island, Antarctica. The effects of experimental passive warming on the morphology, sexual reproductive effort and stress physiology of a common dioicous Antarctic moss, Polytrichastrum alpinum ,: were tested, gaining the first species-specific mechanistic insight into moss responses to warming in the Antarctic. Additionally community analyses were conducted examining the impact of warming on overall moss percentage cover and sporophyte production in intact Antarctic moss communities. Our results show a generally greater percentage moss cover under warming conditions as well as increased gametangia production in P. alpinum Distinct morphological and physiological shifts in P. alpinum were found under passive warming compared with those without warming: warmed mosses reduced investment in cellular stress defences, but invested more towards primary productivity and gametangia development. Taken together, results from this study of mosses under passive warming imply that in ice-free moss-dominated regions, continued climate warming will probably have profound impacts on moss biology and colonization along the Western Antarctic Peninsula. Such findings highlight the fundamental role that mosses will play in influencing the terrestrialization of a warming Antarctica. © The Author 2016. Published by Oxford University Press on behalf of the Annals of Botany Company. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  3. Cropping system innovation for coping with climatic warming in China

    Directory of Open Access Journals (Sweden)

    Aixing Deng

    2017-04-01

    Full Text Available China is becoming the largest grain producing and carbon-emitting country in the world, with a steady increase in population and economic development. A review of Chinese experiences in ensuring food self-sufficiency and reducing carbon emission in the agricultural sector can provide a valuable reference for similar countries and regions. According to a comprehensive review of previous publications and recent field observations, China has experienced on average a larger and faster climatic warming trend than the global trend, and there are large uncertainties in precipitation change, which shows a non-significantly increasing trend. Existing evidence shows that the effects of climatic warming on major staple crop production in China could be markedly negative or positive, depending on the specific cropping region, season, and crop. However, historical data analysis and field warming experiments have shown that moderate warming, of less than 2.0 °C, could benefit crop production in China overall. During the most recent warming decades, China has made successful adaptations in cropping systems, such as new cultivar breeding, cropping region adjustment, and cropping practice optimization, to exploit the positive rather than to avoid the negative effects of climatic warming on crop growth. All of these successful adaptations have greatly increased crop yield, leading to higher resource use efficiency as well as greatly increased soil organic carbon content with reduced greenhouse gas emissions. Under the warming climate, China has not only achieved great successes in crop production but also realized a large advance in greenhouse gas emission mitigation. Chinese experiences in cropping system innovation for coping with climatic warming demonstrate that food security and climatic warming mitigation can be synergized through policy, knowledge, and technological innovation. With the increasingly critical status of food security and climatic warming

  4. The Great Warming Brian Fagan

    Science.gov (United States)

    Fagan, B. M.

    2010-12-01

    The Great Warming is a journey back to the world of a thousand years ago, to the Medieval Warm Period. Five centuries of irregular warming from 800 to 1250 had beneficial effects in Europe and the North Atlantic, but brought prolonged droughts to much of the Americas and lands affected by the South Asian monsoon. The book describes these impacts of warming on medieval European societies, as well as the Norse and the Inuit of the far north, then analyzes the impact of harsh, lengthy droughts on hunting societies in western North America and the Ancestral Pueblo farmers of Chaco Canyon, New Mexico. These peoples reacted to drought by relocating entire communities. The Maya civilization was much more vulnerable that small-scale hunter-gatherer societies and subsistence farmers in North America. Maya rulers created huge water storage facilities, but their civilization partially collapsed under the stress of repeated multiyear droughts, while the Chimu lords of coastal Peru adapted with sophisticated irrigation works. The climatic villain was prolonged, cool La Niñalike conditions in the Pacific, which caused droughts from Venezuela to East Asia, and as far west as East Africa. The Great Warming argues that the warm centuries brought savage drought to much of humanity, from China to Peru. It also argues that drought is one of the most dangerous elements in today’s humanly created global warming, often ignored by preoccupied commentators, but with the potential to cause over a billion people to starve. Finally, I use the book to discuss the issues and problems of communicating multidisciplinary science to the general public.

  5. Warm Up to a Good Sound

    Science.gov (United States)

    Tovey, David C.

    1977-01-01

    Most choral directors in schools today have been exposed to a variety of warm-up procedures. Yet, many do not use the warm-up time effectively as possible. Considers the factors appropriate to a warm-up exercise and three basic warm-up categories. (Author/RK)

  6. How warm days increase belief in global warming

    Science.gov (United States)

    Zaval, Lisa; Keenan, Elizabeth A.; Johnson, Eric J.; Weber, Elke U.

    2014-02-01

    Climate change judgements can depend on whether today seems warmer or colder than usual, termed the local warming effect. Although previous research has demonstrated that this effect occurs, studies have yet to explain why or how temperature abnormalities influence global warming attitudes. A better understanding of the underlying psychology of this effect can help explain the public's reaction to climate change and inform approaches used to communicate the phenomenon. Across five studies, we find evidence of attribute substitution, whereby individuals use less relevant but available information (for example, today's temperature) in place of more diagnostic but less accessible information (for example, global climate change patterns) when making judgements. Moreover, we rule out alternative hypotheses involving climate change labelling and lay mental models. Ultimately, we show that present temperature abnormalities are given undue weight and lead to an overestimation of the frequency of similar past events, thereby increasing belief in and concern for global warming.

  7. Calcium ions facilitate body heat emission response to warming.

    Science.gov (United States)

    Tkachenko, E Ya; Khramova, G M; Kozyreva, T V

    2015-01-01

    Involvement of various areas of the body surface in heat emission response to warming is characterized by a certain succession. The first response preceding the deep body temperature rise is dilation of ear skin vessels. Then, an increase in deep body temperature is counterbalanced by vascular reaction in the tail region, which plays the leading role in up-regulation of heat emission. Calcium ions accelerate the vascular response to warming in both regions, although they produce no effect on the maximum level of heat emission. Our findings confirm the involvement of Ca(2+)-dependent mechanisms in activation of the processes aimed at stabilization of body temperature in warm-blooded animals. The role of heat-sensitive TRPV1 ion channels determining modality of the temperature signal and direction of effector reactions is discussed.

  8. Early emergence in a butterfly causally linked to anthropogenic warming.

    Science.gov (United States)

    Kearney, Michael R; Briscoe, Natalie J; Karoly, David J; Porter, Warren P; Norgate, Melanie; Sunnucks, Paul

    2010-10-23

    There is strong correlative evidence that human-induced climate warming is contributing to changes in the timing of natural events. Firm attribution, however, requires cause-and-effect links between observed climate change and altered phenology, together with statistical confidence that observed regional climate change is anthropogenic. We provide evidence for phenological shifts in the butterfly Heteronympha merope in response to regional warming in the southeast Australian city of Melbourne. The mean emergence date for H. merope has shifted -1.5 days per decade over a 65-year period with a concurrent increase in local air temperatures of approximately 0.16°C per decade. We used a physiologically based model of climatic influences on development, together with statistical analyses of climate data and global climate model projections, to attribute the response of H. merope to anthropogenic warming. Such mechanistic analyses of phenological responses to climate improve our ability to forecast future climate change impacts on biodiversity.

  9. Australia's Unprecedented Future Temperature Extremes Under Paris Limits to Warming

    Science.gov (United States)

    Lewis, Sophie C.; King, Andrew D.; Mitchell, Daniel M.

    2017-10-01

    Record-breaking temperatures can detrimentally impact ecosystems, infrastructure, and human health. Previous studies show that climate change has influenced some observed extremes, which are expected to become more frequent under enhanced future warming. Understanding the magnitude, as a well as frequency, of such future extremes is critical for limiting detrimental impacts. We focus on temperature changes in Australian regions, including over a major coral reef-building area, and assess the potential magnitude of future extreme temperatures under Paris Agreement global warming targets (1.5°C and 2°C). Under these limits to global mean warming, we determine a set of projected high-magnitude unprecedented Australian temperature extremes. These include extremes unexpected based on observational temperatures, including current record-breaking events. For example, while the difference in global-average warming during the hottest Australian summer and the 2°C Paris target is 1.1°C, extremes of 2.4°C above the observed summer record are simulated. This example represents a more than doubling of the magnitude of extremes, compared with global mean change, and such temperatures are unexpected based on the observed record alone. Projected extremes do not necessarily scale linearly with mean global warming, and this effect demonstrates the significant potential benefits of limiting warming to 1.5°C, compared to 2°C or warmer.

  10. Global warming and infectious disease.

    Science.gov (United States)

    Khasnis, Atul A; Nettleman, Mary D

    2005-01-01

    Global warming has serious implications for all aspects of human life, including infectious diseases. The effect of global warming depends on the complex interaction between the human host population and the causative infectious agent. From the human standpoint, changes in the environment may trigger human migration, causing disease patterns to shift. Crop failures and famine may reduce host resistance to infections. Disease transmission may be enhanced through the scarcity and contamination of potable water sources. Importantly, significant economic and political stresses may damage the existing public health infrastructure, leaving mankind poorly prepared for unexpected epidemics. Global warming will certainly affect the abundance and distribution of disease vectors. Altitudes that are currently too cool to sustain vectors will become more conducive to them. Some vector populations may expand into new geographic areas, whereas others may disappear. Malaria, dengue, plague, and viruses causing encephalitic syndromes are among the many vector-borne diseases likely to be affected. Some models suggest that vector-borne diseases will become more common as the earth warms, although caution is needed in interpreting these predictions. Clearly, global warming will cause changes in the epidemiology of infectious diseases. The ability of mankind to react or adapt is dependent upon the magnitude and speed of the change. The outcome will also depend on our ability to recognize epidemics early, to contain them effectively, to provide appropriate treatment, and to commit resources to prevention and research.

  11. Role of radiatively forced temperature changes in enhanced semi-arid warming over East Asia

    Science.gov (United States)

    Guan, X.; Huang, J.; Guo, R.; Lin, P.; Zhang, Y.

    2015-08-01

    As the climate change occurred over East Asia since 1950s, intense interest and debate have arisen concerning the contribution of human activities to the warming observed in previous decades. In this study, we investigate surface temperature change using a recently developed methodology that can successfully identify and separate the dynamically induced temperature (DIT) and radiatively forced temperature (RFT) changes in raw surface air temperature (SAT) data. For regional averages, DIT and RFT make 43.7 and 56.3 % contributions to the SAT over East Asia, respectively. The DIT changes dominate the SAT decadal variability and are mainly determined by internal climate variability, such as the North Atlantic Oscillation (NAO), Pacific Decadal Oscillation (PDO), and Atlantic Multi-decadal Oscillation (AMO). The radiatively forced SAT changes made major contribution to the global-scale warming trend and the regional-scale enhanced semi-arid warming (ESAW). Such enhanced warming is also found in radiatively forced daily maximum and minimum SAT. The long-term global-mean SAT warming trend is mainly related to radiative forcing produced by global well-mixed greenhouse gases. The regional anthropogenic radiative forcing, however, caused the enhanced warming in the semi-arid region, which may be closely associated with local human activities. Finally, the relationship between global warming hiatus and regional enhanced warming is discussed.

  12. Peranan Environmental Accounting Terhadap Global Warming

    OpenAIRE

    Martusa, Riki

    2009-01-01

    This article explores about is global warming. The distortion of nature causes global warming. Industrial sector is one of global warming incurred. Some nations create a group to cope this matter. They try to reduce carbon emission as one of global warming causes by controlling industrial carbon emission through financial reporting. This article explores normatively roles of environmental accounting in cope with global warming.  

  13. Unabated global surface temperature warming: evaluating the evidence

    Science.gov (United States)

    Karl, T. R.; Arguez, A.

    2015-12-01

    New insights related to time-dependent bias corrections in global surface temperatures have led to higher rates of warming over the past few decades than previously reported in the IPCC Fifth Assessment Report (2014). Record high global temperatures in the past few years have also contributed to larger trends. The combination of these factors and new analyses of the rate of temperature change show unabated global warming since at least the mid-Twentieth Century. New time-dependent bias corrections account for: (1) differences in temperatures measured from ships and drifting buoys; (2) improved corrections to ship measured temperatures; and (3) the larger rates of warming in polar regions (particularly the Arctic). Since 1951, the period over which IPCC (2014) attributes over half of the observed global warming to human causes, it is shown that there has been a remarkably robust and sustained warming, punctuated with inter-annual and decadal variability. This finding is confirmed through simple trend analysis and Empirical Mode Decomposition (EMD). Trend analysis however, especially for decadal trends, is sensitive to selection bias of beginning and ending dates. EMD has no selection bias. Additionally, it can highlight both short- and long-term processes affecting the global temperature times series since it addresses both non-linear and non-stationary processes. For the new NOAA global temperature data set, our analyses do not support the notion of a hiatus or slowing of long-term global warming. However, sub-decadal periods of little (or no warming) and rapid warming can also be found, clearly showing the impact of inter-annual and decadal variability that previously has been attributed to both natural and human-induced non-greenhouse forcings.

  14. Designing connected marine reserves in the face of global warming.

    Science.gov (United States)

    Álvarez-Romero, Jorge G; Munguía-Vega, Adrián; Beger, Maria; Del Mar Mancha-Cisneros, Maria; Suárez-Castillo, Alvin N; Gurney, Georgina G; Pressey, Robert L; Gerber, Leah R; Morzaria-Luna, Hem Nalini; Reyes-Bonilla, Héctor; Adams, Vanessa M; Kolb, Melanie; Graham, Erin M; VanDerWal, Jeremy; Castillo-López, Alejandro; Hinojosa-Arango, Gustavo; Petatán-Ramírez, David; Moreno-Baez, Marcia; Godínez-Reyes, Carlos R; Torre, Jorge

    2018-02-01

    Marine reserves are widely used to protect species important for conservation and fisheries and to help maintain ecological processes that sustain their populations, including recruitment and dispersal. Achieving these goals requires well-connected networks of marine reserves that maximize larval connectivity, thus allowing exchanges between populations and recolonization after local disturbances. However, global warming can disrupt connectivity by shortening potential dispersal pathways through changes in larval physiology. These changes can compromise the performance of marine reserve networks, thus requiring adjusting their design to account for ocean warming. To date, empirical approaches to marine prioritization have not considered larval connectivity as affected by global warming. Here, we develop a framework for designing marine reserve networks that integrates graph theory and changes in larval connectivity due to potential reductions in planktonic larval duration (PLD) associated with ocean warming, given current socioeconomic constraints. Using the Gulf of California as case study, we assess the benefits and costs of adjusting networks to account for connectivity, with and without ocean warming. We compare reserve networks designed to achieve representation of species and ecosystems with networks designed to also maximize connectivity under current and future ocean-warming scenarios. Our results indicate that current larval connectivity could be reduced significantly under ocean warming because of shortened PLDs. Given the potential changes in connectivity, we show that our graph-theoretical approach based on centrality (eigenvector and distance-weighted fragmentation) of habitat patches can help design better-connected marine reserve networks for the future with equivalent costs. We found that maintaining dispersal connectivity incidentally through representation-only reserve design is unlikely, particularly in regions with strong asymmetric patterns of

  15. Temperature response of soil respiration largely unaltered with experimental warming

    Science.gov (United States)

    Carey, Joanna C.; Tang, Jianwu; Templer, Pamela H.; Kroeger, Kevin D.; Crowther, Thomas W.; Burton, Andrew J.; Dukes, Jeffrey S.; Emmett, Bridget; Frey, Serita D.; Heskel, Mary A.; Jiang, Lifen; Machmuller, Megan B.; Mohan, Jacqueline; Panetta, Anne Marie; Reich, Peter B.; Reinsch, Sabine; Wang, Xin; Allison, Steven D.; Bamminger, Chris; Bridgham, Scott; Collins, Scott L.; de Dato, Giovanbattista; Eddy, William C.; Enquist, Brian J.; Estiarte, Marc; Harte, John; Henderson, Amanda; Johnson, Bart R.; Steenberg Larsen, Klaus; Luo, Yiqi; Marhan, Sven; Melillo, Jerry M.; Penuelas, Josep; Pfeifer-Meister, Laurel; Poll, Christian; Rastetter, Edward B.; Reinmann, Andrew B.; Reynolds, Lorien L.; Schmidt, Inger K.; Shaver, Gaius R.; Strong, Aaron L.; Suseela, Vidya; Tietema, Albert

    2016-01-01

    The respiratory release of carbon dioxide (CO2) from soil is a major yet poorly understood flux in the global carbon cycle. Climatic warming is hypothesized to increase rates of soil respiration, potentially fueling further increases in global temperatures. However, despite considerable scientific attention in recent decades, the overall response of soil respiration to anticipated climatic warming remains unclear. We synthesize the largest global dataset to date of soil respiration, moisture, and temperature measurements, totaling >3,800 observations representing 27 temperature manipulation studies, spanning nine biomes and over 2 decades of warming. Our analysis reveals no significant differences in the temperature sensitivity of soil respiration between control and warmed plots in all biomes, with the exception of deserts and boreal forests. Thus, our data provide limited evidence of acclimation of soil respiration to experimental warming in several major biome types, contrary to the results from multiple single-site studies. Moreover, across all nondesert biomes, respiration rates with and without experimental warming follow a Gaussian response, increasing with soil temperature up to a threshold of ∼25 °C, above which respiration rates decrease with further increases in temperature. This consistent decrease in temperature sensitivity at higher temperatures demonstrates that rising global temperatures may result in regionally variable responses in soil respiration, with colder climates being considerably more responsive to increased ambient temperatures compared with warmer regions. Our analysis adds a unique cross-biome perspective on the temperature response of soil respiration, information critical to improving our mechanistic understanding of how soil carbon dynamics change with climatic warming.

  16. Global warming at the summit

    Science.gov (United States)

    Showstack, Randy

    During the recent summit meeting between Russian President Vladimir Putin and U.S. President Bill Clinton, the two leaders reaffirmed their concerns about global warming and the need to continue to take actions to try to reduce the threat.In a June 4 joint statement, they stressed the need to develop flexibility mechanisms, including international emissions trading, under the Kyoto Protocol to the United Nations Framework Convention on Climate Change. They also noted that initiatives to reduce the risk of greenhouse warming, including specific mechanisms of the Kyoto Protocol, could potentially promote economic growth.

  17. Frontiers and challenges in warm dense matter

    CERN Document Server

    Desjarlais, Michael; Redmer, Ronald; Trickey, Samuel

    2014-01-01

    Warm Dense Matter (WDM) occupies a loosely defined region of phase space intermediate between solid, liquid, gas, and plasma, and typically shares characteristics of two or more of these phases. WDM is generally associated with the combination of strongly coupled ions and moderately degenerate electrons, and careful attention to quantum physics and electronic structure is essential. The lack of a small perturbation parameter greatly limits approximate attempts at its accurate description. Since WDM resides at the intersection of solid state and high energy density physics, many high energy density physics (HEDP) experiments pass through this difficult region of phase space. Thus, understanding and modeling WDM is key to the success of experiments on diverse facilities. These include the National Ignition Campaign centered on the National Ignition Facility (NIF), pulsed-power driven experiments on the Z machine, ion-beam-driven WDM experiments on the NDCX-II, and fundamental WDM research at the Linear Coherent...

  18. Global Warming and the Microwave Background

    Directory of Open Access Journals (Sweden)

    Robitaille P.-M.

    2009-04-01

    Full Text Available In the work, the importance of assigning the microwave background to the Earth is ad- dressed while emphasizing the consequences for global climate change. Climate mod- els can only produce meaningful forecasts when they consider the real magnitude of all radiative processes. The oceans and continents both contribute to terrestrial emis- sions. However, the extent of oceanic radiation, particularly in the microwave region, raises concerns. This is not only since the globe is covered with water, but because the oceans themselves are likely to be weaker emitters than currently believed. Should the microwave background truly be generated by the oceans of the Earth, our planet would be a much less efficient emitter of radiation in this region of the electromagnetic spectrum. Furthermore, the oceans would appear unable to increase their emissions in the microwave in response to temperature elevation, as predicted by Stefan’s law. The results are significant relative to the modeling of global warming.

  19. The effects of different warm stratification periods on the seed ...

    African Journals Online (AJOL)

    PRECIOUS

    2009-09-11

    Sep 11, 2009 ... In this study, the effects of different warm stratification periods on the seed germination of some Rosa species such as Rosa heckellana ssp. vanheurckiana, Rosa canina, Rosa pulverelanta and Rosa dumalis naturally grown in the Van region were investigated. In 2007, seeds of these species were kept.

  20. Global warming triggers the loss of a key Arctic refugium.

    Science.gov (United States)

    Rühland, K M; Paterson, A M; Keller, W; Michelutti, N; Smol, J P

    2013-12-07

    We document the rapid transformation of one of the Earth's last remaining Arctic refugia, a change that is being driven by global warming. In stark contrast to the amplified warming observed throughout much of the Arctic, the Hudson Bay Lowlands (HBL) of subarctic Canada has maintained cool temperatures, largely due to the counteracting effects of persistent sea ice. However, since the mid-1990s, climate of the HBL has passed a tipping point, the pace and magnitude of which is exceptional even by Arctic standards, exceeding the range of regional long-term variability. Using high-resolution, palaeolimnological records of algal remains in dated lake sediment cores, we report that, within this short period of intense warming, striking biological changes have occurred in the region's freshwater ecosystems. The delayed and intense warming in this remote region provides a natural observatory for testing ecosystem resilience under a rapidly changing climate, in the absence of direct anthropogenic influences. The environmental repercussions of this climate change are of global significance, influencing the huge store of carbon in the region's extensive peatlands, the world's southern-most polar bear population that depends upon Hudson Bay sea ice and permafrost for survival, and native communities who rely on this landscape for sustenance.

  1. Warming and nitrogen fertilization effects on winter wheat yields in northern China varied between four years

    DEFF Research Database (Denmark)

    Liu, Liting; Hu, Chunsheng; Olesen, Jørgen E

    2013-01-01

    Global warming is expected to affect wheat productivity significantly, but with large regional differences depending on current climatic conditions. We conducted a study that aimed to investigate how wheat growth and development as well as yield and yield components respond to warming combined...... with nitrogen fertilization. Infrared heaters were applied above the crop and soil to provide a warming of around 2 °C at 5 cm soil depth during the whole winter wheat growing season from 2008 to 2012 at a site near Shijiazhuang in the North China Plain. Two temperature levels (warming and ambient) for winter...

  2. Plant movements and climate warming

    DEFF Research Database (Denmark)

    De Frenne, Pieter; Coomes, David A.; De Schrijver, An

    2014-01-01

    •Most range shift predictions focus on the dispersal phase of the colonization process. Because moving populations experience increasingly dissimilar nonclimatic environmental conditions as they track climate warming, it is also critical to test how individuals originating from contrasting therma...

  3. Global warming: it's not only size that matters

    Science.gov (United States)

    Hegerl, Gabriele C.

    2011-09-01

    Observed and model simulated warming is particularly large in high latitudes, and hence the Arctic is often seen as the posterchild of vulnerability to global warming. However, Mahlstein et al (2011) point out that the signal of climate change is emerging locally from that of climate variability earliest in regions of low climate variability, based on climate model data, and in agreement with observations. This is because high latitude regions are not only regions of strong feedbacks that enhance the global warming signal, but also regions of substantial climate variability, driven by strong dynamics and enhanced by feedbacks (Hall 2004). Hence the spatial pattern of both observed warming and simulated warming for the 20th century shows strong warming in high latitudes, but this warming occurs against a backdrop of strong variability. Thus, the ratio of the warming to internal variability is not necessarily highest in the regions that warm fastest—and Mahlstein et al illustrate that it is actually the low-variability regions where the signal of local warming emerges first from that of climate variability. Thus, regions with strongest warming are neither the most important to diagnose that forcing changes climate, nor are they the regions which will necessarily experience the strongest impact. The importance of the signal-to-noise ratio has been known to the detection and attribution community, but has been buried in technical 'optimal fingerprinting' literature (e.g., Hasselmann 1979, Allen and Tett 1999), where it was used for an earlier detection of climate change by emphasizing aspects of the fingerprint of global warming associated with low variability in estimates of the observed warming. What, however, was not discussed was that the local signal-to-noise ratio is of interest also for local climate change: where temperatures emerge from the range visited by internal climate variability, it is reasonable to assume that changes in climate will also cause more

  4. Evaluating the Dominant Components of Warming in Pliocene Climate Simulations

    Science.gov (United States)

    Hill, D. J.; Haywood, A. M.; Lunt, D. J.; Hunter, S. J.; Bragg, F. J.; Contoux, C.; Stepanek, C.; Sohl, L.; Rosenbloom, N. A.; Chan, W.-L.; hide

    2014-01-01

    The Pliocene Model Intercomparison Project (PlioMIP) is the first coordinated climate model comparison for a warmer palaeoclimate with atmospheric CO2 significantly higher than pre-industrial concentrations. The simulations of the mid-Pliocene warm period show global warming of between 1.8 and 3.6 C above pre-industrial surface air temperatures, with significant polar amplification. Here we perform energy balance calculations on all eight of the coupled ocean-atmosphere simulations within PlioMIP Experiment 2 to evaluate the causes of the increased temperatures and differences between the models. In the tropics simulated warming is dominated by greenhouse gas increases, with the cloud component of planetary albedo enhancing the warming in most of the models, but by widely varying amounts. The responses to mid-Pliocene climate forcing in the Northern Hemisphere midlatitudes are substantially different between the climate models, with the only consistent response being a warming due to increased greenhouse gases. In the high latitudes all the energy balance components become important, but the dominant warming influence comes from the clear sky albedo, only partially offset by the increases in the cooling impact of cloud albedo. This demonstrates the importance of specified ice sheet and high latitude vegetation boundary conditions and simulated sea ice and snow albedo feedbacks. The largest components in the overall uncertainty are associated with clouds in the tropics and polar clear sky albedo, particularly in sea ice regions. These simulations show that albedo feedbacks, particularly those of sea ice and ice sheets, provide the most significant enhancements to high latitude warming in the Pliocene.

  5. Global warming and thermohaline circulation stability.

    Science.gov (United States)

    Wood, Richard A; Vellinga, Michael; Thorpe, Robert

    2003-09-15

    The Atlantic thermohaline circulation (THC) plays an important role in global climate. Theoretical and palaeoclimatic evidence points to the possibility of rapid changes in the strength of the THC, including a possible quasi-permanent shutdown. The climatic impacts of such a shutdown would be severe, including a cooling throughout the Northern Hemisphere, which in some regions is greater in magnitude than the changes expected from global warming in the next 50 years. Other climatic impacts would likely include a severe alteration of rainfall patterns in the tropics, the Indian subcontinent and Europe. Modelling the future behaviour of the THC focuses on two key questions. (i) Is a gradual weakening of the THC likely in response to global warming, and if so by how much? (ii) Are there thresholds beyond which rapid or irreversible changes in the THC are likely? Most projections of the response of the THC to increasing concentrations of greenhouse gases suggest a gradual weakening over the twenty-first century. However, there is a wide variation between different models over the size of the weakening. Rapid or irreversible THC shutdown is considered a low-probability (but high-impact) outcome; however, some climate models of intermediate complexity do show the possibility of such events. The question of the future of the THC is beset with conceptual, modelling and observational uncertainties, but some current and planned projects show promise to make substantial progress in tackling these uncertainties in future.

  6. Separating warming-induced drought from drought-induced warming

    Science.gov (United States)

    Roderick, Michael; Wolf, Sebastian; Yin, Dongqin

    2017-04-01

    A very widely held public perception is that increasing temperature is a cause of "drying" and drought. The atmospheric-focused meteorologic community has often assumed that the warmer temperatures increase evaporation and that this contributes to worsening drought via atmospheric demand. On the other hand, the agricultural and hydrologic scientific communities have a very different interpretation linked to water supply, with the lack of available water leading to reduced evaporation and enhanced surface warming. This is a classic chicken-or-the-egg problem that has resisted definitive explanation probably due to the lack of radiative observations at suitable spatial and temporal scales. Here we use recently released NASA CERES satellite radiation data to study the 2013-2014 Californian drought. We evaluate whether the observed increase in near-surface air temperature should be considered a forcing (as per standard meteorological approaches) or a feedback (as per standard agricultural and hydrologic approaches). We find that the radiative perturbation associated with the drought has a distinct radiative signature for more incoming shortwave- and less incoming longwave-radiation. That result, coupled with estimates of decreased evapotranspiration show that around two-third of the warming has a radiative origin and the remaining one-third is the result of a surface feedback from reduced evaporative cooling. Hence, the radiative perturbation during the recent Californian drought was distinctly different from the projected radiative perturbation of the enhanced greenhouse effect. We conclude that the warming experienced during meteorological drought is very different from the warming projected as a consequence of the enhanced greenhouse effect.

  7. The Great Season Climatic Oscillation and the Global Warming

    CERN Document Server

    Boucenna, Ahmed

    2008-01-01

    The present earth warming up is often explained by the atmosphere gas greenhouse effect. This explanation is in contradiction with the thermodynamics second law. The warming up by greenhouse effect is quite improbable. It is cloud reflection that gives to the earth s ground its 15 degres C mean temperature. Since the reflection of the radiation by gases is negligible, the role of the atmosphere greenhouse gases in the earth warming up by earth radiation reflection loses its importance. We think that natural climatic oscillations contribute more to earth climatic disturbances. The oscillation that we hypothesize to exist has a long period (800 to 1000 years). The glacier melting and regeneration cycles lead to variations in the cold region ocean water density and thermal conductibility according to their salinity. These variations lead one to think about a macro climate oscillating between maximum hot and minimum cold temperatures. This oscillation is materialized by the passages of the planet through hot, mil...

  8. Surface measurements of global warming causing atmospheric constituents in Korea.

    Science.gov (United States)

    Oh, S N; Youn, Y H; Park, K J; Min, H K; Schnell, R C

    2001-07-01

    The expansion of the industrial economy and the increase of population in Northeast Asian countries have caused much interest in climate monitoring related to global warming. However, new techniques and better platforms for the measurement of global warming and regional databases are still old-fashioned and are not being developed sufficiently. With respect to this agenda, since 1993, at the request of the World Meteorological Organization (WMO), to monitor functions of global warming, the Korea Meteorological Administration (KMA) has set up a Global Atmospheric Watch (GAW) Station on the western coast of Korea (Anmyun-do) and has been actively monitoring global warming over Northeast Asia. In addition, atmospheric carbon dioxide (CO2) has been measured for a similar KMA global warming program at Kosan, Cheju Island since 1990. Aerosol and radiation have also been measured at both sites as well as in Seoul. The observations have been analyzed using diagnostics of climate change in Northeast Asia and also have been internationally compared. Results indicate that greenhouse gases are in good statistic agreement with the NOAA/Climate Monitoring and Diagnostics Laboratory (CMDL) long-term trends of monthly mean concentrations and seasonal cycles. Atmospheric particulate matter has also been analyzed for particular Asian types in terms of optical depth, number concentration and size distribution.

  9. Amplified summer warming in Europe-West Asia and Northeast Asia after the mid-1990s

    Science.gov (United States)

    Hong, Xiaowei; Lu, Riyu; Li, Shuanglin

    2017-09-01

    Regional temperature changes are a crucial factor in affecting agriculture, ecosystems and societies, which depend greatly on local temperatures. We identify a nonuniform warming pattern in summer around the mid-1990s over the Eurasian continent, with a predominant amplified warming over Europe-West Asia and Northeast Asia but much weaker warming over Central Asia. It is found that the nonuniform warming concurs with both the phase shift of the Atlantic Multi-decadal Oscillation (AMO) and the decadal change in the Silk Road Pattern (SRP), which is an upper-tropospheric teleconnection pattern over the Eurasian continent during summer. We suggest that the AMO may modulate the decadal change in SRP and then induce the zonal asymmetry in temperature changes. Our results have important implications for decadal prediction of regional warming pattern in Eurasia based on the predictable AMO.

  10. More losers than winners in a century of future Southern Ocean seafloor warming

    Science.gov (United States)

    Griffiths, Huw J.; Meijers, Andrew J. S.; Bracegirdle, Thomas J.

    2017-10-01

    The waters of the Southern Ocean are projected to warm over the coming century, with potential adverse consequences for native cold-adapted organisms. Warming waters have caused temperate marine species to shift their ranges poleward. The seafloor animals of the Southern Ocean shelf have long been isolated by the deep ocean surrounding Antarctica and the Antarctic Circumpolar Current, with little scope for southward migration. How these largely endemic species will react to future projected warming is unknown. By considering 963 invertebrate species, we show that within the current century, warming temperatures alone are unlikely to result in wholesale extinction or invasion affecting Antarctic seafloor life. However, 79% of Antarctica's endemic species do face a significant reduction in suitable temperature habitat (an average 12% reduction). Our findings highlight the species and regions most likely to respond significantly (negatively and positively) to warming and have important implications for future management of the region.

  11. Global Warming Blame the Sun

    CERN Document Server

    Calder, N

    1997-01-01

    Concern about climate change reaches a political peak at a UN conference in Kyoto, 1-10 December, but behind the scenes the science is in turmoil. A challenge to the hypothesis that greenhouse gases are responsible for global warming comes from the discovery that cosmic rays from the Galaxy are involved in making clouds (Svensmark and Friis-Christensen, 1997). During the 20th Century the wind from the Sun has grown stronger and the count of cosmic rays has diminished. With fewer clouds, the EarthÕs surface has warmed up. This surprising mechanism explains the link between the Sun and climate change that astronomers and geophysicists have suspected for 200 years.

  12. Hydrological consequences of global warming

    Energy Technology Data Exchange (ETDEWEB)

    Miller, Norman L.

    2009-06-01

    The 2007 Intergovernmental Panel for Climate Change indicates there is strong evidence that the atmospheric concentration of carbon dioxide far exceeds the natural range over the last 650,000 years, and this recent warming of the climate system is unequivocal, resulting in more frequent extreme precipitation events, earlier snowmelt runoff, increased winter flood likelihoods, increased and widespread melting of snow and ice, longer and more widespread droughts, and rising sea level. The effects of recent warming has been well documented and climate model projections indicate a range of hydrological impacts with likely to very likely probabilities (67 to 99 percent) of occurring with significant to severe consequences in response to a warmer lower atmosphere with an accelerating hydrologic cycle.

  13. PR Software: Warm Water Energie met grafieken

    NARCIS (Netherlands)

    Kanis, J.; Verstappen-Boerekamp, J.

    1999-01-01

    Het computerprogramma Warm Water Energie (WWE) berekent het verbruik van (warm) water, energie en reinigingsmiddelen bij de melkwinning. De nieuwste versie bevat grafieken die in één oogopslag de productie en het verbruik van warm water weergeven. In de overzichtelijke rapportage staan nu ook de

  14. Economic Theory and Global Warming

    Science.gov (United States)

    Uzawa, Hirofumi

    2003-08-01

    Hirofumi Uzawa's theoretical framework addresses three major problems concerning global warming and other environmental hazards. First, it considers all phenomena involved with global environmental issues that exhibit externalities of one kind or another. Secondly, it covers global environmental issues involving international and intergenerational equity and justice. Lastly, it deals with global environmental issues concerning the management of the atmosphere, the oceans, water, soil, and other natural resources having to be decided by a consensus of affected countries.

  15. Early Onset of Industrial-Era Warming Across the Oceans and Continents

    Science.gov (United States)

    Abram, N.; McGregor, H. V.; Tierney, J. E.; Evans, M. N.; McKay, N.; Kaufman, D. S.; Pages 2k Consortium*, T.

    2016-12-01

    The evolution of industrial-era warming provides critical context for future climate change, and has fundamental importance for determining climate sensitivity and the processes that control regional warming. Palaeoclimate data from the Common Era - a period when natural and anthropogenic climate forcings are reasonably well constrained - provide valuable perspectives on anthropogenic greenhouse warming, but have focused mainly on the Northern Hemisphere using records derived primarily from terrestrial settings. Given the importance of the oceans in determining the pace and regional structure of climate changes, it is essential to extend our palaeoclimate assessments to determine how regional-scale warming developed in the oceans and over land during the Industrial Era. Here we use post-1500CE palaeoclimate records to show that sustained industrial-era warming of the tropical oceans first developed during the mid-19th Century, and was near-synchronous with Northern Hemisphere continental warming. The early onset of sustained, significant warming in palaeoclimate records and model simulations suggests greenhouse forcing of industrial-era warming commenced as early as the mid-19th Century, and included an enhanced equatorial ocean response mechanism. The development of Southern Hemisphere warming is delayed in reconstructions, but this apparent delay is not reproduced in climate simulations. Our findings imply that instrumental records are too short to comprehensively assess anthropogenic climate change, and in some regions 180 years of industrial-era warming has already caused surface temperatures to emerge above pre-industrial variability. *PAGES 2k Consortium authors are: Kaustubh Thirumalai, Belen Martrat, Hugues Goosse, Steven J. Phipps, Eric J. Steig, K. Halimeda Kilbourne, Casey P. Saenger, Jens Zinke, Guillaume Leduc, Jason A. Addison, P. Graham Mortyn, Marit-Solveig Seidenkrantz, Marie-Alexandrine Sicre, Kandasamy Selvaraj, Helena L. Filipsson, Raphael

  16. The Discovery of Global Warming

    Science.gov (United States)

    MacCracken, Michael C.

    2004-07-01

    At the beginning of the twentieth century, the prospect of ``global warming'' as a result of human activities was thought to be far off, and in any case, likely to be beneficial. As we begin the twenty-first century, science adviser to the British government, Sir David King, has said that he considers global warming to be the world's most important problem, including terrorism. Yet, dealing with it has become the subject of a contentious international protocol, numerous conferences of international diplomats, and major scientific assessments and research programs. Spencer Weart, who is director of the Center for History of Physics of the American Institute of Physics, has taken on the challenge of explaining how this came to be. In the tradition of the Intergovernmental Panel on Climate Change (IPCC), which was established in 1988 to evaluate and assess the state of global warming science, this book is roughly equivalent to the Technical Summary, in terms of its technical level, being quite readable, but with substantive content about the main lines of evidence. Underpinning this relatively concise presentation, there is a well-developed-and still developing-Web site that, like the detailed chapters of the full IPCC assessment reports, provides vastly more information and linkages to a much wider set of reference materials (see http://www.aip.org/history/climate).

  17. Research on trend of warm-humid climate in Central Asia

    Science.gov (United States)

    Gong, Zhi; Peng, Dailiang; Wen, Jingyi; Cai, Zhanqing; Wang, Tiantian; Hu, Yuekai; Ma, Yaxin; Xu, Junfeng

    2017-07-01

    Central Asia is a typical arid area, which is sensitive and vulnerable part of climate changes, at the same time, Central Asia is the Silk Road Economic Belt of the core district, the warm-humid climate change will affect the production and economic development of neighboring countries. The average annual precipitation, average anneal temperature and evapotranspiration are the important indexes to weigh the climate change. In this paper, the annual precipitation, annual average temperature and evapotranspiration data of every pixel point in Central Asia are analyzed by using long-time series remote sensing data to analyze the trend of warm and humid conditions. Finally, using the model to analyzed the distribution of warm-dry trend, the warm-wet trend, the cold-dry trend and the cold-wet trend in Central Asia and Xinjiang area. The results showed that most of the regions of Central Asia were warm-humid and warm-dry trends, but only a small number of regions showed warm-dry and cold-dry trends. It is of great significance to study the climatic change discipline and guarantee the ecological safety and improve the ability to cope with climate change in the region. It also provide scientific basis for the formulation of regional climate change program. The first section in your paper

  18. Recent high mountain rockfalls and warm daily temperature extremes

    Science.gov (United States)

    Allen, S. K.; Huggel, C.

    2012-04-01

    Linkages between longer term warming of the climate, related changes in the cryosphere, and destabilisation of high mountain rockwalls have been documented in several studies. Although understanding is far from complete, a range of physical processes related to longer term warming are understood to have an effect on slope stability. More recently, some attention has turned to the possible influence of much shorter periods of extremely warm temperatures, as a contributing factor, or even trigger of slope failures. So far, studies have not extended beyond highlighting one or a few individual events, and no common approach to quantifying the 'extremity' of the prevailing temperatures has been used. In the current study, we integrate established practices used in the climatology community in the analyses of climate extremes, together with an inventory of ca. 20 recent rock failures (1987 - 2010) in the central European Alps, to assess temporal relationships between daily air temperature extremes and rock failure occurrence. Using data from three high elevation recording sites across Switzerland, we focus on daily maximum temperatures in the 4 weeks immediately prior to each rockfall occurrence, where an extremely warm day is defined as exceeding the 95th percentile during the climatological reference period of 1971 - 2000. The 95th percentile is calculated in a 21 day moving window, so that extreme temperatures are considered relative to the time of year, and not on an annual basis. In addition, rock failures from the Southern Alps of New Zealand are analysed, although high elevation climate data are limited from this region. Results from the European Alps show that a majority of recent slope failures have been preceded by one or more extreme, unseasonably warm days, most notably in the week immediately prior to the failure. For example, for 9 slope failures in the Valais - Mt Blanc region (based on Grand St Bernhard climate data), 6 were proceeded by extremely warm

  19. Does the projected pathway to global warming targets matter?

    Science.gov (United States)

    Bärring, Lars; Strandberg, Gustav

    2018-02-01

    Since the ‘Paris agreement’ in 2015 there has been much focus on what a +1.5 °C or +2 °C warmer world would look like. Since the focus lies on policy relevant global warming targets, or specific warming levels (SWLs), rather than a specific point in time, projections are pooled together to form SWL ensembles based on the target temperature rather than emission scenario. This study uses an ensemble of CMIP5 global model projections to analyse how well SWL ensembles represent the stabilized climate of global warming targets. The results show that the SWL ensembles exhibit significant trends that reflect the transient nature of the RCP scenarios. These trends have clear effect on the timing and clustering of monthly cold and hot extremes, even though the effect on the temperature of the extreme months is less visible. In many regions there is a link between choice of RCP scenario used in the SWL ensemble and climate change signal in the highest monthly temperatures. In other regions there is no such clear-cut link. From this we conclude that comprehensive analyses of what prospects the different global warming targets bring about will require stabilization scenarios. Awaiting such targeted scenarios we suggest that prudent use of SWL scenarios, taking their characteristics and limitations into account, may serve as reasonable proxies in many situations.

  20. Signature of ocean warming in global fisheries catch.

    Science.gov (United States)

    Cheung, William W L; Watson, Reg; Pauly, Daniel

    2013-05-16

    Marine fishes and invertebrates respond to ocean warming through distribution shifts, generally to higher latitudes and deeper waters. Consequently, fisheries should be affected by 'tropicalization' of catch (increasing dominance of warm-water species). However, a signature of such climate-change effects on global fisheries catch has so far not been detected. Here we report such an index, the mean temperature of the catch (MTC), that is calculated from the average inferred temperature preference of exploited species weighted by their annual catch. Our results show that, after accounting for the effects of fishing and large-scale oceanographic variability, global MTC increased at a rate of 0.19 degrees Celsius per decade between 1970 and 2006, and non-tropical MTC increased at a rate of 0.23 degrees Celsius per decade. In tropical areas, MTC increased initially because of the reduction in the proportion of subtropical species catches, but subsequently stabilized as scope for further tropicalization of communities became limited. Changes in MTC in 52 large marine ecosystems, covering the majority of the world's coastal and shelf areas, are significantly and positively related to regional changes in sea surface temperature. This study shows that ocean warming has already affected global fisheries in the past four decades, highlighting the immediate need to develop adaptation plans to minimize the effect of such warming on the economy and food security of coastal communities, particularly in tropical regions.

  1. Global warming and obesity: a systematic review.

    Science.gov (United States)

    An, R; Ji, M; Zhang, S

    2018-02-01

    Global warming and the obesity epidemic are two unprecedented challenges mankind faces today. A literature search was conducted in the PubMed, Web of Science, EBSCO and Scopus for articles published until July 2017 that reported findings on the relationship between global warming and the obesity epidemic. Fifty studies were identified. Topic-wise, articles were classified into four relationships - global warming and the obesity epidemic are correlated because of common drivers (n = 21); global warming influences the obesity epidemic (n = 13); the obesity epidemic influences global warming (n = 13); and global warming and the obesity epidemic influence each other (n = 3). We constructed a conceptual model linking global warming and the obesity epidemic - the fossil fuel economy, population growth and industrialization impact land use and urbanization, motorized transportation and agricultural productivity and consequently influences global warming by excess greenhouse gas emission and the obesity epidemic by nutrition transition and physical inactivity; global warming also directly impacts obesity by food supply/price shock and adaptive thermogenesis, and the obesity epidemic impacts global warming by the elevated energy consumption. Policies that endorse deployment of clean and sustainable energy sources, and urban designs that promote active lifestyles, are likely to alleviate the societal burden of global warming and obesity. © 2017 World Obesity Federation.

  2. CFC Destruction of Ozone - Major Cause of Recent Global Warming!

    Science.gov (United States)

    Ashworth, R. A.

    2008-12-01

    There has been a lot of discussion about global warming. Some say anthropogenic carbon dioxide (CO2) emissions caused the earth to warm. Others say there is no abnormality at all, that it is just natural warming. As you will see from the data presented and analyzed, a greater than normal warming did occur in recent times but no measurements confirm an increase in CO2, whether anthropogenic or natural, had any effect on global temperatures. There is however, strong evidence that anthropogenic emissions of chlorofluorocarbons (CFCs) were the major cause of the recent abnormal warming. CFCs have created both unnatural atmospheric cooling and warming based on these facts: CFCs have destroyed ozone in the lower stratosphere/ upper troposphere causing these zones in the atmosphere to cool 1.37°C from 1966 to 1998. This time span was selected to eliminate the effect of the natural solar irradiance (cooling-warming) cycle effect on the earth's temperature. The loss of ozone allowed more UV light to pass through the stratosphere at a sufficient rate to warm the lower troposphere plus 8-3/4" of the earth by 0.48°C (1966 to 1998). Mass and energy balances show that the energy that was absorbed in the lower stratosphere and upper troposphere hit the lower troposphere/earth at a sustainable level of 1.69 × 10 18 Btu more in 1998 than it did in 1966. Greater ozone depletion in the Polar Regions has caused these areas to warm some two and one-half (2 1/2) times that of the average earth temperature -1.2°C versus 0.48°C. This has caused permafrost to melt, which is releasing copious quantities of methane, estimated at 100 times that of manmade CO2 release, to the atmosphere. Methane in the atmosphere slowly converts to CO2 and water vapor and its release has contributed to higher CO2 concentrations in the atmosphere. There is a temperature anomaly in Antarctica. The Signey Island landmass further north, warmed like the rest of the Polar Regions; but south at Vostok, there has

  3. Antarctic shelf warming under climate change: Insights from eddying climate models

    Science.gov (United States)

    Goddard, Paul; Dufour, Carolina O.; Yin, Jianjun; Griffies, Stephen M.; Winton, Michael

    2017-04-01

    Ocean warming around the Antarctic Ice Sheet has important implications for ice sheet mass loss and global sea level rise. Understanding the ocean processes responsible for Antarctic shelf warming is thus critical to improve climate projections. Several recent studies have pointed out the role of ocean mesoscale eddies in bringing heat onto the shelf with a focus on specific regions, such as the Western Antarctic Peninsula. However, we still lack a more general picture of ocean warming over the whole Antarctic shelf region and a detailed analysis of the response of heat transport to climate change. In this study, we present an analysis of the response of ocean heat transport at the Antarctic shelf break to climate change, and we address the role of mesoscale eddies in this transport. To do so, we use two eddying climate models of different resolutions in the ocean (0.25° and 0.10°) each run under a preindustrial forcing scenario and a climate change forcing scenario. Analyses of the heat transport across the Antarctic Slope Front (ASF) are carried out with a decomposition of the transport into its time-mean and eddy components. Heat budgets over the shelf region are also performed to investigate the role of other processes (e.g. surface fluxes) in shelf warming. Finally, the Antarctic shelf region is divided into several sub-regions to examine geographical variations in the warming. We find that the shelf regions warm under climate change due to a combination of warmer atmospheric temperatures, a large reduction of sea ice coverage, increased heat transport across the ASF or increased freshening at the surface. We discuss the impact of each of these factors on shelf warming in the different regions, as well as the contribution of mesoscale eddies to this warming.

  4. Global Warming and 21st Century Drying

    Science.gov (United States)

    Cook, Benjamin I.; Smerdun, Jason E.; Seager, Richard; Coats, Sloan

    2014-01-01

    Global warming is expected to increase the frequency and intensity of droughts in the twenty-first century, but the relative contributions from changes in moisture supply (precipitation) versus evaporative demand (potential evapotranspiration; PET) have not been comprehensively assessed. Using output from a suite of general circulation model (GCM) simulations from phase 5 of the Coupled Model Intercomparison Project, projected twentyfirst century drying and wetting trends are investigated using two offline indices of surface moisture balance: the Palmer Drought Severity Index (PDSI) and the Standardized Precipitation Evapotranspiration Index (SPEI). PDSI and SPEI projections using precipitation and Penman- Monteith based PET changes from the GCMs generally agree, showing robust cross-model drying in western North America, Central America, the Mediterranean, southern Africa, and the Amazon and robust wetting occurring in the Northern Hemisphere high latitudes and east Africa (PDSI only). The SPEI is more sensitive to PET changes than the PDSI, especially in arid regions such as the Sahara and Middle East. Regional drying and wetting patterns largely mirror the spatially heterogeneous response of precipitation in the models, although drying in the PDSI and SPEI calculations extends beyond the regions of reduced precipitation. This expansion of drying areas is attributed to globally widespread increases in PET, caused by increases in surface net radiation and the vapor pressure deficit. Increased PET not only intensifies drying in areas where precipitation is already reduced, it also drives areas into drought that would otherwise experience little drying or even wetting from precipitation trends alone. This PET amplification effect is largest in the Northern Hemisphere mid-latitudes, and is especially pronounced in western North America, Europe, and southeast China. Compared to PDSI projections using precipitation changes only, the projections incorporating both

  5. GLOBAL WARMING AND CLIMATE CHANGE IN SOUTH AMERICA

    Directory of Open Access Journals (Sweden)

    PATRICK PATERSON

    2017-12-01

    Full Text Available Global warming presents one of the most serious threats to South American nations. Countries in the region are at risk of a variety of climate change related problems: rising sea levels, diminishing potable water supplies, forest res, intense storms and ooding, heat waves and the spread of diseases. These disasters are occurring more frequently in the region and will likely increase in intensity also. The armed forces in the region are the only government departments with both the capacity and the manpower to respond to these massive catastrophes. Military support to civilian authorities will be required more frequently and under more severe conditions as climate change conditions worsen.

  6. Global warming: knowledge and views of Iranian students.

    Science.gov (United States)

    Yazdanparast, Taraneh; Salehpour, Sousan; Masjedi, Mohammad Reza; Seyedmehdi, Seyed Mohammad; Boyes, Eddie; Stanisstreet, Martin; Attarchi, Mirsaeed

    2013-04-06

    Study of students' knowledge about global warming can help authorities to have better imagination of this critical environmental problem. This research examines high school students' ideas about greenhouse effect and the results may be useful for the respective authorities to improve cultural and educational aspects of next generation. In this cross-sectional study, a 42 question questionnaire with mix of open and closed questions was used to evaluate high school students' view about the mechanism, consequences, causes and cures of global warming. To assess students' knowledge, cognitive score was also calculated. 1035 students were randomly selected from 19 educational districts of Tehran. Sampling method was multi stage. Only 5.1% of the students could explain greenhouse effect correctly and completely. 88.8% and 71.2% respectively believed "if the greenhouse effect gets bigger the Earth will get hotter" and "incidence of more skin cancers is a consequence of global warming". 69.6% and 68.8% respectively thought "the greenhouse effect is made worse by too much carbon dioxide" and "presence of ozone holes is a cause of greenhouse effect". 68.4% believed "not using cars so much is a cure for global warming". While a student's 'cognitive score' could range from -36 to +36, Students' mean cognitive score was equal to +1.64. Mean cognitive score of male students and grade 2 & 3 students was respectively higher than female ones (P<0.01) and grade 1 students (P<0.001) but there was no statistically significant difference between students of different regions (P>0.05). In general, students' knowledge about global warming was not acceptable and there were some misconceptions in the students' mind, such as supposing ozone holes as a cause and more skin cancer as a consequence of global warming. The Findings of this survey indicate that, this important stratum of society have been received no sufficient and efficient education and sensitization on this matter.

  7. Cutaneous warming promotes sleep onset.

    Science.gov (United States)

    Raymann, Roy J E M; Swaab, Dick F; Van Someren, Eus J W

    2005-06-01

    Sleep occurs in close relation to changes in body temperature. Both the monophasic sleep period in humans and the polyphasic sleep periods in rodents tend to be initiated when core body temperature is declining. This decline is mainly due to an increase in skin blood flow and consequently skin warming and heat loss. We have proposed that these intrinsically occurring changes in core and skin temperatures could modulate neuronal activity in sleep-regulating brain areas (Van Someren EJW, Chronobiol Int 17: 313-54, 2000). We here provide results compatible with this hypothesis. We obtained 144 sleep-onset latencies while directly manipulating core and skin temperatures within the comfortable range in eight healthy subjects under controlled conditions. The induction of a proximal skin temperature difference of only 0.78 +/- 0.03 degrees C (mean +/- SE) around a mean of 35.13 +/- 0.11 degrees C changed sleep-onset latency by 26%, i.e., by 3.09 minutes [95% confidence interval (CI), 1.91 to 4.28] around a mean of 11.85 min (CI, 9.74 to 14.41), with faster sleep onsets when the proximal skin was warmed. The reduction in sleep-onset latency occurred despite a small but significant decrease in subjective comfort during proximal skin warming. The induction of changes in core temperature (delta = 0.20 +/- 0.02 degrees C) and distal skin temperature (delta = 0.74 +/- 0.05 degrees C) were ineffective. Previous studies have demonstrated correlations between skin temperature and sleep-onset latency. Also, sleep disruption by ambient temperatures that activate thermoregulatory defense mechanisms has been shown. The present study is the first to experimentally demonstrate a causal contribution to sleep-onset latency of skin temperature manipulations within the normal nocturnal fluctuation range. Circadian and sleep-appetitive behavior-induced variations in skin temperature might act as an input signal to sleep-regulating systems.

  8. Cosmic Rays and Global Warming

    OpenAIRE

    Sloan, T.; Wolfendale, A W

    2007-01-01

    It has been claimed by others that observed temporal correlations of terrestrial cloud cover with `the cosmic ray intensity' are causal. The possibility arises, therefore, of a connection between cosmic rays and Global Warming. If true, the implications would be very great. We have examined this claim to look for evidence to corroborate it. So far we have not found any and so our tentative conclusions are to doubt it. Such correlations as appear are more likely to be due to the small variatio...

  9. [Medical consequences of global warming].

    Science.gov (United States)

    Swynghedauw, Bernard

    2009-04-01

    The global warming of the planet and its anthropogenic origin are no longer debatable. Nevertheless, from a medical point of view, while the epidemiological consequences of the warming are rather well-known, the biological consequences are still poorly documented. This is a good example of evolutionary (or darwinian) medicine. The research strategy of this systematic review is based on both PubMed during the period of 2000-2007 and several reviews articles for the period >2000. From a medical point of view, there are four types of consequences. 1-The simple elevation of the average external temperature is accompanied by an increased global mortality and morbidity, the mortality/external temperature is a J curve, with the warm branch more pronounced than the cold one. A recent study on 50 different cities had confirmed that global, and more specifically cardiovascular mortalities were enhanced at the two extreme of the temperatures. 2-The acute heatwaves, such as that which happened in France in August 2003, have been studied in detail by several groups. The mortality which was observed during the recent heatwaves was not compensated by harvesting, strongly suggesting that we were dealing with heat stroke, and that such an increased mortality was more reflecting the limits of our adaptational capacities than aggravation of a previously altered health status. 3-Climate changes have modified the repartition and virulence of pathogenic agents (dengue, malaria...) and above all their vectors. Such modifications were exponential and are likely to reflect the biological properties of parasites. 4-Indirect consequences of global warming include variations in the hydraulic cycle, the new form of tropical hurricanes and many different changes affecting both biodiversity and ecosystems. They will likely result in an increased level of poverty. These finding gave rise to several basic biological questions, rarely evoked, and that concern the limits of the adaptational

  10. Drought under Global Warming: A Review

    Science.gov (United States)

    Dai, A.

    2011-12-01

    One of the big concerns associated with global warming is the potential change to land surface moisture conditions that could have a huge impact on agriculture, freshwater resources, and many other aspects of our society and the environment. How drought has changed during recent past and how it might change in the coming decades is increasingly becoming a great concern as global warming continues and more severe droughts are reported in the media. In this presentation, I will provide an overview, based on my own and others' work, of how drought has changed in the last several centuries and during recent decades over many regions around the world based on historical records, and how it might change in the coming decades based on IPCC AR4 model-predicted climate changes. I will present results from analyses of changes in precipitation, streamflow, soil moisture, and (improved) Palmer Drought Severity Index (PDSI) to show that aridity has increased during the last 50-60 years over many land areas, and rapid warming since the 1980s has contributed significantly to this drying. The PDSI (with improved evapotranspiration estimates) calculated from the AR4 multi-model predicted future climate suggests severe drying in the next 20-50 years over most land areas except the northern high-latitudes and parts of Asia. This drying pattern is consistent with other analyses of model-predicted soil moisture and precipitation changes. Although the quantitative interpretation of the future PDSI values may need to be cautious, combined with the other analyses, the PDSI result points to a dire situation with more severe to extreme droughts in the coming decades over the continental U.S., most of Africa and South America, Australia, southern Europe, and western and southeastern Asia. Changes in precipitation play an important role over many land areas, but enhanced evaporation due to increased radiative heating is also a major factor for the model-predicted drying. For more details, see

  11. Climate variability and dengue fever in warm and humid Mexico.

    Science.gov (United States)

    Colón-González, Felipe J; Lake, Iain R; Bentham, Graham

    2011-05-01

    Multiple linear regression models were fitted to look for associations between changes in the incidence rate of dengue fever and climate variability in the warm and humid region of Mexico. Data were collected for 12 Mexican provinces over a 23-year period (January 1985 to December 2007). Our results show that the incidence rate or risk of infection is higher during El Niño events and in the warm and wet season. We provide evidence to show that dengue fever incidence was positively associated with the strength of El Niño and the minimum temperature, especially during the cool and dry season. Our study complements the understanding of dengue fever dynamics in the region and may be useful for the development of early warning systems.

  12. Population growth and global warming

    Science.gov (United States)

    Short, R.V.

    2009-01-01

    When I was born in 1930, the human population of the world was a mere 2 billion. Today, it has already reached 6.8 billion, and is projected to reach 9.1 billion by 2050. That is unsustainable. It is slowly beginning to dawn on us that Global Warming is the result of increasing human CO2 emissions, and the more people there are in the world, the worse it will become. Ultimately, it is the sky that will prove to be the limit to our numbers. The developed countries of the world are the most affluent, and also the most effluent, so we must lead by example and contain our own population growth and per capita emissions. We also have a big debt to repay to former colonial territories in Africa, Asia and South America, who desperately need our help to contain their excessive rates of population growth. Belgian and Dutch obstetricians and gynaecologists can play a critical role in this endeavour. After all, we already have a pill that will stop global warming – the oral contraceptive pill. PMID:25478068

  13. Multi-scale responses to warming in an experimental insect metacommunity.

    Science.gov (United States)

    Grainger, Tess Nahanni; Gilbert, Benjamin

    2017-12-01

    In metacommunities, diversity is the product of species interactions at the local scale and dispersal between habitat patches at the regional scale. Although warming can alter both species interactions and dispersal, the combined effects of warming on these two processes remains uncertain. To determine the independent and interactive effects of warming-induced changes to local species interactions and dispersal, we constructed experimental metacommunities consisting of enclosed milkweed patches seeded with five herbivorous milkweed specialist insect species. We treated metacommunities with two levels of warming (unwarmed and warmed) and three levels of connectivity (isolated, low connectivity, high connectivity). Based on metabolic theory, we predicted that if plant resources were limited, warming would accelerate resource drawdown, causing local insect declines and increasing both insect dispersal and the importance of connectivity to neighboring patches for insect persistence. Conversely, given abundant resources, warming could have positive local effects on insects, and the risk of traversing a corridor to reach a neighboring patch could outweigh the benefits of additional resources. We found support for the latter scenario. Neither resource drawdown nor the weak insect-insect associations in our system were affected by warming, and most insect species did better locally in warmed conditions and had dispersal responses that were unchanged or indirectly affected by warming. Dispersal across the matrix posed a species-specific risk that led to declines in two species in connected metacommunities. Combined, this scaled up to cause an interactive effect of warming and connectivity on diversity, with unwarmed metacommunities with low connectivity incurring the most rapid declines in diversity. Overall, this study demonstrates the importance of integrating the complex outcomes of species interactions and spatial structure in understanding community response to climate

  14. Using historical and experimental data to reveal warming effects on ant assemblages.

    Directory of Open Access Journals (Sweden)

    Julian Resasco

    Full Text Available Historical records of species are compared with current records to elucidate effects of recent climate change. However, confounding variables such as succession, land-use change, and species invasions make it difficult to demonstrate a causal link between changes in biota and changes in climate. Experiments that manipulate temperature can overcome this issue of attribution, but long-term impacts of warming are difficult to test directly. Here we combine historical and experimental data to explore effects of warming on ant assemblages in southeastern US. Observational data span a 35-year period (1976-2011, during which mean annual temperatures had an increasing trend. Mean summer temperatures in 2010-2011 were ∼ 2.7 °C warmer than in 1976. Experimental data come from an ongoing study in the same region, for which temperatures have been increased ∼ 1.5-5.5 °C above ambient from 2010 to 2012. Ant species richness and evenness decreased with warming under natural but not experimental warming. These discrepancies could have resulted from differences in timescales of warming, abiotic or biotic factors, or initial species pools. Species turnover tended to increase with temperature in observational and experimental datasets. At the species level, the observational and experimental datasets had four species in common, two of which exhibited consistent patterns between datasets. With natural and experimental warming, collections of the numerically dominant, thermophilic species, Crematogaster lineolata, increased roughly two-fold. Myrmecina americana, a relatively heat intolerant species, decreased with temperature in natural and experimental warming. In contrast, species in the Solenopsis molesta group did not show consistent responses to warming, and Temenothorax pergandei was rare across temperatures. Our results highlight the difficulty of interpreting community responses to warming based on historical records or experiments alone. Because some

  15. Natural resource management: implications for global warming

    Energy Technology Data Exchange (ETDEWEB)

    Shen, S. (Harvard University, Cambridge, MA (USA))

    1990-01-01

    The opportunities offered by the global warming alert for global natural resource management are reviewed. The author systematically introduced a new discipline of managing risks involved in local large scale climatic swings which is based on international and interdisciplinary transfer of knowledge, benefiting citizens of industrialized nations, the industrializing nations, as well as the developing nations. Several programs to utilize the opportunities are outlined, including (A) the monitoring of increased availability of forest land in the circumpolar subarctic area, (B) the deployment of biologically engineered reforestation methods and (C) the production of grain-based and wood based liquid fuel and plastic feedstock to tackle the new energy crisis. Policies must represent collective wisdom in the socio-economic as well as scientific contexts. Newly industralized countries must take into account the existing energy politics which affects energy economics and energy and material security. The paramount importance of the ability to use thermodynamically sound technologies and technologies that are based on renewable resources is to be recognized. The choice of technology must be based on the technology's material and energy efficiency. The basic philosophy of cooperation between nations and coordination of activities to improve resource management in the long term must be based on a responsibility system applicable internationally, and an understanding of resource management that can be translated into policy action. Transboundary environmental and economic development problems are best solved regionally by a regional band of nations. 30 refs.

  16. Changes in aridity in response to the global warming hiatus

    Science.gov (United States)

    Guan, Xiaodan; Huang, Jianping; Guo, Ruixia

    2017-02-01

    The global warming slowdown or warming hiatus, began around the year 2000 and has persisted for nearly 15 years. Most studies have focused on the interpretation of the hiatus in temperature. In this study, changes in a global aridity index (AI) were analyzed by using a newly developed dynamical adjustment method that can successfully identify and separate dynamically induced and radiatively forced aridity changes in the raw data. The AI and Palmer Drought Severity Index produced a wetting zone over the mid-to-high latitudes of the Northern Hemisphere in recent decades. The dynamical adjustment analysis suggested that this wetting zone occurred in response to the global warming hiatus. The dynamically induced AI (DAI) played a major role in the AI changes during the hiatus period, and its relationships with the North Atlantic Oscillation (NAO), Pacific Decadal Oscillation (PDO), and Atlantic Multi-decadal Oscillation (AMO) also indicated that different phases of the NAO, PDO, and AMO contributed to different performances of the DAI over the Northern Hemisphere. Although the aridity wetting over the mid-to-high latitudes may relieve long-term drying in certain regions, the hiatus is temporary, and so is the relief. Accelerated global warming will return when the NAO, PDO, and AMO revert to their opposite phases in the future, and the wetting zone is likely to disappear.

  17. Tree water dynamics in a drying and warming world.

    Science.gov (United States)

    Grossiord, Charlotte; Sevanto, Sanna; Borrego, Isaac; Chan, Allison M; Collins, Adam D; Dickman, Lee T; Hudson, Patrick J; McBranch, Natalie; Michaletz, Sean T; Pockman, William T; Ryan, Max; Vilagrosa, Alberto; McDowell, Nate G

    2017-09-01

    Disentangling the relative impacts of precipitation reduction and vapour pressure deficit (VPD) on plant water dynamics and determining whether acclimation may influence these patterns in the future is an important challenge. Here, we report sap flux density (FD ), stomatal conductance (Gs ), hydraulic conductivity (KL ) and xylem anatomy in piñon pine (Pinus edulis) and juniper (Juniperus monosperma) trees subjected to five years of precipitation reduction, atmospheric warming (elevated VPD) and their combined effects. No acclimation occurred under precipitation reduction: lower Gs and FD were found for both species compared to ambient conditions. Warming reduced the sensibility of stomata to VPD for both species but resulted in the maintenance of Gs and FD to ambient levels only for piñon. For juniper, reduced soil moisture under warming negated benefits of stomatal adjustments and resulted in reduced FD , Gs and KL . Although reduced stomatal sensitivity to VPD also occurred under combined stresses, reductions in Gs , FD and KL took place to similar levels as under single stresses for both species. Our results show that stomatal conductance adjustments to high VPD could minimize but not entirely prevent additive effects of warming and drying on water use and carbon acquisition of trees in semi-arid regions. © 2017 John Wiley & Sons Ltd.

  18. Sustainable construction in remote cold regions.

    Science.gov (United States)

    2015-12-01

    The goal of this project was to identify sustainable construction techniques appropriate for remote and cold regions, some of which apply to : operations and maintenance as well. The vast body of literature regarding green construction in warm region...

  19. Daytime warming has stronger negative effects on soil nematodes than night-time warming.

    Science.gov (United States)

    Yan, Xiumin; Wang, Kehong; Song, Lihong; Wang, Xuefeng; Wu, Donghui

    2017-03-20

    Warming of the climate system is unequivocal, that is, stronger warming during night-time than during daytime. Here we focus on how soil nematodes respond to the current asymmetric warming. A field infrared heating experiment was performed in the western of the Songnen Plain, Northeast China. Three warming modes, i.e. daytime warming, night-time warming and diurnal warming, were taken to perform the asymmetric warming condition. Our results showed that the daytime and diurnal warming treatment significantly decreased soil nematodes density, and night-time warming treatment marginally affected the density. The response of bacterivorous nematode and fungivorous nematode to experimental warming showed the same trend with the total density. Redundancy analysis revealed an opposite effect of soil moisture and soil temperature, and the most important of soil moisture and temperature in night-time among the measured environment factors, affecting soil nematode community. Our findings suggested that daily minimum temperature and warming induced drying are most important factors affecting soil nematode community under the current global asymmetric warming.

  20. Daytime warming has stronger negative effects on soil nematodes than night-time warming.

    Science.gov (United States)

    Yan, Xiumin; Wang, Kehong; Song, Lihong; Wang, Xuefeng; Wu, Donghui

    2017-03-07

    Warming of the climate system is unequivocal, that is, stronger warming during night-time than during daytime. Here we focus on how soil nematodes respond to the current asymmetric warming. A field infrared heating experiment was performed in the western of the Songnen Plain, Northeast China. Three warming modes, i.e. daytime warming, night-time warming and diurnal warming, were taken to perform the asymmetric warming condition. Our results showed that the daytime and diurnal warming treatment significantly decreased soil nematodes density, and night-time warming treatment marginally affected the density. The response of bacterivorous nematode and fungivorous nematode to experimental warming showed the same trend with the total density. Redundancy analysis revealed an opposite effect of soil moisture and soil temperature, and the most important of soil moisture and temperature in night-time among the measured environment factors, affecting soil nematode community. Our findings suggested that daily minimum temperature and warming induced drying are most important factors affecting soil nematode community under the current global asymmetric warming.

  1. Global warming reduces plant reproductive output for temperate multi-inflorescence species on the Tibetan plateau.

    Science.gov (United States)

    Liu, Yinzhan; Mu, Junpeng; Niklas, Karl J; Li, Guoyong; Sun, Shucun

    2012-07-01

    • Temperature is projected to increase more during the winter than during the summer in cold regions. The effects of winter warming on reproductive effort have not been examined for temperate plant species. • Here, we report the results of experimentally induced seasonal winter warming (0.4 and 2.4°C increases in growing and nongrowing seasons, respectively, using warmed and ambient open-top chambers in a Tibetan Plateau alpine meadow) for nine indeterminate-growing species producing multiple (single-flowered or multi-flowered) inflorescences and three determinate-growing species producing single inflorescences after a 3-yr period of warming. • Warming reduced significantly flower number and seed production per plant for all nine multi-inflorescence species, but not for the three single-inflorescence species. Warming had an insignificant effect on the fruit to flower number ratio, seed size and seed number per fruit among species. The reduction in seed production was largely attributable to the decline in flower number per plant. The flowering onset time was unaffected for nine of the 12 species. Therefore, the decline in flower production and seed production in response to winter warming probably reflects a physiological response (e.g. metabolic changes associated with flower production). • Collectively, the data indicate that global warming may reduce flower and seed production for temperate herbaceous species and will probably have a differential effect on single- vs multi-inflorescence species. © 2012 The Authors. New Phytologist © 2012 New Phytologist Trust.

  2. GLOBAL WARMING BETWEEN SCIENCE AND POLITICS

    Directory of Open Access Journals (Sweden)

    Eugen Străuțiu

    2015-03-01

    Full Text Available During the last three decades, the scientific theory of global warming has become a political ideology. Significant political components are found both in the premises and (especially in the consequences. But witnessed also at least a decade of negationism: global warming research programs are questionable regarding methodology and the ethics of research. Face to all contestations, “Global warming theory” has already become “Global climate change theory”. It is true that global warming ideology preparing a global governing over a strictly limited number of people?

  3. Recent warming in the San Francisco Bay and the California coastal ocean

    Science.gov (United States)

    Chao, Yi; Farrara, John; Zhang, Carrie

    2017-05-01

    During 2014 exceptionally warm water temperatures developed across a wide area off the California coast and within San Francisco Bay (SFB) and persisted through the middle of 2016. Observations and numerical model output are used to document this warming and its origins. The coastal warming was mostly confined to the upper 100 meters of the ocean and was manifested strongly in the two leading modes of upper ocean (0-100 m) temperature variability in the extra-tropical eastern Pacific. Observations in the suggest that the coastal warming in 2014 propagated into nearshore regions from the west and later indicate a warming influence that propagates from south to north into the region associated with the 2015-16 El Niño event. An analysis of the upper ocean (0-100 m) heat budget in a Regional Ocean Modeling System hindcast simulation confirmed this scenario. The results from a set of sensitivity runs with the model in which the lateral boundary conditions varied supports the conclusions drawn from the heat budget analysis. Concerning the warming in the SFB, an examination of the observations and the heat budget in an unstructured-grid numerical model simulation suggests that the warming during the second half of 2014 and early 2016 originates in the adjacent California coastal ocean and propagates through the Golden Gate into the Bay. The finding that the coastal and Bay warming are due to the relatively slow propagation of signals from remote sources raise the possibility that such warming events may be predictable several months in advance.

  4. Contrasting above- and belowground organic matter decomposition and carbon and nitrogen dynamics in response to warming in High Arctic tundra.

    Science.gov (United States)

    Blok, Daan; Faucherre, Samuel; Banyasz, Imre; Rinnan, Riikka; Michelsen, Anders; Elberling, Bo

    2017-12-13

    Tundra regions are projected to warm rapidly during the coming decades. The tundra biome holds the largest terrestrial carbon pool, largely contained in frozen permafrost soils. With warming, these permafrost soils may thaw and become available for microbial decomposition, potentially providing a positive feedback to global warming. Warming may directly stimulate microbial metabolism but may also indirectly stimulate organic matter turnover through increased plant productivity by soil priming from root exudates and accelerated litter turnover rates. Here, we assess the impacts of experimental warming on turnover rates of leaf litter, active layer soil and thawed permafrost sediment in two high-arctic tundra heath sites in NE-Greenland, either dominated by evergreen or deciduous shrubs. We incubated shrub leaf litter on the surface of control and warmed plots for 1 and 2 years. Active layer soil was collected from the plots to assess the effects of 8 years of field warming on soil carbon stocks. Finally, we incubated open cores filled with newly thawed permafrost soil for 2 years in the active layer of the same plots. After field incubation, we measured basal respiration rates of recovered thawed permafrost cores in the lab. Warming significantly reduced litter mass loss by 26% after 1 year incubation, but differences in litter mass loss among treatments disappeared after 2 years incubation. Warming also reduced litter nitrogen mineralization and decreased the litter carbon to nitrogen ratio. Active layer soil carbon stocks were reduced 15% by warming, while soil dissolved nitrogen was reduced by half in warmed plots. Warming had a positive legacy effect on carbon turnover rates in thawed permafrost cores, with 10% higher respiration rates measured in cores from warmed plots. These results demonstrate that warming may have contrasting effects on above- and belowground tundra carbon turnover, possibly governed by microbial resource availability. © 2017 John

  5. Global Warming and the Combatant Commander: Engaging the Arctic Region

    Science.gov (United States)

    2006-10-23

    negatively affected Earth’s natural greenhouse heating mechanism. Most believe the distributed excess of heat-trapping carbon dioxide emissions into...in Earth’s temperature will further melt Arctic glaciers , increase precipitation, and intensify river runoff totals. As a result, more freshwater...Territory, and Oil Exploration The United States and seven other countries (Russia, Canada, Denmark, Norway, Iceland , Sweden, and Finland,) known

  6. Shrub expansion in SW Greenland under modest regional warming

    DEFF Research Database (Denmark)

    Jørgensen, Rasmus Halfdan; Meilby, Henrik; Kollmann, Johannes

    2013-01-01

    Shrub expansion has been observed widely in tundra areas across the Arctic. This phenomenon has been partially attributed to increasing temperatures over the past century. However, relationships among shrub expansion, grazing, and human disturbance have been studied little. SW Greenland is a suba...

  7. Enhanced warming of the subtropical mode water in the North Pacific and North Atlantic

    Science.gov (United States)

    Sugimoto, Shusaku; Hanawa, Kimio; Watanabe, Tomowo; Suga, Toshio; Xie, Shang-Ping

    2017-09-01

    Over the past six decades, the subtropical surface ocean has warmed at rates close to those of global mean surface ocean temperature except in western boundary current regions where the surface warming is locally enhanced by a factor of two. Changes in the subsurface ocean, however, remain unclear because of lack of data. Compiling historical temperature measurements--some available for the first time--here we show that the subtropical mode water has warmed over the past six decades in both the North Pacific and North Atlantic. The rate of the warming is twice as large in the mode waters than at the surface. Subtropical mode waters are important water masses of vertically uniform temperature that are a few hundred metres thick and distributed widely in the main thermocline of the subtropical oceans. The enhanced warming of subtropical mode waters can be traced back to the surface warming in the formation regions along the western boundary current extensions. Furthermore, we detect increased temperature stratification and decreased dissolved oxygen in the subtropical mode waters. The latter change has clear implications for predicting biogeochemical responses to climate warming.

  8. Automobility: Global Warming as Symptomatology

    Directory of Open Access Journals (Sweden)

    Gary Backhaus

    2009-04-01

    Full Text Available The argument of this paper is that sustainability requires a new worldview-paradigm. It critically evaluates Gore’s liberal-based environmentalism in order to show how “shallow ecologies” are called into question by deeper ecologies. This analysis leads to the notion that global warming is better understood as a symptom indicative of the worldview that is the source for environmental crises. Heidegger’s ontological hermeneutics and its critique of modern technology show that the modern worldview involves an enframing (a totalizing technological ordering of the natural. Enframing reveals entities as standing reserve (on demand energy suppliers. My thesis maintains that enframing is geographically expressed as automobility. Because of the energy needs used to maintain automobility, reaching the goal of sustainability requires rethinking the spatial organization of life as a function of stored energy technologies.

  9. Warm liquid calorimetry for LHC

    CERN Document Server

    Geulig,E; Wallraff,W; Bézaguet, Alain-Arthur; Cavanna, F; Cinnini, P; Cittolin, Sergio; Dreesen, P; Demoulin, M; Dunps, L; Fucci, A; Gallay, G; Givernaud, Alain; Gonidec, A; Jank, Werner; Maurin, Guy; Placci, Alfredo; Porte, J P; Radermacher, E; Samyn, D; Schinzel, D; Schmidt, W F; CERN. Geneva. Detector Research and Development Committee

    1990-01-01

    Results from the beam tests of the U/TMP "warm liquid" calorimeter show that such a technique is very promising for the LHC. Our aim is to extend this programme and design a calorimeter that can satisfy the requirements of high rates, high radiation levels, compensation, uniformity and granularity, as well as fully contain hadronic showers. We propose to construct liquid ionization chambers operated at very high fields, capable of collecting the total charge produced by ionizing particles within times comparable to the bunch crossing time of the future Collider. For this reason we plan to extend the current programme on tetramethylpentane (TMP) to tetramethylsilane (TMSi). An electromagnetic calorimeter consisting of very high field ionization chambers filled with TMSi as sensitive medium with Uranium and/or other high density material as absorber will first be built (to be followed by a full-scale calorimeter module), on which newly designed fast amplifiers and readout electronics will be tested. In addition...

  10. DPIS for warm dense matter

    Energy Technology Data Exchange (ETDEWEB)

    Kondo, K.; Kanesue, T.; Horioka, K.; Okamura, M.

    2010-05-23

    Warm Dense Matter (WDM) offers an challenging problem because WDM, which is beyond ideal plasma, is in a low temperature and high density state with partially degenerate electrons and coupled ions. WDM is a common state of matter in astrophysical objects such as cores of giant planets and white dwarfs. The WDM studies require large energy deposition into a small target volume in a shorter time than the hydrodynamical time and need uniformity across the full thickness of the target. Since moderate energy ion beams ({approx} 0.3 MeV/u) can be useful tool for WDM physics, we propose WDM generation using Direct Plasma Injection Scheme (DPIS). In the DPIS, laser ion source is connected to the Radio Frequency Quadrupole (RFQ) linear accelerator directly without the beam transport line. DPIS with a realistic final focus and a linear accelerator can produce WDM.

  11. Enhanced greenhouse gas emissions from the Arctic with experimental warming

    Science.gov (United States)

    Voigt, Carolina; Lamprecht, Richard E.; Marushchak, Maija E.; Lind, Saara E.; Novakovskiy, Alexander; Aurela, Mika; Martikainen, Pertti J.; Biasi, Christina

    2017-04-01

    Temperatures in the Arctic are projected to increase more rapidly than in lower latitudes. With temperature being a key factor for regulating biogeochemical processes in ecosystems, even a subtle temperature increase might promote the release of greenhouse gases (GHGs) to the atmosphere. Usually, carbon dioxide (CO2) and methane (CH4) are the GHGs dominating the climatic impact of tundra. However, bare, patterned ground features in the Arctic have recently been identified as hot spots for nitrous oxide (N2O). N2O is a potent greenhouse gas, which is almost 300 times more effective in its global warming potential than CO2; but studies on arctic N2O fluxes are rare. In this study we examined the impact of temperature increase on the seasonal GHG balance of all three important GHGs (CO2, CH4 and N2O) from three tundra surface types (vegetated peat soils, unvegetated peat soils, upland mineral soils) in the Russian Arctic (67˚ 03' N 62˚ 55' E), during the course of two growing seasons. We deployed open-top chambers (OTCs), inducing air and soil surface warming, thus mimicking predicted warming scenarios. We combined detailed CO2, CH4 and N2O flux studies with concentration measurements of these gases within the soil profile down to the active layer-permafrost interface, and complemented these GHG measurements with detailed soil nutrient (nitrate and ammonium) and dissolved organic carbon (DOC) measurements in the soil pore water profile. In our study, gentle air warming (˜1.0 ˚ C) increased the seasonal GHG release of all dominant surface types: the GHG budget of vegetated peat and mineral soils, which together cover more than 80 % of the land area in our study region, shifted from a sink to a source of -300 to 144 g CO2-eq m-2 and from -198 to 105 g CO2-eq m-2, respectively. While the positive warming response was governed by CO2, we provide here the first in situ evidence that warming increases arctic N2O emissions: Warming did not only enhance N2O emissions from

  12. Design and performance of combined infrared canopy and belowground warming in the B4WarmED (Boreal Forest Warming at an Ecotone in Danger) experiment.

    Science.gov (United States)

    Rich, Roy L; Stefanski, Artur; Montgomery, Rebecca A; Hobbie, Sarah E; Kimball, Bruce A; Reich, Peter B

    2015-06-01

    Conducting manipulative climate change experiments in complex vegetation is challenging, given considerable temporal and spatial heterogeneity. One specific challenge involves warming of both plants and soils to depth. We describe the design and performance of an open-air warming experiment called Boreal Forest Warming at an Ecotone in Danger (B4WarmED) that addresses the potential for projected climate warming to alter tree function, species composition, and ecosystem processes at the boreal-temperate ecotone. The experiment includes two forested sites in northern Minnesota, USA, with plots in both open (recently clear-cut) and closed canopy habitats, where seedlings of 11 tree species were planted into native ground vegetation. Treatments include three target levels of plant canopy and soil warming (ambient, +1.7°C, +3.4°C). Warming was achieved by independent feedback control of voltage input to aboveground infrared heaters and belowground buried resistance heating cables in each of 72-7.0 m(2) plots. The treatments emulated patterns of observed diurnal, seasonal, and annual temperatures but with superimposed warming. For the 2009 to 2011 field seasons, we achieved temperature elevations near our targets with growing season overall mean differences (∆Tbelow ) of +1.84°C and +3.66°C at 10 cm soil depth and (∆T(above) ) of +1.82°C and +3.45°C for the plant canopies. We also achieved measured soil warming to at least 1 m depth. Aboveground treatment stability and control were better during nighttime than daytime and in closed vs. open canopy sites in part due to calmer conditions. Heating efficacy in open canopy areas was reduced with increasing canopy complexity and size. Results of this study suggest the warming approach is scalable: it should work well in small-statured vegetation such as grasslands, desert, agricultural crops, and tree saplings (<5 m tall). © 2015 John Wiley & Sons Ltd.

  13. Efficient Warm-ups: Creating a Warm-up That Works.

    Science.gov (United States)

    Lauffenburger, Sandra Kay

    1992-01-01

    Proper warm-up is important for any activity, but designing an effective warm-up can be time consuming. An alternative approach is to take a cue from Laban Movement Analysis (LMA) and consider movement design from the perspective of space and planes of motion. Efficient warm-up exercises using LMA are described. (SM)

  14. The response of Picea crassifolia forest to climate warming

    Science.gov (United States)

    He, Zhibin; Du, Jun; Yang, Junjun; Chen, Longfei; Zhu, Xi

    2014-05-01

    Picea crassifolia forest, an endemic genus mainly distributing in the Qilian Mountain of Northwest China, is very sensitive to climate warming. In the present study, the response of treeline, phenological period, and sap flow of P. crassifolia forest to climate warming were analyzed though a set of observations and experiments. The result showed: (1) During the past 50 years, the temperature had raised at a mean rate of 0.29° C per decade in this region, especially since 1980s (had increased by a total of more than 1.25° C), obviously higher than increment degree IPCC reported. This resulted in the increase of tree recruitment which was significantly positively correlated with the mean growing season temperature and with the mean minimum temperature in June and in winter. Treeline elevation shifted upward by 5.7 to 13.6 m from 1907 to 1957 and by 6.1 to 10.4 m after 1957. (2) By quantifying the canopy phenology events based on satellite-derived datasets (MODIS-NDVI) from 2001 to 2011, and investigating the correlation with climate factors, a conclusion had been drawn which revealed a 3.7 days/decade advance in the length of growing season. Our results suggested that temperature controlled treeline dynamics and phenological period more strongly than precipitation in the Qilian Mountains. (3) In the case of experimental warming (mean daily temperature was increased 0.83° C, mean daily maximum temperature was increased 4.7° C), the trend for the mass growth of P. crassifolia sapling presented a notable increase under conditions of warming, especially for tree height. The data of sap flow showed that warming facilitated the sap flow of sapling in the end of growing season, which indicated the temperature was a major restriction to sap flow rate, especially in the condition of lower temperature.

  15. Ocean acidification and warming will lower coral reef resilience

    Science.gov (United States)

    Anthony, Kenneth R N; Maynard, Jeffrey A; Diaz-Pulido, Guillermo; Mumby, Peter J; Marshall, Paul A; Cao, Long; Hoegh-Guldberg, Ove

    2011-01-01

    Ocean warming and acidification from increasing levels of atmospheric CO2 represent major global threats to coral reefs, and are in many regions exacerbated by local-scale disturbances such as overfishing and nutrient enrichment. Our understanding of global threats and local-scale disturbances on reefs is growing, but their relative contribution to reef resilience and vulnerability in the future is unclear. Here, we analyse quantitatively how different combinations of CO2 and fishing pressure on herbivores will affect the ecological resilience of a simplified benthic reef community, as defined by its capacity to maintain and recover to coral-dominated states. We use a dynamic community model integrated with the growth and mortality responses for branching corals (Acropora) and fleshy macroalgae (Lobophora). We operationalize the resilience framework by parameterizing the response function for coral growth (calcification) by ocean acidification and warming, coral bleaching and mortality by warming, macroalgal mortality by herbivore grazing and macroalgal growth via nutrient loading. The model was run for changes in sea surface temperature and water chemistry predicted by the rise in atmospheric CO2 projected from the IPCC's fossil-fuel intensive A1FI scenario during this century. Results demonstrated that severe acidification and warming alone can lower reef resilience (via impairment of coral growth and increased coral mortality) even under high grazing intensity and low nutrients. Further, the threshold at which herbivore overfishing (reduced grazing) leads to a coral–algal phase shift was lowered by acidification and warming. These analyses support two important conclusions: Firstly, reefs already subjected to herbivore overfishing and nutrification are likely to be more vulnerable to increasing CO2. Secondly, under CO2 regimes above 450–500 ppm, management of local-scale disturbances will become critical to keeping reefs within an Acropora-rich domain.

  16. Sea level rise with warming above 2 degree

    Science.gov (United States)

    Jevrejeva, Svetlana; Jackson, Luke; Riva, Riccardo; Grinsted, Aslak; Moore, John

    2017-04-01

    Holding the increase in the global average temperature to below 2 °C above pre-industrial levels, and pursuing efforts to limit the temperature increase to 1.5 °C, has been agreed by the representatives of the 196 parties of United Nations, as an appropriate threshold beyond which climate change risks become unacceptably high. Sea level rise is one of the most damaging aspects of warming climate for the more than 600 million people living in low-elevation coastal areas less than 10 meters above sea level. Fragile coastal ecosystems and increasing concentrations of population and economic activity in coastal areas, are reasons why future sea level rise is one of the most damaging aspects of the warming climate. Furthermore, sea level is set to continue to rise for centuries after greenhouse gas emissions concentrations are stabilised due to system inertia and feedback time scales. Impact, risk, adaptation policies and long-term decision making in coastal areas depend on regional and local sea level rise projections and local projections can differ substantially from the global one. Here we provide probabilistic sea level rise projections for the global coastline with warming above the 2 degree goal. A warming of 2°C makes global ocean rise on average by 20 cm, but more than 90% of coastal areas will experience greater rises, 40 cm along the Atlantic coast of North America and Norway, due to ocean dynamics. If warming continues above 2°C, then by 2100 sea level will rise with speeds unprecedented throughout human civilization, reaching 0.9 m (median), and 80% of the global coastline will exceed the global ocean sea level rise upper 95% confidence limit of 1.8 m. Coastal communities of rapidly expanding cities in the developing world, small island states, and vulnerable tropical coastal ecosystems will have a very limited time after mid-century to adapt to sea level rises.

  17. Historical phenological responses in apple to contrasting warming contexts may clarify future crucial responses in Europe

    OpenAIRE

    Legave, Jean-Michel; Farrera, Isabelle; El Yaacoubi, Adnane; Malagi,Gustavo

    2016-01-01

    Phenological responses to warming in temperate fruit trees have rarely been investigated in contrasting warming contexts. This framework is appropriate for highlighting varying responses that would combine chill accumulation declines and heat accumulation increases. A comprehensive overview of historical responses might clarify crucial future responses in the warmest European regions. To examine this issue, a dataset was constituted in apple from flowering dates collected for main...

  18. Species interactions slow warming-induced upward shifts of treelines on the Tibetan Plateau

    OpenAIRE

    Liang, Eryuan

    2016-01-01

    The alpine treeline is commonly regarded as being sensitive to climatic warming because regeneration and growth of trees at treeline generally are limited by low temperature. The alpine treelines of the Tibetan Plateau (TP) occur at the highest elevations (4,900 m above sea level) in the Northern Hemisphere. Ongoing climatic warming is expected to shift treelines upward. Studies of treeline dynamics at regional and local scales, however, have yielded conflicting results, indicating either unc...

  19. Stomatal acclimation to vapour pressure deficit doubles transpiration of small tree seedlings with warming

    DEFF Research Database (Denmark)

    Marchin, Renée M.; Broadhead, Alice A.; Bostic, Laura E.

    2016-01-01

    Future climate change is expected to increase temperature (T) and atmospheric vapour pressure deficit (VPD) in many regions, but the effect of persistent warming on plant stomatal behaviour is highly uncertain. We investigated the effect of experimental warming of 1.9-5.1 °C and increased VPD of ...... with increasing VPD and may necessitate revision of current models based on this assumption....

  20. Nitrogen and Warming Control the Vegetation in Inner Mongolia Tourist Area

    OpenAIRE

    Sun, Qiong; Hu, Xiaobing; Zhang, Chi

    2016-01-01

    The global warming and atmospheric nitrogen deposition problem has become more and more serious under the influence of human activities, and it has become one of the hot issues in this field, which will have far-reaching impact on all kinds of vegetation, thus the functioning of the ecosystem will be changed, which will be reflected in climate warming process. Inner Mongolia Autonomous Region is mainly composed of desert grasslands, so the development and protection of vegetation has consider...

  1. Global Warming: Lessons from Ozone Depletion

    Science.gov (United States)

    Hobson, Art

    2010-01-01

    My teaching and textbook have always covered many physics-related social issues, including stratospheric ozone depletion and global warming. The ozone saga is an inspiring good-news story that's instructive for solving the similar but bigger problem of global warming. Thus, as soon as students in my physics literacy course at the University of…

  2. Strategies for mitigation of global warming

    DEFF Research Database (Denmark)

    Meyer, Niels I

    2009-01-01

    The paper analyses the international negotions on climate change leading up to COP15 in Copenhagen. Supplementary policies for mitigation of global warming are proposed.......The paper analyses the international negotions on climate change leading up to COP15 in Copenhagen. Supplementary policies for mitigation of global warming are proposed....

  3. Exploring the Sociopolitical Dimensions of Global Warming

    Science.gov (United States)

    Sadler, Troy D.; Klosterman, Michelle L.

    2009-01-01

    The authors present an activity to help high school students conceptualize the sociopolitical complexity of global warming through an exploration of varied perspectives on the issue. They argue that socioscientific issues such as global warming present important contexts for learning science and that the social and political dimensions of these…

  4. Awareness And Perception of Global Warming Among ...

    African Journals Online (AJOL)

    BACKGROUND: Increase in the emission of green house gases and the attendant climatic changes have led to the phenomenon of global warming with all its catastrophic consequences. OBJECTIVE: To assess knowledge and perception of the concept of global warming among undergraduate medical students

  5. National Security Implications of Global Warming Policy

    Science.gov (United States)

    2010-03-01

    Although numerous historical examples demonstrate how actual climate change has contributed to the rise and fall of powers, global warming , in and of...become convinced that global warming is universally bad and humans are the primary cause, political leaders may develop ill-advised policies restricting

  6. Warming of Water in a Glass

    Science.gov (United States)

    Paulins, Paulis; Krauze, Armands; Ozolinsh, Maris; Muiznieks, Andris

    2016-01-01

    The article focuses on the process of water warming from 0 °C in a glass. An experiment is performed that analyzes the temperature in the top and bottom layers of water during warming. The experimental equipment is very simple and can be easily set up using devices available in schools. The temperature curves obtained from the experiment help us…

  7. Global warming: Evidence from satellite observations

    National Research Council Canada - National Science Library

    Prabhakara, C; Iacovazzi, R; Yoo, J.‐M; Dalu, G

    2000-01-01

    ...‐weighted global‐mean temperature of the atmosphere, with a peak weight near the mid troposphere, warmed at the rate of 0.13±0.05 Kdecade −1 during 1980 to 1999. The global warming deduced from conventional meteorological data that have been corrected for urbanization effects agrees reasonably with this satellite‐deduced result.

  8. Global Warming: How Much and Why?

    Science.gov (United States)

    Lanouette, William

    1990-01-01

    Summarizes the history of the study of global warming and includes a discussion of the role of gases, like carbon dioxide, methane, and chlorofluorocarbon (CFC). Discusses modern research on the global warming, including computer modelling and the super-greenhouse effect. (YP)

  9. Turkish Students' Ideas about Global Warming

    Science.gov (United States)

    Kilinc, Ahmet; Stanisstreet, Martin; Boyes, Edward

    2008-01-01

    A questionnaire was used to explore the prevalence of ideas about global warming in Year 10 (age 15-16 years) school students in Turkey. The frequencies of individual scientific ideas and misconceptions about the causes, consequences and "cures" of global warming were identified. In addition, several general findings emerged from this…

  10. Implications of climate change (global warming) for the healthcare system.

    Science.gov (United States)

    Raffa, R B; Eltoukhy, N S; Raffa, K F

    2012-10-01

    Temperature-sensitive pathogenic species and their vectors and hosts are emerging in previously colder regions as a consequence of several factors, including global warming. As a result, an increasing number of people will be exposed to pathogens against which they have not previously needed defences. We illustrate this with a specific example of recent emergence of Cryptococcus gattii infections in more temperate climates. The outbreaks in more temperate climates of the highly virulent--but usually tropically restricted--C. gattii is illustrative of an anticipated growing challenge for the healthcare system. There is a need for preparedness by healthcare professionals in anticipation and for management of such outbreaks, including other infections whose recent increased prevalence in temperate climates can be at least partly associated with global warming. (Re)emergence of temperature-sensitive pathogenic species in more temperate climates will present new challenges for healthcare systems. Preparation for outbreaks should precede their occurrence. © 2012 Blackwell Publishing Ltd.

  11. Prolonged warming of the Brazil Current precedes deglaciations

    Science.gov (United States)

    Santos, Thiago P.; Lessa, Douglas O.; Venancio, Igor M.; Chiessi, Cristiano M.; Mulitza, Stefan; Kuhnert, Henning; Govin, Aline; Machado, Thiago; Costa, Karen B.; Toledo, Felipe; Dias, Bruna B.; Albuquerque, Ana Luiza S.

    2017-04-01

    Paleoceanographic reconstructions from the Brazil Current are scarce and lack the required temporal resolution to appropriately represent its variability during key periods of the last glacial-interglacial cycles. Here, we present the first high-temporal resolution multiproxy reconstruction of the Brazil Current at 24 °S covering the last 185 ka. During the last and penultimate glacial periods, our Mg/Ca-derived sea surface temperature (SST) record shows a strong cooling at ca. 47 and ca. 156 ka, respectively, that is followed by a warming trend from late-Marine Isotope Stage (MIS) 3 to MIS 1 and from late-MIS 6 to MIS5e, respectively. Importantly, the Brazil Current warmed uninterruptedly towards Termination I (II) after the low SST at ca. 47 and ca. 156 ka, with no SST minima during the Last Glacial Maximum or penultimate glacial maximum. The reason for the strong cooling and the warming trend during late-MIS 3 and late-MIS 6 could reside in the favorable obliquity configuration. However, this mechanism is not sufficient to sustain the warming observed for the rest of the last and penultimate glacial periods. We propose that the change in the Atlantic meridional overturning circulation (AMOC), as described in the literature, from a "warm" to a "cold mode" for MIS 2 and MIS 6 is responsible for the accumulation of warm waters in the subtropical western South Atlantic, preventing SST minima during the last and penultimate glacial maxima in the region. Change in benthic δ13 C corroborates that a fundamental modification in the AMOC mode might have triggered the heat accumulation. Our data also show a sudden increase in SST and surface salinity during the last glacial descent (MIS 4), indicating that the western portion of the subtropical gyres may have acted as a heat and salt reservoir, while higher latitude climates transited to a glacial background. Our findings imply that the AMOC "cold mode" induces heat storage in the subtropical western South Atlantic and

  12. Warm Dark Matter and Cosmic Reionization

    Science.gov (United States)

    Villanueva-Domingo, Pablo; Gnedin, Nickolay Y.; Mena, Olga

    2018-01-01

    In models with dark matter made of particles with keV masses, such as a sterile neutrino, small-scale density perturbations are suppressed, delaying the period at which the lowest mass galaxies are formed and therefore shifting the reionization processes to later epochs. In this study, focusing on Warm Dark Matter (WDM) with masses close to its present lower bound, i.e., around the 3 keV region, we derive constraints from galaxy luminosity functions, the ionization history and the Gunn–Peterson effect. We show that even if star formation efficiency in the simulations is adjusted to match the observed UV galaxy luminosity functions in both CDM and WDM models, the full distribution of Gunn–Peterson optical depth retains the strong signature of delayed reionization in the WDM model. However, until the star formation and stellar feedback model used in modern galaxy formation simulations is constrained better, any conclusions on the nature of dark matter derived from reionization observables remain model-dependent.

  13. Observed warming over northern South America has an anthropogenic origin

    Science.gov (United States)

    Barkhordarian, Armineh; von Storch, Hans; Zorita, Eduardo; Loikith, Paul C.; Mechoso, Carlos R.

    2017-10-01

    We investigate whether the recently observed trends in daily maximum and minimum near-surface air temperature (Tmax and Tmin, respectively) over South America (SA) are consistent with the simulated response of Tmin and Tmax to anthropogenic forcing. Results indicate that the recently observed warming in the dry seasons is well beyond the range of natural (internal) variability. In the wet season the natural modes of variability explain a substantial portion of Tmin and Tmax variability. We demonstrate that the large-scale component of greenhouse gas (GHG) forcing is detectable in dry-seasonal warming. However, none of the global and regional climate change projections reproduce the observed warming of up to 0.6 K/Decade in Tmax in 1983-2012 over northern SA during the austral spring (SON). Thus, besides the global manifestation of GHG forcing, other external drivers have an imprint. Using aerosols-only forcing simulations, our results provide evidence that anthropogenic aerosols also have a detectable influence in SON and that the indirect effect of aerosols on cloud's lifetime is more compatible with the observed record. In addition, there is an increasing trend in the observed incoming solar radiation over northern SA in SON, which is larger than expected from natural (internal) variability alone. We further show that in the dry seasons the spread of projected trends based on the RCP4.5 scenario derived from 30 CMIP5 models encompasses the observed area-averaged trends in Tmin and Tmax. This may imply that the observed excessive warming in the dry seasons serve as an illustration of plausible future expected change in the region.

  14. Global warming and nuclear power

    Energy Technology Data Exchange (ETDEWEB)

    Hodgson, P.E. [Nuclear and Particle Physics Laboratory, Department of Physics, Oxford Univ., Oxford (United Kingdom)

    1999-09-01

    The concentration of carbon dioxide in the atmosphere is steadily increasing and it is widely believed that this will lead to global warming that will have serious consequences for life on earth. The Intergovernmental Panel on Climate Change has estimated that the temperature of the earth will increase by between 1 and 3.5 degrees in the next century. This will melt some of the Antarctic ice cap, raise the sea level and flood many low-lying countries, and also produce unpredictable changes in the earth's climate. The possible ways of reducing carbon dioxide emission are discussed. It is essential to reduce the burning of fossil fuels, but then how are we to obtain the energy we need? We can try to reduce energy use, but we will still need to generate large amounts energy. Some possible ways of doing this are by using wind and solar generators, by hydroelectric and tidal plants, and also by nuclear power. These possibilities will be critically examined. (author)

  15. Warm antibody autoimmune hemolytic anemia.

    Science.gov (United States)

    Kalfa, Theodosia A

    2016-12-02

    Autoimmune hemolytic anemia (AIHA) is a rare and heterogeneous disease that affects 1 to 3/100 000 patients per year. AIHA caused by warm autoantibodies (w-AIHA), ie, antibodies that react with their antigens on the red blood cell optimally at 37°C, is the most common type, comprising ∼70% to 80% of all adult cases and ∼50% of pediatric cases. About half of the w-AIHA cases are called primary because no specific etiology can be found, whereas the rest are secondary to other recognizable underlying disorders. This review will focus on the postulated immunopathogenetic mechanisms in idiopathic and secondary w-AIHA and report on the rare cases of direct antiglobulin test-negative AIHA, which are even more likely to be fatal because of inherent characteristics of the causative antibodies, as well as because of delays in diagnosis and initiation of appropriate treatment. Then, the characteristics of w-AIHA associated with genetically defined immune dysregulation disorders and special considerations on its management will be discussed. Finally, the standard treatment options and newer therapeutic approaches for this chronic autoimmune blood disorder will be reviewed. © 2016 by The American Society of Hematology. All rights reserved.

  16. Potential impacts of global warming on the diversity and distribution of stream insects in South Korea.

    Science.gov (United States)

    Li, Fengqing; Kwon, Yong-Su; Bae, Mi-Jung; Chung, Namil; Kwon, Tae-Sung; Park, Young-Seuk

    2014-04-01

    Globally, the East Asian monsoon region is one of the richest environments in terms of biodiversity. The region is undergoing rapid human development, yet its river ecosystems have not been well studied. Global warming represents a major challenge to the survival of species in this region and makes it necessary to assess and reduce the potential consequences of warming on species of conservation concern. We projected the effects of global warming on stream insect (Ephemeroptera, Odonata, Plecoptera, and Trichoptera [EOPT]) diversity and predicted the changes of geographical ranges for 121 species throughout South Korea. Plecoptera was the most sensitive (decrease of 71.4% in number of species from the 2000s through the 2080s) order, whereas Odonata benefited (increase of 66.7% in number of species from the 2000s through the 2080s) from the effects of global warming. The impact of global warming on stream insects was predicted to be minimal prior to the 2060s; however, by the 2080s, species extirpation of up to 20% in the highland areas and 2% in the lowland areas were predicted. The projected responses of stream insects under global warming indicated that species occupying specific habitats could undergo major reductions in habitat. Nevertheless, habitat of 33% of EOPT (including two-thirds of Odonata and one-third of Ephemeroptera, Plecoptera, and Trichoptera) was predicted to increase due to global warming. The community compositions predicted by generalized additive models varied over this century, and a large difference in community structure in the highland areas was predicted between the 2000s and the 2080s. However, stream insect communities, especially Odonata, Plecoptera, and Trichoptera, were predicted to become more homogenous under global warming. © 2013 Society for Conservation Biology.

  17. Global Warming and Its Health Impact

    Directory of Open Access Journals (Sweden)

    Antonella Rossati

    2017-01-01

    Full Text Available Since the mid-19th century, human activities have increased greenhouse gases such as carbon dioxide, methane, and nitrous oxide in the Earth's atmosphere that resulted in increased average temperature. The effects of rising temperature include soil degradation, loss of productivity of agricultural land, desertification, loss of biodiversity, degradation of ecosystems, reduced fresh-water resources, acidification of the oceans, and the disruption and depletion of stratospheric ozone. All these have an impact on human health, causing non-communicable diseases such as injuries during natural disasters, malnutrition during famine, and increased mortality during heat waves due to complications in chronically ill patients. Direct exposure to natural disasters has also an impact on mental health and, although too complex to be quantified, a link has even been established between climate and civil violence. Over time, climate change can reduce agricultural resources through reduced availability of water, alterations and shrinking arable land, increased pollution, accumulation of toxic substances in the food chain, and creation of habitats suitable to the transmission of human and animal pathogens. People living in low-income countries are particularly vulnerable. Climate change scenarios include a change in distribution of infectious diseases with warming and changes in outbreaks associated with weather extreme events. After floods, increased cases of leptospirosis, campylobacter infections and cryptosporidiosis are reported. Global warming affects water heating, rising the transmission of water-borne pathogens. Pathogens transmitted by vectors are particularly sensitive to climate change because they spend a good part of their life cycle in a cold-blooded host invertebrate whose temperature is similar to the environment. A warmer climate presents more favorable conditions for the survival and the completion of the life cycle of the vector, going as far

  18. Global Warming and Its Health Impact.

    Science.gov (United States)

    Rossati, Antonella

    2017-01-01

    Since the mid-19th century, human activities have increased greenhouse gases such as carbon dioxide, methane, and nitrous oxide in the Earth's atmosphere that resulted in increased average temperature. The effects of rising temperature include soil degradation, loss of productivity of agricultural land, desertification, loss of biodiversity, degradation of ecosystems, reduced fresh-water resources, acidification of the oceans, and the disruption and depletion of stratospheric ozone. All these have an impact on human health, causing non-communicable diseases such as injuries during natural disasters, malnutrition during famine, and increased mortality during heat waves due to complications in chronically ill patients. Direct exposure to natural disasters has also an impact on mental health and, although too complex to be quantified, a link has even been established between climate and civil violence. Over time, climate change can reduce agricultural resources through reduced availability of water, alterations and shrinking arable land, increased pollution, accumulation of toxic substances in the food chain, and creation of habitats suitable to the transmission of human and animal pathogens. People living in low-income countries are particularly vulnerable. Climate change scenarios include a change in distribution of infectious diseases with warming and changes in outbreaks associated with weather extreme events. After floods, increased cases of leptospirosis, campylobacter infections and cryptosporidiosis are reported. Global warming affects water heating, rising the transmission of water-borne pathogens. Pathogens transmitted by vectors are particularly sensitive to climate change because they spend a good part of their life cycle in a cold-blooded host invertebrate whose temperature is similar to the environment. A warmer climate presents more favorable conditions for the survival and the completion of the life cycle of the vector, going as far as to speed it up

  19. Effects of extreme global warming in Northern Europe

    DEFF Research Database (Denmark)

    Drews, Martin; Christensen, Jens Hesselbjerg

    2015-01-01

    In this Climate Research (CR) Special, the Centre for Regional Change in the Earth System (CRES) brings together scientific expertise (ranging from climate to social sciences) with practitioners and stakeholders to present thematic research addressing gaps in (1) our understanding of climate-syst...... in this CR Special highlight potential effects of extreme global warming with a focus on Denmark and northern Europe.......In this Climate Research (CR) Special, the Centre for Regional Change in the Earth System (CRES) brings together scientific expertise (ranging from climate to social sciences) with practitioners and stakeholders to present thematic research addressing gaps in (1) our understanding of climate......-system behaviour at a regional scale and in particular at the upper fringes of current climate scenarios; (2) what the effects of such changes might be; and (3) potential adaptations. CRES has developed a broad set of tools related to climate adaptation; this includes improved regional climate and hydrological...

  20. Relative roles of differential SST warming, uniform SST warming and land surface warming in determining the Walker circulation changes under global warming

    Science.gov (United States)

    Zhang, Lei; Li, Tim

    2017-02-01

    Most of CMIP5 models projected a weakened Walker circulation in tropical Pacific, but what causes such change is still an open question. By conducting idealized numerical simulations separating the effects of the spatially uniform sea surface temperature (SST) warming, extra land surface warming and differential SST warming, we demonstrate that the weakening of the Walker circulation is attributed to the western North Pacific (WNP) monsoon and South America land effects. The effect of the uniform SST warming is through so-called "richest-get-richer" mechanism. In response to a uniform surface warming, the WNP monsoon is enhanced by competing moisture with other large-scale convective branches. The strengthened WNP monsoon further induces surface westerlies in the equatorial western-central Pacific, weakening the Walker circulation. The increase of the greenhouse gases leads to a larger land surface warming than ocean surface. As a result, a greater thermal contrast occurs between American Continent and equatorial Pacific. The so-induced zonal pressure gradient anomaly forces low-level westerly anomalies over the equatorial eastern Pacific and weakens the Walker circulation. The differential SST warming also plays a role in driving low-level westerly anomalies over tropical Pacific. But such an effect involves a positive air-sea feedback that amplifies the weakening of both east-west SST gradient and Pacific trade winds.

  1. On the two tales of Warm Jupiters

    Science.gov (United States)

    Huang, Chelsea; Wu, Yanqin

    2017-06-01

    Warm Jupiters often refer to giant planets with intermediate orbit periods between 10-200 days. Their period range corresponds to the so-called "period valley", the observed dip in occupation in-between the hot Jupiters and cold Jupiters. Observational evidences suggest that they are a distinct population from the hot Jupiters and are likely to be formed from at least two different channels themselves. Earlier radial velocity surveys show that at least a fraction of the warm Jupiters have modest to high eccentricities, supporting these planets migrate to their current location through either secular perturbations or planet-planet scatterings. On the other hand, transiting warm Jupiters found in Kepler are likely to have close-by transiting low mass companions interior/exterior to the warm Jupiter orbits. The existence of the companions indicating the system needs to be near coplanar, and near circular, unlike their radial velocity counter parts. In this talk, I will review observational properties to date of the warm Jupiters, as well as recent advances in the theory of the warm Jupiter formation. I will then discuss how new discoveries from TESS can help with understanding the transition between the hot and warm Jupiter population, and distinguish the contribution from different formation channels.

  2. Herbivory enables marine communities to resist warming.

    Science.gov (United States)

    Kordas, Rebecca L; Donohue, Ian; Harley, Christopher D G

    2017-10-01

    Climate change can influence ecosystems via both direct effects on individual organisms and indirect effects mediated by species interactions. However, we understand little about how these changes will ripple through ecosystems or whether there are particular ecological characteristics that might make ecosystems more susceptible-or more resistant-to warming. By combining in situ experimental warming with herbivore manipulations in a natural rocky intertidal community for over 16 months, we show that herbivory regulates the capacity of marine communities to resist warming. We found that limpet herbivores helped to preserve trophic and competitive interactions under experimental warming, dampening the impact of warming on overall community composition. The presence of limpets facilitated the survival of the main habitat modifier (barnacles) under warmer conditions, which, in turn, facilitated the presence of a consumer guild. When limpets were removed, environmental warming altered trophic, competitive, and facilitative interactions, with cascading impacts on community succession and stability. We conclude that conserving trophic structure and the integrity of interaction networks is vitally important as Earth continues to warm.

  3. Concentration dynamics and biodegradability of dissolved organic matter in wetland soils subjected to experimental warming.

    Science.gov (United States)

    Wang, Hang; Holden, Joseph; Zhang, Zhijian; Li, Meng; Li, Xia

    2014-02-01

    Dissolved organic matter (DOM) is the most bioavailable soil organic pool. Understanding how DOM responds to elevated temperature is important for forecasting soil carbon (C) dynamics under climate warming. Here a 4.5-year field microcosm experiment was carried out to examine temporal DOM concentration dynamics in soil pore-water from six different subtropical wetlands. Results are compared between control (ambient temperature) and warmed (+5°C) treatments. UV-visible and fluorescence spectroscopy was performed to reveal DOM structural complexity at the end of the warming incubation. Elevated temperature resulted in initially (1 to 2.5 years) high pore-water DOM concentrations in warmed samples. These effects gradually diminished over longer time periods. Of the spectral indices, specific UV absorbance at 280 nm and humification index were significantly higher, while the signal intensity ratio of the fulvic-like to humic-like fluorescence peak was lower in warmed samples, compared to the control. Fluorescence regional integration analysis further suggested that warming enhanced the contribution of humic-like substances to DOM composition for all tested wetlands. These spectral fingerprints implied a declined fraction of readily available substrates in DOM allocated to microbial utilization in response to 4.5 years of warming. As a negative feedback, decreased DOM biodegradability may have the potential to counteract initial DOM increases and alleviate C loss in water-saturated wetland soils. © 2013.

  4. Five Years of Experimental Warming Increases the Biodiversity and Productivity of Phytoplankton.

    Directory of Open Access Journals (Sweden)

    Gabriel Yvon-Durocher

    2015-12-01

    Full Text Available Phytoplankton are key components of aquatic ecosystems, fixing CO2 from the atmosphere through photosynthesis and supporting secondary production, yet relatively little is known about how future global warming might alter their biodiversity and associated ecosystem functioning. Here, we explore how the structure, function, and biodiversity of a planktonic metacommunity was altered after five years of experimental warming. Our outdoor mesocosm experiment was open to natural dispersal from the regional species pool, allowing us to explore the effects of experimental warming in the context of metacommunity dynamics. Warming of 4°C led to a 67% increase in the species richness of the phytoplankton, more evenly-distributed abundance, and higher rates of gross primary productivity. Warming elevated productivity indirectly, by increasing the biodiversity and biomass of the local phytoplankton communities. Warming also systematically shifted the taxonomic and functional trait composition of the phytoplankton, favoring large, colonial, inedible phytoplankton taxa, suggesting stronger top-down control, mediated by zooplankton grazing played an important role. Overall, our findings suggest that temperature can modulate species coexistence, and through such mechanisms, global warming could, in some cases, increase the species richness and productivity of phytoplankton communities.

  5. Warming experiments elucidate the drivers of observed directional changes in tundra vegetation

    Science.gov (United States)

    Hollister, Robert D; May, Jeremy L; Kremers, Kelseyann S; Tweedie, Craig E; Oberbauer, Steven F; Liebig, Jennifer A; Botting, Timothy F; Barrett, Robert T; Gregory, Jessica L

    2015-01-01

    Few studies have clearly linked long-term monitoring with in situ experiments to clarify potential drivers of observed change at a given site. This is especially necessary when findings from a site are applied to a much broader geographic area. Here, we document vegetation change at Barrow and Atqasuk, Alaska, occurring naturally and due to experimental warming over nearly two decades. An examination of plant cover, canopy height, and community indices showed more significant differences between years than due to experimental warming. However, changes with warming were more consistent than changes between years and were cumulative in many cases. Most cases of directional change observed in the control plots over time corresponded with a directional change in response to experimental warming. These included increases in canopy height and decreases in lichen cover. Experimental warming resulted in additional increases in evergreen shrub cover and decreases in diversity and bryophyte cover. This study suggests that the directional changes occurring at the sites are primarily due to warming and indicates that further changes are likely in the next two decades if the regional warming trend continues. These findings provide an example of the utility of coupling in situ experiments with long-term monitoring to accurately document vegetation change in response to global change and to identify the underlying mechanisms driving observed changes. PMID:26140204

  6. Five Years of Experimental Warming Increases the Biodiversity and Productivity of Phytoplankton.

    Science.gov (United States)

    Yvon-Durocher, Gabriel; Allen, Andrew P; Cellamare, Maria; Dossena, Matteo; Gaston, Kevin J; Leitao, Maria; Montoya, José M; Reuman, Daniel C; Woodward, Guy; Trimmer, Mark

    2015-12-01

    Phytoplankton are key components of aquatic ecosystems, fixing CO2 from the atmosphere through photosynthesis and supporting secondary production, yet relatively little is known about how future global warming might alter their biodiversity and associated ecosystem functioning. Here, we explore how the structure, function, and biodiversity of a planktonic metacommunity was altered after five years of experimental warming. Our outdoor mesocosm experiment was open to natural dispersal from the regional species pool, allowing us to explore the effects of experimental warming in the context of metacommunity dynamics. Warming of 4°C led to a 67% increase in the species richness of the phytoplankton, more evenly-distributed abundance, and higher rates of gross primary productivity. Warming elevated productivity indirectly, by increasing the biodiversity and biomass of the local phytoplankton communities. Warming also systematically shifted the taxonomic and functional trait composition of the phytoplankton, favoring large, colonial, inedible phytoplankton taxa, suggesting stronger top-down control, mediated by zooplankton grazing played an important role. Overall, our findings suggest that temperature can modulate species coexistence, and through such mechanisms, global warming could, in some cases, increase the species richness and productivity of phytoplankton communities.

  7. The Warm Plasma Composition in the Inner Magnetosphere During 2012-2015

    Science.gov (United States)

    Jahn, J.-M.; Goldstein, J.; Reeves, G. D.; Fernandes, P. A.; Skoug, R. M.; Larsen, B. A.; Spence, H. E.

    2017-11-01

    Ionospheric heavy ions play an important role in the dynamics of Earth's magnetosphere. The greater mass and gyroradius of ionospheric oxygen differentiates its behavior from protons at the same energies. Oxygen may have an impact on tail reconnection processes, and it can at least temporarily dominate the energy content of the ring current during geomagnetic storms. At sub-keV energies, multispecies ion populations in the inner magnetosphere form the warm plasma cloak, occupying the energy range between the plasmasphere and the ring current. Lastly, cold lighter ions from the midlatitude ionosphere create the corotating plasmasphere whose outer regions can interact with the plasma cloak, plasma sheet, ring current, and outer electron belt. In this paper we present a statistical view of warm, cloak-like ion populations in the inner magnetosphere, contrasting, in particular, the warm plasma composition during quiet and active times. We study the relative abundances and absolute densities of warm plasma measured by the Van Allen Probes, whose two spacecraft cover the inner magnetosphere from plasmaspheric altitudes close to Earth to just inside geostationary orbit. We observe that warm (>30 eV) oxygen is most abundant closer to the plasmasphere boundary, whereas warm hydrogen dominates closer to geostationary orbit. Warm helium is usually a minor constituent but shows a noticeable enhancement in the near-Earth dusk sector.

  8. Expansion of World Drylands Under Global Warming

    Science.gov (United States)

    Feng, S.; Fu, Q.; Hu, Q. S.

    2012-12-01

    The world drylands including both semi-arid and arid regions comprise of one-third of the global land surfaces, which support 14% of the world's inhabitants and a significant share of the world agriculture. Because of meager annual precipitation and large potential evaporative water loss, the ecosystems over drylands are fragile and sensitive to the global change. By analyzing the observations during 1948-2008 and 20 fully coupled climate model simulations from CMIP5 for the period 1900-2100, this study evaluated the changes of the world drylands that are defined with a modified form of the Thornthwaite's moisture index. The results based on observational data showed that the world drylands are steadily expanding during the past 60 years. The areas occupied by drylands in 1994-2008 is about 2.0×10^6km^2 (or 4%) larger than the average during the 1950s. Such an expansion is also a robust feature in the simulations of the 20 global climate models, though the rate is much smaller in the models. A stronger expanding rate is projected during the first half of this century than the simulations in the last century, followed by accelerating expansion after 2050s under the high greenhouse gas emission scenario (RCP8.5). By the end of this century, the world drylands are projected to be over 58×10^6km^2 (or 11% increase compared to the 1961-1990 climatology). The projected expansion of drylands, however, is not homogeneous over the world drylands, with major expansion of arid regions over the southwest North America, the northern fringe of Africa, southern Africa and Australia. Major expansions of semi-arid regions are projected over the north side of the Mediterranean, southern Africa, North and South America. The global warming is the main factor causing the increase of potential evapotranspiration estimated by Penman-Monteith algorithm, which in turn dominants the expansion of drylands. The widening of Hadley cell, which has impact on both temperature and precipitation

  9. Urban warming reduces aboveground carbon storage

    DEFF Research Database (Denmark)

    Meineke, Emily; Youngsteadt, Elsa; Dunn, Robert Roberdeau

    2016-01-01

    sequestration (carbon stored per year) of mature trees. Urban warming increased herbivorous arthropod abundance on trees, but these herbivores had negligible effects on tree carbon sequestration. Instead, urban warming was associated with an estimated 12% loss of carbon sequestration, in part because...... photosynthesis was reduced at hotter sites. Ecosystem service assessments that do not consider urban conditions may overestimate urban tree carbon storage. Because urban and global warming are becoming more intense, our results suggest that urban trees will sequester even less carbon in the future....

  10. The influence of land warming on precipitation and atmospheric circulation change

    Science.gov (United States)

    Chadwick, Robin; Ackerley, Duncan; Dommenget, Dietmar

    2017-04-01

    One robust aspect of climate change is that the land surface warms more than the ocean surface, and this is expected to influence precipitation and the atmospheric circulation. A new set of experiments are described, where the effect of land surface temperature change on precipitation and circulation change is isolated, and compared with the effects of sea-surface temperature (SST) change, direct CO2 radiative forcing, and the plant physiological effect. Land warming generally leads to enhanced low-level convergence and precipitation over land, while SST warming leads to reduced precipitation over land and increases over the oceans. However the combination of the two effects is strongly nonlinear. Direct radiative forcing drives precipitation change both through heating of the atmosphere, and through land warming, and this is particularly important in some monsoon regions. The plant physiological effect directly drives large reductions in transpiration and precipitation over tropical forest regions, as stomata close in response to elevated CO2 concentrations. However the plant effect also produces significant land warming, which leads to increased convergence and precipitation in some tropical forest regions. Therefore the overall result of the plant effect in each region depends on the balance between these two mechanisms.

  11. Impact of Ocean Warming on Tropical Cyclone Size and Its Destructiveness.

    Science.gov (United States)

    Sun, Yuan; Zhong, Zhong; Li, Tim; Yi, Lan; Hu, Yijia; Wan, Hongchao; Chen, Haishan; Liao, Qianfeng; Ma, Chen; Li, Qihua

    2017-08-15

    The response of tropical cyclone (TC) destructive potential to global warming is an open issue. A number of previous studies have ignored the effect of TC size change in the context of global warming, which resulted in a significant underestimation of the TC destructive potential. The lack of reliable and consistent historical data on TC size limits the confident estimation of the linkage between the observed trend in TC size and that in sea surface temperature (SST) under the background of global climate warming. A regional atmospheric model is used in the present study to investigate the response of TC size and TC destructive potential to increases in SST. The results show that a large-scale ocean warming can lead to not only TC intensification but also TC expansion. The TC size increase in response to the ocean warming is possibly attributed to the increase in atmospheric convective instability in the TC outer region below the middle troposphere, which facilitates the local development of grid-scale ascending motion, low-level convergence and the acceleration of tangential winds. The numerical results indicate that TCs will become stronger, larger, and unexpectedly more destructive under global warming.

  12. Climatic bisection of the last interglacial warm period in the Polar North Atlantic

    Science.gov (United States)

    Bauch, Henning A.; Kandiano, Evguenia S.; Helmke, Jan; Andersen, Nils; Rosell-Mele, Antoni; Erlenkeuser, Helmut

    2011-07-01

    New multiproxy marine data of the Eemian interglacial (MIS5e) from the Norwegian Sea manifest a cold event with near-glacial surface ocean summer temperatures (3-4 °C). This mid-Eemian cooling divided the otherwise relatively warm interglacial climate and was associated with widespread expansions of winter sea-ice and polar water masses due to changes in atmospheric circulation and ocean stability. While the data also verify a late rather than early last interglacial warm peak, which is in general disharmony with northern hemisphere insolation maximum and the regional climatic progression of the early Holocene, the cold event itself was likely instrumental for delaying the last interglacial climate development in the Polar North when compared with regions farther south. Such a 'climatic decoupling' of the Polar region may bear profound implications for the employment of Eemian conditions to help evaluate the present and future state of the Arctic cryosphere during a warming interglacial.

  13. Experimental soil warming at the treeline shifts fungal communities species

    Science.gov (United States)

    Solly, Emily; Lindahl, Björn; Dawes, Melissa; Peter, Martina; Rixen, Christian; Hagedorn, Frank

    2016-04-01

    In terrestrial ecosystems, fungi play a major role in decomposition processes, plant nutrient uptake and nutrient cycling. In high elevation ecosystems in Alpine and Arctic regions, the fungal community may be particularly sensitive to climate warming due to the removal of temperature limitation in the plant and soil system, faster nutrient cycling and changes in plant carbon allocation to maintain roots systems and sustain the rhizosphere. In our study, we estimated the effects of 9 years CO2 enrichment and three years of experimental soil warming on the community structure of fungal microorganisms in an alpine treeline ecosystem. In the Swiss Alps, we worked on a total of 40 plots, with c. 40-year-old Larix decidua and Pinus mugo ssp. uncinata trees (20 plots for each tree species). Half of the plots with each tree species were randomly assigned to an elevated CO2 treatment (ambient concentration +200 ppm), whereas the remaining plots received no supplementary CO2. Five individual plots for each combination of CO2 concentration and tree species were heated by an average of 4°C during the growing season with heating cables at the soil surface. At the treeline, the fungal diversity analyzed by high-throughput 454-sequencing of genetic markers, was generally low as compared to low altitude systems and mycorrhizal species made a particularly small contribution to the total fungal DNA. Soil warming led to a shift in the structure and composition of the fungal microbial community, with an increase of litter degraders and ectomycorrhizal fungi. We further observed changes in the productivity of specific fungal fruiting bodies (i.e. more Lactarius rufus sporocarps and less Hygrophorus lucorum sporocarps) during the course of the experiment, that were consistent with the 454-sequencing data. The warming effect was more pronounced in the Larix plots. These shifts were accompanied by an increased soil CO2 efflux (+40%), evidence of increased N availability and a

  14. Persisting and strong warming hiatus over eastern China during the past two decades

    Science.gov (United States)

    Chen, Yang; Zhai, Panmao

    2017-10-01

    During the past two decades since 1997, eastern China has experienced a warming hiatus punctuated by significant cooling in daily-minimum temperature (Tmin), particularly during early-mid winter. By arbitrarily configuring start and end years, a ‘vantage hiatus period’ in eastern China is detected over 1998-2013, during when the domain-averaged Tmin exhibited the strongest cooling trend and the number of significant cooling stations peaked. Regions most susceptible to the warming hiatus are located in North China, the Yangtze-Huai River Valley and South China, where significant cooling in Tmin persisted through 2016. This sustained hiatus gave rise to increasingly frequent and severe cold extremes there. Concerning its prolonged persistency and great cooling rate, the recent warming hiatus over eastern China deviates much from most historical short-term trends during the past five decades, and thus could be viewed as an outlier against the prevalent warming context.

  15. Impacts of a warming marginal sea on torrential rainfall organized under the Asian summer monsoon

    Science.gov (United States)

    Manda, Atsuyoshi; Nakamura, Hisashi; Asano, Naruhiko; Iizuka, Satoshi; Miyama, Toru; Moteki, Qoosaku; Yoshioka, Mayumi K.; Nishii, Kazuaki; Miyasaka, Takafumi

    2014-07-01

    Monsoonal airflow from the tropics triggers torrential rainfall over coastal regions of East Asia in summer, bringing flooding situations into areas of growing population and industries. However, impacts of rapid seasonal warming of the shallow East China Sea ECS and its pronounced future warming upon extreme summertime rainfall have not been explored. Here we show through cloudresolving atmospheric model simulations that observational tendency for torrential rainfall events over western Japan to occur most frequently in July cannot be reproduced without the rapid seasonal warming of ECS. The simulations also suggest that the future ECS warming will increase precipitation substantially in such an extreme event as observed in midJuly 2012 and also the likelihood of such an event occurring in June. A need is thus urged for reducing uncertainties in future temperature projections over ECS and other marginal seas for better projections of extreme summertime rainfall in the surrounding areas.

  16. Species-specific vulnerability of Arctic copepods to oil contamination and global warming

    DEFF Research Database (Denmark)

    Dinh, Khuong Van; Nielsen, Torkel Gissel

    of temperatures. Notably, exposure to high pyrene resulted in ca. 70% of mortality in C. finmarchicus, the species with North Atlantic Origin, that was two times higher than the mortality observed for C. glacialis, the true Arctic species. These results suggest that extreme temperature under global warming......Arctic ecosystems are predicted to have more severe effects from global warming as during the last decades the temperatures have increased in this region at a rate of 2-4 times higher than the global average. In addition, oil exploitation and shipping activities in the Arctic are predicted...... to increase under global warming as the result of the retreat of sea ice, posing the risk of oil contamination. It is poorly known how cold adapted copepods in the Arctic deal with the combined effects of global warming and oil exposure. To address this, we exposed females of two copepods species Calanus...

  17. Lagging adaptation to warming climate in Arabidopsis thaliana.

    Science.gov (United States)

    Wilczek, Amity M; Cooper, Martha D; Korves, Tonia M; Schmitt, Johanna

    2014-06-03

    If climate change outpaces the rate of adaptive evolution within a site, populations previously well adapted to local conditions may decline or disappear, and banked seeds from those populations will be unsuitable for restoring them. However, if such adaptational lag has occurred, immigrants from historically warmer climates will outperform natives and may provide genetic potential for evolutionary rescue. We tested for lagging adaptation to warming climate using banked seeds of the annual weed Arabidopsis thaliana in common garden experiments in four sites across the species' native European range: Valencia, Spain; Norwich, United Kingdom; Halle, Germany; and Oulu, Finland. Genotypes originating from geographic regions near the planting site had high relative fitness in each site, direct evidence for broad-scale geographic adaptation in this model species. However, genotypes originating in sites historically warmer than the planting site had higher average relative fitness than local genotypes in every site, especially at the northern range limit in Finland. This result suggests that local adaptive optima have shifted rapidly with recent warming across the species' native range. Climatic optima also differed among seasonal germination cohorts within the Norwich site, suggesting that populations occurring where summer germination is common may have greater evolutionary potential to persist under future warming. If adaptational lag has occurred over just a few decades in banked seeds of an annual species, it may be an important consideration for managing longer-lived species, as well as for attempts to conserve threatened populations through ex situ preservation.

  18. Effect of warming temperatures on US wheat yields.

    Science.gov (United States)

    Tack, Jesse; Barkley, Andrew; Nalley, Lawton Lanier

    2015-06-02

    Climate change is expected to increase future temperatures, potentially resulting in reduced crop production in many key production regions. Research quantifying the complex relationship between weather variables and wheat yields is rapidly growing, and recent advances have used a variety of model specifications that differ in how temperature data are included in the statistical yield equation. A unique data set that combines Kansas wheat variety field trial outcomes for 1985-2013 with location-specific weather data is used to analyze the effect of weather on wheat yield using regression analysis. Our results indicate that the effect of temperature exposure varies across the September-May growing season. The largest drivers of yield loss are freezing temperatures in the Fall and extreme heat events in the Spring. We also find that the overall effect of warming on yields is negative, even after accounting for the benefits of reduced exposure to freezing temperatures. Our analysis indicates that there exists a tradeoff between average (mean) yield and ability to resist extreme heat across varieties. More-recently released varieties are less able to resist heat than older lines. Our results also indicate that warming effects would be partially offset by increased rainfall in the Spring. Finally, we find that the method used to construct measures of temperature exposure matters for both the predictive performance of the regression model and the forecasted warming impacts on yields.

  19. Using radiative signatures to diagnose the cause of warming during the 2013-2014 Californian drought

    Science.gov (United States)

    Wolf, Sebastian; Yin, Dongqin; Roderick, Michael L.

    2017-10-01

    California recently experienced among the worst droughts of the last century, with exceptional precipitation deficits and co-occurring record high temperatures. The dry conditions caused severe water shortages in one of the economically most important agricultural regions of the US. It has recently been hypothesized that anthropogenic warming is increasing the likelihood of such extreme droughts in California, or more specifically, that warmer temperatures from the enhanced greenhouse effect intensify drought conditions. However, separating the cause and effect is difficult because the dry conditions lead to a reduction in evaporative cooling that contributes to the warming. Here we investigate and compare the forcing of long-term greenhouse-induced warming with the short-term warming during the 2013-2014 Californian drought. We use the concept of radiative signatures to investigate the source of the radiative perturbation during the drought, relate the signatures to expected changes due to anthropogenic warming, and assess the cause of warming based on observed changes in the surface energy balance compared to the period 2001-2012. We found that the recent meteorological drought based on precipitation deficits was characterised by an increase in incoming shortwave radiation coupled with a decline in incoming longwave radiation, which contributed to record warm temperatures. In contrast, climate models project that anthropogenic warming is accompanied by little change in incoming shortwave but a large increase in incoming longwave radiation. The warming during the drought was associated with increased incoming shortwave radiation in combination with reduced evaporative cooling from water deficits, which enhanced surface temperatures and sensible heat transfer to the atmosphere. Our analyses demonstrate that radiative signatures are a powerful tool to differentiate the source of perturbations in the surface energy balance at monthly to seasonal time scales.

  20. Past and future warming of a deep European lake (Lake Lugano): What are the climatic drivers?

    Science.gov (United States)

    Lepori, Fabio; Roberts, James J.

    2015-01-01

    We used four decades (1972–2013) of temperature data from Lake Lugano, Switzerland and Italy, to address the hypotheses that: [i] the lake has been warming; [ii] part of the warming reflects global trends and is independent from climatic oscillations and [iii] the lake will continue to warm until the end of the 21st century. During the time spanned by our data, the surface waters of the lake (0–5 m) warmed at rates of 0.2–0.9 °C per decade, depending on season. The temperature of the deep waters (50-m bottom) displayed a rising trend in a meromictic basin of the lake and a sawtooth pattern in the other basin, which is holomictic. Long-term variation in surfacewater temperature correlated to global warming and multidecadal variation in two climatic oscillations, the Atlantic Multidecadal Oscillation (AMO) and the East Atlantic Pattern (EA).However, we did not detect an influence of the EA on the lake's temperature (as separate from the effect of global warming). Moreover, the effect of the AMO, estimated to a maximum of +1 °C, was not sufficient to explain the observed temperature increase (+2–3 °C in summer). Based on regional climate projections, we predicted that the lake will continue to warm at least until the end of the 21st century. Our results strongly suggest that the warming of Lake Lugano is tied to globalclimate change. To sustain current ecosystem conditions in Lake Lugano, we suggest that manage- ment plans that curtail eutrophication and (or) mitigation of global warming be pursued.

  1. Reconciling controversies about the 'global warming hiatus'.

    Science.gov (United States)

    Medhaug, Iselin; Stolpe, Martin B; Fischer, Erich M; Knutti, Reto

    2017-05-03

    Between about 1998 and 2012, a time that coincided with political negotiations for preventing climate change, the surface of Earth seemed hardly to warm. This phenomenon, often termed the 'global warming hiatus', caused doubt in the public mind about how well anthropogenic climate change and natural variability are understood. Here we show that apparently contradictory conclusions stem from different definitions of 'hiatus' and from different datasets. A combination of changes in forcing, uptake of heat by the oceans, natural variability and incomplete observational coverage reconciles models and data. Combined with stronger recent warming trends in newer datasets, we are now more confident than ever that human influence is dominant in long-term warming.

  2. Effects of Global Warming on Vibrio Ecology

    National Research Council Canada - National Science Library

    Vezzulli, Luigi; Pezzati, Elisabetta; Brettar, Ingrid; Höfle, Manfred; Pruzzo, Carla

    2015-01-01

    .... Rise in global sea surface temperature (SST), which is approximately 1 °C higher now than 140 years ago and is one of the primary physical impacts of global warming, has been linked to such increases...

  3. Global Surface Warming Hiatus Analysis Data

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — These data were used to conduct the study of the global surface warming hiatus, an apparent decrease in the upward trend of global surface temperatures since 1998....

  4. Palaeoclimate: Volcanism caused ancient global warming

    Science.gov (United States)

    Meissner, Katrin J.; Bralower, Timothy J.

    2017-08-01

    A study confirms that volcanism set off one of Earth's fastest global-warming events. But the release of greenhouse gases was slow enough for negative feedbacks to mitigate impacts such as ocean acidification. See Letter p.573

  5. A review of warm mix asphalt.

    Science.gov (United States)

    2008-12-01

    Warm Mix Asphalt (WMA) technology, recently developed in Europe, is gaining strong interest in the US. By : lowering the viscosity of asphalt binder and/or increasing the workability of mixture using minimal heat, WMA : technology allows the mixing, ...

  6. Ecological stability in response to warming

    NARCIS (Netherlands)

    Fussmann, Katarina E.; Schwarzmueller, Florian; Brose, Ulrich; Jousset, Alexandre|info:eu-repo/dai/nl/370632656; Rall, Bjoern C.

    That species' biological rates including metabolism, growth and feeding scale with temperature is well established from warming experiments(1). The interactive influence of these changes on population dynamics, however, remains uncertain. As a result, uncertainty about ecological stability in

  7. Teaching cases on transportation and global warming.

    Science.gov (United States)

    2013-03-01

    This project developed a series of three teaching cases that explore the implications of global : warming for transportation policy in the United States. The cases are intended to be used in : graduate and undergraduate courses on transportation poli...

  8. A Scientific Look at Global Warming

    Science.gov (United States)

    Glanz, Peter

    2007-10-01

    Scientists like we should ask ``Where's the Beef?'' when a global warming discussion comes up. Current issues like melting glaciers, rising sea levels, disappearing polar bears and increasing tornado activity (among many) are put to the WTB test.

  9. Chamberless residential warm air furnace design

    Energy Technology Data Exchange (ETDEWEB)

    Godfree, J. [Product Design consultant, Pugwash (Canada)

    1996-07-01

    This brief paper is an introduction to the concept of designing residential warm air furnaces without combustion chambers. This is possible since some small burners do not require the thermal support of a combustion chamber to complete the combustion process.

  10. Global temperatures and the global warming ``debate''

    Science.gov (United States)

    Aubrecht, Gordon

    2009-04-01

    Many ordinary citizens listen to pronouncements on talk radio casting doubt on anthropogenic global warming. Some op-ed columnists likewise cast doubts, and are read by credulous citizens. For example, on 8 March 2009, the Boston Globe published a column by Jeff Jacoby, ``Where's global warming?'' According to Jacoby, ``But it isn't such hints of a planetary warming trend that have been piling up in profusion lately. Just the opposite.'' He goes on to write, ``the science of climate change is not nearly as important as the religion of climate change,'' and blamed Al Gore for getting his mistaken views accepted. George Will at the Washington Post also expressed denial. As a result, 44% of U.S. voters, according to the January 19 2009 Rasmussen Report, blame long-term planetary trends for global warming, not human beings. Is there global cooling, as skeptics claim? We examine the temperature record.

  11. Enhanced Decadal Warming of the Southeast Indian Ocean During the Recent Global Surface Warming Slowdown

    Science.gov (United States)

    Li, Yuanlong; Han, Weiqing; Zhang, Lei

    2017-10-01

    The rapid Indian Ocean warming during the early-21th century was a major heat sink for the recent global surface warming slowdown. Analysis of observational data and ocean model experiments reveals that during 2003-2012 more than half of the increased upper Indian Ocean heat content was concentrated in the southeast Indian Ocean (SEIO), causing a warming "hot spot" of 0.8-1.2 K decade-1 near the west coast of Australia. This SEIO warming was primarily induced by the enhancements of the Pacific trade winds and Indonesian throughflow associated with the Interdecadal Pacific Oscillation's (IPO) transition to its negative phase, and to a lesser degree by local atmospheric forcing within the Indian Ocean. Large-ensemble climate model simulations suggest that this warming event was likely also exacerbated by anthropogenic forcing and thus unprecedentedly strong as compared to previous IPO transition periods. Climate model projections suggest an increasing possibility of such strong decadal warming in future.

  12. Power Engineering and Global Climate Warming

    OpenAIRE

    Канило, П. М.

    2016-01-01

    Presently, three ecological problems are in the focus of humanities concern: the global climate warming on Earth, the future of the ozone layer and the circularity of global bio-geo-chemical cycles (the concept of biotic regulation of the environment). Further climate warming can result in adverse consequences such as enhanced evaporation of World Ocean water and intensification of the greenhouse effect, stratosphere cooling and respective thinning of the protective ozone screen, a rising lev...

  13. Should we be concerned about global warming?

    Science.gov (United States)

    Diaz, James H

    2006-01-01

    Accurate scientific predictions of the true human health outcomes of global climate change are significantly confounded by several effect modifiers that cannot be adjusted for analytically. Nevertheless, with the documented increase in average global surface temperature of 0.6 C. since 1975, there is uniform consensus in the international scientific community that the earth is warming from a variety of climatic effects, including cyclical re-warming and the cascading effects of greenhouse gas emissions to support human activities.

  14. Book ReviewL Global Warming

    Directory of Open Access Journals (Sweden)

    Nadia Astriani

    2015-04-01

    Full Text Available Global Warming is part of Greenhaven’s Contemporary Issues Companion series published by, Thomson Gale on 2005. Each volume of the anthologyseries focuses on a topic of current interest, presenting informative and thought-provoking selection written from wide-variety viewpoints. It is an ideal launching point for research on a particular topic. Each anthology in the series is composed of readings taken from an extensive gamut of resources, including periodical, newspapers, books, governmentdocuments, the publications of private and public organization an internet website. Readers will find factual support suitable for use in reports, debate, speeches and research papers. In understanding Environmental Law, student must understand the environmental issues first. Global warming is the latest issue in Environmental Law field, it has been discuss for more than a decade. It is hard for law student, who don’t have any scientific background to understand this issue. That’s why this anthology series is perfect start for student to understanding Global Warming Issue. This book consist of three part, namely: Understanding Global Warming, The Consequences of Global warming and Solving the Global warming Problem. Each chapter contains 6-7 articles.

  15. Global warming and nuclear power

    Energy Technology Data Exchange (ETDEWEB)

    Wood, L., LLNL

    1998-07-10

    -fold reduction might be attained. Even the first such halving of carbon intensivity of stationary-source energy production world-wide might permit continued slow power-demand growth in the highly developed countries and rapid development of the other 80% of the world, both without active governmental suppression of fossil fuel usage - while also stabilizing carbon input-rates into the Earth`s atmosphere. The second two-fold reduction might obviate most global warming concerns.

  16. Significant Atmospheric Boundary Layer Change Observed above an Agulhas Current Warm Cored Eddy

    Directory of Open Access Journals (Sweden)

    C. Messager

    2016-01-01

    Full Text Available The air-sea impact of a warm cored eddy ejected from the Agulhas Retroflection region south of Africa was assessed through both ocean and atmospheric profiling measurements during the austral summer. The presence of the eddy causes dramatic atmospheric boundary layer deepening, exceeding what was measured previously over such a feature in the region. This deepening seems mainly due to the turbulent heat flux anomaly above the warm eddy inducing extensive deep and persistent changes in the atmospheric boundary layer thermodynamics. The loss of heat by turbulent processes suggests that this kind of oceanic feature is an important and persistent source of heat for the atmosphere.

  17. Bidirectional infrasonic ducts associated with sudden stratospheric warming events

    Science.gov (United States)

    Assink, J. D.; Waxler, R.; Smets, P.; Evers, L. G.

    2014-02-01

    In January 2011, the state of the polar vortex in the midlatitudes changed significantly due to a minor sudden stratospheric warming event. As a result, a bidirectional duct for infrasound propagation developed in the middle atmosphere that persisted for 2 weeks. The ducts were due to two zonal wind jets, one between 30 and 50 km and the other around 70 km altitude. In this paper, using microbarom source modeling, a previously unidentified source region in the eastern Mediterranean is identified, besides the more well known microbarom source regions in the Atlantic Ocean. Infrasound data are then presented in which the above mentioned bidirectional duct is observed in microbarom signals recorded at the International Monitoring System station I48TN in Tunisia, from the Mediterranean region to the east and from the Atlantic Ocean to the west. While the frequency bands of the two sources overlap, the Mediterranean signal is coherent up to about 0.6 Hz. This observation is consistent with the microbarom source modeling; the discrepancy in the frequency band is related to differences in the ocean wave spectra for the two basins considered. This work demonstrates the sensitivity of infrasound to stratospheric dynamics and illustrates that the classic paradigm of a unidirectional stratospheric duct for infrasound propagation can be broken during a sudden stratospheric warming event.

  18. A new mechanism for warm-season precipitation response to global warming based on convection-permitting simulations

    Science.gov (United States)

    Dai, Aiguo; Rasmussen, Roy M.; Liu, Changhai; Ikeda, Kyoko; Prein, Andreas F.

    2017-08-01

    Climate models project increasing precipitation intensity but decreasing frequency as greenhouse gases increase. However, the exact mechanism for the frequency decrease remains unclear. Here we investigate this by analyzing hourly data from regional climate change simulations with 4 km grid spacing covering most of North America using the Weather Research and Forecasting model. The model was forced with present and future boundary conditions, with the latter being derived by adding the CMIP5 19-model ensemble mean changes to the ERA-interim reanalysis. The model reproduces well the observed seasonal and spatial variations in precipitation frequency and histograms, and the dry interval between rain events over the contiguous US. Results show that overall precipitation frequency indeed decreases during the warm season mainly due to fewer light-moderate precipitation (0.1 10 mm/h) events increase. Dry spells become longer and more frequent, together with a reduction in time-mean relative humidity (RH) in the lower troposphere during the warm season. The increased dry hours and decreased RH lead to a reduction in overall precipitation frequency and also for light-moderate precipitation events, while water vapor-induced increases in precipitation intensity and the positive latent heating feedback in intense storms may be responsible for the large increase in intense precipitation. The size of intense storms increases while their number decreases in the future climate, which helps explain the increase in local frequency of heavy precipitation. The results generally support a new hypothesis for future warm-season precipitation: each rainstorm removes ≥7% more moisture from the air per 1 K local warming, and surface evaporation and moisture advection take slightly longer than currently to replenish the depleted moisture before the next storm forms, leading to longer dry spells and a reduction in precipitation frequency, as well as decreases in time-mean RH and vertical

  19. Amplification of Arctic warming by past air pollution reductions in Europe

    Science.gov (United States)

    Acosta Navarro, J. C.; Varma, V.; Riipinen, I.; Seland, Ø.; Kirkevåg, A.; Struthers, H.; Iversen, T.; Hansson, H.-C.; Ekman, A. M. L.

    2016-04-01

    The Arctic region is warming considerably faster than the rest of the globe, with important consequences for the ecosystems and human exploration of the region. However, the reasons behind this Arctic amplification are not entirely clear. As a result of measures to enhance air quality, anthropogenic emissions of particulate matter and its precursors have drastically decreased in parts of the Northern Hemisphere over the past three decades. Here we present simulations with an Earth system model with comprehensive aerosol physics and chemistry that show that the sulfate aerosol reductions in Europe since 1980 can potentially explain a significant fraction of Arctic warming over that period. Specifically, the Arctic region receives an additional 0.3 W m-2 of energy, and warms by 0.5 °C on annual average in simulations with declining European sulfur emissions in line with historical observations, compared with a model simulation with fixed European emissions at 1980 levels. Arctic warming is amplified mainly in fall and winter, but the warming is initiated in summer by an increase in incoming solar radiation as well as an enhanced poleward oceanic and atmospheric heat transport. The simulated summertime energy surplus reduces sea-ice cover, which leads to a transfer of heat from the Arctic Ocean to the atmosphere. We conclude that air quality regulations in the Northern Hemisphere, the ocean and atmospheric circulation, and Arctic climate are inherently linked.

  20. Can Global Warming be Stopped?

    Science.gov (United States)

    Luria, M.

    2013-12-01

    Earlier this year, the CO2 levels exceeded the 400 ppm level and there is no sign that the 1-2 ppm annual increase is going to slow down. Concerns regarding the danger of global warming have been reported in numerous occasions for more than a generation, ever since CO2 levels reached the 350 ppm range in the mid 1980's. Nevertheless, all efforts to slow down the increase have showed little if any effect. Mobile sources, including surface and marine transportation and aviation, consist of 20% of the global CO2 emission. The only realistic way to reduce the mobile sources' CO2 signature is by improved fuel efficiency. However, any progress in this direction is more than compensated by continuous increased demand. Stationary sources, mostly electric power generation, are responsible for the bulk of the global CO2 emission. The measurements have shown, that the effect of an increase in renewable sources, like solar wind and geothermal, combined with conversion from coal to natural gas where possible, conservation and efficiency improvement, did not compensate the increased demand mostly in developing countries. Increased usage of nuclear energy can provide some relief in carbon emission but has the potential of even greater environmental hazard. A major decrease in carbon emission can be obtained by either significant reduction in the cost of non-carbon based energy sources or by of carbon sequestration. The most economical way to make a significant decrease in carbon emission is to apply carbon sequestration technology at large point sources that use coal. Worldwide there are about 10,000 major sources that burn >7 billion metric tons of coal which generate the equivalent of 30 trillion kwh. There is a limited experience in CO2 sequestration of such huge quantities of CO2, however, it is estimated that the cost would be US$ 0.01-0.1 per kwh. The cost of eliminating this quantity can be estimated at an average of 1.5 trillion dollars annually. The major emitters, US

  1. Regional climate change and national responsibilities

    Science.gov (United States)

    Hansen, James; Sato, Makiko

    2016-03-01

    Global warming over the past several decades is now large enough that regional climate change is emerging above the noise of natural variability, especially in the summer at middle latitudes and year-round at low latitudes. Despite the small magnitude of warming relative to weather fluctuations, effects of the warming already have notable social and economic impacts. Global warming of 2 °C relative to preindustrial would shift the ‘bell curve’ defining temperature anomalies a factor of three larger than observed changes since the middle of the 20th century, with highly deleterious consequences. There is striking incongruity between the global distribution of nations principally responsible for fossil fuel CO2 emissions, known to be the main cause of climate change, and the regions suffering the greatest consequences from the warming, a fact with substantial implications for global energy and climate policies.

  2. Global warming and water sustainability

    Directory of Open Access Journals (Sweden)

    Cassardo Claudio

    2014-03-01

    Full Text Available Water is a primary element in the human diet and a necessary resource for the agriculture. In addition, industrial practices need a growing amount of water. Since human population is continuously growing at a quasi-exponential rate, water demand, for domestic, agricultural and industrial uses, is increasing too. However, considering that the water resources on the Earth are finite, even disregarding the potential threats due to the climate change, this situation appears as one of the biggest challenges of the current era. Actually, one-third of the world’s population is water-stressed, of which 12% severely: in these nations, a large portion of the population lives below the minimum threshold judged permissible for a decent life. In practice, almost every nation deals with problems related to water sustainability. In some countries, the water supply is ensured only thanks to the extraction of fossil water, which is a limited resource that will not last indefinitely. The impact on water quality has also dramatically increased. The scarcity of water resources is expected to spread to wider areas in the near future, mostly in developing countries, if the actual trends of development and population growth do not change. The rapid urbanizing rate will also create additional stress. Climate change can in turn alter both water supply and demand: increasing temperatures will reflect in increased evaporation and decreased stream flows. Rising seas could contaminate groundwater resources, and increasingly variable precipitation will likely mean more frequent high-intensity droughts and floods and less available rainfall in arid and semiarid regions. The effects of these changes will increase the natural variability of the climate, exacerbating the extreme climatic phenomena (drought and flood events, increasing the difficulty of managing water resources, especially in the most vulnerable regions, and affecting water availability even in regions that are

  3. Global warming: A Northwest perspective

    Energy Technology Data Exchange (ETDEWEB)

    Scott, M.J.; Counts, C.A. (eds.)

    1990-02-01

    The Northwest Power Planning Council convened a symposium in Olympia, Washington, on the subject of global climate change ( the greenhouse effect'') and its potential for affecting the Pacific Northwest. The symposium was organized in response to a need by the Power Council to understand global climate change and its potential impacts on resource planning and fish and wildlife planning for the region, as well as a need to understand national policy developing toward climate change and the Pacific Northwest's role in it. 40 figs., 15 tabs.

  4. Non-linear intensification of Sahel rainfall as a possible dynamic response to future warming

    Science.gov (United States)

    Schewe, Jacob; Levermann, Anders

    2017-07-01

    Projections of the response of Sahel rainfall to future global warming diverge significantly. Meanwhile, paleoclimatic records suggest that Sahel rainfall is capable of abrupt transitions in response to gradual forcing. Here we present climate modeling evidence for the possibility of an abrupt intensification of Sahel rainfall under future climate change. Analyzing 30 coupled global climate model simulations, we identify seven models where central Sahel rainfall increases by 40 to 300 % over the 21st century, owing to a northward expansion of the West African monsoon domain. Rainfall in these models is non-linearly related to sea surface temperature (SST) in the tropical Atlantic and Mediterranean moisture source regions, intensifying abruptly beyond a certain SST warming level. We argue that this behavior is consistent with a self-amplifying dynamic-thermodynamical feedback, implying that the gradual increase in oceanic moisture availability under warming could trigger a sudden intensification of monsoon rainfall far inland of today's core monsoon region.

  5. Warming of the Global Ocean: Spatial Structure and Water-Mass Trends

    Science.gov (United States)

    Hakkinen, Sirpa; Rhines, Peter B.; Worthen, Denise L.

    2016-01-01

    This study investigates the multidecadal warming and interannual-to-decadal heat content changes in the upper ocean (0-700 m), focusing on vertical and horizontal patterns of variability. These results support a nearly monotonic warming over much of the World Ocean, with a shift toward Southern Hemisphere warming during the well-observed past decade. This is based on objectively analyzed gridded observational datasets and on a modeled state estimate. Besides the surface warming, a warming climate also has a subsurface effect manifesting as a strong deepening of the midthermocline isopycnals, which can be diagnosed directly from hydrographic data. This deepening appears to be a result of heat entering via subduction and spreading laterally from the high-latitude ventilation regions of subtropical mode waters. The basin-average multidecadal warming mainly expands the subtropical mode water volume, with weak changes in the temperature-salinity (u-S) relationship (known as ''spice'' variability). However, the spice contribution to the heat content can be locally large, for example in Southern Hemisphere. Multidecadal isopycnal sinking has been strongest over the southern basins and weaker elsewhere with the exception of the Gulf Stream/North Atlantic Current/subtropical recirculation gyre. At interannual to decadal time scales, wind-driven sinking and shoaling of density surfaces still dominate ocean heat content changes, while the contribution from temperature changes along density surfaces tends to decrease as time scales shorten.

  6. Divergent responses to spring and winter warming drive community level flowering trends.

    Science.gov (United States)

    Cook, Benjamin I; Wolkovich, Elizabeth M; Parmesan, Camille

    2012-06-05

    Analyses of datasets throughout the temperate midlatitude regions show a widespread tendency for species to advance their springtime phenology, consistent with warming trends over the past 20-50 y. Within these general trends toward earlier spring, however, are species that either have insignificant trends or have delayed their timing. Various explanations have been offered to explain this apparent nonresponsiveness to warming, including the influence of other abiotic cues (e.g., photoperiod) or reductions in fall/winter chilling (vernalization). Few studies, however, have explicitly attributed the historical trends of nonresponding species to any specific factor. Here, we analyzed long-term data on phenology and seasonal temperatures from 490 species on two continents and demonstrate that (i) apparent nonresponders are indeed responding to warming, but their responses to fall/winter and spring warming are opposite in sign and of similar magnitude; (ii) observed trends in first flowering date depend strongly on the magnitude of a given species' response to fall/winter vs. spring warming; and (iii) inclusion of fall/winter temperature cues strongly improves hindcast model predictions of long-term flowering trends compared with models with spring warming only. With a few notable exceptions, climate change research has focused on the overall mean trend toward phenological advance, minimizing discussion of apparently nonresponding species. Our results illuminate an understudied source of complexity in wild species responses and support the need for models incorporating diverse environmental cues to improve predictability of community level responses to anthropogenic climate change.

  7. Interactions between rates of temperature change and acclimation affect latitudinal patterns of warming tolerance.

    Science.gov (United States)

    Allen, Jessica L; Chown, Steven L; Janion-Scheepers, Charlene; Clusella-Trullas, Susana

    2016-01-01

    Critical thermal limits form an increasing component of the estimation of impacts of global change on ectotherms. Whether any consistent patterns exist in the interactive effects of rates of temperature change (or experimental ramping rates) and acclimation on critical thermal limits and warming tolerance (one way of assessing sensitivity to climate change) is, however, far from clear. Here, we examine the interacting effects of ramping rate and acclimation on the critical thermal maxima (CTmax) and minima (CTmin) and warming tolerance of six species of springtails from sub-tropical, temperate and polar regions. We also provide microhabitat temperatures from 26 sites spanning 5 years in order to benchmark environmentally relevant rates of temperature change. Ramping rate has larger effects than acclimation on CTmax, but the converse is true for CTmin. Responses to rate and acclimation effects are more consistent among species for CTmax than for CTmin. In the latter case, interactions among ramping rate and acclimation are typical of polar species, less marked for temperate ones, and reduced in species from the sub-tropics. Ramping rate and acclimation have substantial effects on estimates of warming tolerance, with the former being more marked. At the fastest ramping rates (>1.0°C/min), tropical species have estimated warming tolerances similar to their temperate counterparts, whereas at slow ramping rates (warming tolerance is much reduced in tropical species. Rates of temperate change in microhabitats relevant to the springtails are typically warming tolerance approach.

  8. Global warming without global mean precipitation increase?

    Science.gov (United States)

    Salzmann, Marc

    2016-06-01

    Global climate models simulate a robust increase of global mean precipitation of about 1.5 to 2% per kelvin surface warming in response to greenhouse gas (GHG) forcing. Here, it is shown that the sensitivity to aerosol cooling is robust as well, albeit roughly twice as large. This larger sensitivity is consistent with energy budget arguments. At the same time, it is still considerably lower than the 6.5 to 7% K(-1) decrease of the water vapor concentration with cooling from anthropogenic aerosol because the water vapor radiative feedback lowers the hydrological sensitivity to anthropogenic forcings. When GHG and aerosol forcings are combined, the climate models with a realistic 20th century warming indicate that the global mean precipitation increase due to GHG warming has, until recently, been completely masked by aerosol drying. This explains the apparent lack of sensitivity of the global mean precipitation to the net global warming recently found in observations. As the importance of GHG warming increases in the future, a clear signal will emerge.

  9. Warm eyes provide superior vision in swordfishes.

    Science.gov (United States)

    Fritsches, Kerstin A; Brill, Richard W; Warrant, Eric J

    2005-01-11

    Large and powerful ocean predators such as swordfishes, some tunas, and several shark species are unique among fishes in that they are capable of maintaining elevated body temperatures (endothermy) when hunting for prey in deep and cold water . In these animals, warming the central nervous system and the eyes is the one common feature of this energetically costly adaptation . In the swordfish (Xiphias gladius), a highly specialized heating system located in an extraocular muscle specifically warms the eyes and brain up to 10 degrees C-15 degrees C above ambient water temperatures . Although the function of neural warming in fishes has been the subject of considerable speculation , the biological significance of this unusual ability has until now remained unknown. We show here that warming the retina significantly improves temporal resolution, and hence the detection of rapid motion, in fast-swimming predatory fishes such as the swordfish. Depending on diving depth, temporal resolution can be more than ten times greater in these fishes than in fishes with eyes at the same temperature as the surrounding water. The enhanced temporal resolution allowed by heated eyes provides warm-blooded and highly visual oceanic predators, such as swordfishes, tunas, and sharks, with a crucial advantage over their agile, cold-blooded prey.

  10. Effect of global warming in Thailand

    Directory of Open Access Journals (Sweden)

    Suphat Vongvisessomjai

    2010-08-01

    Full Text Available The earth absorbs much radiation from the sun to warm the atmosphere, the land, and the oceans. This energy is reradiatedback into space. In the past, the thermal budget of the earth is more or less balanced, with radiation from the sun onpar with thermal radiation from the earth. With increasing greenhouse gases in the atmosphere, some of the thermal radiationis absorbed by these gases resulting in an increase of global mean surface temperature, melting of polar ices and thuscontributing to a rising of sea level. However, sea-level changes depend upon four main processes: 1 Glacio-eustasy, 2Emergence/subsidence of land, 3 Man-made activities, and 4 Ocean-atmosphere effects. The assessment report of the IntergovernmentalPanel on Climate Change (IPCC, 1990, which was based on past data in Europe and the USA, including theNorth Atlantic Ocean, published a mean temperature of 14°C and an actual increase of 1°C in the last century, plus an increaseof CO2 from 370 ppmv to 550 ppmv, and a three-fold temperature increase of 3°C in this century. All these changes are projectinga sea level rise (SLR of 31-110 cm per century on global scale, which was in fact applicable to the North Atlantic. Theassessment report of the IPCC Working Group I (1996 has realized that differential SLR occurs due to different geographicalconditions. It identified ten regions on earth and compared the actual climate change to what it was postulated to be, andcame up with SLR of 15-95 cm per century. The assessment report of the IPCC Working Group II (2001 employed improveddata obtained from tide gauges and satellite images as well as mathematical model results with the most convincing evidencein the North Atlantic, and it concluded an SLR of 9-88 cm per century. But it had, however, noted a lack of data in the Pacificand Indian Ocean. The assessment report of the IPCC Summary for Policy Makers (SPM, 2007 that included six differentarctic and antarctic climate science

  11. Greenland warming of 1920-1930 and 1995-2005

    Science.gov (United States)

    Chylek, Petr; Dubey, M. K.; Lesins, G.

    2006-06-01

    We provide an analysis of Greenland temperature records to compare the current (1995-2005) warming period with the previous (1920-1930) Greenland warming. We find that the current Greenland warming is not unprecedented in recent Greenland history. Temperature increases in the two warming periods are of a similar magnitude, however, the rate of warming in 1920-1930 was about 50% higher than that in 1995-2005.

  12. Simple additive simulation overestimates real influence: altered nitrogen and rainfall modulate the effect of warming on soil carbon fluxes.

    Science.gov (United States)

    Ni, Xiangyin; Yang, Wanqin; Qi, Zemin; Liao, Shu; Xu, Zhenfeng; Tan, Bo; Wang, Bin; Wu, Qinggui; Fu, Changkun; You, Chengming; Wu, Fuzhong

    2017-08-01

    Experiments and models have led to a consensus that there is positive feedback between carbon (C) fluxes and climate warming. However, the effect of warming may be altered by regional and global changes in nitrogen (N) and rainfall levels, but the current understanding is limited. Through synthesizing global data on soil C pool, input and loss from experiments simulating N deposition, drought and increased precipitation, we quantified the responses of soil C fluxes and equilibrium to the three single factors and their interactions with warming. We found that warming slightly increased the soil C input and loss by 5% and 9%, respectively, but had no significant effect on the soil C pool. Nitrogen deposition alone increased the soil C input (+20%), but the interaction of warming and N deposition greatly increased the soil C input by 49%. Drought alone decreased the soil C input by 17%, while the interaction of warming and drought decreased the soil C input to a greater extent (-22%). Increased precipitation stimulated the soil C input by 15%, but the interaction of warming and increased precipitation had no significant effect on the soil C input. However, the soil C loss was not significantly affected by any of the interactions, although it was constrained by drought (-18%). These results implied that the positive C fluxes-climate warming feedback was modulated by the changing N and rainfall regimes. Further, we found that the additive effects of [warming × N deposition] and [warming × drought] on the soil C input and of [warming × increased precipitation] on the soil C loss were greater than their interactions, suggesting that simple additive simulation using single-factor manipulations may overestimate the effects on soil C fluxes in the real world. Therefore, we propose that more multifactorial experiments should be considered in studying Earth systems. © 2016 John Wiley & Sons Ltd.

  13. Responses of arthropod populations to warming depend on latitude: evidence from urban heat islands.

    Science.gov (United States)

    Youngsteadt, Elsa; Ernst, Andrew F; Dunn, Robert R; Frank, Steven D

    2017-04-01

    Biological effects of climate change are expected to vary geographically, with a strong signature of latitude. For ectothermic animals, there is systematic latitudinal variation in the relationship between climate and thermal performance curves, which describe the relationship between temperature and an organism's fitness. Here, we ask whether these documented latitudinal patterns can be generalized to predict arthropod responses to warming across mid- and high temperate latitudes, for taxa whose thermal physiology has not been measured. To address this question, we used a novel natural experiment consisting of a series of urban warming gradients at different latitudes. Specifically, we sampled arthropods from a single common street tree species across temperature gradients in four US cities, located from 35.8 to 42.4° latitude. We captured 6746 arthropods in 34 families from 111 sites that varied in summer average temperature by 1.7-3.4 °C within each city. Arthropod responses to warming within each city were characterized as Poisson regression coefficients describing change in abundance per °C for each family. Family responses in the two midlatitude cities were heterogeneous, including significantly negative and positive effects, while those in high-latitude cities varied no more than expected by chance within each city. We expected high-latitude taxa to increase in abundance with warming, and they did so in one of the two high-latitude cities; in the other, Queens (New York City), most taxa declined with warming, perhaps due to habitat loss that was correlated with warming in this city. With the exception of Queens, patterns of family responses to warming were consistent with predictions based on known latitudinal patterns in arthropod physiology relative to regional climate. Heterogeneous responses in midlatitudes may be ecologically disruptive if interacting taxa respond oppositely to warming. © 2016 John Wiley & Sons Ltd.

  14. Surface diurnal warming in the East China Sea derived from satellite remote sensing

    Science.gov (United States)

    Song, Dan; Duan, Zhigang; Zhai, Fangguo; He, Qiqi

    2017-09-01

    Process of sea surface diurnal warming has drawn a lot of attention in recent years, but that occurs in shelf seas was rarely addressed. In the present work, surface diurnal warming strength in the East China Sea was calculated by the sea surface temperature (SST) data derived from the MODIS sensors carried by the satellites Aqua and Terra. Due to transit time difference, both the number of valid data and the surface diurnal warming strength computed by the MODIS-Aqua data are relatively larger than Terra. Therefore, the 10-year MODIS-Aqua data from 2005 to 2014 were used to analyze the monthly variability of the surface diurnal warming. Generally, the surface diurnal warming in the East China sea is stronger in summer and autumn but weaker in winter and spring, while it shows different peaks in different regions. Large events with ΔT≥5 K have also been discussed. They were found mainly in coastal area, especially near the Changjiang (Yangtze) River estuary. And there exists a high-incidence period from April to July. Furthermore, the relationship between surface diurnal warming and wind speed was discussed. Larger diurnal warming mainly lies in areas with low wind speed. And its possibility decreases with the increase of wind speed. Events with ΔT≥2.5 K rarely occur when wind speed is over 12 m/s. Study on surface diurnal warming in the East China Sea may help to understand the daily scale air-sea interaction in the shelf seas. A potential application might be in the marine weather forecasts by numerical models. Its impact on the coastal eco-system and the activities of marine organisms can also be pursued.

  15. CO2-Induced Ocean Warming of the Antarctic Continental Shelf in an Eddying Global Climate Model

    Science.gov (United States)

    Goddard, Paul B.; Dufour, Carolina O.; Yin, Jianjun; Griffies, Stephen M.; Winton, Michael

    2017-10-01

    Ocean warming near the Antarctic ice shelves has critical implications for future ice sheet mass loss and global sea level rise. A global climate model with an eddying ocean is used to quantify the mechanisms contributing to ocean warming on the Antarctic continental shelf in an idealized 2xCO2 experiment. The results indicate that relatively large warm anomalies occur both in the upper 100 m and at depths above the shelf floor, which are controlled by different mechanisms. The near-surface ocean warming is primarily a response to enhanced onshore advective heat transport across the shelf break. The deep shelf warming is initiated by onshore intrusions of relatively warm Circumpolar Deep Water (CDW), in density classes that access the shelf, as well as the reduction of the vertical mixing of heat. CO2-induced shelf freshening influences both warming mechanisms. The shelf freshening slows vertical mixing by limiting gravitational instabilities and the upward diffusion of heat associated with CDW, resulting in the buildup of heat at depth. Meanwhile, freshening near the shelf break enhances the lateral density gradient of the Antarctic Slope Front (ASF) and disconnect isopycnals between the shelf and CDW, making cross-ASF heat exchange more difficult. However, at several locations along the ASF, the cross-ASF heat transport is less inhibited and heat can move onshore. Once onshore, lateral and vertical heat advection work to disperse the heat anomalies across the shelf region. Understanding the inhomogeneous Antarctic shelf warming will lead to better projections of future ice sheet mass loss.

  16. Impact of Soil Warming on the Plant Metabolome of Icelandic Grasslands

    Science.gov (United States)

    Gargallo-Garriga, Albert; Ayala-Roque, Marta; Granda, Victor; Sigurdsson, Bjarni D.; Leblans, Niki I. W.; Oravec, Michal; Urban, Otmar; Janssens, Ivan A.

    2017-01-01

    Climate change is stronger at high than at temperate and tropical latitudes. The natural geothermal conditions in southern Iceland provide an opportunity to study the impact of warming on plants, because of the geothermal bedrock channels that induce stable gradients of soil temperature. We studied two valleys, one where such gradients have been present for centuries (long-term treatment), and another where new gradients were created in 2008 after a shallow crustal earthquake (short-term treatment). We studied the impact of soil warming (0 to +15 °C) on the foliar metabolomes of two common plant species of high northern latitudes: Agrostis capillaris, a monocotyledon grass; and Ranunculus acris, a dicotyledonous herb, and evaluated the dependence of shifts in their metabolomes on the length of the warming treatment. The two species responded differently to warming, depending on the length of exposure. The grass metabolome clearly shifted at the site of long-term warming, but the herb metabolome did not. The main up-regulated compounds at the highest temperatures at the long-term site were saccharides and amino acids, both involved in heat-shock metabolic pathways. Moreover, some secondary metabolites, such as phenolic acids and terpenes, associated with a wide array of stresses, were also up-regulated. Most current climatic models predict an increase in annual average temperature between 2–8 °C over land masses in the Arctic towards the end of this century. The metabolomes of A. capillaris and R. acris shifted abruptly and nonlinearly to soil warming >5 °C above the control temperature for the coming decades. These results thus suggest that a slight warming increase may not imply substantial changes in plant function, but if the temperature rises more than 5 °C, warming may end up triggering metabolic pathways associated with heat stress in some plant species currently dominant in this region. PMID:28832555

  17. Implications of global warming for the climate of African rainforests.

    Science.gov (United States)

    James, Rachel; Washington, Richard; Rowell, David P

    2013-01-01

    African rainforests are likely to be vulnerable to changes in temperature and precipitation, yet there has been relatively little research to suggest how the regional climate might respond to global warming. This study presents projections of temperature and precipitation indices of relevance to African rainforests, using global climate model experiments to identify local change as a function of global temperature increase. A multi-model ensemble and two perturbed physics ensembles are used, one with over 100 members. In the east of the Congo Basin, most models (92%) show a wet signal, whereas in west equatorial Africa, the majority (73%) project an increase in dry season water deficits. This drying is amplified as global temperature increases, and in over half of coupled models by greater than 3% per °C of global warming. Analysis of atmospheric dynamics in a subset of models suggests that this could be partly because of a rearrangement of zonal circulation, with enhanced convection in the Indian Ocean and anomalous subsidence over west equatorial Africa, the Atlantic Ocean and, in some seasons, the Amazon Basin. Further research to assess the plausibility of this and other mechanisms is important, given the potential implications of drying in these rainforest regions.

  18. To what extent can cirrus seeding counteract global warming?

    Science.gov (United States)

    Gasparini, Blaz; Lohmann, Ulrike

    2017-04-01

    The idea of modifying cirrus clouds to directly counteract greenhouse gas warming has gained a lot of momentum in recent years, despite large disputes over its physical feasibility. We use the ECHAM-HAM general circulation model to evaluate the temperature and precipitation responses to cirrus thinning by seeding with efficient ice nucleating particles and increasing ice crystal sedimentation velocities in a 1.5xCO2 world. The seeding scenario can counteract about 40% of the warming and precipitation increase induced by 1.5 x CO2 concentrations with respect to present day values. The idealized ice crystal sedimentation velocity increase scenario on the other hand fully restores the global annual temperature but counteracts only half of the precipitation increase. Moreover, we define a climate damage function, quadratic in temperature and precipitation anomalies to calculate the damage of the different scenarios in 21 selected land regions. Seeding can decrease about 55% of the CO2 induced damage, while the sedimentation velocity increase can counteract about 95% of the damage. A regional analysis shows the negative responses of seeding are minimal both in terms of precipitation and temperature, which makes cirrus seeding an attractive geoengineering method.

  19. Modelling middle pliocene warm climates of the USA

    Science.gov (United States)

    Haywood, A.M.; Valdes, P.J.; Sellwood, B.W.; Kaplan, J.O.; Dowsett, H.J.

    2001-01-01

    The middle Pliocene warm period represents a unique time slice in which to model and understand climatic processes operating under a warm climatic regime. Palaeoclimatic model simulations, focussed on the United States of America (USA), for the middle Pliocene (ca 3 Ma) were generated using the USGS PRISM2 2?? ?? 2?? data set of boundary conditions and the UK Meteorological Office's HadAMS General Circulation Model (GCM). Model results suggest that conditions in the USA during the middle Pliocene can be characterised as annually warmer (by 2?? to 4??C), less seasonal, wetter (by a maximum of 4 to 8 mm/day) and with an absence of freezing winters over the central and southern Great Plains. A sensitivity experiment suggests that the main forcing mechanisms for surface temperature changes in near coastal areas are the imposed Pliocene sea surface temperatures (SST's). In interior regions, reduced Northern Hemisphere terrestrial ice, combined with less snow cover and a reduction in the elevation of the western cordillera of North America, generate atmospheric circulation changes and positive albedo feedbacks that raise surface temperatures. A complex set of climatic feedback mechanisms cause an enhancement of the hydrological cycle magnifying the moisture bearing westerly wind belt during the winter season (Dec., Jan., Feb.). Predictions produced by the model are in broad agreement with available geological evidence. However, the GCM appears to underestimate precipitation levels in the interior and central regions of the southern USA. Copyright: Palaeontological Association, 22 June 2001.

  20. Thermal stability of warm-rolled tungsten

    DEFF Research Database (Denmark)

    Alfonso Lopez, Angel

    , and recrystallization fitted to JMAK recrystallization kinetics, which in turn allowed thecalculation of recrystallization activation energies. Much faster recovery and recrystallizationkinetics were found for the plate warm-rolled to 90% thickness reduction, as compared to the platewarm-rolled to 67% thickness...... and recrystallization occur in tungsten, and quantifying the kinetics and microstructuralaspects of these restoration processes. Two warm-rolled tungsten plates are annealed attemperatures between 1100 °C and 1350 °C, under vacuum conditions or argon atmosphere. Theeffects of annealing on the microstructure...... reduction. An initial incubation time before recrystallization wasfound for both plates warm-rolled to 67% and 90% thickness reductions. The different Avramiexponents found for the two plates were explained microstructurally in terms of nucleation. The microstructural evolution during recovery...

  1. Short-term herbivory has long-term consequences in warmed and ambient high Arctic tundra

    Science.gov (United States)

    Little, Chelsea J.; Cutting, Helen; Alatalo, Juha; Cooper, Elisabeth

    2017-02-01

    Climate change is occurring across the world, with effects varying by ecosystem and region but already occurring quickly in high-latitude and high-altitude regions. Biotic interactions are important in determining ecosystem response to such changes, but few studies have been long-term in nature, especially in the High Arctic. Mesic tundra plots on Svalbard, Norway, were subjected to grazing at two different intensities by captive Barnacle geese from 2003-2005, in a factorial design with warming by Open Top Chambers. Warming manipulations were continued through 2014, when we measured vegetation structure and composition as well as growth and reproduction of three dominant species in the mesic meadow. Significantly more dead vascular plant material was found in warmed compared to ambient plots, regardless of grazing history, but in contrast to many short-term experiments no difference in the amount of living material was found. This has strong implications for nutrient and carbon cycling and could feed back into community productivity. Dominant species showed increased flowering in warmed plots, especially in those plots where grazing had been applied. However, this added sexual reproduction did not translate to substantial shifts in vegetative cover. Forbs and rushes increased slightly in warmed plots regardless of grazing, while the dominant shrub, Salix polaris, generally declined with effects dependent on grazing, and the evergreen shrub Dryas octopetala declined with previous intensive grazing. There were no treatment effects on community diversity or evenness. Thus despite no changes in total live abundance, a typical short-term response to environmental conditions, we found pronounced changes in dead biomass indicating that tundra ecosystem processes respond to medium- to long-term changes in conditions caused by 12 seasons of summer warming. We suggest that while high arctic tundra plant communities are fairly resistant to current levels of climate warming

  2. Effect of Soil Moisture on the Response of Soil Respiration to Open-Field Experimental Warming and Precipitation Manipulation

    Directory of Open Access Journals (Sweden)

    Guanlin Li

    2017-02-01

    Full Text Available Soil respiration (RS, Soil CO2 efflux is the second largest carbon (C flux in global terrestrial ecosystems, and thus, plays an important role in global and regional C cycling; moreover, it acts as a feedback mechanism between C cycling and global climate change. RS is highly responsive to temperature and moisture, factors that are closely related to climate warming and changes in precipitation regimes. Here, we examined the direct and interactive effects of climate change drivers on RS of Pinus densiflora Sieb. et Zucc. seedlings in a multifactor climate change experiment involving atmospheric temperature warming (+3 °C and precipitation manipulations (−30% and +30%. Our results indicated that atmospheric temperature warming induced significant changes in RS (p < 0.05, enhancing RS by an average of 54.6% and 59.7% in the control and elevated precipitation plots, respectively, whereas atmospheric temperature warming reduced RS by 19.4% in plots subjected to lower rates of precipitation. However, the warming effect on RS was influenced by soil moisture. On the basis of these findings, we suggest that atmospheric temperature warming significantly influenced RS, but the warming effect on RS may be weakened by warming-induced soil drying in water-limited environments.

  3. Long-term experimental warming alters community composition of ascomycetes in Alaskan moist and dry arctic tundra.

    Science.gov (United States)

    Semenova, Tatiana A; Morgado, Luis N; Welker, Jeffrey M; Walker, Marilyn D; Smets, Erik; Geml, József

    2015-01-01

    Arctic tundra regions have been responding to global warming with visible changes in plant community composition, including expansion of shrubs and declines in lichens and bryophytes. Even though it is well known that the majority of arctic plants are associated with their symbiotic fungi, how fungal community composition will be different with climate warming remains largely unknown. In this study, we addressed the effects of long-term (18 years) experimental warming on the community composition and taxonomic richness of soil ascomycetes in dry and moist tundra types. Using deep Ion Torrent sequencing, we quantified how OTU assemblage and richness of different orders of Ascomycota changed in response to summer warming. Experimental warming significantly altered ascomycete communities with stronger responses observed in the moist tundra compared with dry tundra. The proportion of several lichenized and moss-associated fungi decreased with warming, while the proportion of several plant and insect pathogens and saprotrophic species was higher in the warming treatment. The observed alterations in both taxonomic and ecological groups of ascomycetes are discussed in relation to previously reported warming-induced shifts in arctic plant communities, including decline in lichens and bryophytes and increase in coverage and biomass of shrubs. © 2014 John Wiley & Sons Ltd.

  4. Experimental warming alters migratory caribou forage quality.

    Science.gov (United States)

    Zamin, Tara J; Côté, Steeve D; Tremblay, Jean-Pierre; Grogan, Paul

    2017-10-01

    Global declines in caribou and reindeer (Rangifer) populations have drawn attention to the myriad of stressors that these Arctic and boreal forest herbivores currently face. Arctic warming has resulted in increased tundra shrub growth and therefore Rangifer forage quantity. However, its effects on forage quality have not yet been addressed although they may be critical to Rangifer body condition and fecundity. We investigated the impact of 8 yrs of summer warming on the quality of forage available to the Bathurst caribou herd using experimental greenhouses (n = 5) located in mesic birch hummock tundra in the central Canadian Low Arctic. Leaf forage quality and digestibility characteristics associated with nutrients (nitrogen and phosphorus), phenolics, and fiber were measured on the deciduous shrub Betula glandulosa (an important Rangifer diet component) at six time points through the growing season, and on five other very common vascular plant and lichen species in late summer. Experimental warming reduced B. glandulosa leaf nitrogen concentrations by ~10% in both late June and mid-July, but not afterwards. It also reduced late summer forage quality of the graminoid Eriophorum vaginatum by increasing phenolic concentrations 38%. Warming had mixed effects on forage quality of the lichen Cetraria cucullata in that it increased nutrient concentrations and tended to decrease fiber contents, but it also increased phenolics. Altogether, these warming-induced changes in forage quality over the growing season, and response differences among species, highlight the importance of Rangifer adaptability in diet selection. Furthermore, the early season reduction in B. glandulosa nitrogen content is a particular concern given the importance of this time for calf growth. Overall, our demonstration of the potential for significant warming impacts on forage quality at critical times for these animals underscores the importance of effective Rangifer range conservation to ensure

  5. The dynamic warm pool: A new paradigm for understanding the role of the tropics in the global heat balance

    Science.gov (United States)

    Webster, P. J.; Hoyos, C. D.

    2008-12-01

    The region of atmospheric heating in the tropics, here termed the dynamic warm pool, represents the "boiler box" of the planetary heat engine and plays a determining role in global climate and tropical weather variability, modulating the genesis and intensification of tropical cyclones, the ascending branches of the Walker and Hadley circulations, monsoons and ENSO variability, and the nature of global teleconnections emanating from the tropics. Hence, it is important to understand how the tropical warm pool has changed in the past and how it may change in the future, and how these changes may alter climate both regionally and globally. The concept of the dynamic warm pool, which encloses the region of net atmospheric convective heating in the tropics, is fundamentally different to the traditionally defined oceanic warm pool corresponding to the area occupied by sea surface temperatures above a pre-defined threshold, typically 28C. While the traditionally defined warm pool has expanded as a result of global warming, the dynamical warm pool has remained constant as a result of an increasing column integrated heating-sea surface temperature threshold. In other words, in a warming climate the convective area does not expand with the area of SST>28C. However, despite the near constancy of the dynamic warm pool area, the magnitude of the column integrated heating in the tropics increases substantially. In light of these results, the traditional warm pool definition and the thresholds for convection and cyclogenesis are not climatically meaningful and lack a physical basis. Rather than a static definition set by a constant temperature, the climatically active warm pool should be defined dynamically by the large-scale coupled ocean-atmosphere system rather than just by the temperature of the ocean surface. In this work we use the concept of the dynamical warm pool as a physical basis to explore and understand long-term variability of tropical cyclogenesis and

  6. Attribution of the United States "warming hole": aerosol indirect effect and precipitable water vapor.

    Science.gov (United States)

    Yu, Shaocai; Alapaty, Kiran; Mathur, Rohit; Pleim, Jonathan; Zhang, Yuanhang; Nolte, Chris; Eder, Brian; Foley, Kristen; Nagashima, Tatsuya

    2014-11-06

    Aerosols can influence the climate indirectly by acting as cloud condensation nuclei and/or ice nuclei, thereby modifying cloud optical properties. In contrast to the widespread global warming, the central and south central United States display a noteworthy overall cooling trend during the 20(th) century, with an especially striking cooling trend in summertime daily maximum temperature (Tmax) (termed the U.S. "warming hole"). Here we used observations of temperature, shortwave cloud forcing (SWCF), longwave cloud forcing (LWCF), aerosol optical depth and precipitable water vapor as well as global coupled climate models to explore the attribution of the "warming hole". We find that the observed cooling trend in summer Tmax can be attributed mainly to SWCF due to aerosols with offset from the greenhouse effect of precipitable water vapor. A global coupled climate model reveals that the observed "warming hole" can be produced only when the aerosol fields are simulated with a reasonable degree of accuracy as this is necessary for accurate simulation of SWCF over the region. These results provide compelling evidence of the role of the aerosol indirect effect in cooling regional climate on the Earth. Our results reaffirm that LWCF can warm both winter Tmax and Tmin.

  7. Use of emulsion for warm mix asphalt

    Directory of Open Access Journals (Sweden)

    Mahabir Panda

    2017-06-01

    Full Text Available Due to increase in energy costs and emission problems in hot mix asphalt usually used, it brought a great interest to the researchers to develop the warm mix technology for pavement constructions. Commonly known as warm mix asphalt (WMA, it is a typical method in the bituminous paving technology, which allows production and placement of bituminous mixes at lower temperatures than that used for hot mix asphalt (HMA. The WMA involves an environmental friendly production process that utilises organic additives, chemical additives and water based technologies. The organic and chemical additives are normally very costly and still involve certain amount of environmental issues. These factors motivated the authors to take up this technology using simple, environment friendly and somewhat cost effective procedure. In this study, an attempt has been made to prepare warm mixes by first pre-coating the aggregates with medium setting bitumen emulsion (MS and then mixing the semi-coated aggregates with VG 30 bitumen at a lower temperature than normally required. After a number of trials it was observed that mostly three mixing temperatures, namely temperatures 110 °C, 120 °C and 130 °C were appropriate to form the bituminous mixes with satisfactory homogeneity and consistency and as such were maintained throughout this study. Marshall samples for paving mixes were prepared using this procedure for dense bituminous macadam (DBM gradings as per the specifications of Ministry of Road Transport and Highways (MORTH and subsequently Marshall properties of the resultant mixes were studied with the main objective of deciding the different parameters that were considered for development of appropriate warm mix asphalt. In this study it has been observed that out of three mixing temperatures tried, the mixes prepared at 120 °C with bitumen-emulsion composition of 80B:20E for DBM warm mix, offer highest Marshall stability and highest indirect tensile strength

  8. Forecasting effects of global warming on biodiversity

    DEFF Research Database (Denmark)

    Botkin, D.B.; Saxe, H.; Araújo, M.B.

    2007-01-01

    The demand for accurate forecasting of the effects of global warming on biodiversity is growing, but current methods for forecasting have limitations. In this article, we compare and discuss the different uses of four forecasting methods: (1) models that consider species individually, (2) niche...... and theoretical ecological results suggest that many species could be at risk from global warming, during the recent ice ages surprisingly few species became extinct. The potential resolution of this conundrum gives insights into the requirements for more accurate and reliable forecasting. Our eight suggestions...

  9. A real-time Global Warming Index.

    Science.gov (United States)

    Haustein, K; Allen, M R; Forster, P M; Otto, F E L; Mitchell, D M; Matthews, H D; Frame, D J

    2017-11-13

    We propose a simple real-time index of global human-induced warming and assess its robustness to uncertainties in climate forcing and short-term climate fluctuations. This index provides improved scientific context for temperature stabilisation targets and has the potential to decrease the volatility of climate policy. We quantify uncertainties arising from temperature observations, climate radiative forcings, internal variability and the model response. Our index and the associated rate of human-induced warming is compatible with a range of other more sophisticated methods to estimate the human contribution to observed global temperature change.

  10. Global warming potential impact of bioenergy systems

    DEFF Research Database (Denmark)

    Tonini, Davide; Hamelin, L.; Wenzel, H.

    environmental consequences related to land use changes. In this study the global warming potential impact associated with six alternative bioenergy systems based on willow and Miscanthus was assessed by means of life-cycle assessment. The results showed that bioenergy production may generate higher global...... warming impacts than the reference fossil fuel system, when the impacts from indirect land use changes are accounted for. In a life-cycle perspective, only highly-efficient co-firing with fossil fuel achieved a (modest) GHG emission reduction....

  11. Initial response of the nitrogen cycle to soil warming in Northern Minnesota peatlands

    Science.gov (United States)

    Peatlands store 30% of global soil carbon. Many of these peatlands are located in boreal regions which are expected to have the highest temperature increases in response to climate change. As climate warms, peat decomposition may accelerate and release greenhouse gases. Spruce a...

  12. Linking an ecosystem model and a landscape model to study forest species response to climate warming

    Science.gov (United States)

    Hong S. He; David J. Mladenoff; Thomas R. Crow

    1999-01-01

    No single model can address forest change from single tree to regional scales. We discuss a framework linking an ecosystem process model {LINKAGES) with a spatial landscape model (LANDIS) to examine forest species responses to climate warming for a large, heterogeneous landscape in northern Wisconsin, USA. Individual species response at the ecosystem scale was...

  13. Arctic winter warming amplified by the thermal inversion and consequent low infrared cooling to space

    NARCIS (Netherlands)

    Bintanja, R.; Graversen, R.G.; Hazeleger, W.

    2011-01-01

    Pronounced warming in the Arctic region, coined Arctic amplification, is an important feature of observed and modelled climate change1, 2. Arctic amplification is generally attributed to the retreat of sea-ice3 and snow, and the associated surface-albedo feedback4, in conjunction with other

  14. Impacts of +2 °C global warming on winter tourism demand in Europe

    NARCIS (Netherlands)

    Damm, Andrea; Greuell, Wouter; Landgren, Oskar; Prettenthaler, Franz

    2017-01-01

    Increasing temperatures and snow scarce winter seasons challenge the winter tourism industry. In this study the impacts of +2 °C global warming on winter tourism demand in Europe's ski tourism related NUTS-3 regions are quantified. Using time series regression models, the relationship between

  15. Examining processes that contribute to enhanced warming rates at high elevations

    Science.gov (United States)

    Miller, James; Chen, Yonghua; Ghatak, Debjani; Naud, Catherine; Rangwala, Imtiaz; Sinsky, Eric; Su, Xiaoou; van Oppen, Stephanie; Xu, Ming

    2017-04-01

    During the last several decades, many studies, although not all, have found enhanced warming rates in high elevation regions relative to their lower elevation surroundings. Using a combination of observations and CMIP5 climate model simulations, we provide examples of how processes associated with three different climate variables (water vapor, snow cover, and clouds) can contribute to elevation dependent warming (EDW) through their effect on shortwave and longwave radiation both in recent decades as well as for model projections later this century. We provide explanations for why EDW can be found in some studies but not in others, sometimes even in the same regions. We also analyze the relationship between 21st century model projections of changes in free-air temperatures with temperature changes at the same elevations in mountains. The primary focus is on the Tibetan Plateau region and North America where we also consider lower mountain regions ( 1500 m) than found in most EDW studies.

  16. Abrupt warming of the Red Sea

    KAUST Repository

    Raitsos, D. E.

    2011-07-19

    Coral reef ecosystems, often referred to as “marine rainforests,” concentrate the most diverse life in the oceans. Red Sea reef dwellers are adapted in a very warm environment, fact that makes them vulnerable to further and rapid warming. The detection and understanding of abrupt temperature changes is an important task, as ecosystems have more chances to adapt in a slowly rather than in a rapid changing environment. Using satellite derived sea surface and ground based air temperatures, it is shown that the Red Sea is going through an intense warming initiated in the mid-90s, with evidence for an abrupt increase after 1994 (0.7°C difference pre and post the shift). The air temperature is found to be a key parameter that influences the Red Sea marine temperature. The comparisons with Northern Hemisphere temperatures revealed that the observed warming is part of global climate change trends. The hitherto results also raise additional questions regarding other broader climatic impacts over the area.

  17. CERN plans global-warming experiment

    CERN Multimedia

    De Laine, M

    1998-01-01

    A controversial theory that proposes that cosmic rays are responsible for global warming, is going to be tested at CERN. Experimentalists will use a cloud chamber to mimic the Earth's atmosphere in order to try and find out if cloud formation is influenced by solar activity (1 page).

  18. Effects of global warming on respiratory diseases

    African Journals Online (AJOL)

    Abe Olugbenga

    Review Article. ABSTRACT. Background: Global warming is a consequence of air pollution resulting in climate change due to trapping of excess greenhouse gases in the earth's atmosphere that affects biodiversity and constitutes a serious health hazard, especially tothe respiratory system. These greenhouse gases include ...

  19. Greenhouse warming and changes in sea level

    NARCIS (Netherlands)

    Oerlemans, J.

    1989-01-01

    It is likely that the anticipated warming due to the effect of increasing concentration of carbon dioxide and other greenhouse gases will lead to a further and faster rise in world mean sea level. There are many processes in the climate system controlling sea level, but the most important

  20. Global Warming 'Pause' - Oceans Reshuffle Heat

    Science.gov (United States)

    Nieves, V.; Willis, J. K.; Patzert, W. C.

    2015-12-01

    Despite the fact that greenhouse gases are still increasing and all other indicators show warming-related change (+0.0064 °C/year since 1880 or +0.0077 °C/year during 1993-2002), surface temperatures stopped climbing steadily during the past decade at a rate of +0.0010 °C/year from 2003 to 2012. We show that in recent years, the heat was being trapped in the subsurface waters of the western Pacific and eastern Indian oceans between 100 and 300 m. The movement of warm Pacific water below the surface, also related to the Pacific Decadal Oscillation climatic pattern, temporarily affected surface temperatures and accounted for the global cooling trend in surface temperature. With the Pacific Decadal Oscillation possibly changing to a warm phase, it is likely that the oceans will drive a major surge in global surface warming sometime in the next decade or two. Reference: Nieves, V., Willis, J. K., and Patzert, W. C. (2015). Recent hiatus caused by decadal shift in Indo-Pacific heating. Science, aaa4521.

  1. Revisiting CMB constraints on warm inflation

    Science.gov (United States)

    Arya, Richa; Dasgupta, Arnab; Goswami, Gaurav; Prasad, Jayanti; Rangarajan, Raghavan

    2018-02-01

    We revisit the constraints that Planck 2015 temperature, polarization and lensing data impose on the parameters of warm inflation. To this end, we study warm inflation driven by a single scalar field with a quartic self interaction potential in the weak dissipative regime. We analyse the effect of the parameters of warm inflation, namely, the inflaton self coupling λ and the inflaton dissipation parameter QP on the CMB angular power spectrum. We constrain λ and QP for 50 and 60 number of e-foldings with the full Planck 2015 data (TT, TE, EE + lowP and lensing) by performing a Markov-Chain Monte Carlo analysis using the publicly available code CosmoMC and obtain the joint as well as marginalized distributions of those parameters. We present our results in the form of mean and 68 % confidence limits on the parameters and also highlight the degeneracy between λ and QP in our analysis. From this analysis we show how warm inflation parameters can be well constrained using the Planck 2015 data.

  2. Microclimate moderates plant responses to macroclimate warming

    NARCIS (Netherlands)

    Frenne, De P.; Rodríguez-Sánchez, F.; Coomes, D.; Baeten, L.; Verstraeten, G.; Hommel, P.W.F.M.

    2013-01-01

    Recent global warming is acting across marine, freshwater, and terrestrial ecosystems to favor species adapted to warmer conditions and/or reduce the abundance of cold-adapted organisms (i.e., “thermophilization” of communities). Lack of community responses to increased temperature, however, has

  3. NASA: Black soot fuels global warming

    CERN Multimedia

    2003-01-01

    New research from NASA's Goddard Space Center scientists suggests emissions of black soot have been altering the way sunlight reflects off Earth's snow. The research indicates the soot could be responsible for as much as 25 percent of global warming over the past century (assorted news items, 1 paragraph each).

  4. Wind changes above warm Agulhas Current eddies

    CSIR Research Space (South Africa)

    Roualt, M

    2016-10-01

    Full Text Available Sea-surface temperature (SST), altimetry derived sea-level anomalies (SLA) and surface current are used south of the Agulhas Current to identify warm core mesoscale ocean eddies presenting a distinct SST perturbation superior to 1(supo...

  5. Wind changes above warm Agulhas Current eddies

    CSIR Research Space (South Africa)

    Rouault, M

    2016-01-01

    Full Text Available speeds above the eddies at the instantaneous scale; 20 % of cases had incomplete data due to partial global coverage by the scatterometer for one path. For cases where the wind is stronger above warm eddies, there is no relationship between the increase...

  6. Desert Amplification in a Warming Climate

    Science.gov (United States)

    Zhou, Liming

    2016-01-01

    Here I analyze the observed and projected surface temperature anomalies over land between 50°S-50°N for the period 1950–2099 by large-scale ecoregion and find strongest warming consistently and persistently seen over driest ecoregions such as the Sahara desert and the Arabian Peninsula during various 30-year periods, pointing to desert amplification in a warming climate. This amplification enhances linearly with the global mean greenhouse gases(GHGs) radiative forcing and is attributable primarily to a stronger GHGs-enhanced downward longwave radiation forcing reaching the surface over drier ecoregions as a consequence of a warmer and thus moister atmosphere in response to increasing GHGs. These results indicate that desert amplification may represent a fundamental pattern of global warming associated with water vapor feedbacks over land in low- and mid- latitudes where surface warming rates depend inversely on ecosystem dryness. It is likely that desert amplification might involve two types of water vapor feedbacks that maximize respectively in the tropical upper troposphere and near the surface over deserts, with both being very dry and thus extremely sensitive to changes of water vapor. PMID:27538725

  7. The global warming hiatus: Slowdown or redistribution?

    Science.gov (United States)

    Yan, Xiao-Hai; Boyer, Tim; Trenberth, Kevin; Karl, Thomas R.; Xie, Shang-Ping; Nieves, Veronica; Tung, Ka-Kit; Roemmich, Dean

    2016-11-01

    Global mean surface temperatures (GMST) exhibited a smaller rate of warming during 1998-2013, compared to the warming in the latter half of the 20th Century. Although, not a "true" hiatus in the strict definition of the word, this has been termed the "global warming hiatus" by IPCC (2013). There have been other periods that have also been defined as the "hiatus" depending on the analysis. There are a number of uncertainties and knowledge gaps regarding the "hiatus." This report reviews these issues and also posits insights from a collective set of diverse information that helps us understand what we do and do not know. One salient insight is that the GMST phenomenon is a surface characteristic that does not represent a slowdown in warming of the climate system but rather is an energy redistribution within the oceans. Improved understanding of the ocean distribution and redistribution of heat will help better monitor Earth's energy budget and its consequences. A review of recent scientific publications on the "hiatus" shows the difficulty and complexities in pinpointing the oceanic sink of the "missing heat" from the atmosphere and the upper layer of the oceans, which defines the "hiatus." Advances in "hiatus" research and outlooks (recommendations) are given in this report.

  8. Dynamical Analysis of the Global Warming

    Directory of Open Access Journals (Sweden)

    J. A. Tenreiro Machado

    2012-01-01

    Full Text Available Global warming is a major concern nowadays. Weather conditions are changing, and it seems that human activity is one of the main causes. In fact, since the beginning of the industrial revolution, the burning of fossil fuels has increased the nonnatural emissions of carbon dioxide to the atmosphere. Carbon dioxide is a greenhouse gas that absorbs the infrared radiation produced by the reflection of the sunlight on the Earth’s surface, trapping the heat in the atmosphere. Global warming and the associated climate changes are being the subject of intensive research due to their major impact on social, economic, and health aspects of human life. This paper studies the global warming trend in the perspective of dynamical systems and fractional calculus, which is a new standpoint in this context. Worldwide distributed meteorological stations and temperature records for the last 100 years are analysed. It is shown that the application of Fourier transforms and power law trend lines leads to an assertive representation of the global warming dynamics and a simpler analysis of its characteristics.

  9. Arctic decadal variability in a warming world

    NARCIS (Netherlands)

    Linden, van der Eveline C.; Bintanja, Richard; Hazeleger, Wilco

    2017-01-01

    Natural decadal variability of surface air temperature might obscure Arctic temperature trends induced by anthropogenic forcing. It is therefore imperative to know how Arctic decadal variability (ADV) will change as the climate warms. In this study, we evaluate ADV characteristics in three

  10. Can Global Warming Heat Up Environmental Education?

    Science.gov (United States)

    Mazzatenta, Claudio

    2008-01-01

    Bronx Community College (CUNY) launched "Global Warming Campus Awareness and Action Days" in celebration of Earth Day, 2007. The purpose of this program was to raise awareness of environmental issues in the college population, especially students. To let more students have a grasp of what Environmental Education (EE) is all about, the author…

  11. Environmental-genotype responses to global warming

    African Journals Online (AJOL)

    ARC-IRENE

    Global warming will change Southern Africa's environments from grass dominated vegetation to dry woodland and desert with ... An improved understanding of the adaptation of livestock to their production ... important role in selection for disease and parasite resistance or tolerance, since it is difficult to measure these traits ...

  12. Global Warming, A Tragedy of the Commons

    Science.gov (United States)

    Philander, S. G.

    2016-12-01

    What is the appropriate balance between our responsibilities towards future generations, and our obligations to those who live in abject poverty today? Global warming, a tragedy of the commons, brings such ethical questions to the fore but, whether "matured" or not, is itself mute on ethical issues.

  13. Hiatus on the upward staircase of global warming

    Science.gov (United States)

    Xie, S. P.; Kosaka, Y.

    2016-12-01

    Since the 19th century, global-mean surface temperature (GMST) has risen in staircase-like stages due to contributions from both radiative forcing and internal variability. Our earlier study showed that tropical Pacific variability, specifically the La Nina-like cooling, caused the current hiatus of global warming. We have extended the Pacific Ocean-Global Atmosphere (POGA) pacemaker experiment back to the late 19th century, by restoring tropical Pacific sea surface temperature anomalies towards the observed history. POGA reproduces annual-mean GMST variability with high correlation. We quantify relative contributions from the radiative forcing and tropical Pacific variability for various epochs of the staircase. Beyond the global mean, POGA also captures observed regional trends of surface temperature for these periods, especially over the tropical Indian Ocean, Indian subcontinent, North and South Pacific and North America. The POGA effect for the recent hiatus is comparable in magnitude with that at the beginning of the 20th century, but lasts the longest in duration over the past 150 years. The attendant strengthening of the Pacific trade winds since the 1990s is unprecedented on the instrumental record. To the extent that POGA captures much of the internal variability in GMST, we can infer radiatively forced GMST response. This method has the advantage of being independent of the model's radiative forcing and climate sensitivity. While raw data show a warming of 0.9 degree C for the recent five-year period of 2010-2014 relative to 1900, our new calculation yields a much higher anthropogenic warming of 1.2 C after correcting for the internal variability effect. This indicates that the task is more challenging than thought to implement the Paris consensus of limiting global average temperature change to below 2 C above preindustrial levels.

  14. Gravity waves in the thermosphere during a sudden stratospheric warming

    Science.gov (United States)

    Yigit, E.; Medvedev, A. S.

    2012-12-01

    For the first time, the propagation and dissipation of internal gravity waves (GWs) of lower atmospheric origin to the thermosphere above the turbopause (~105 km) during a sudden stratospheric warming (SSW) are examined. The study is performed with a general circulation model (GCM) coupling the lower atmosphere with the thermosphere and the implemented spectral nonlinear extended GW parameterization of Yigit et al. (2008). The Yigit et al. (2008) extended GW parameterization calculates the propagation and dissipation of small-scale GWs in the whole atmosphere system by physically taking into account ion drag, molecular viscosity and thermal conduction, eddy viscosity, nonlinear diffusion, and radiative damping in form of Newtonian cooling. Model simulations reveal a strong modulation by SSWs of GW activity, momentum deposition rates, and the circulation feedbacks at heights up to F region altitudes (~270 km). Wave-induced root mean square wind fluctuations increase several times during the warming in the thermosphere above the turbopause. This occurs mainly due to a reduction of filtering eastward traveling GWs by the weaker stratospheric jet. These waves propagate higher under the favorable conditions, grow in amplitude, and produce stronger forcing on the mean flow, compared to pre-warming period, when they are dissipated in the thermosphere. The evolution of stratospheric and mesospheric winds during an SSW life-cycle creates a robust and distinctive response in GW activity and mean fields deeply in the thermosphere. Yigit, E., A.~D. Aylward, and A.~S. Medvedev (2008), Parameterization of the effects of vertically propagating gravity waves for thermosphere general circulation models: Sensitivity study, J. Geophys. Res., 113, D19106, doi:10.1029/2008JD010135.

  15. Hydrologic response and watershed sensitivity to climate warming in California's Sierra Nevada.

    Science.gov (United States)

    Null, Sarah E; Viers, Joshua H; Mount, Jeffrey F

    2010-04-01

    This study focuses on the differential hydrologic response of individual watersheds to climate warming within the Sierra Nevada mountain region of California. We describe climate warming models for 15 west-slope Sierra Nevada watersheds in California under unimpaired conditions using WEAP21, a weekly one-dimensional rainfall-runoff model. Incremental climate warming alternatives increase air temperature uniformly by 2 degrees, 4 degrees, and 6 degrees C, but leave other climatic variables unchanged from observed values. Results are analyzed for changes in mean annual flow, peak runoff timing, and duration of low flow conditions to highlight which watersheds are most resilient to climate warming within a region, and how individual watersheds may be affected by changes to runoff quantity and timing. Results are compared with current water resources development and ecosystem services in each watershed to gain insight into how regional climate warming may affect water supply, hydropower generation, and montane ecosystems. Overall, watersheds in the northern Sierra Nevada are most vulnerable to decreased mean annual flow, southern-central watersheds are most susceptible to runoff timing changes, and the central portion of the range is most affected by longer periods with low flow conditions. Modeling results suggest the American and Mokelumne Rivers are most vulnerable to all three metrics, and the Kern River is the most resilient, in part from the high elevations of the watershed. Our research seeks to bridge information gaps between climate change modeling and regional management planning, helping to incorporate climate change into the development of regional adaptation strategies for Sierra Nevada watersheds.

  16. Deep time evidence for climate sensitivity increase with warming

    DEFF Research Database (Denmark)

    Shaffer, Gary; Huber, Matthew; Rondanelli, Roberto

    2016-01-01

    Future global warming from anthropogenic greenhouse gas emissions will depend on climate feedbacks, the effect of which is expressed by climate sensitivity, the warming for a doubling of atmospheric CO2 content. It is not clear how feedbacks, sensitivity, and temperature will evolve in our warming...... world, but past warming events may provide insight. Here we employ paleoreconstructions and new climate-carbon model simulations in a novel framework to explore a wide scenario range for the Paleocene-Eocene Thermal Maximum (PETM) carbon release and global warming event 55.8Ma ago, a possible future...... indicates climate sensitivity increase with global warming....

  17. Frequency of Deep Convective Clouds and Global Warming

    Science.gov (United States)

    Aumann, Hartmut H.; Teixeira, Joao

    2008-01-01

    This slide presentation reviews the effect of global warming on the formation of Deep Convective Clouds (DCC). It concludes that nature responds to global warming with an increase in strong convective activity. The frequency of DCC increases with global warming at the rate of 6%/decade. The increased frequency of DCC with global warming alone increases precipitation by 1.7%/decade. It compares the state of the art climate models' response to global warming, and concludes that the parametrization of climate models need to be tuned to more closely emulate the way nature responds to global warming.

  18. The Late Cryogenian Warm Interval, NE Svalbard:Chemostratigraphy and genesis

    OpenAIRE

    Fairchild, Ian J.; Bonnand, Pierre; Davies, Tesni; Fleming, Edward J.; Grassineau, Nathalie; Halverson, Galen P.; Hambrey, Michael J.; McMillan, Emily M.; McKay, Elizabeth; Parkinson, Ian J.; Stevenson, Carl T. E.

    2016-01-01

    The Late Cryogenian Warm Interval (LCWI) refers to a non-glacial interval that separates presumed representatives of the Sturtian and Marinoan panglaciations. Its duration is poorly constrained radiometrically and its deposits are relatively poorly known in most geographic regions. This paper aims to constrain the duration, palaeoenvironments and petrogenesis of such deposits in the classic region of NE Spitsbergen, Svalbard. The succession comprises a 200–205 m dolomitic shale (Macdonaldrygg...

  19. Effect of the droplet activation process on microphysical properties of warm clouds

    OpenAIRE

    Suzuki, Kentaroh; NAKAJIMA, Teruyuki; Nakajima, Takashi Y.; Stephens, Graeme L.

    2010-01-01

    This study investigates the effect of the droplet activation process on microphysical characteristics of warm clouds represented by correlation statistics between cloud droplet effective radius re and cloud optical thickness τc. The conceptual adiabatic model is first employed to interpret satellite-observed re-τc correlation statistics over two different regions and to reveal distinctively different increasing patterns of droplet number concentration between these regions. This difference is...

  20. Changes in Intense Precipitation Events in West Africa and the central U.S. under Global Warming

    Energy Technology Data Exchange (ETDEWEB)

    Cook, Kerry H. [Univ. of Texas, Austin, TX (United States); Vizy, Edward [Univ. of Texas, Austin, TX (United States)

    2016-02-08

    The purpose of the proposed project is to improve our understanding of the physical processes and large-scale connectivity of changes in intense precipitation events (high rainfall rates) under global warming in West Africa and the central U.S., including relationships with low-frequency modes of variability. This is in response to the requested subject area #2 “simulation of climate extremes under a changing climate … to better quantify the frequency, duration, and intensity of extreme events under climate change and elucidate the role of low frequency climate variability in modulating extremes.” We will use a regional climate model and emphasize an understanding of the physical processes that lead to an intensification of rainfall. The project objectives are as follows: 1. Understand the processes responsible for simulated changes in warm-season rainfall intensity and frequency over West Africa and the Central U.S. associated with greenhouse gas-induced global warming 2. Understand the relationship between changes in warm-season rainfall intensity and frequency, which generally occur on regional space scales, and the larger-scale global warming signal by considering modifications of low-frequency modes of variability. 3. Relate changes simulated on regional space scales to global-scale theories of how and why atmospheric moisture levels and rainfall should change as climate warms.

  1. Respiratory muscle specific warm-up and elite swimming performance.

    Science.gov (United States)

    Wilson, Emma E; McKeever, Tricia M; Lobb, Claire; Sherriff, Tom; Gupta, Luke; Hearson, Glenn; Martin, Neil; Lindley, Martin R; Shaw, Dominick E

    2014-05-01

    Inspiratory muscle training has been shown to improve performance in elite swimmers, when used as part of routine training, but its use as a respiratory warm-up has yet to be investigated. To determine the influence of inspiratory muscle exercise (IME) as a respiratory muscle warm-up in a randomised controlled cross-over trial. A total of 15 elite swimmers were assigned to four different warm-up protocols and the effects of IME on 100 m freestyle swimming times were assessed.Each swimmer completed four different IME warm-up protocols across four separate study visits: swimming-only warm-up; swimming warm-up plus IME warm-up (2 sets of 30 breaths with a 40% maximum inspiratory mouth pressure load using the Powerbreathe inspiratory muscle trainer); swimming warm-up plus sham IME warm-up (2 sets of 30 breaths with a 15% maximum inspiratory mouth pressure load using the Powerbreathe inspiratory muscle trainer); and IME-only warm-up. Swimmers performed a series of physiological tests and scales of perception (rate of perceived exertion and dyspnoea) at three time points (pre warm-up, post warm-up and post time trial). The combined standard swimming warm-up and IME warm-up were the fastest of the four protocols with a 100 m time of 57.05 s. This was significantly faster than the IME-only warm-up (mean difference=1.18 s, 95% CI 0.44 to 1.92, pswim-only warm-up (mean difference=0.62 s, 95% CI 0.001 to 1.23, p=0.05). Using IME combined with a standard swimming warm-up significantly improves 100 m freestyle swimming performance in elite swimmers.

  2. Medieval Warm Period Archives Preserved in Limpet Shells (Patella Vulgata) From Viking Deposits, United Kingdom

    Science.gov (United States)

    Mobilia, M.; Surge, D.

    2008-12-01

    The Medieval Warm Period (700-1100 YBP) represents a recent period of warm climate, and as such provides a powerful comparison to today's continuing warming trend. However, the spatial and temporal variability inherent in the Medieval Warm Period (MWP) makes it difficult to differentiate between global climate trends and regional variability. The continued study of this period will allow for the better understanding of temperature variability, both regional and global, during this climate interval. Our study is located in the Orkney Islands, Scotland, which is a critical area to understand climate dynamics. The North Atlantic Oscillation and Gulf Stream heavily influence climate in this region, and the study of climate intervals during the MWP will improve our understanding of the behavior of these climate mechanisms during this interval. Furthermore, the vast majority of the climate archive has been derived from either deep marine or arctic environments. Studying a coastal environment will offer valuable insight into the behavior of maritime climate during the MWP. Estimated seasonal sea surface temperature data were derived through isotopic analysis of limpet shells (Patella vulgata). Analysis of modern shells confirms that growth temperature tracks seasonal variation in ambient water temperature. Preliminary data from MWP shells record a seasonal temperature range comparable to that observed in the modern temperature data. We will extend the range of temperature data from the 10th through 14th centuries to advance our knowledge of seasonal temperature variability during the late Holocene.

  3. Experimental warming decreases arbuscular mycorrhizal fungal colonization in prairie plants along a Mediterranean climate gradient

    Directory of Open Access Journals (Sweden)

    Hannah Wilson

    2016-06-01

    Full Text Available Background: Arbuscular mycorrhizal fungi (AMF provide numerous services to their plant symbionts. Understanding climate change effects on AMF, and the resulting plant responses, is crucial for predicting ecosystem responses at regional and global scales. We investigated how the effects of climate change on AMF-plant symbioses are mediated by soil water availability, soil nutrient availability, and vegetation dynamics. Methods: We used a combination of a greenhouse experiment and a manipulative climate change experiment embedded within a Mediterranean climate gradient in the Pacific Northwest, USA to examine this question. Structural equation modeling (SEM was used to determine the direct and indirect effects of experimental warming on AMF colonization. Results: Warming directly decreased AMF colonization across plant species and across the climate gradient of the study region. Other positive and negative indirect effects of warming, mediated by soil water availability, soil nutrient availability, and vegetation dynamics, canceled each other out. Discussion: A warming-induced decrease in AMF colonization would likely have substantial consequences for plant communities and ecosystem function. Moreover, predicted increases in more intense droughts and heavier rains for this region could shift the balance among indirect causal pathways, and either exacerbate or mitigate the negative, direct effect of increased temperature on AMF colonization.

  4. Inconsistent Subsurface and Deeper Ocean Warming Signals During Recent Global Warming and Hiatus

    Science.gov (United States)

    Su, Hua; Wu, Xiangbai; Lu, Wenfang; Zhang, Weiwei; Yan, Xiao-Hai

    2017-10-01

    Ocean heat content (OHC) evolutions calculated from the data sets (WOA, MyOcean, ORAS4, and SODA) were examined at different depth ranges in this study. According to the OHC changes, the subsurface and deeper ocean (SDO, 300-2000 m) heat content rapidly increased over the world's ocean basins during 1998-2013, indicating significant warming in the SDO during the recent global surface warming hiatus. Almost all the ocean basins warmed up, but with various contributions to the global SDO warming tied to the recent hiatus. The role of the Indian Ocean is particularly important as it has accounted for about 30% of global SDO heat uptake during the hiatus. The combined use of multiple data sets can reveal inconsistencies in SDO warming analysis results, and improve our understanding of the role of the SDO in the recent hiatus. The heat uptake in global SDO during the hiatus was about 2.37, 5.44, 3.75, and 2.44 × 1022 joules with trends of 0.40, 0.70, 0.77, and 0.48 W m-2 according to WOA, MyOcean, ORAS4, and SODA respectively, presenting obviously inconsistent SDO warming signals. MyOcean shows OHC overestimates in different ocean basins, while ORAS4 presents more reliable SDO OHC analysis. In general, the global SDO has sequestered a significant amount of heat—about 3.50 × 1022 joules with trends of 0.59 W m-2 on average among the four data sets—during the recent hiatus, demonstrating widespread and significant warming signals in the global SDO. There remain substantial uncertainties and discrepancies, however (especially in the PO and SO), in the available SDO warming information due to insufficient subsurface observation coverage and variations in the data set generation techniques used among different researchers.

  5. Cutoff in the Lyman-$\\alpha$ forest power spectrum: warm IGM or warm dark matter?

    OpenAIRE

    Garzilli, Antonella; Boyarsky, Alexey; Ruchayskiy, Oleg

    2015-01-01

    We re-analyse high redshift and high resolution Lyman-$\\alpha$ forest spectra considered in (Viel et al 2013), seeking to constrain the properties of warm dark matter particles. Compared to this previous work, we consider a wider range of thermal histories of the intergalactic medium. We find that both warm and cold dark matter models can explain the cut-off observed in the flux power spectra of high-resolution observations equally well. This implies, however, very different thermal histories...

  6. Cutoff in the Lyman- α forest power spectrum: Warm IGM or warm dark matter?

    OpenAIRE

    Garzilli, Antonella; Boyarsky, Alexey; Ruchayskiy, Oleg

    2017-01-01

    We re-analyse high redshift and high resolution Lyman- α forest spectra considered in [1] , seeking to constrain the properties of warm dark matter particles. Compared to this previous work, we consider a wider range of thermal histories of the intergalactic medium. We find that both warm and cold dark matter models can explain the cut-off observed in the flux power spectra of high-resolution observations equally well. This implies, however, very different thermal histories and underlying rei...

  7. Cutoff in the Lyman-α forest power spectrum: Warm IGM or warm dark matter?

    OpenAIRE

    Antonella Garzilli; Alexey Boyarsky; Oleg Ruchayskiy

    2017-01-01

    We re-analyse high redshift and high resolution Lyman-α forest spectra considered in [1], seeking to constrain the properties of warm dark matter particles. Compared to this previous work, we consider a wider range of thermal histories of the intergalactic medium. We find that both warm and cold dark matter models can explain the cut-off observed in the flux power spectra of high-resolution observations equally well. This implies, however, very different thermal histories and underlying reion...

  8. North Atlantic warming: patterns of long-term trend and multidecadal variability

    Energy Technology Data Exchange (ETDEWEB)

    Polyakov, Igor V.; Alexeev, Vladimir A.; Zhang, Xiangdong [University of Alaska Fairbanks, International Arctic Research Center, Fairbanks, AK (United States); Bhatt, Uma S. [University of Alaska Fairbanks, Geophysical Institute, Fairbanks, AK (United States); Polyakova, Evgenia I. [Stanford University, Department of Geological and Environmental Studies, Stanford, CA (United States)

    2010-02-15

    Climate fluctuations in the North Atlantic Ocean have wide-spread implications for Europe, Africa, and the Americas. This study assesses the relative contribution of the long-term trend and variability of North Atlantic warming using EOF analysis of deep-ocean and near-surface observations. Our analysis demonstrates that the recent warming over the North Atlantic is linked to both long-term (including anthropogenic and natural) climate change and multidecadal variability (MDV, {proportional_to}50-80 years). Our results suggest a general warming trend of 0.031 {+-} 0.006 C/decade in the upper 2,000 m North Atlantic over the last 80 years of the twentieth century, although during this time there are periods in which short-term trends were strongly amplified by MDV. For example, MDV accounts for {proportional_to}60% of North Atlantic warming since 1970. The single-sign basin-scale pattern of MDV with prolonged periods of warming (cooling) in the upper ocean layer and opposite tendency in the lower layer is evident from observations. This pattern is associated with a slowdown (enhancement) of the North Atlantic thermohaline overturning circulation during negative (positive) MDV phases. In contrast, the long-term trend exhibits warming in tropical and mid-latitude North Atlantic and a pattern of cooling in regions associated with major northward heat transports, consistent with a slowdown of the North Atlantic circulation as evident from observations and confirmed by selected modeling results. This localized cooling has been masked in recent decades by warming during the positive phase of MDV. Finally, since the North Atlantic Ocean plays a crucial role in establishing and regulating the global thermohaline circulation, the multidecadal fluctuations discussed here should be considered when assessing long-term climate change and variability, both in the North Atlantic and at global scales. (orig.)

  9. How to preserve the tundra in a warming climate?

    Science.gov (United States)

    Käyhkö, Jukka

    2014-05-01

    The warming climate of the polar regions may change much of the current arctic-alpine tundra to forest or dense scrubland. This modification requires adaptation by traditional livelihoods such as reindeer herding, which relies on diverse, seasonal pasturelands. Vegetation change may also trigger positive warming feedbacks, where more abundant forest-scrub vegetation will decrease the global albedo. NCoE Tundra team investigates the complex climate-animal-plant interaction of the tundra ecosystem and aim to unravel the capability of herbivorous mammals to control the expansion of woody vegetation. Our interdisciplinary approach involves several work packages, whose results will be summarised in the presentation. In the ecological WPs, we study the dynamics of the natural food chains involving small herbivorous and the impacts of reindeer on the vegetation and the population dynamics of those arctic-alpine plants, which are most likely to become threatened in a warmer climate. Our study demonstrates the potential of a relatively sparse reindeer stocks (2-5 heads per km2) together with natural populations of arvicoline rodents to prevent the expansion of erect woody plants at the arctic-alpine timberline. In the climatic WPs we study the impact of grazing-dependent vegetation differences on the fraction of solar energy converted to heat. In the socio-economic WPs, we study the conditions for maintaining the economic and cultural viability of reindeer herding while managing the land use so that the arctic-alpine biota would be preserved.

  10. Ab initio thermodynamic results for warm dense matter

    Science.gov (United States)

    Bonitz, Michael

    2016-10-01

    Warm dense matter (WDM) - an exotic state where electrons are quantum degenerate and ions may be strongly correlated - is ubiquitous in dense astrophysical plasmas and highly compressed laboratory systems including inertial fusion. Accurate theoretical predictions require precision thermodynamic data for the electron gas at high density and finite temperature around the Fermi temperature. First such data have been obtained by restricted path integral Monte Carlo (restricted PIMC) simulations and transformed into analytical fits for the free energy. Such results are also key input for novel finite temperature density functional theory. However, the RPIMC data of Ref. 1 are limited to moderate densities, and even there turned out to be surprisingly inaccurate, which is a consequence of the fermion sign problem. These problems were recently overcome by the development of alternative QMC approaches in Kiel (configuration PIMC and permutation blocking PIMC) and Imperial College (Density matrix QMC). The three methods have their strengths and limitations in complementary parameter regions and provide highly accurate thermodynamic data for the electronic contributions in WDM. While the original results were obtained for small particle numbers, recently accurate finite size corrections were derived allowing to compute ab initio thermodynamic data with an unprecedented accuracy of better than 0.3 percent. This provides the final step for the use as benchmark data for experiments and models of Warm dense matter. Co-authors: T. Schoof, S. Groth, T. Dornheim, F. D. Malone, M. Foulkes, and T. Sjostroem, Funded by: DFG via SFB-TR24 and project BO1366-10.

  11. Thermal regimes of Rocky Mountain lakes warm with climate change.

    Science.gov (United States)

    Roberts, James J; Fausch, Kurt D; Schmidt, Travis S; Walters, David M

    2017-01-01

    Anthropogenic climate change is causing a wide range of stresses in aquatic ecosystems, primarily through warming thermal conditions. Lakes, in response to these changes, are experiencing increases in both summer temperatures and ice-free days. We used continuous records of lake surface temperature and air temperature to create statistical models of daily mean lake surface temperature to assess thermal changes in mountain lakes. These models were combined with downscaled climate projections to predict future thermal conditions for 27 high-elevation lakes in the southern Rocky Mountains. The models predict a 0.25°C·decade-1 increase in mean annual lake surface temperature through the 2080s, which is greater than warming rates of streams in this region. Most striking is that on average, ice-free days are predicted to increase by 5.9 days ·decade-1, and summer mean lake surface temperature is predicted to increase by 0.47°C·decade-1. Both could profoundly alter the length of the growing season and potentially change the structure and function of mountain lake ecosystems. These results highlight the changes expected of mountain lakes and stress the importance of incorporating climate-related adaptive strategies in the development of resource management plans.

  12. Thermal regimes of Rocky Mountain lakes warm with climate change

    Science.gov (United States)

    Roberts, James J.; Fausch, Kurt D.; Schmidt, Travis S.; Walters, David M.

    2017-01-01

    Anthropogenic climate change is causing a wide range of stresses in aquatic ecosystems, primarily through warming thermal conditions. Lakes, in response to these changes, are experiencing increases in both summer temperatures and ice-free days. We used continuous records of lake surface temperature and air temperature to create statistical models of daily mean lake surface temperature to assess thermal changes in mountain lakes. These models were combined with downscaled climate projections to predict future thermal conditions for 27 high-elevation lakes in the southern Rocky Mountains. The models predict a 0.25°C·decade-1increase in mean annual lake surface temperature through the 2080s, which is greater than warming rates of streams in this region. Most striking is that on average, ice-free days are predicted to increase by 5.9 days ·decade-1, and summer mean lake surface temperature is predicted to increase by 0.47°C·decade-1. Both could profoundly alter the length of the growing season and potentially change the structure and function of mountain lake ecosystems. These results highlight the changes expected of mountain lakes and stress the importance of incorporating climate-related adaptive strategies in the development of resource management plans.

  13. Shift in tuna catches due to ocean warming.

    Directory of Open Access Journals (Sweden)

    Alberto Monllor-Hurtado

    Full Text Available Ocean warming is already affecting global fisheries with an increasing dominance of catches of warmer water species at higher latitudes and lower catches of tropical and subtropical species in the tropics. Tuna distributions are highly conditioned by sea temperature, for this reason and their worldwide distribution, their populations may be a good indicator of the effect of climate change on global fisheries. This study shows the shift of tuna catches in subtropical latitudes on a global scale. From 1965 to 2011, the percentage of tropical tuna in longliner catches exhibited a significantly increasing trend in a study area that included subtropical regions of the Atlantic and western Pacific Oceans and partially the Indian Ocean. This may indicate a movement of tropical tuna populations toward the poles in response to ocean warming. Such an increase in the proportion of tropical tuna in the catches does not seem to be due to a shift of the target species, since the trends in Atlantic and Indian Oceans of tropical tuna catches are decreasing. Our results indicate that as populations shift towards higher latitudes the catches of these tropical species did not increase. Thus, at least in the Atlantic and Indian Oceans, tropical tuna catches have reduced in tropical areas.

  14. The subtle origins of surface-warming hiatuses

    Science.gov (United States)

    Hedemann, Christopher; Mauritsen, Thorsten; Jungclaus, Johann; Marotzke, Jochem

    2017-04-01

    During the first decade of the twenty-first century, the Earth's surface warmed more slowly than climate models simulated. This surface-warming hiatus is attributed by some studies to model errors in external forcing, while others point to heat rearrangements in the ocean caused by internal variability, the timing of which cannot be predicted by the models. However, observational analyses disagree about which ocean region is responsible. Here we show that the hiatus could also have been caused by internal variability in the top-of-atmosphere energy imbalance. Energy budgeting for the ocean surface layer over a 100-member historical ensemble reveals that hiatuses are caused by energy-flux deviations as small as 0.08 W m-2, which can originate at the top of the atmosphere, in the ocean, or both. Budgeting with existing observations cannot constrain the origin of the recent hiatus, because the uncertainty in observations dwarfs the small flux deviations that could cause a hiatus. The sensitivity of these flux deviations to the observational dataset and to energy budget choices helps explain why previous studies conflict, and suggests that the origin of the recent hiatus may never be identified.

  15. Physics of greenhouse effect and convection in warm oceans

    Science.gov (United States)

    Inamdar, A. K.; Ramanathan, V.

    1994-01-01

    Sea surface temperature (SST) in roughly 50% of the tropical Pacific Ocean is warm enough (SST greater than 300 K) to permit deep convection. This paper examines the effects of deep convection on the climatological mean vertical distributions of water vapor and its greenhouse effect over such warm oceans. The study, which uses a combination of satellite radiation budget observations, atmospheric soundings deployed from ships, and radiation model calculations, also examines the link between SST, vertical distribution of water vapor, and its greenhouse effect in the tropical oceans. Since the focus of the study is on the radiative effects of water vapor, the radiation model calculations do not include the effects of clouds. The data are grouped into nonconvective and convective categories using SST as an index for convective activity. On average, convective regions are more humid, trap significantly more longwave radiation, and emit more radiation to the sea surface. The greenhouse effect in regions of convection operates as per classical ideas, that is, as the SST increases, the atmosphere traps the excess longwave energy emitted by the surface and reradiates it locally back to the ocean surface. The important departure from the classical picture is that the net (up minus down) fluxes at the surface and at the top of the atmosphere decrease with an increase in SST; that is, the surface and the surface-troposphere column lose the ability to radiate the excess energy to space. The cause of this super greenhouse effect at the surface is the rapid increase in the lower-troposphere humidity with SST; that of the column is due to a combination of increase in humidity in the entire column and increase in the lapse rate within the lower troposphere. The increase in the vertical distribution of humidity far exceeds that which can be attributed to the temperature dependence of saturation vapor pressure; that is, the tropospheric relative humidity is larger in convective

  16. Seepage from an arctic shallow marine gas hydrate reservoir is insensitive to momentary ocean warming

    Science.gov (United States)

    Hong, Wei-Li; Torres, Marta E.; Carroll, Jolynn; Crémière, Antoine; Panieri, Giuliana; Yao, Haoyi; Serov, Pavel

    2017-06-01

    Arctic gas hydrate reservoirs located in shallow water and proximal to the sediment-water interface are thought to be sensitive to bottom water warming that may trigger gas hydrate dissociation and the release of methane. Here, we evaluate bottom water temperature as a potential driver for hydrate dissociation and methane release from a recently discovered, gas-hydrate-bearing system south of Spitsbergen (Storfjordrenna, ~380 m water depth). Modelling of the non-steady-state porewater profiles and observations of distinct layers of methane-derived authigenic carbonate nodules in the sediments indicate centurial to millennial methane emissions in the region. Results of temperature modelling suggest limited impact of short-term warming on gas hydrates deeper than a few metres in the sediments. We conclude that the ongoing and past methane emission episodes at the investigated sites are likely due to the episodic ventilation of deep reservoirs rather than warming-induced gas hydrate dissociation in this shallow water seep site.

  17. Warm-adapted microbial communities enhance their carbon-use efficiency in warmed soils

    Science.gov (United States)

    Rousk, Johannes; Frey, Serita

    2017-04-01

    Ecosystem models predict that climate warming will stimulate microbial decomposition of soil carbon (C), resulting in a positive feedback to increasing temperatures. The current generation of models assume that the temperature sensitivities of microbial processes do not respond to warming. However, recent studies have suggested that the ability of microbial communities to adapt to warming can lead both strengthened and weakened feedbacks. A further complication is that the balance between microbial C used for growth to that used for respiration - the microbial carbon-use efficiency (CUE) - also has been shown through both modelling and empirical study to respond to warming. In our study, we set out to assess how chronic warming (+5°C over ambient during 9 years) of a temperate hardwood forest floor (Harvard Forest LTER, USA) affected temperature sensitivities of microbial processes in soil. To do this, we first determined the temperature relationships for bacterial growth, fungal growth, and respiration in plots exposed to warmed or ambient conditions. Secondly, we parametrised the established temperature functions microbial growth and respiration with plot-specific measured soil temperature data at a hourly time-resolution over the course of 3 years to estimate the real-time variation of in situ microbial C production and respiration. To estimate the microbial CUE, we also divided the microbial C production with the sum of microbial C production and respiration as a proxy for substrate use. We found that warm-adapted bacterial and fungal communities both shifted their temperature relationships to grow at higher rates in warm conditions which coincided with reduced rates at cool conditions. As such, their optimal temperature (Topt), minimum temperature (Tmin) and temperature sensitivity (Q10) were all increased. The temperature relationship for temperature, in contrast, was only marginally shifted in the same direction, but at a much smaller effect size, with

  18. Gas Flaring: Carbon dioxide Contribution to Global Warming ...

    African Journals Online (AJOL)

    PROF HORSFALL

    .info and www.bioline.org.br/ja. Gas Flaring: Carbon dioxide Contribution to Global Warming. *AMAECHI ... contributor to global warming, environmental degradation, health risk and economic loss. The ... risks of climate change. Meeting ...

  19. Alabama warm mix asphalt field study : final report.

    Science.gov (United States)

    2010-05-01

    The Alabama Department of Transportation hosted a warm mix asphalt field demonstration in August 2007. The warm mix asphalt technology demonstrated was Evotherm Dispersed Asphalt Technology. The WMA and hot mix asphalt produced for the demonstration ...

  20. Causes of warming and thawing permafrost in Alaska

    National Research Council Canada - National Science Library

    Osterkamp, T. E

    2007-01-01

    There is a perception that climatic warming was the cause of the twentieth‐century global warming and thawing of permafrost and associated terrain instability (thermokarst) [ Gore , 2006; Perkins , 2007; Zielinski , 2007; Delisle , 2007...

  1. Large Diurnal Warming Events in the Upper Ocean and Their Implications for CO2 Uptake

    Science.gov (United States)

    Soloviev, A.

    2001-12-01

    Strong dependence of the CO2 solubility on temperature suggests that the large diurnal warming events may cause significant deviations from the bulk flux formulation. Since under low wind speed conditions the air-sea gas exchange is smaller but nonzero, the effect of large diurnal warming events on the estimate of CO2 uptake cannot be ignored. Large diurnal warming events develop under low wind speed conditions and are usually localized within the upper few meters of the ocean. With rear exception, the large diurnal events are undetected during shipboard surveys and are mostly unaccounted at estimating the CO2 uptake by the ocean. A stochastic model of the diurnal cycle and a cool skin model, which are forced by the global heat, mass, and momentum fluxes, elucidate the geographical distribution of the large diurnal warming events as well as their seasonal, and, at some extent, inter-annual variability. Since the diurnal cycle under low wind speed conditions is a strongly non-linear process, a composite diurnal cycle rather than a simple parameterization forced by averaged heat and momentum fluxes is used. The correction for sea surface temperature relating to the large diurnal warming events is used to exrapolate pCO2 to the sea surface. The JGOFS data sets from BATS, HOT, and the Arabian Sea Process Study are used to refine these techniques in different regions. This work leads to an improved estimate of the global CO2 uptake by oceans.

  2. The coastal ocean response to the global warming acceleration and hiatus

    Science.gov (United States)

    Liao, Enhui; Lu, Wenfang; Yan, Xiao-Hai; Jiang, Yuwu; Kidwell, Autumn

    2015-01-01

    Coastlines are fundamental to humans for habitation, commerce, and natural resources. Many coastal ecosystem disasters, caused by extreme sea surface temperature (SST), were reported when the global climate shifted from global warming to global surface warming hiatus after 1998. The task of understanding the coastal SST variations within the global context is an urgent matter. Our study on the global coastal SST from 1982 to 2013 revealed a significant cooling trend in the low and mid latitudes (31.4% of the global coastlines) after 1998, while 17.9% of the global coastlines changed from a cooling trend to a warming trend concurrently. The trend reversals in the Northern Pacific and Atlantic coincided with the phase shift of Pacific Decadal Oscillation and North Atlantic Oscillation, respectively. These coastal SST changes are larger than the changes of the global mean and open ocean, resulting in a fast increase of extremely hot/cold days, and thus extremely hot/cold events. Meanwhile, a continuous increase of SST was detected for a considerable portion of coastlines (46.7%) with a strengthened warming along the coastlines in the high northern latitudes. This suggests the warming still continued and strengthened in some regions after 1998, but with a weaker pattern in the low and mid latitudes. PMID:26568024

  3. Establishing Sprinkling Requirements on Trailers Transporting Market Weight Pigs in Warm and Hot Weather

    Directory of Open Access Journals (Sweden)

    Rebecca Kephart

    2014-04-01

    Full Text Available This study was conducted July of 2012 in Iowa, in WARM (<26.7 °C and HOT (≥26.7 °C weather. Four sprinkling methods were compared, with one treatment being randomly assigned to each load: control- no sprinkling (not applied in HOT weather, pigs only, bedding only, or pigs and bedding. Experiment 1 used 51 loads in WARM- and 86 loads in HOT weather to determine sprinkling effects on pig measures (surface temperature, vocalizations, slips and falls, and stress signs. Experiment 2 used 82 loads in WARM- and 54 loads in HOT weather to determine the sprinkling effects on transport losses (non-ambulatory, dead, and total transport losses. Experiment 1 found that, in WARM weather, there were no differences between sprinkling treatments for surface temperature, vocalizations, or slips and falls (p ≥ 0.18. However, stress signs were 2% greater when sprinkling pigs- or bedding only- compared to control (p = 0.03. Experiment 2 found that, in WARM and HOT weather, sprinkling did not affect non-ambulatory, dead, or total transport losses (p ≥ 0.18. Although the current study did not find any observed sprinkling effects for pig measures or transport losses it is extremely important to note that the inference space of this study is relatively small, so further studies should be conducted to see if these results are applicable to other geographical regions and seasons.

  4. A century of ocean warming on Florida Keys coral reefs: historic in situ observations

    Science.gov (United States)

    Kuffner, Ilsa B.; Lidz, Barbara H.; Hudson, J. Harold; Anderson, Jeffery S.

    2015-01-01

    There is strong evidence that global climate change over the last several decades has caused shifts in species distributions, species extinctions, and alterations in the functioning of ecosystems. However, because of high variability on short (i.e., diurnal, seasonal, and annual) timescales as well as the recency of a comprehensive instrumental record, it is difficult to detect or provide evidence for long-term, site-specific trends in ocean temperature. Here we analyze five in situ datasets from Florida Keys coral reef habitats, including historic measurements taken by lighthouse keepers, to provide three independent lines of evidence supporting approximately 0.8 °C of warming in sea surface temperature (SST) over the last century. Results indicate that the warming observed in the records between 1878 and 2012 can be fully accounted for by the warming observed in recent decades (from 1975 to 2007), documented using in situ thermographs on a mid-shore patch reef. The magnitude of warming revealed here is similar to that found in other SST datasets from the region and to that observed in global mean surface temperature. The geologic context and significance of recent ocean warming to coral growth and population dynamics are discussed, as is the future prognosis for the Florida reef tract.

  5. Discharge, water temperature, and water quality of Warm Mineral Springs, Sarasota County, Florida: A retrospective analysis

    Science.gov (United States)

    Metz, Patricia A.

    2016-09-27

    in inland areas, and upward flow toward the surface in coastal areas, such as at Warm Mineral Springs. Warm Mineral Springs is located in a discharge area. Changes in water use in the region have affected the potentiometric surface of the Upper Floridan aquifer. Historical increase in groundwater withdrawals resulted in a 10- to 20-foot regional decline in the potentiometric surface of the Upper Floridan aquifer by May 1975 relative to predevelopment levels and remained at approximately that level in May 2007 in the area of Warm Mineral Springs. Discharge measurements at Warm Mineral Springs (1942–2014) decreased from about 11–12 cubic feet per second in the 1940s to about 6–9 cubic feet per second in the 1970s and remained at about that level for the remainder of the period of record. Similarity of changes in regional water use and discharge at Warm Mineral Springs indicates that basin-scale changes to the groundwater system have affected discharge at Warm Mineral Springs. Water temperature had no significant trend in temperature over the period of record, 1943–2015, and outliers were identified in the data that might indicate inconsistencies in measurement methods or locations.Within the regional groundwater basin, Warm Mineral Springs is influenced by deep Upper Floridan aquifer flow paths that discharge toward the coast. Associated with these flow paths, the groundwater temperatures increase with depth and toward the coast. Multiple lines of evidence indicate that a source of warm groundwater to Warm Mineral Springs is likely the permeable zone of the Avon Park Formation within the Upper Floridan aquifer at a depth of about 1,400 to 1,600 feet, or deeper sources. The permeable zone contains saline groundwater with water temperatures of at least 95 degrees Fahrenheit.The water quality of Warm Mineral Springs, when compared with other springs in Florida had the highest temperature and the greatest mineralized content. Warm Mineral Springs water is

  6. Potential impacts of global warming on water resources in southern California.

    Science.gov (United States)

    Beuhler, M

    2003-01-01

    Global warming will have a significant impact on water resources within the 20 to 90-year planning period of many water projects. Arid and semi-arid regions such as Southern California are especially vulnerable to anticipated negative impacts of global warming on water resources. Long-range water facility planning must consider global climate change in the recommended mix of new facilities needed to meet future water requirements. The generally accepted impacts of global warming include temperature, rising sea levels, more frequent and severe floods and droughts, and a shift from snowfall to rain. Precipitation changes are more difficult to predict. For Southern California, these impacts will be especially severe on surface water supplies. Additionally, rising sea levels will exacerbate salt-water intrusion into freshwater and impact the quality of surface water supplies. Integrated water resources planning is emerging as a tool to develop water supplies and demand management strategies that are less vulnerable to the impacts of global warming. These tools include water conservation, conjunctive use of surface and groundwater and desalination of brackish water and possibly seawater. Additionally, planning for future water needs should include explicit consideration of the potential range of global warming impacts through techniques such as scenario planning.

  7. The influence of global warming on natural disasters and their public health outcomes.

    Science.gov (United States)

    Diaz, James H

    2007-01-01

    With a documented increase in average global surface temperatures of 0.6 degrees C since 1975, Earth now appears to be warming due to a variety of climatic effects, most notably the cascading effects of greenhouse gas emissions resulting from human activities. There remains, however, no universal agreement on how rapidly, regionally, or asymmetrically the planet will warm or on the true impact of global warming on natural disasters and public health outcomes. Most reports to date of the public health impact of global warming have been anecdotal and retrospective in design and have focused on the increase in heat-stroke deaths following heat waves and on outbreaks of airborne and arthropod-borne diseases following tropical rains and flooding that resulted from fluctuations in ocean temperatures. The effects of global warming on rainfall and drought, tropical cyclone and tsunami activity, and tectonic and volcanic activity will have far-reaching public health effects not only on environmentally associated disease outbreaks but also on global food supplies and population movements. As a result of these and other recognized associations between climate change and public health consequences, many of which have been confounded by deficiencies in public health infrastructure and scientific debates over whether climate changes are spawned by atmospheric cycles or anthropogenic influences, the active responses to progressive climate change must include combinations of economic, environmental, legal, regulatory, and, most importantly, public health measures.

  8. Snowmelt response to simulated warming across a large elevation gradient, southern Sierra Nevada, California

    Science.gov (United States)

    Musselman, Keith N.; Molotch, Noah P.; Margulis, Steven A.

    2017-12-01

    In a warmer climate, the fraction of annual meltwater produced at high melt rates in mountainous areas is projected to decline due to a contraction of the snow-cover season, causing melt to occur earlier and under lower energy conditions. How snowmelt rates, including extreme events relevant to flood risk, may respond to a range of warming over a mountain front is poorly known. We present a model sensitivity study of snowmelt response to warming across a 3600 m elevation gradient in the southern Sierra Nevada, USA. A snow model was run for three distinct years and verified against extensive ground observations. To simulate the impact of climate warming on meltwater production, measured meteorological conditions were modified by +1 to +6 °C. The total annual snow water volume exhibited linear reductions (-10 % °C-1) consistent with previous studies. However, the sensitivity of snowmelt rates to successive degrees of warming varied nonlinearly with elevation. Middle elevations and years with more snowfall were prone to the largest reductions in snowmelt rates, with lesser changes simulated at higher elevations. Importantly, simulated warming causes extreme daily snowmelt (99th percentiles) to increase in spatial extent and intensity, and shift from spring to winter. The results offer insight into the sensitivity of mountain snow water resources and how the rate and timing of water availability may change in a warmer climate. The identification of future climate conditions that may increase extreme melt events is needed to address the climate resilience of regional flood control systems.

  9. The coastal ocean response to the global warming acceleration and hiatus.

    Science.gov (United States)

    Liao, Enhui; Lu, Wenfang; Yan, Xiao-Hai; Jiang, Yuwu; Kidwell, Autumn

    2015-11-16

    Coastlines are fundamental to humans for habitation, commerce, and natural resources. Many coastal ecosystem disasters, caused by extreme sea surface temperature (SST), were reported when the global climate shifted from global warming to global surface warming hiatus after 1998. The task of understanding the coastal SST variations within the global context is an urgent matter. Our study on the global coastal SST from 1982 to 2013 revealed a significant cooling trend in the low and mid latitudes (31.4% of the global coastlines) after 1998, while 17.9% of the global coastlines changed from a cooling trend to a warming trend concurrently. The trend reversals in the Northern Pacific and Atlantic coincided with the phase shift of Pacific Decadal Oscillation and North Atlantic Oscillation, respectively. These coastal SST changes are larger than the changes of the global mean and open ocean, resulting in a fast increase of extremely hot/cold days, and thus extremely hot/cold events. Meanwhile, a continuous increase of SST was detected for a considerable portion of coastlines (46.7%) with a strengthened warming along the coastlines in the high northern latitudes. This suggests the warming still continued and strengthened in some regions after 1998, but with a weaker pattern in the low and mid latitudes.

  10. Competing influences of greenhouse warming and aerosols on Asian summer monsoon circulation and rainfall

    Science.gov (United States)

    Lau, William Ka-Ming; Kim, Kyu-Myong

    2017-05-01

    In this paper, we have compared and contrasted competing influences of greenhouse gases (GHG) warming and aerosol forcing on Asian summer monsoon circulation and rainfall based on CMIP5 historical simulations. Under GHG-only forcing, the land warms much faster than the ocean, magnifying the pre-industrial climatological land-ocean thermal contrast and hemispheric asymmetry, i.e., warmer northern than southern hemisphere. A steady increasing warm-ocean-warmer-land (WOWL) trend has been in effect since the 1950's substantially increasing moisture transport from adjacent oceans, and enhancing rainfall over the Asian monsoon regions. However, under GHG warming, increased atmospheric stability due to strong reduction in mid-tropospheric and near surface relative humidity coupled to an expanding subsidence areas, associated with the Deep Tropical Squeeze (DTS, Lau and Kim, 2015b) strongly suppress monsoon convection and rainfall over subtropical and extratropical land, leading to a weakening of the Asian monsoon meridional circulation. Increased anthropogenic aerosol emission strongly masks WOWL, by over 60% over the northern hemisphere, negating to a large extent the rainfall increase due to GHG warming, and leading to a further weakening of the monsoon circulation, through increasing atmospheric stability, most likely associated with aerosol solar dimming and semi-direct effects. Overall, we find that GHG exerts stronger positive rainfall sensitivity, but less negative circulation sensitivity in SASM compared to EASM. In contrast, aerosols exert stronger negative impacts on rainfall, but less negative impacts on circulation in EASM compared to SASM.

  11. Winter transport of subsurface warm water toward the Arctic Chukchi Borderland

    Science.gov (United States)

    Watanabe, Eiji; Onodera, Jonaotaro; Itoh, Motoyo; Nishino, Shigeto; Kikuchi, Takashi

    2017-10-01

    Winter subsurface transport of the Pacific-origin warm water toward the Arctic Chukchi Borderland located west of the Canada Basin was investigated by mooring measurements and modeling analyses. In mid-winter or spring of 2011-2014, subsurface warming signals under sea ice were detected by the multi-year bottom-tethered mooring data in the Chukchi Abyssal Plain (CAP) of the western Chukchi Borderland. Lateral advection of shelf-origin ocean heat is a key process for the subsurface warming. To address the detailed pathways and processes of subsurface warm water transport, which have not been deeply explored, an interannual experiment for 2001-2014 was performed using a pan-Arctic sea ice-ocean model configured in a high-resolution framework. The horizontal grid size was set to approximately 5 km so that narrow intense currents along complex sharp topography could be resolved. The model result captured the similar seasonality of subsurface temperature in the CAP region and produced interannual variability in the ocean heat content associated with the shelf-origin water distribution around the Chukchi Borderland. In addition to the Barrow Canyon throughflow, westward jets along the steep flank of the Chukchi shelf break constituted a primary pathway for the subsurface warm water transport toward the Chukchi Borderland in the model experiment. Since the simulated shelf break jet was much faster than main streams of the Beaufort Gyre, its role in ocean heat transport should be considered separately. Whereas ocean heat in the Chukchi shelf break region was partly lost via wind-driven turbulent mixing into upper halocline depths of approximately 20 m, a substantial amount of the subsurface warm water remained even after mid-winter. The highly stratified condition due to anomalous sea ice meltwater assisted the winter heat transport.

  12. Changes of reanalysis-derived Northern Hemisphere summer warm extreme indices during 1948-2006 and links with climate variability

    Science.gov (United States)

    Fang, Xingqin; Wang, Anyu; Fong, Soi-kun; Lin, Wenshi; Liu, Ji

    2008-08-01

    Using1948-2006 surface 2 m daily temperature, daily maximum temperature and daily minimum temperature of National Centers for Environmental Prediction (NCEP) reanalysis dataset, summer warm extreme indices, warm days (TG90P), warm-spell days (WSFI), warm day-times (TX90P) and warm nights (TN90P) are calculated for Gaussian grids, a complete Northern Hemisphere (NH) picture of changes of summer warm extremes is presented, and their links with El Niño/La Niña & Southern Oscillation (ENSO), Pacific Decadal Oscillation (PDO) and North Atlantic Oscillation (NAO) are also examined in this paper. The results on the NH summer seasonal basis are as follows. Warm days, warm-spell days, warm day-times and warm nights increase at rates of 2.18, 1.23, 2.31 and 2.00 days/decade respectively during 1948-2006. A broader area is exposed to frequent occurrence of warm extremes in the recent 30 years than in the last 30 years. The 59-year long-term upward trend is characterized by a positive trend reversion in the late 1970s, with a slight downward trend in the last 30 years and a rapid upward trend in the recent 30 years, representing the main form of interdecadal variance of NH warm extremes. Warm days, warm-spell days, warm day-times and warm nights increase at rates of 4.53, 3.36, 4.44 and 4.21 days/decade respectively during 1977-2006. During 1948-2006, the largest increasing rate is at central tropical Atlantic and the largest decreasing rate in Mongolia and north China. Significant (level of 0.05) upward trends cover about half of the NH during 1948-2006 and about a third of the NH during 1977-2006 with the very significant upward trends more focused, while very sparse regions have significant downward trends during these two periods. In the recent 30 years, although NH-land summer warms at a faster rate than NH-water, warm extremes on NH-water increase much faster than those on NH-land, the average warm extreme indices and their increasing trends on NH are most modulated by

  13. Plants reverse warming effect on ecosystem water balance

    OpenAIRE

    Zavaleta, Erika S.; Thomas, Brian D.; Chiariello, Nona R.; Asner, Gregory P.; Shaw, M. Rebecca; Christopher B. Field

    2003-01-01

    Models predict that global warming may increase aridity in water-limited ecosystems by accelerating evapotranspiration. We show that interactions between warming and the dominant biota in a grassland ecosystem produced the reverse effect. In a 2-year field experiment, simulated warming increased spring soil moisture by 5–10% under both ambient and elevated CO2. Warming also accelerated the decline of canopy greenness (normalized difference vegetation index) each spring...

  14. Quantifying global soil carbon losses in response to warming

    OpenAIRE

    Crowther, TW; Todd-Brown, KEO; Rowe, CW; Wieder, WR; Carey, JC; Machmuller, MB; Snoek, BL; Fang, S.; Zhou, G.; Allison, SD; Blair, JM; Bridgham, SD; Burton, AJ; Carrillo, Y.; Reich, PB

    2016-01-01

    © 2016 Macmillan Publishers Limited. All rights reserved. The majority of the Earth's terrestrial carbon is stored in the soil. If anthropogenic warming stimulates the loss of this carbon to the atmosphere, it could drive further planetary warming. Despite evidence that warming enhances carbon fluxes to and from the soil, the net global balance between these responses remains uncertain. Here we present a comprehensive analysis of warming-induced changes in soil carbon stocks by assembling dat...

  15. Microbial communities respond to experimental warming, but site matters

    OpenAIRE

    Cregger, Melissa A.; Sanders, Nathan J.; Dunn, Robert R.; Classen, Aimée T.

    2014-01-01

    Because microorganisms are sensitive to temperature, ongoing global warming is predicted to influence microbial community structure and function. We used large-scale warming experiments established at two sites near the northern and southern boundaries of US eastern deciduous forests to explore how microbial communities and their function respond to warming at sites with differing climatic regimes. Soil microbial community structure and function responded to warming at the southern but not th...

  16. Testing Paradigms of Ecosystem Change under Climate Warming in Antarctica

    Science.gov (United States)

    Melbourne-Thomas, Jessica; Constable, Andrew; Wotherspoon, Simon; Raymond, Ben

    2013-01-01

    Antarctic marine ecosystems have undergone significant changes as a result of human activities in the past and are now responding in varied and often complicated ways to climate change impacts. Recent years have seen the emergence of large-scale mechanistic explanations–or “paradigms of change”–that attempt to synthesize our understanding of past and current changes. In many cases, these paradigms are based on observations that are spatially and temporally patchy. The West Antarctic Peninsula (WAP), one of Earth’s most rapidly changing regions, has been an area of particular research focus. A recently proposed mechanistic explanation for observed changes in the WAP region relates changes in penguin populations to variability in krill biomass and regional warming. While this scheme is attractive for its simplicity and chronology, it may not account for complex spatio-temporal processes that drive ecosystem dynamics in the region. It might also be difficult to apply to other Antarctic regions that are experiencing some, though not all, of the changes documented for the WAP. We use qualitative network models of differing levels of complexity to test paradigms of change for the WAP ecosystem. Importantly, our approach captures the emergent effects of feedback processes in complex ecological networks and provides a means to identify and incorporate uncertain linkages between network elements. Our findings highlight key areas of uncertainty in the drivers of documented trends, and suggest that a greater level of model complexity is needed in devising explanations for ecosystem change in the Southern Ocean. We suggest that our network approach to evaluating a recent and widely cited paradigm of change for the Antarctic region could be broadly applied in hypothesis testing for other regions and research fields. PMID:23405116

  17. Cognitive Egocentrism Differentiates Warm and Cold People.

    Science.gov (United States)

    Boyd, Ryan L; Bresin, Konrad; Ode, Scott; Robinson, Michael D

    2013-02-01

    Warmth-coldness is a fundamental dimension of social behavior. Cold individuals are egocentric in their social relations, whereas warm individuals are not. Previous theorizing suggests that cognitive egocentrism underlies social egocentrism. It was hypothesized that higher levels of interpersonal coldness would predict greater cognitive egocentrism. Cognitive egocentrism was assessed in basic terms through tasks wherein priming a lateralized self-state biased subsequent visual perceptions in an assimilation-related manner. Such effects reflect a tendency to assume that the self's incidental state provides meaningful information concerning the external world. Cognitive egocentrism was evident at high, but not low, levels of interpersonal coldness. The findings reveal a basic difference between warm and cold people, encouraging future research linking cognitive egocentrism to variability in relationship functioning.

  18. AGN warm absorption with the ATHENA

    Science.gov (United States)

    Różańska, Agata; Gronkiewicz, Dominik; Hryniewicz, Krzysztof; Adhikari, Tek Prasad; Rataj, Mirosław; Skup, Konrad

    2016-06-01

    X-ray astronomy requires satellites to make progress in searching the distribution of hot matter in the Universe. Approximately 15 years period of time is needed for full construction of the flight instrument from the mission concept up to the launch. A new generation X-ray telescope ATHENA (the Advanced Telescope for High Energy Astrophysics) was approved by European Space Agency as a large mission with a launch foreseen in 2028. In this paper we show how microcalorimeter on the board of ATHENA will help us to study warm absorption observed in active galactic nuclei (AGN). We show that future observations will allow us to identify hundreds of lines from highly ionized elements and to measure Galactic warm absorption with very high precision.

  19. Management of drought risk under global warming

    Science.gov (United States)

    Zhang, Qiang; Han, Lanying; Jia, Jianying; Song, Lingling; Wang, Jinsong

    2016-07-01

    Drought is a serious ecological problem around the world, and its impact on crops and water availability for humans can jeopardize human life. Although drought has always been common, the drought risk has become increasingly prominent because of the climatic warming that has occurred during the past century. However, it still does not comprehensively understand the mechanisms that determine the occurrence of the drought risk it poses to humans, particularly in the context of global climate change. In this paper, we summarize the progress of research on drought and the associated risk, introduce the principle of a drought "transition" from one stage to another, synthesize the characteristics of key factors and their interactions, discuss the potential effect of climatic warming on drought risk, and use this discussion to define the basic requirements for a drought risk management system. We also discuss the main measures that can be used to prevent or mitigate droughts in the context of a risk management strategy.

  20. Fossil-fuel constraints on global warming

    Energy Technology Data Exchange (ETDEWEB)

    Zecca, Antonio; Chiari, Luca [Physics Department, University of Trento, Via Sommarive 14, I-38050 Povo TN (Italy)

    2010-01-15

    In 2008 and 2009 two papers by Kharecha and Hansen and by Nel and Cooper examined possible fossil energy availability and energy consumption scenarios and consequences for future climate. The papers yield somewhat similar results regarding atmospheric CO{sub 2} levels, but they reach substantially different conclusions regarding future climate change. Here, we compare their methods and results. Our work shows that Nel and Cooper's paper significantly underestimates future warming. Nel and Cooper conclude that even if all the available fossil fuels would be burned at the maximum possible rate during this century, the consequent warming would cap at less than 1 C above the 2000 level. We find that - under Nel and Cooper's assumption of an intensive exploitation of fossil fuels - the global temperature in 2100 will likely reach levels which would lead to severely damaging long-term impacts. (author)

  1. The Effect of Arousal on Warm Up Decrement.

    Science.gov (United States)

    Anshel, Mark H.

    1985-01-01

    This study examined whether particular strategies would enhance affective arousal and if these techniques would affect warm-up decrement during performance of a sport skill. One strategy eliminated warm-up decrement and two had no effect. Positive and negative arousal and the correlation of arousal level to warm-up decrement are explored.…

  2. Quantifying global soil carbon losses in response to warming

    NARCIS (Netherlands)

    Crowther, T W; Todd-Brown, K E O; Rowe, C W; Wieder, W R; Carey, J C; Machmuller, M B; Snoek, B L; Fang, S; Zhou, G; Allison, S D; Blair, J M; Bridgham, S D; Burton, A J; Carrillo, Y; Reich, P B; Clark, J S; Classen, A T; Dijkstra, F A|info:eu-repo/dai/nl/30484473X; Elberling, B; Emmett, B A; Estiarte, M; Frey, S D; Guo, J; Harte, J; Jiang, L; Johnson, B R; Kröel-Dulay, G; Larsen, K S; Laudon, H; Lavallee, J M; Lupascu, M; Ma, L N; Marhan, S; Michelsen, A; Mohan, J; Niu, S; Pendall, E; Peñuelas, J; Pfeifer-Meister, L; Poll, C; Reinsch, S; Reynolds, L L; Schmidt, I K; Sistla, S; Sokol, N W; Templer, P H; Treseder, K K; Welker, J M; Bradford, M A

    2016-01-01

    The majority of the Earth's terrestrial carbon is stored in the soil. If anthropogenic warming stimulates the loss of this carbon to the atmosphere, it could drive further planetary warming. Despite evidence that warming enhances carbon fluxes to and from the soil, the net global balance between

  3. Quantifying global soil carbon losses in response to warming

    NARCIS (Netherlands)

    Crowther, T. W.; Todd-Brown, K. E. O.; Rowe, C. W.; Wieder, W. R.; Carey, J. C.; Machmuller, M. B.; Snoek, B. L.; Fang, S.; Zhou, G.; Allison, S. D.; Blair, J. M.; Bridgham, S. D.; Burton, A. J.; Carrillo, Y.; Reich, P. B.; Clark, J. S.; Classen, A. T.; Dijkstra, F. A.; Elberling, B.; Emmett, B. A.; Estiarte, M.; Frey, S. D.; Guo, J.; Harte, J.; Jiang, L.; Johnson, B. R.; Kröel-Dulay, G.; Larsen, K. S.; Laudon, H.; Lavallee, J. M.; Luo, Y.; Lupascu, M.; Ma, L. N.; Marhan, S.; Michelsen, A.; Mohan, J.; Niu, S.; Pendall, E.; Peñuelas, J.; Pfeifer-Meister, L.; Poll, C.; Reinsch, S.; Reynolds, L. L.; Schmidt, I. K.; Sistla, S.; Sokol, N. W.; Templer, P. H.; Treseder, K. K.; Welker, J. M.; Bradford, M. A.

    2016-01-01

    The majority of the Earth’s terrestrial carbon is stored in the soil. If anthropogenic warming stimulates the loss of this carbon to the atmosphere, it could drive further planetary warming1, 2, 3, 4. Despite evidence that warming enhances carbon fluxes to and from the soil5, 6, the net global

  4. Quantifying global soil carbon losses in response to warming

    NARCIS (Netherlands)

    Crowther, T.W.; Todd-Brown, K.E.O.; Rowe, C.W.; Wieder, W.R.; Carey, J.C.; Machmuller, M.B.; Snoek, B.L.; Fang, S.; Zhou, G.; Allison, S.D.; Blair, J.M.; Bridgham, S.D.; Burton, A.J.; Carrillo, Y.; Reich, P.B.; Clark, J.S.; Classen, A.T.; Dijkstra, F.A.; Elberling, B.; Emmett, B.A.; Estiarte, M.; Frey, S.D.; Guo, J.; Harte, J.; Jiang, L.; Johnson, B.R.; Kröel-Dulay, G.; Larsen, K.S.; Laudon, H.; Lavallee, J.M.; Luo, Y.; Lupascu, M.; Ma, L.N.; Marhan, S.; Michelsen, A.; Mohan, J.; Niu, S.; Pendall, E.; Peñuelas, J.; Pfeifer-Meister, L.; Poll, C.; Reinsch, S.; Reynolds, L.L.; Schmidt, I.K.; Sistla, S.; Sokol, N.W.; Templer, P.H.; Treseder, K.K.; Welker, J.M.; Bradford, M.A.

    2016-01-01

    The majority of the Earth’s terrestrial carbon is stored in the soil. If anthropogenic warming stimulates the loss of this carbon to the atmosphere, it could drive further planetary warming. Despite evidence that warming enhances carbon fluxes to and from the soil the net global balance between

  5. Competitive warm-up in basketball: literature review and proposal

    Directory of Open Access Journals (Sweden)

    Daniel Berdejo-del-Fresno

    2011-05-01

    Full Text Available Abstract Warm-up is used, accepted and performed by every participant before practising any sport. Warm-up is also considered by most sportmen as fundamental to achieve optimal performance. However, there is little scientific evidence supporting its effectiveness. This lack of evidence, together with the diversity of sports, requires the standardisation of common warm-up patterns for each sport activity. As elite basketball is concerned, a large scientific gap has been found, which the present article will attempt to fill in. Therefore, the objectives of this paper are: first, conducting a literature review on all aspects of warm-up, i.e. warm-up definition, warm up types, warm-up benefits, warm-up structure (intensity, duration, recovery and specificity, influential factors, as well as what kind of stretching must be included in the warm-up; and secondly, from the conclusions obtained,  describing and proposing a methodology which is adapted to competitive warm-up for high-level basketball, so this methodology serves as a justified reference guide when going through the pre-game phase.Key Words: static stretching, dynamic stretching, generic warm-up, specific warm-up, basketball.

  6. A cascade of warming impacts brings bluefin tuna to Greenland waters

    DEFF Research Database (Denmark)

    MacKenzie, Brian; Payne, Mark; Boje, Jesper

    in ecological isolation from others. Here we show that a large highly migratory top predator fish species has entered a high latitude sub-polar area. Bluefin tuna, Thunnus thynnus Linnaeus 1758, were captured in waters east of Greenland (65o N) in August 2012 during exploratory fishing for Atlantic mackerel......, Scomber scombrus Linnaeus 1758. The bluefin tuna were captured in a single net-haul in 9-11o C water together with 6 tonnes of mackerel, which is a preferred prey species and itself a new immigrant to the area. Regional temperatures in August 2012 were historically high and contributed to a warming trend...... since 1985, when temperatures began to rise. The presence of bluefin tuna in this region is likely due to a combination of warm temperatures that are physiologically more tolerable and immigration of an important prey species into the region. We conclude that a cascade of climate change impacts...

  7. A cascade of warming impacts brings bluefin tuna to Greenland waters

    DEFF Research Database (Denmark)

    MacKenzie, Brian R.; Payne, Mark R.; Boje, Jesper

    2014-01-01

    in ecological isolation from others. Here, we show that a large highly migratory top predator fish species has entered a high latitude subpolar area beyond its usual range. Bluefin tuna, Thunnus thynnus Linnaeus 1758, were captured in waters east of Greenland (65°N) in August 2012 during exploratory fishing...... for Atlantic mackerel, Scomber scombrus Linnaeus 1758. The bluefin tuna were captured in a single net-haul in 9-11 °C water together with 6 tonnes of mackerel, which is a preferred prey species and itself a new immigrant to the area. Regional temperatures in August 2012 were historically high and contributed...... to a warming trend since 1985, when temperatures began to rise. The presence of bluefin tuna in this region is likely due to a combination of warm temperatures that are physiologically more tolerable and immigration of an important prey species to the region. We conclude that a cascade of climate change...

  8. Book ReviewL Global Warming

    OpenAIRE

    Nadia Astriani

    2015-01-01

    Global Warming is part of Greenhaven’s Contemporary Issues Companion series published by, Thomson Gale on 2005. Each volume of the anthologyseries focuses on a topic of current interest, presenting informative and thought-provoking selection written from wide-variety viewpoints. It is an ideal launching point for research on a particular topic. Each anthology in the series is composed of readings taken from an extensive gamut of resources, including periodical, newspapers, books, governmentdo...

  9. Response to Skeptics of Global Warming.

    Science.gov (United States)

    Kellogg, William W.

    1991-04-01

    The majority of the scientific community involved in climate research is convinced of the reality of a current and future global warming due to the greenhouse effect, a change that must be largely caused by human activities. However, a minority of scientists is still skeptical of the notion that mankind is significantly influencing the climate of the earth, and it therefore argues against taking certain measures to avert this alleged global warming. In recent years the media have given considerable coverage to the statements of these skeptics. Reasons for their statements range from a simple argument that we do not understand the earth's climate system well enough to predict the future, to more complex arguments involving negative feed-backs and changes of solar activity. They question whether the global temperature increase in this century of up to 0.6 K is primarily a result of worldwide burning of fossil fuels. The purpose of this article is to show that the statements of this skeptical school of thought need to be critically analyzed (and in some cases refuted) in the light of current understanding of the planetary system that determines our climate. There is also another school of thought that agrees about the reality of present and future global warming, and claims that this will be beneficial for most of mankind and that it should be encouraged. The policy implications of the latter view are in many respects similar to those of the group that are not convinced that a significant global warming will occur. Both schools of thought argue against taking immediate steps to slow the climate change.

  10. Divergent surface and total soil moisture projections under global warming

    Science.gov (United States)

    Berg, Alexis; Sheffield, Justin; Milly, Paul C.D.

    2017-01-01

    Land aridity has been projected to increase with global warming. Such projections are mostly based on off-line aridity and drought metrics applied to climate model outputs but also are supported by climate-model projections of decreased surface soil moisture. Here we comprehensively analyze soil moisture projections from the Coupled Model Intercomparison Project phase 5, including surface, total, and layer-by-layer soil moisture. We identify a robust vertical gradient of projected mean soil moisture changes, with more negative changes near the surface. Some regions of the northern middle to high latitudes exhibit negative annual surface changes but positive total changes. We interpret this behavior in the context of seasonal changes in the surface water budget. This vertical pattern implies that the extensive drying predicted by off-line drought metrics, while consistent with the projected decline in surface soil moisture, will tend to overestimate (negatively) changes in total soil water availability.

  11. Properties of Whistler Waves in Warm Electron Plasmas

    Science.gov (United States)

    Zhao, Jinsong

    2017-11-01

    Dispersion relation and electromagnetic properties of obliquely propagating whistler waves are investigated on the basis of a warm electron fluid model. The magnetic field of whistler waves is nearly circularly polarized with respect to the wave vector in a plasma where the electron plasma frequency {{{Ω }}}{pe} is much larger than the electron cyclotron frequency {{{Ω }}}{ce}, and the magnetic field polarization can become elliptical, or even linear, polarization as {{{Ω }}}{pe}≲ {{{Ω }}}{ce}. In the plasmas with {{{Ω }}}{pe}wave approximates a quasi-magnetostatic mode, not a quasi-electrostatic mode in the cold electron plasmas. Moreover, the detailed mode properties are given in Earth’s magnetosphere, the solar active region, and Jupiter’s polar cap. Furthermore, the study proposes that the ratio of the electrostatic to electromagnetic component of the electric field can be used to distinguish the whistler mode from the Z-mode in the frequency range of {{{Ω }}}{pe}polar cap.

  12. A Robust Response of the Hadley Circulation to Global Warming

    Science.gov (United States)

    Lau, William K M.; Kim, Kyu-Myong

    2014-01-01

    Tropical rainfall is expected to increase in a warmer climate. Yet, recent studies have inferred that the Hadley Circulation (HC), which is primarily driven by latent heating from tropical rainfall, is weakened under global warming. Here, we show evidence of a robust intensification of the HC from analyses of 33 CMIP5 model projections under a scenario of 1 per year CO2 emission increase. The intensification is manifested in a deep-tropics squeeze, characterized by a pronounced increase in the zonal mean ascending motion in the mid and upper troposphere, a deepening and narrowing of the convective zone and enhanced rainfall in the deep tropics. These changes occur in conjunction with a rise in the region of maximum outflow of the HC, with accelerated meridional mass outflow in the uppermost branch of the HC away from the equator, coupled to a weakened inflow in the return branches of the HC in the lower troposphere.

  13. Warming Oceans, Phytoplankton, and River Discharge: Implications for Cholera Outbreaks

    Science.gov (United States)

    Jutla, Antarpreet S.; Akanda, Ali S.; Griffiths, Jeffrey K.; Colwell, Rita; Islam, Shafiqul

    2011-01-01

    Phytoplankton abundance is inversely related to sea surface temperature (SST). However, a positive relationship is observed between SST and phytoplankton abundance in coastal waters of Bay of Bengal. This has led to an assertion that in a warming climate, rise in SST may increase phytoplankton blooms and, therefore, cholera outbreaks. Here, we explain why a positive SST-phytoplankton relationship exists in the Bay of Bengal and the implications of such a relationship on cholera dynamics. We found clear evidence of two independent physical drivers for phytoplankton abundance. The first one is the widely accepted phytoplankton blooming produced by the upwelling of cold, nutrient-rich deep ocean waters. The second, which explains the Bay of Bengal findings, is coastal phytoplankton blooming during high river discharges with terrestrial nutrients. Causal mechanisms should be understood when associating SST with phytoplankton and subsequent cholera outbreaks in regions where freshwater discharge are a predominant mechanism for phytoplankton production. PMID:21813852

  14. Effects of Global Warming on Vibrio Ecology.

    Science.gov (United States)

    Vezzulli, Luigi; Pezzati, Elisabetta; Brettar, Ingrid; Höfle, Manfred; Pruzzo, Carla

    2015-06-01

    Vibrio-related infections are increasing worldwide both in humans and aquatic animals. Rise in global sea surface temperature (SST), which is approximately 1 °C higher now than 140 years ago and is one of the primary physical impacts of global warming, has been linked to such increases. In this chapter, major known effects of increasing SST on the biology and ecology of vibrios are described. They include the effects on bacterial growth rate, both in the field and in laboratory, culturability, expression of pathogenicity traits, and interactions with aquatic organisms and abiotic surfaces. Special emphasis is given to the effect of ocean warming on Vibrio interactions with zooplankters, which represent one of the most important aquatic reservoirs for these bacteria. The reported findings highlight the biocomplexity of the interactions between vibrios and their natural environment in a climate change scenario, posing the need for interdisciplinary studies to properly understand the connection between ocean warming and persistence and spread of vibrios in sea waters and the epidemiology of the diseases they cause.

  15. Global Warming: Evidence from Satellite Observations

    Science.gov (United States)

    Prabhakara, C.; Iacovazzi, R., Jr.; Yoo, J.-M.

    2001-01-01

    Observations made in Channel 2 (53.74 GHz) of the Microwave Sounding Unit (MSU) radiometer, flown on-board sequential, sun-synchronous, polar orbiting NOAA operational satellites, indicate that the mean temperature of the atmosphere over the globe increased during the period 1980 to 1999. In this study we have minimized systematic errors in the time series introduced by the satellite orbital drift in an objective manner. This is done with the help the onboard warm black body temperature, which is used in the calibration of the MSU radiometer. The corrected MSU Channel 2 observations of the NOAA satellite series reveal that the vertically weighted global mean temperature of the atmosphere, with a peak weight near the mid-troposphere, warmed at the rate of 0.13 K per decade (with an uncertainty of 0.05 K per decade) during 1980 to 1999. The global warming deduced from conventional meteorological data that have been corrected for urbanization effects agrees reasonably with this satellite deuced result.

  16. Scientists' views about attribution of global warming.

    Science.gov (United States)

    Verheggen, Bart; Strengers, Bart; Cook, John; van Dorland, Rob; Vringer, Kees; Peters, Jeroen; Visser, Hans; Meyer, Leo

    2014-08-19

    Results are presented from a survey held among 1868 scientists studying various aspects of climate change, including physical climate, climate impacts, and mitigation. The survey was unique in its size, broadness and level of detail. Consistent with other research, we found that, as the level of expertise in climate science grew, so too did the level of agreement on anthropogenic causation. 90% of respondents with more than 10 climate-related peer-reviewed publications (about half of all respondents), explicitly agreed with anthropogenic greenhouse gases (GHGs) being the dominant driver of recent global warming. The respondents' quantitative estimate of the GHG contribution appeared to strongly depend on their judgment or knowledge of the cooling effect of aerosols. The phrasing of the IPCC attribution statement in its fourth assessment report (AR4)-providing a lower limit for the isolated GHG contribution-may have led to an underestimation of the GHG influence on recent warming. The phrasing was improved in AR5. We also report on the respondents' views on other factors contributing to global warming; of these Land Use and Land Cover Change (LULCC) was considered the most important. Respondents who characterized human influence on climate as insignificant, reported having had the most frequent media coverage regarding their views on climate change.

  17. Geographical and experimental contexts modulate the effect of warming on top-down control: a meta-analysis.

    Science.gov (United States)

    Marino, Nicholas Dos Anjos Cristiano; Romero, Gustavo Quevedo; Farjalla, Vinicius Fortes

    2018-01-24

    Ecologists have extensively investigated the effect of warming on consumer-resource interactions, with experiments revealing that warming can strengthen, weaken or have no net effect on top-down control of resources. These experiments have inspired a body of theoretical work to explain the variation in the effect of warming on top-down control. However, there has been no quantitative attempt to reconcile theory with outcomes from empirical studies. To address the gap between theory and experiment, we performed a meta-analysis to examine the combined effect of experimental warming and top-down control on resource biomass and determined potential sources of variation across experiments. We show that differences in experimental outcomes are related to systematic variation in the geographical distribution of studies. Specifically, warming strengthened top-down control when experiments were conducted in colder regions, but had the opposite effect in warmer regions. Furthermore, we found that differences in the thermoregulation strategy of the consumer and openness of experimental arenas to dispersal can contribute to some deviation from the overall geographical pattern. These results reconcile empirical findings and support the expectation of geographical variation in the response of consumer-resource interactions to warming. © 2018 John Wiley & Sons Ltd/CNRS.

  18. Multisectoral Climate Impact Hotspots in a Warming World

    Science.gov (United States)

    Piontek, Franziska; Mueller, Christoph; Pugh, Thomas A. M.; Clark, Douglas B.; Deryng, Delphine; Elliott, Joshua; deJesusColonGonzalez, Felipe; Floerke, Martina; Folberth, Christian; Franssen, Wietse; hide

    2014-01-01

    The impacts of global climate change on different aspects of humanity's diverse life-support systems are complex and often difficult to predict. To facilitate policy decisions on mitigation and adaptation strategies, it is necessary to understand, quantify, and synthesize these climate-change impacts, taking into account their uncertainties. Crucial to these decisions is an understanding of how impacts in different sectors overlap, as overlapping impacts increase exposure, lead to interactions of impacts, and are likely to raise adaptation pressure. As a first step we develop herein a framework to study coinciding impacts and identify regional exposure hotspots. This framework can then be used as a starting point for regional case studies on vulnerability and multifaceted adaptation strategies. We consider impacts related to water, agriculture, ecosystems, and malaria at different levels of global warming. Multisectoral overlap starts to be seen robustly at a mean global warming of 3 degC above the 1980-2010 mean, with 11% of the world population subject to severe impacts in at least two of the four impact sectors at 4 degC. Despite these general conclusions, we find that uncertainty arising from the impact models is considerable, and larger than that from the climate models. In a low probability-high impact worst-case assessment, almost the whole inhabited world is at risk for multisectoral pressures. Hence, there is a pressing need for an increased research effort to develop a more comprehensive understanding of impacts, as well as for the development of policy measures under existing uncertainty.

  19. CARBON-CHAIN SPECIES IN WARM-UP MODELS

    Energy Technology Data Exchange (ETDEWEB)

    Hassel, George E.; Harada, Nanase [Department of Physics, Ohio State University, Columbus, OH 43210 (United States); Herbst, Eric, E-mail: ghassel@siena.edu [Departments of Chemistry, Astronomy, and Physics, University of Virginia, Charlottesville, VA 22904 (United States)

    2011-12-20

    In previous warm-up chemical models of the low-mass star-forming region L1527, we investigated the evolution of carbon-chain unsaturated hydrocarbon species when the envelope temperature is slightly elevated to T Almost-Equal-To 30 K. These models demonstrated that enhanced abundances of such species can be explained by gas-phase ion-molecule chemistry following the partial sublimation of methane from grain surfaces. We also concluded that the abundances of hydrocarbon radicals such as the C{sub n}H family should be further enhanced as the temperatures increase to higher values, but this conclusion stood in contrast with the lack of unambiguous detection of these species toward hot core and corino sources. Meanwhile, observational surveys have identified C{sub 2}H, C{sub 4}H, CH{sub 3}CCH, and CH{sub 3}OH toward hot corinos (especially IRAS 16293-2422) as well as toward L1527, with lower abundances for the carbon-chain radicals and higher abundances for the other two species toward the hot corinos. In addition, the Herschel Space Telescope has detected the bare linear chain C{sub 3} in 50 K material surrounding young high-mass stellar objects. To understand these new results, we revisit previous warm-up models with an augmented gas-grain network that incorporated reactions from a gas-phase network that was constructed for use with increased temperature up to 800 K. Some of the newly adopted reactions between carbon-chain species and abundant H{sub 2} possess chemical activation energy barriers. The revised model results now better reproduce the observed abundances of unsaturated carbon chains under hot corino (100 K) conditions and make predictions for the abundances of bare carbon chains in the 50 K regions observed by the Herschel HIFI detector.

  20. Investigating warming trends and spatial patterns of Land Surface Temperatures over the Greater Los Angeles Area using new MODIS and VIIRS LST products

    Science.gov (United States)

    Malakar, N. K.; Hulley, G. C.

    2016-12-01

    The Los Angeles (LA) metropolitan area is one of the fastest growing urban centers in the United States, and home to roughly 18 million people. Understanding the trends and impacts of warming temperatures in urban environments is an increasingly important issue in our changing climate. We used thermal infrared data from Moderate Resolution Imaging Spectroradiometer (MODIS), and Visible Infrared Imaging Radiometer Suite (VIIRS) sensors to retrieve Land Surface Temperature using a new Temperature Emissivity Separation algorithm adapted for these sensors. We analyzed day and night LST retrievals to study the warming trends of LST for the greater LA region from 2002-2015. The average warming trend over LA for summer days and nights over this period for MODIS Aqua data was 1.1 °C per decade, while a more rapid warming is observed for the years 2012-2016 for both MODIS and VIIRS observations. We have also found that inland LA regions are warming more rapidly than the other regions. We further investigate the underlying cause of the warming by looking into the physical factors such as changes in net radiation, cloud cover, and evapotranspiration. The results will help to understand how indicators of climate change are evolving in the beginning of the 21st century, and how they compare with global climate model projections. Identification of potential impacts, and underlying causes of warming trends in various LA regions will help decision makers to develop policies to help mitigate the effects of rising temperatures.

  1. GLOBAL WARMING: IS A NEW THREAT?

    Energy Technology Data Exchange (ETDEWEB)

    Ayca Eminoglu

    2008-09-30

    In the Post Cold War era, the concepts of ''security'', ''national security'', and ''international security'' have changed with regard to their contents and meanings. Such developments made states to renew their national security policies. Security is a special form of politics as well. All security issues are political problems but not all political conflicts are security issues. In the Post Cold War era, differentiating and increasing numbers of elements that constitutes threat changed the concept of threat and widen the capacity of security. In this term, many elements lost its effect of being a threat but also new threatening elements emerged. Environmental problems, human rights, mass migration, micro nationalism, ethnic conflicts, religious fundamentalism, contagious diseases, international terrorism, economic instabilities, drug and weapon smuggling and human trafficking are the new problems emerged in international security agenda. Environmental problems no longer take place in security issues and can be mentioned as a ''low security'' issue. They are threats to the global commons i.e. the oceans, the seas, the ozone layer and the climate system, which are life supports for mankind as a whole. Global warming is one of the most important environmental issues of our day that effects human life in every field and can be defined as a 'serious threat to international security'. Because of global warming, environmental changes will occur and these changes will cause conflicting issues in international relations. Because of global warming dwindling freshwater supplies, food shortages, political instability and other conflicts may take place. Some IR scholars see a need for global cooperation in order to face the threat. At the background of global warming and its effects, states have to get preventive measures and normally, each state form its own measures, therefore as a

  2. Changes in fungal community composition in response to experimental soil warming at the alpine treeline

    Science.gov (United States)

    Solly, Emily; Lindahl, Bjorn; Dawes, Melissa; Peter, Martina; Souza, Romulo; Rixen, Christian; Hagedorn, Frank

    2017-04-01

    data and the colonization of ectomycorrhizal root tips. Several fungal taxa known to be involved in needle degradation responded positively to the warming treatment by increasing in their relative abundance. These findings provide novel insights into the spatial distribution of functional groups of fungi both vertically in the soil and between different rhizospheres of trees. Moreover, they indicate that traits related to nitrogen utilization are important in determining responses of ectomycorrhizal fungi to warming in cold regions, such as high-elevation ecosystems, with low N availability. Shifts in the overall fungal community composition in response to higher temperatures may alter fungal-driven processes with potential feedbacks on ecosystem nitrogen cycling and carbon storage at the alpine treeline.

  3. Who decides who has won the bet? Total and Anthropogenic Warming Indices

    Science.gov (United States)

    Haustein, K.; Allen, M. R.; Otto, F. E. L.; Schmidt, A.; Frame, D. J.; Forster, P.; Matthews, D.

    2016-12-01

    An extension of the idea of betting markets as a means of revealing opinions about future climate are climate policies indexed to geophysical indicators: for example, to ensure net zero global carbon dioxide emissions by the time anthropogenic warming reaches 1.5 degrees above pre-industrial, given about 1 degree of warming already, emissions must fall, on average, by 20% of their current value for every tenth of a degree of anthropogenic warming from now on. In principle, policies conditioned on some measure of attributable warming are robust to uncertainty in the global climate response: the risk of a higher or lower response than expected is borne by those affected by climate change mitigation policy rather than those affected by climate change impacts, as is the case with emission targets for specific years based on "current understanding" of the response. To implement any indexed policy, or to agree payout terms for any bet on future climate, requires consensus on the definition of the index: how is it calculated, and who is responsible for releasing it? The global mean surface temperature of the current decade relative to pre-industrial may vary by 0.1 degree or more depending on precisely what is measured, what is defined as pre-industrial, and the treatment of regions with sparse data coverage in earlier years. Indices defined using different conventions, however, are all expected to evolve very similarly over the coming decades, so agreeing on a conservative, traceable index such as HadCRUT is more important than debating the "true" global temperature. A more important question is whether indexed policies and betting markets should focus on total warming, including natural and anthropogenic drivers and internal variability, or an Anthropogenic Warming Index (AWI) representing an unbiased estimate of warming attributable to human influence to date. We propose a simple AWI based solely on observed temperatures and global natural and anthropogenic forcing

  4. Elevational ranges of birds on a tropical montane gradient lag behind warming temperatures.

    Directory of Open Access Journals (Sweden)

    German Forero-Medina

    Full Text Available BACKGROUND: Species may respond to a warming climate by moving to higher latitudes or elevations. Shifts in geographic ranges are common responses in temperate regions. For the tropics, latitudinal temperature gradients are shallow; the only escape for species may be to move to higher elevations. There are few data to suggest that they do. Yet, the greatest loss of species from climate disruption may be for tropical montane species. METHODOLOGY/PRINCIPAL FINDINGS: We repeat a historical transect in Peru and find an average upward shift of 49 m for 55 bird species over a 41 year interval. This shift is significantly upward, but also significantly smaller than the 152 m one expects from warming in the region. To estimate the expected shift in elevation we first determined the magnitude of warming in the locality from historical data. Then we used the temperature lapse rate to infer the required shift in altitude to compensate for warming. The range shifts in elevation were similar across different trophic guilds. CONCLUSIONS: Endothermy may provide birds with some flexibility to temperature changes and allow them to move less than expected. Instead of being directly dependent on temperature, birds may be responding to gradual changes in the nature of the habitat or availability of food resources, and presence of competitors. If so, this has important implications for estimates of mountaintop extinctions from climate change.

  5. Landslides as a Delayed Signal of Warm Phase of ENSO in the Aconcagua Park (32 Sl)

    Science.gov (United States)

    Moreiras, S.; Lisboa, M.

    2013-05-01

    The Aconcagua mount (6,929 m asl), the top of the Andes, is characterised by high elevations and abrupt topography that seem to have favoured the occurrence of landslides affecting 25% of the Aconcagua Park (Fig 1). Concerning to triggering mechanism, rainfall are mentioned as the main cause of landslides in historical sources; but this assertion could not be confirmed on the basis of available meteorological data beginning after 1940. The most reliable rainfall threshold value corresponds to a 19 mm (daily precipitation) representing 8.7% of the annual precipitation and 8% of the mean annual precipitation for this region. However, main cause of landslides is related to terrain saturation by snow melting and ice thawing of ice-core moraines or rock glaciers during the warm season (November - February). A delayed link between warm phases of ENSO and slope instability could be established by a relationship found between landslides and local river stream flow (Fig. 2). The typical warm phase of ENSO begins in November of one year, increasing during July—August, and ends in February of the following year. Greater snowfall and positive glacier balance has been linked to the ENSO-warm phase. Consequently, increased stream flows of Andean rivers will be measured the following summer. In fact, ENSO-related features in the tropical Pacific play a major role in regulating the hydrological variability in the region with increased (decreased) summer and annual river discharges following El Niño (La Niña) events.; ;

  6. Deep peat warming increases surface methane and carbon dioxide emissions in a black spruce-dominated ombrotrophic bog.

    Science.gov (United States)

    Gill, Allison L; Giasson, Marc-André; Yu, Rieka; Finzi, Adrien C

    2017-12-01

    Boreal peatlands contain approximately 500 Pg carbon (C) in the soil, emit globally significant quantities of methane (CH4 ), and are highly sensitive to climate change. Warming associated with global climate change is likely to increase the rate of the temperature-sensitive processes that decompose stored organic carbon and release carbon dioxide (CO2 ) and CH4 . Variation in the temperature sensitivity of CO2 and CH4 production and increased peat aerobicity due to enhanced growing-season evapotranspiration may alter the nature of peatland trace gas emission. As CH4 is a powerful greenhouse gas with 34 times the warming potential of CO2 , it is critical to understand how factors associated with global change will influence surface CO2 and CH4 fluxes. Here, we leverage the Spruce and Peatland Responses Under Changing Environments (SPRUCE) climate change manipulation experiment to understand the impact of a 0-9°C gradient in deep belowground warming ("Deep Peat Heat", DPH) on peat surface CO2 and CH4 fluxes. We find that DPH treatments increased both CO2 and CH4 emission. Methane production was more sensitive to warming than CO2 production, decreasing the C-CO2 :C-CH4 of the respired carbon. Methane production is dominated by hydrogenotrophic methanogenesis but deep peat warming increased the δ13 C of CH4 suggesting an increasing contribution of acetoclastic methanogenesis to total CH4 production with warming. Although the total quantity of C emitted from the SPRUCE Bog as CH4 is 50% of seasonal C emissions in the highest-warming treatments when adjusted for CO2 equivalents on a 100-year timescale. These results suggest that warming in boreal regions may increase CH4 emissions from peatlands and result in a positive feedback to ongoing warming. © 2017 John Wiley & Sons Ltd.

  7. Scenario dependence of future changes in climate extremes under 1.5 °C and 2 °C global warming.

    Science.gov (United States)

    Wang, Zhili; Lin, Lei; Zhang, Xiaoye; Zhang, Hua; Liu, Liangke; Xu, Yangyang

    2017-04-20

    The 2015 Paris Agreement aims to limit global warming below 2 °C and pursue efforts to even limit it to 1.5 °C relative to pre-industrial levels. Decision makers need reliable information on the impacts caused by these warming levels for climate mitigation and adaptation measures. We explore the changes in climate extremes, which are closely tied to economic losses and casualties, under 1.5 °C and 2 °C global warming and their scenario dependence using three sets of ensemble global climate model simulations. A warming of 0.5 °C (from 1.5 °C to 2 °C) leads to significant increases in temperature and precipitation extremes in most regions. However, the projected changes in climate extremes under both warming levels highly depend on the pathways of emissions scenarios, with different greenhouse gas (GHG)/aerosol forcing ratio and GHG levels. Moreover, there are multifold differences in several heavily polluted regions, among the scenarios, in the changes in precipitation extremes due to an additional 0.5 °C warming from 1.5 °C to 2 °C. Our results demonstrate that the chemical compositions of emissions scenarios, not just the total radiative forcing and resultant warming level, must be considered when assessing the impacts of global 1.5/2 °C warming.

  8. Scenario dependence of future changes in climate extremes under 1.5 °C and 2 °C global warming

    Science.gov (United States)

    Wang, Zhili; Lin, Lei; Zhang, Xiaoye; Zhang, Hua; Liu, Liangke; Xu, Yangyang

    2017-04-01

    The 2015 Paris Agreement aims to limit global warming below 2 °C and pursue efforts to even limit it to 1.5 °C relative to pre-industrial levels. Decision makers need reliable information on the impacts caused by these warming levels for climate mitigation and adaptation measures. We explore the changes in climate extremes, which are closely tied to economic losses and casualties, under 1.5 °C and 2 °C global warming and their scenario dependence using three sets of ensemble global climate model simulations. A warming of 0.5 °C (from 1.5 °C to 2 °C) leads to significant increases in temperature and precipitation extremes in most regions. However, the projected changes in climate extremes under both warming levels highly depend on the pathways of emissions scenarios, with different greenhouse gas (GHG)/aerosol forcing ratio and GHG levels. Moreover, there are multifold differences in several heavily polluted regions, among the scenarios, in the changes in precipitation extremes due to an additional 0.5 °C warming from 1.5 °C to 2 °C. Our results demonstrate that the chemical compositions of emissions scenarios, not just the total radiative forcing and resultant warming level, must be considered when assessing the impacts of global 1.5/2 °C warming.

  9. Scenario dependence of future changes in climate extremes under 1.5 °C and 2 °C global warming

    Science.gov (United States)

    Wang, Zhili; Lin, Lei; Zhang, Xiaoye; Zhang, Hua; Liu, Liangke; Xu, Yangyang

    2017-01-01

    The 2015 Paris Agreement aims to limit global warming below 2 °C and pursue efforts to even limit it to 1.5 °C relative to pre-industrial levels. Decision makers need reliable information on the impacts caused by these warming levels for climate mitigation and adaptation measures. We explore the changes in climate extremes, which are closely tied to economic losses and casualties, under 1.5 °C and 2 °C global warming and their scenario dependence using three sets of ensemble global climate model simulations. A warming of 0.5 °C (from 1.5 °C to 2 °C) leads to significant increases in temperature and precipitation extremes in most regions. However, the projected changes in climate extremes under both warming levels highly depend on the pathways of emissions scenarios, with different greenhouse gas (GHG)/aerosol forcing ratio and GHG levels. Moreover, there are multifold differences in several heavily polluted regions, among the scenarios, in the changes in precipitation extremes due to an additional 0.5 °C warming from 1.5 °C to 2 °C. Our results demonstrate that the chemical compositions of emissions scenarios, not just the total radiative forcing and resultant warming level, must be considered when assessing the impacts of global 1.5/2 °C warming. PMID:28425445

  10. Both seed germination and seedling mortality increase with experimental warming and fertilization in a subarctic tundra

    Science.gov (United States)

    Vandeplas, Nicolas; Kockelbergh, Fred; Nijs, Ivan

    2017-01-01

    Abstract Climate change is expected to force many species in arctic regions to migrate and track their climatic niche. This requires recruitment from seed, which currently shows very low rates in arctic regions, where long-lived and vegetatively reproducing plants dominate. Therefore, we pose the question whether recruitment (germination and seedling establishment) in arctic regions will significantly improve in a warmer world, and thus allow species to follow their climatic niche. We used a full factorial experiment to examine if realistic warmer temperatures (+3 °C; infrared radiation) and increased nitrogen availability (+1.4 g N m−2 year−1) affected germination, seedling survival and above- and below-ground seedling biomass in five species common in subarctic regions (Anthoxanthum odoratum, Betula nana, Pinus sylvestris, Solidago virgaurea, Vaccinium myrtillus). We found that warming increased seedling emergence in all species, but that subsequent mortality also increased, resulting in no net warming effect on seedling establishment. Warming slightly increased above-ground seedling biomass. Fertilization, on the other hand, did not influence seedling biomass, but it increased seedling establishment in B. nana while it reduced establishment in V. myrtillus. This may help B. nana dominate over V. myrtillus in warmer tundra. Surprisingly, no interactive effects between warming and fertilization were found. The lack of a general positive response of seedling establishment to warmer and more nutrient-rich conditions suggests that (sub)arctic species may experience difficulties in tracking their climatic niche. Predictions of future species distributions in arctic regions solely based on abiotic factors may therefore overestimate species’ ranges due to their poor establishment. Also, the opposite response to fertilization of two key (sub)arctic dwarf shrubs, i.e. B. nana and V. myrtillus, could have important implications for the future development of arctic

  11. Effects of experimental warming on fungal disease progress in oilseed rape.

    Science.gov (United States)

    Siebold, Magdalena; von Tiedemann, Andreas

    2013-06-01

    Global warming will influence the growth and development of both crops and pathogens. The aims of this study were to investigate potential effects of future warming on oilseed rape growth and the epidemiology of the three economically important pathogens Verticillium longisporum, Sclerotinia sclerotiorum, and Leptosphaeria maculans (anamorph: Phoma lingam). We utilized climate chambers and a soil warming facility, where treatments represented regional warming scenarios for Lower Saxony, Germany, by 2050 and 2100, and compared results of both approaches on a thermal time scale by calculating degree-days (dd) from day of sowing, December 1st and March 1st until sampling, the latter correlating best with disease progress. Regression analysis showed that plant growth and growth stages in spring responded almost linearly to increasing thermal time until 1000-1500 dd. Colonization of plant tissue by V. longisporum showed an exponential increase when exceeding 1300-1500 dd and reaching plant growth stage BBCH 74/75 (pod development). V. longisporum colonization of plants may be advanced, potentially leading to higher inoculum densities after harvest and increased economic importance of this pathogen under future warming. Sclerotia germination of S. sclerotiorum reached its maximum at 600-900 dd. Advance of these critical degree-days may lead to earlier apothecia production, potentially advancing the infection window, whereas the future importance of S. sclerotiorum may remain constant. Severity of phoma crown canker increased linearly with increasing thermal time, but showed also large variation in response to the warming scenarios, suggesting that factors such as canopy microclimate in fall or leaf shedding over winter may play a bigger role for L. maculans infection and disease severity than higher soil temperatures. Thermal time was a suitable tool to combine and integrate data on biological responses to soil and air temperature increases from climate chamber and field

  12. Marine species distribution shifts on the U.S. Northeast Continental Shelf under continued ocean warming

    Science.gov (United States)

    Kleisner, Kristin M.; Fogarty, Michael J.; McGee, Sally; Hare, Jonathan A.; Moret, Skye; Perretti, Charles T.; Saba, Vincent S.

    2017-04-01

    The U.S. Northeast Continental Shelf marine ecosystem has warmed much faster than the global ocean and it is expected that this enhanced warming will continue through this century. Complex bathymetry and ocean circulation in this region have contributed to biases in global climate model simulations of the Shelf waters. Increasing the resolution of these models results in reductions in the bias of future climate change projections and indicates greater warming than suggested by coarse resolution climate projections. Here, we used a high-resolution global climate model and historical observations of species distributions from a trawl survey to examine changes in the future distribution of suitable thermal habitat for various demersal and pelagic species on the Shelf. Along the southern portion of the shelf (Mid-Atlantic Bight and Georges Bank), a projected 4.1 °C (surface) to 5.0 °C (bottom) warming of ocean temperature from current conditions results in a northward shift of the thermal habitat for the majority of species. While some southern species like butterfish and black sea bass are projected to have moderate losses in suitable thermal habitat, there are potentially significant increases for many species including summer flounder, striped bass, and Atlantic croaker. In the north, in the Gulf of Maine, a projected 3.7 °C (surface) to 3.9 °C (bottom) warming from current conditions results in substantial reductions in suitable thermal habitat such that species currently inhabiting this region may not remain in these waters under continued warming. We project a loss in suitable thermal habitat for key northern species including Acadian redfish, American plaice, Atlantic cod, haddock, and thorney skate, but potential gains for some species including spiny dogfish and American lobster. We illustrate how changes in suitable thermal habitat of important commercially fished species may impact local fishing communities and potentially impact major fishing ports

  13. Cutoff in the Lyman-α forest power spectrum: Warm IGM or warm dark matter?

    Directory of Open Access Journals (Sweden)

    Antonella Garzilli

    2017-10-01

    Full Text Available We re-analyse high redshift and high resolution Lyman-α forest spectra considered in [1], seeking to constrain the properties of warm dark matter particles. Compared to this previous work, we consider a wider range of thermal histories of the intergalactic medium. We find that both warm and cold dark matter models can explain the cut-off observed in the flux power spectra of high-resolution observations equally well. This implies, however, very different thermal histories and underlying reionization models. We discuss how to remove this degeneracy.

  14. Cutoff in the Lyman-α forest power spectrum: Warm IGM or warm dark matter?

    Science.gov (United States)

    Garzilli, Antonella; Boyarsky, Alexey; Ruchayskiy, Oleg

    2017-10-01

    We re-analyse high redshift and high resolution Lyman-α forest spectra considered in [1], seeking to constrain the properties of warm dark matter particles. Compared to this previous work, we consider a wider range of thermal histories of the intergalactic medium. We find that both warm and cold dark matter models can explain the cut-off observed in the flux power spectra of high-resolution observations equally well. This implies, however, very different thermal histories and underlying reionization models. We discuss how to remove this degeneracy.

  15. Simulation of future global warming scenarios in rice paddies with an open-field warming facility

    Directory of Open Access Journals (Sweden)

    Rehmani Muhammad

    2011-12-01

    Full Text Available Abstract To simulate expected future global warming, hexagonal arrays of infrared heaters have previously been used to warm open-field canopies of upland crops such as wheat. Through the use of concrete-anchored posts, improved software, overhead wires, extensive grounding, and monitoring with a thermal camera, the technology was safely and reliably extended to paddy rice fields. The system maintained canopy temperature increases within 0.5°C of daytime and nighttime set-point differences of 1.3 and 2.7°C 67% of the time.

  16. Simulation of future global warming scenarios in rice paddies with an open-field warming facility.

    Science.gov (United States)

    Rehmani, Muhammad Ishaq Asif; Zhang, Jingqi; Li, Ganghua; Ata-Ul-Karim, Syed Tahir; Wang, Shaohua; Kimball, Bruce A; Yan, Chuan; Liu, Zhenghui; Ding, Yanfeng

    2011-12-06

    To simulate expected future global warming, hexagonal arrays of infrared heaters have previously been used to warm open-field canopies of upland crops such as wheat. Through the use of concrete-anchored posts, improved software, overhead wires, extensive grounding, and monitoring with a thermal camera, the technology was safely and reliably extended to paddy rice fields. The system maintained canopy temperature increases within 0.5°C of daytime and nighttime set-point differences of 1.3 and 2.7°C 67% of the time.

  17. Observed high-altitude warming and snow cover retreat over Tibet and the Himalayas enhanced by black carbon aerosols

    Directory of Open Access Journals (Sweden)

    Y. Xu

    2016-02-01

    Full Text Available Himalayan mountain glaciers and the snowpack over the Tibetan Plateau provide the headwater of several major rivers in Asia. In situ observations of snow cover extent since the 1960s suggest that the snowpack in the region have retreated significantly, accompanied by a surface warming of 2–2.5 °C observed over the peak altitudes (5000 m. Using a high-resolution ocean–atmosphere global climate model and an observationally constrained black carbon (BC aerosol forcing, we attribute the observed altitude dependence of the warming trends as well as the spatial pattern of reductions in snow depths and snow cover extent to various anthropogenic factors. At the Tibetan Plateau altitudes, the increase in atmospheric CO2 concentration exerted a warming of 1.7 °C, BC 1.3 °C where as cooling aerosols cause about 0.7 °C cooling, bringing the net simulated warming consistent with the anomalously large observed warming. We therefore conclude that BC together with CO2 has contributed to the snow retreat trends. In particular, BC increase is the major factor in the strong elevation dependence of the observed surface warming. The atmospheric warming by BC as well as its surface darkening of snow is coupled with the positive snow albedo feedbacks to account for the disproportionately large role of BC in high-elevation regions. These findings reveal that BC impact needs to be properly accounted for in future regional climate projections, in particular on high-altitude cryosphere.

  18. Scientists' Views about Attribution of Global Warming

    Science.gov (United States)

    Verheggen, Bart; Strengers, Bart; Cook, John; van Dorland, Rob; Vringer, Kees; Peters, Jeroen; Visser, Hans; Meyer, Leo

    2015-04-01

    What do scientists think? That is an important question when engaging in science communication, in which an attempt is made to communicate the scientific understanding to a lay audience. To address this question we undertook a large and detailed survey among scientists studying various aspects of climate change , dubbed "perhaps the most thorough survey of climate scientists ever" by well-known climate scientist and science communicator Gavin Schmidt. Among more than 1800 respondents we found widespread agreement that global warming is predominantly caused by human greenhouse gases. This consensus strengthens with increased expertise, as defined by the number of self-reported articles in the peer-reviewed literature. 90% of respondents with more than 10 climate-related peer-reviewed publications (about half of all respondents), agreed that anthropogenic greenhouse gases are the dominant cause of recent global warming, i.e. having contributed more than half of the observed warming. With this survey we specified what the consensus position entails with much greater specificity than previous studies. The relevance of this consensus for science communication will be discussed. Another important result from our survey is that the main attribution statement in IPCC's fourth assessment report (AR4) may lead to an underestimate of the greenhouse gas contribution to warming, because it implicitly includes the lesser known masking effect of cooling aerosols. This shows the importance of the exact wording in high-profile reports such as those from IPCC in how the statement is perceived, even by fellow scientists. The phrasing was improved in the most recent assessment report (AR5). Respondents who characterized the human influence on climate as insignificant, reported having the most frequent media coverage regarding their views on climate change. This shows that contrarian opinions are amplified in the media in relation to their prevalence in the scientific community. This

  19. Climate Models have Accurately Predicted Global Warming

    Science.gov (United States)

    Nuccitelli, D. A.

    2016-12-01

    Climate model projections of global temperature changes over the past five decades have proven remarkably accurate, and yet the myth that climate models are inaccurate or unreliable has formed the basis of many arguments denying anthropogenic global warming and the risks it poses to the climate system. Here we compare average global temperature predictions made by both mainstream climate scientists using climate models, and by contrarians using less physically-based methods. We also explore the basis of the myth by examining specific arguments against climate model accuracy and their common characteristics of science denial.

  20. Resource Letter: GW-1: Global warming

    Science.gov (United States)

    Firor, John W.

    1994-06-01

    This Resource Letter provides a guide to the literature on the possibility of a human-induced climate change—a global warming. Journal articles and books are cited for the following topics: the Greenhouse Effect, sources of infrared-trapping gases, climate models and their uncertainties, verification of climate models, past climate changes, and economics, ethics, and politics of policy responses to climate change. [The letter E after an item indicates elementary level or material of general interest to persons becoming informed in the field. The letter I, for intermediate level, indicates material of somewhat more specialized nature, and the letter A indicates rather specialized or advanced material.

  1. Uses of warmed water in agriculture. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Garrett, R.E.

    1978-11-01

    Energy in the form of warmed water is available from condenser cooling water from fossil fuel or nuclear-electric power-generating facilities, geothermal power plants, geothermal fluids, or spent steam and cooling water from industrial processes. A re-analysis of the characteristics of possible agricultural uses of warmed water has revealed the need to decouple considerations of warmed water sources from those of warmed water users. Conflicting objectives and managerial requirements seem to preclude an integrated system approach. Rather an interface must be established with separate costs and benefits identified for a reliable warmed water source and for its various potential uses. These costs and benefits can be utilized as a basis for decisions separately by the energy supplier and the prospective energy users. A method of classifying uses of warmed water according to need, volume, objective, temperature, and quality is presented and preliminary classifications are discussed for several potential agricultural uses of warmed water. Specific uses for soil warming, space heating in greenhouses, and irrigation are noted. Specific uses in aquaculture for catfish, lobster, and prawn production are discussed. Warmed water use in animal shelters is mentioned. Low-quality heat is required for methane generation from biomass and warmed water heating could be utilized in this industry. 53 references. (MCW)

  2. Spherical warm shield design for infrared imaging systems

    Science.gov (United States)

    Tian, Qijie; Chang, Songtao; He, Fengyun; Li, Zhou; Qiao, Yanfeng

    2017-09-01

    The F-number matching is the primary means to suppress stray radiation for infrared imaging systems. However, it is difficult to achieve exact F-number matching, owing to the restriction from detectors, or multiple F-number design. Hence, an additional shield is required to block the certain thermal radiation. Typical shield is called flat warm shield, which is flat and operates at room temperature. For flat warm shield, it cannot suppress stray radiation while achieving F-number matching. To overcome the restriction, a spherical reflective warm shield is required. First of all, the detailed theory of spherical warm shield design is developed on basis of the principle that stray radiation cannot directly reach the infrared focal plane array. According to the theory developed above, a polished spherical warm shield, whose radius is 18 mm, is designed to match an F/2 infrared detector with an F/4 infrared imaging system. Then, the performance and alignment errors of the designed spherical warm shield are analyzed by simulation. Finally, a contrast experiment between the designed spherical warm shield and two differently processed flat warm shields is performed in a chamber with controllable inside temperatures. The experimental results indicate that the designed spherical warm shield cannot only achieve F-number matching but suppress stray radiation sufficiently. Besides, it is demonstrated that the theory of spherical warm shield design developed in this paper is valid and can be employed by arbitrary infrared imaging systems.

  3. Global warming and prairie wetlands: potential consequences for waterfowl habitat

    Science.gov (United States)

    Poiani, Karen A.; Johnson, W. Carter

    1991-01-01

    The accumulation of greenhouse gasses in the atmosphere is expected to warm the earth's climate at an unprecedented rate (Ramanathan 1988, Schneider 1989). If the climate models are correct, within 100 years the earth will not only be warmer than it has been during the past million years, but the change will have occurred more rapidly than any on record. Many profound changes in the earth's environment are expected, including rising sea level, increasing aridity in continental interiors, and melting permafrost. Ecosystems are expected to respond variously to a rapidly changing climate. Tree ranges in eastern North American are expected to shift northward, and seed dispersal may not be adequate to maintain current diversity (Cohn 1989, Johnson and Webb 1989). In coastal wetlands, rising sea level from melting icecaps and thermal expansion could flood salt-grass marshes and generally reduce the size and productivity of the intertidal zone (Peters and Darling 1985). As yet, little attention has been given to the possible effects of climatic warming on inland prairie wetland ecosystems. These wetlands, located in the glaciated portion of the North American Great Plains (Figure 1), constitute the single most important breeding area for waterfowl on this continent (Hubbard 1988). This region annually produces 50-80% of the continent's total duck production (Batt et al. 1989). These marshes also support a variety of other wildlife, including many species of nongame birds, muskrat, and mink (Kantrud et al. 1989a). Prairie wetlands are relatively shallow, water-holding depressions that vary in size, water permanence, and water chemistry. Permanence types include temporary ponds (typically holding water for a few weeks in the springs), seasonal ponds (holding water from spring until early summer), semipermanent ponds (holding water throughout the growing season during most years), and large permanent lakes (Stewart and Kantrud 1971). Refilling usually occurs in spring from

  4. The thermal instability of the warm absorber in NGC 3783

    Science.gov (United States)

    Goosmann, R. W.; Holczer, T.; Mouchet, M.; Dumont, A.-M.; Behar, E.; Godet, O.; Gonçalves, A. C.; Kaspi, S.

    2016-05-01

    Context. The X-ray absorption spectra of active galactic nuclei frequently show evidence of winds with velocities in the order of 103 km s-1 extending up to 104 km s-1 in the case of ultra-fast outflows. At moderate velocities, these winds are often spectroscopically explained by assuming a number of absorbing clouds along the line of sight. In some cases it was shown that the absorbing clouds are in pressure equilibrium with each other. Aims: We assume a photo-ionized medium with a uniform total (gas+radiation) pressure. The irradiation causes the wind to be radiation pressure compressed (RPC). We attempt to reproduce the observed spectral continuum shape, ionic column densities, and X-ray absorption measure distribution (AMD) of the extensively observed warm absorber in the Seyfert galaxy NGC 3783. Methods: We compare the observational characteristics derived from the 900 ks Chandra observation to radiative transfer computations in pressure equilibrium using the radiative transfer code titan. We explore different values of the ionization parameter ξ of the incident flux and adjust the hydrogen-equivalent column density, NH0, of the warm absorber to match the observed soft X-ray continuum. From the resulting models we derive the column densities for a broad range of ionic species of iron and neon and a theoretical AMD that we compare to the observations. Results: We find an extension of the degeneracy between ξ and NH0 for the constant pressure models previously discussed for NGC 3783. Including the ionic column densities of iron and neon in the comparison between observations and data we conclude that a range of ionization parameters between 4000 and 8000 erg cm s-1 is preferred. For the first time, we present theoretical AMDs for a constant pressure wind in NGC 3783 that correctly reproduces the observed level and is in approximate agreement with the observational appearance of an instability region. Conclusions: Using a variety of observational indicators, we

  5. Temperature Deviations in the Midlatitude Mesosphere During Stratospheric Warmings as Measured with Rayleigh-Scatter Lidar

    Directory of Open Access Journals (Sweden)

    Sox Leda

    2016-01-01

    Full Text Available While mesospheric temperature anomalies associated with Sudden Stratospheric Warmings (SSWs have been observed extensively in the polar regions, observations of these anomalies at midlatitudes are sparse. The original Rayleigh-scatter lidar that operated at the Atmospheric Lidar Observatory (ALO; 41.7°N, 111.8°W in the Center for Atmospheric and Space Sciences (CASS on the campus of Utah State University (USU collected an extensive set of temperature data for 11 years in the 45–90 km altitude range. This work focuses on the extensive Rayleigh lidar observations made during six major SSW events that occurred between 1993 and 2004, providing a climatological study of the midlatitude mesospheric temperatures during these SSW events. An overall disturbance pattern was observed in the mesospheric temperatures during these SSWs. It included coolings in the upper mesosphere, comparable to those seen in the polar regions during SSW events, and warmings in the lower mesosphere.

  6. A Robust Response of Precipitation to Global Warming from CMIP5 Models

    Science.gov (United States)

    Lau, K. -M.; Wu, H. -T.; Kim, K. -M.

    2012-01-01

    How precipitation responds to global warming is a major concern to society and a challenge to climate change research. Based on analyses of rainfall probability distribution functions of 14 state-of-the-art climate models, we find a robust, canonical global rainfall response to a triple CO2 warming scenario, featuring 100 250% more heavy rain, 5-10% less moderate rain, and 10-15% more very light or no-rain events. Regionally, a majority of the models project a consistent response with more heavy rain events over climatologically wet regions of the deep tropics, and more dry events over subtropical and tropical land areas. Results suggest that increased CO2 emissions induce basic structural changes in global rain systems, increasing risks of severe floods and droughts in preferred geographic locations worldwide.

  7. Permafrost carbon-climate feedbacks accelerate global warming.

    Science.gov (United States)

    Koven, Charles D; Ringeval, Bruno; Friedlingstein, Pierre; Ciais, Philippe; Cadule, Patricia; Khvorostyanov, Dmitry; Krinner, Gerhard; Tarnocai, Charles

    2011-09-06

    Permafrost soils contain enormous amounts of organic carbon, which could act as a positive feedback to global climate change due to enhanced respiration rates with warming. We have used a terrestrial ecosystem model that includes permafrost carbon dynamics, inhibition of respiration in frozen soil layers, vertical mixing of soil carbon from surface to permafrost layers, and CH(4) emissions from flooded areas, and which better matches new circumpolar inventories of soil carbon stocks, to explore the potential for carbon-climate feedbacks at high latitudes. Contrary to model results for the Intergovernmental Panel on Climate Change Fourth Assessment Report (IPCC AR4), when permafrost processes are included, terrestrial ecosystems north of 60°N could shift from being a sink to a source of CO(2) by the end of the 21st century when forced by a Special Report on Emissions Scenarios (SRES) A2 climate change scenario. Between 1860 and 2100, the model response to combined CO(2) fertilization and climate change changes from a sink of 68 Pg to a 27 + -7 Pg sink to 4 + -18 Pg source, depending on the processes and parameter values used. The integrated change in carbon due to climate change shifts from near zero, which is within the range of previous model estimates, to a climate-induced loss of carbon by ecosystems in the range of 25 + -3 to 85 + -16 Pg C, depending on processes included in the model, with a best estimate of a 62 + -7 Pg C loss. Methane emissions from high-latitude regions are calculated to increase from 34 Tg CH(4)/y to 41-70 Tg CH(4)/y, with increases due to CO(2) fertilization, permafrost thaw, and warming-induced increased CH(4) flux densities partially offset by a reduction in wetland extent.

  8. Warm dense mater: another application for pulsed power hydrodynamics

    Energy Technology Data Exchange (ETDEWEB)

    Reinovsky, Robert Emil [Los Alamos National Laboratory

    2009-01-01

    Pulsed Power Hydrodynamics (PPH) is an application of low-impedance pulsed power, and high magnetic field technology to the study of advanced hydrodynamic problems, instabilities, turbulence, and material properties. PPH can potentially be applied to the study of the properties of warm dense matter (WDM) as well. Exploration of the properties of warm dense matter such as equation of state, viscosity, conductivity is an emerging area of study focused on the behavior of matter at density near solid density (from 10% of solid density to slightly above solid density) and modest temperatures ({approx}1-10 eV). Conditions characteristic of WDM are difficult to obtain, and even more difficult to diagnose. One approach to producing WDM uses laser or particle beam heating of very small quantities of matter on timescales short compared to the subsequent hydrodynamic expansion timescales (isochoric heating) and a vigorous community of researchers are applying these techniques. Pulsed power hydrodynamic techniques, such as large convergence liner compression of a large volume, modest density, low temperature plasma to densities approaching solid density or through multiple shock compression and heating of normal density material between a massive, high density, energetic liner and a high density central 'anvil' are possible ways to reach relevant conditions. Another avenue to WDM conditions is through the explosion and subsequent expansion of a conductor (wire) against a high pressure (density) gas background (isobaric expansion) techniques. However, both techniques demand substantial energy, proper power conditioning and delivery, and an understanding of the hydrodynamic and instability processes that limit each technique. In this paper we will examine the challenges to pulsed power technology and to pulsed power systems presented by the opportunity to explore this interesting region of parameter space.

  9. Recently amplified arctic warming has contributed to a continual global warming trend

    Science.gov (United States)

    Huang, Jianbin; Zhang, Xiangdong; Zhang, Qiyi; Lin, Yanluan; Hao, Mingju; Luo, Yong; Zhao, Zongci; Yao, Yao; Chen, Xin; Wang, Lei; Nie, Suping; Yin, Yizhou; Xu, Ying; Zhang, Jiansong

    2017-12-01

    The existence and magnitude of the recently suggested global warming hiatus, or slowdown, have been strongly debated1-3. Although various physical processes4-8 have been examined to elucidate this phenomenon, the accuracy and completeness of observational data that comprise global average surface air temperature (SAT) datasets is a concern9,10. In particular, these datasets lack either complete geographic coverage or in situ observations over the Arctic, owing to the sparse observational network in this area9. As a consequence, the contribution of Arctic warming to global SAT changes may have been underestimated, leading to an uncertainty in the hiatus debate. Here, we constructed a new Arctic SAT dataset using the most recently updated global SATs2 and a drifting buoys based Arctic SAT dataset11 through employing the `data interpolating empirical orthogonal functions' method12. Our estimate of global SAT rate of increase is around 0.112 °C per decade, instead of 0.05 °C per decade from IPCC AR51, for 1998-2012. Analysis of this dataset shows that the amplified Arctic warming over the past decade has significantly contributed to a continual global warming trend, rather than a hiatus or slowdown.

  10. Acting green elicits a literal warm glow

    Science.gov (United States)

    Taufik, Danny; Bolderdijk, Jan Willem; Steg, Linda

    2015-01-01

    Environmental policies are often based on the assumption that people only act environmentally friendly if some extrinsic reward is implicated, usually money. We argue that people might also be motivated by intrinsic rewards: doing the right thing (such as acting environmentally friendly) elicits psychological rewards in the form of positive feelings, a phenomenon known as warm glow. Given the fact that people's psychological state may affect their thermal state, we expected that this warm glow could express itself quite literally: people who act environmentally friendly may perceive the temperature to be higher. In two studies, we found that people who learned they acted environmentally friendly perceived a higher temperature than people who learned they acted environmentally unfriendly. The underlying psychological mechanism pertains to the self-concept: learning you acted environmentally friendly signals to yourself that you are a good person. Together, our studies show that acting environmentally friendly can be psychologically rewarding, suggesting that appealing to intrinsic rewards can be an alternative way to encourage pro-environmental actions.

  11. Global warming potential impact of bioenergy systems

    Directory of Open Access Journals (Sweden)

    Wenzel H.

    2012-10-01

    Full Text Available Reducing dependence on fossil fuels and mitigation of GHG emissions is a main focus in the energy strategy of many Countries. In the case of Demark, for instance, the long-term target of the energy policy is to reach 100% renewable energy system. This can be achieved by drastic reduction of the energy demand, optimization of production/distribution and substitution of fossil fuels with biomasses. However, a large increase in biomass consumption will finally induce conversion of arable and currently cultivated land into fields dedicated to energy crops production determining significant environmental consequences related to land use changes. In this study the global warming potential impact associated with six alternative bioenergy systems based on willow and Miscanthus was assessed by means of life-cycle assessment. The results showed that bioenergy production may generate higher global warming impacts than the reference fossil fuel system, when the impacts from indirect land use changes are accounted for. In a life-cycle perspective, only highly-efficient co-firing with fossil fuel achieved a (modest GHG emission reduction.

  12. Soil crusts to warm the planet

    Science.gov (United States)

    Garcia-Pichel, Ferran; Couradeau, Estelle; Karaoz, Ulas; da Rocha Ulisses, Nunes; Lim Hsiao, Chiem; Northen, Trent; Brodie, Eoin

    2016-04-01

    Soil surface temperature, an important driver of terrestrial biogeochemical processes, depends strongly on soil albedo, which can be significantly modified by factors such as plant cover. In sparsely vegetated lands, the soil surface can also be colonized by photosynthetic microbes that build biocrust communities. We used concurrent physical, biochemical and microbiological analyses to show that mature biocrusts can increase surface soil temperature by as much as 10 °C through the accumulation of large quantities of a secondary metabolite, the microbial sunscreen scytonemin, produced by a group of late-successional cyanobacteria. Scytonemin accumulation decreases soil albedo significantly. Such localized warming had apparent and immediate consequences for the crust soil microbiome, inducing the replacement of thermosensitive bacterial species with more thermotolerant forms. These results reveal that not only vegetation but also microorganisms are a factor in modifying terrestrial albedo, potentially impacting biosphere feedbacks on past and future climate, and call for a direct assessment of such effects at larger scales. Based on estimates of the global biomass of cyanobacteria in soil biocrusts, one can easily calculate that there must currently exist about 15 million metric tons of scytonemin at work, warming soil surfaces worldwide

  13. Impact of biofuels on contrail warming

    Science.gov (United States)

    Caiazzo, Fabio; Agarwal, Akshat; Speth, Raymond L.; Barrett, Steven R. H.

    2017-11-01

    Contrails and contrail-cirrus may be the largest source of radiative forcing (RF) attributable to aviation. Biomass-derived alternative jet fuels are a potentially major way to mitigate the climate impacts of aviation by reducing lifecycle CO2 emissions. Given the up to 90% reduction in soot emissions from paraffinic biofuels, the potential for a significant impact on contrail RF due to the reduction in contrail-forming ice nuclei (IN) remains an open question. We simulate contrail formation and evolution to quantify RF over the United States under different emissions scenarios. Replacing conventional jet fuels with paraffinic biofuels generates two competing effects. First, the higher water emissions index results in an increase in contrail occurrence (~ +8%). On the other hand, these contrails are composed of larger diameter crystals (~ +58%) at lower number concentrations (~ ‑75%), reducing both contrail optical depth (~ ‑29%) and albedo (~ ‑32%). The net changes in contrail RF induced by switching to biofuels range from ‑4% to +18% among a range of assumed ice crystal habits (shapes). In comparison, cleaner burning engines (with no increase in water emissions index) result in changes to net contrail RF ranging between ‑13% and +5% depending on habit. Thus, we find that even 67% to 75% reductions in aircraft soot emissions are insufficient to substantially reduce warming from contrails, and that the use of biofuels may either increase or decrease contrail warming—contrary to previous expectations of a significant decrease in warming.

  14. Identifying the Molecular Origin of Global Warming

    Science.gov (United States)

    Bera, Partha P.; Francisco, Joseph S.; Lee, Timothy J.

    2009-01-01

    We have investigated the physical characteristics of greenhouse gases (GHGs) to assess which properties are most important in determining the efficiency of a GHG. Chlorofluorcarbons (CFCs), hydrofluorocarbons (HFCs), perfluorocarbons (PFCs), nitrogen fluorides, and various other known atmospheric trace molecules have been included in this study. Compounds containing the halogens F or Cl have in common very polar X-F or X-Cl bonds, particularly the X-F bonds. It is shown that as more F atoms bond to the same central atom, the bond dipoles become larger as a result of the central atom becoming more positive. This leads to a linear increase in the total or integrated XF bond dipole derivatives for the molecule, which leads to a non-linear (quadratic) increase in infrared (IR) intensity. Moreover, virtually all of the X-F bond stretches occur in the atmospheric IR window as opposed to X-H stretches, which do not occur in the atmospheric window. It is concluded that molecules possessing several F atoms will always have a large radiative forcing parameter in the calculation of their global warming potential. Some of the implications for global warming and climate change are discussed.

  15. Asymmetric effects of daytime and night-time warming on Northern Hemisphere vegetation.

    Science.gov (United States)

    Peng, Shushi; Piao, Shilong; Ciais, Philippe; Myneni, Ranga B; Chen, Anping; Chevallier, Frédéric; Dolman, Albertus J; Janssens, Ivan A; Peñuelas, Josep; Zhang, Gengxin; Vicca, Sara; Wan, Shiqiang; Wang, Shiping; Zeng, Hui

    2013-09-05

    Temperature data over the past five decades show faster warming of the global land surface during the night than during the day. This asymmetric warming is expected to affect carbon assimilation and consumption in plants, because photosynthesis in most plants occurs during daytime and is more sensitive to the maximum daily temperature, Tmax, whereas plant respiration occurs throughout the day and is therefore influenced by both Tmax and the minimum daily temperature, Tmin. Most studies of the response of terrestrial ecosystems to climate warming, however, ignore this asymmetric forcing effect on vegetation growth and carbon dioxide (CO2) fluxes. Here we analyse the interannual covariations of the satellite-derived normalized difference vegetation index (NDVI, an indicator of vegetation greenness) with Tmax and Tmin over the Northern Hemisphere. After removing the correlation between Tmax and Tmin, we find that the partial correlation between Tmax and NDVI is positive in most wet and cool ecosystems over boreal regions, but negative in dry temperate regions. In contrast, the partial correlation between Tmin and NDVI is negative in boreal regions, and exhibits a more complex behaviour in dry temperate regions. We detect similar patterns in terrestrial net CO2 exchange maps obtained from a global atmospheric inversion model. Additional analysis of the long-term atmospheric CO2 concentration record of the station Point Barrow in Alaska suggests that the peak-to-peak amplitude of CO2 increased by 23 ± 11% for a +1 °C anomaly in Tmax from May to September over lands north of 51° N, but decreased by 28 ± 14% for a +1 °C anomaly in Tmin. These lines of evidence suggest that asymmetric diurnal warming, a process that is currently not taken into account in many global carbon cycle models, leads to a divergent response of Northern Hemisphere vegetation growth and carbon sequestration to rising temperatures.

  16. Agave as a model CAM crop system for a warming and drying world

    OpenAIRE

    J. Ryan eStewart

    2015-01-01

    As climate change leads to drier and warmer conditions in semi-arid regions, growing resource-intensive C3 and C4 crops will become more challenging. Such crops will be subjected to increased frequency and intensity of drought and heat stress. However, agaves, even more than pineapple (Ananas comosus) and prickly pear (Opuntia ficus-indica and related species), typify highly productive plants that will respond favorably to global warming, both in natural and cultivated settings. With nearly 2...

  17. Ocean Depths: The Mesopelagic and Implications for Global Warming.

    Science.gov (United States)

    Costello, Mark J; Breyer, Sean

    2017-01-09

    The mesopelagic or 'twilight zone' of the oceans occurs too deep for photosynthesis, but is a major part of the world's carbon cycle. Depth boundaries for the mesopelagic have now been shown on a global scale using the distribution of pelagic animals detected by compiling echo-soundings from ships around the world, and been used to predict the effect of global warming on regional fish production. Copyright © 2017 Elsevier Ltd. All rights reserved.

  18. The characterization of wind anomalies over ukraine in warm half-year

    Directory of Open Access Journals (Sweden)

    Галина Петрівна Івус

    2016-07-01

    Full Text Available Features of formation conditions of low-level jet streams over the territory of Ukraine in a warm half (from April to September of 2001-2007 years on the example of eight radio-sounding points in different regions of the state are characterized. The basic structural parameters of the low jets are analyzed and their differences relative to previous periods considering the quality of the modern initial information are discovered

  19. Implications of 2 °C global warming in European summer tourism

    OpenAIRE

    Manolis G. Grillakis; Koutroulis, Aristeidis G.; Seiradakis, Konstantinos D.; Tsanis, Ioannis K.

    2016-01-01

    Tourism is highly dependent on the climatic conditions of a given destination. This study examines the impact of two degrees global warming on European summer tourism from a climate comfort perspective. The changes in summer tourism climate comfort are realized with the aid of the Tourism Climatic Index (TCI). Four ENSEMBLES Regional Climate Models (RCMs) provided the data for Europe under the A1B emission scenario that are used in the analysis of potential changes in tourism favorability. Re...

  20. Impacts of +2 °C global warming on winter tourism demand in Europe

    OpenAIRE

    Damm, Andrea; Greuell, Wouter; Landgren, Oskar; Prettenthaler, Franz

    2017-01-01

    Increasing temperatures and snow scarce winter seasons challenge the winter tourism industry. In this study the impacts of +2 °C global warming on winter tourism demand in Europe’s ski tourism related NUTS-3 regions are quantified. Using time series regression models, the relationship between natural snow conditions and monthly overnight stays is estimated. Based on these model results, we quantify the risk of tourism demand losses due to weather variability and assess the potential impacts o...

  1. El Niño Southern Oscillation (ENSO and global warming

    Directory of Open Access Journals (Sweden)

    B. Nyenzi

    2006-01-01

    Full Text Available It is widely accepted by the international scientific community that human activities have increased atmospheric concentrations of greenhouse gases (GHG and aerosols since the pre-industrial era. This increase has contributed to most of the warming (0.6±0.2°C observed over the 20th century, land areas warming more than the oceans, with the 1990s very likely to be the warmest decade of the 20th century (IPCC, 2001. How this warming influences the occurrence, severity and frequency of ENSO episodes remains highly uncertain. The IPCC (2001 assessment of the scientific literature found insufficient evidence to suggest any direct attribution between increase in ENSO events that occurred in the last 20 to 30 years of the 20th century and global warming (IPCC, 2001. However, assessments carried out since then (e.g. IPCC Fourth Assessment Report (AR4, in preparations suggest El Niño events have become more frequent, persistent and intense during the last 20 to 30 years compared to the previous 100 years. Attribution to global warming, however, remains highly uncertain. Efforts to simulate and model past, present and future behaviour of ENSO under a warming world due to enhanced GHG concentrations produce conflicting results. Since substantial internally-generated variability of ENSO behaviour on multi-decadal to century timescales occurs in long, unforced atmospheric-oceanic general circulation model (AOGCM simulations, the attribution of past and future changes in ENSO amplitude and frequency to external forcing like GHG concentrations cannot be made with certainty. Such attribution would require extensive use of ensemble climate experiments or long experiments with stabilised GHG forcing. Although there are now better ENSO simulations in AOGCM, further model improvements are needed to simulate a more realistic Pacific climatology and seasonal cycle of the key modes influencing the climate of the region, as well as more realistic ENSO variability

  2. Large benefits to marine fisheries of meeting the 1.5°C global warming target.

    Science.gov (United States)

    Cheung, William W L; Reygondeau, Gabriel; Frölicher, Thomas L

    2016-12-23

    Translating the Paris Agreement to limit global warming to 1.5°C above preindustrial level into impact-related targets facilitates communication of the benefits of mitigating climate change to policy-makers and stakeholders. Developing ecologically relevant impact-related targets for marine ecosystem services, such as fisheries, is an important step. Here, we use maximum catch potential and species turnover as climate-risk indicators for fisheries. We project that potential catches will decrease by more than 3 million metric tons per degree Celsius of warming. Species turnover is more than halved when warming is lowered from 3.5° to 1.5°C above the preindustrial level. Regionally, changes in maximum catch potential and species turnover vary across ecosystems, with the biggest risk reduction in the Indo-Pacific and Arctic regions when the Paris Agreement target is achieved. Copyright © 2016, American Association for the Advancement of Science.

  3. Warming-induced shift towards forbs and grasses and its relation to the carbon sequestration in an alpine meadow

    Science.gov (United States)

    Peng, Fei; Xue, Xian; Xu, Manhou; You, Quangang; Jian, Guo; Ma, Shaoxiu

    2017-04-01

    Global warming is often associated with changes in abiotic factors and the community composition across alpine ecosystems. However, the way that an altered community dynamics affects the ecosystem carbon (C) balance remains unclear. A warming experiment was initiated in 2010 to assess the potential impacts of warming-induced changes in the community composition and how these changes affect the C balance in mountain meadows located in the permafrost region of the Qinghai-Tibet Plateau (China). Under warming conditions, we found an increased importance value (IV) of forbs and grasses of 4.9%, in contrast to the IV of sedges, which decreased by 4.4%. For forbs and grasses, the IV showed positive exponential relationships with gross ecosystem production and ecosystem respiration, while negative correlations were found for sedges. These results indicate that a slight change in the IVs of sedges, grasses and forbs favors C sequestration. Moreover, the warming treatment significantly increased the mean height of sedges, grasses and forbs, and the net ecosystem exchange increase was positively correlated with the increase in the mean height of grasses and forbs. In summary, the warming-induced shift toward forb and grass species and the increase in plant height strengthen the C uptake capacity of alpine meadow ecosystems.

  4. Temperature-induced water stress in high-latitude forests in response to natural and anthropogenic warming.

    Science.gov (United States)

    Trahan, Matthew W; Schubert, Brian A

    2016-02-01

    The Arctic is particularly sensitive to climate change, but the independent effects of increasing atmospheric CO2 concentration (pCO2 ) and temperature on high-latitude forests are poorly understood. Here, we present a new, annually resolved record of stable carbon isotope (δ(13) C) data determined from Larix cajanderi tree cores collected from far northeastern Siberia in order to investigate the physiological response of these trees to regional warming. The tree-ring record, which extends from 1912 through 1961 (50 years), targets early twentieth-century warming (ETCW), a natural warming event in the 1920s to 1940s that was limited to Northern hemisphere high latitudes. Our data show that net carbon isotope fractionation (Δ(13) C), decreased by 1.7‰ across the ETCW, which is consistent with increased water stress in response to climate warming and dryer soils. To investigate whether this signal is present across the northern boreal forest, we compiled published carbon isotope data from 14 high-latitude sites within Europe, Asia, and North America. The resulting dataset covered the entire twentieth century and spanned both natural ETCW and anthropogenic Late Twentieth-Century Warming (~0.7 °C per decade). After correcting for a ~1‰ increase in Δ(13) C in response to twentieth century pCO2 rise, a significant negative relationship (r = -0.53, P warming and pCO2 rise across the twentieth century. © 2015 John Wiley & Sons Ltd.

  5. Global warming mitigation by sulphur loading in the stratosphere: dependence of required emissions on allowable residual warming rate

    Science.gov (United States)

    Eliseev, Alexey V.; Chernokulsky, Alexandr V.; Karpenko, Andrey A.; Mokhov, Igor I.

    2010-07-01

    An approach to mitigate global warming via sulphur loading in the stratosphere (geoengineering) is studied, employing a large ensemble of numerical experiments with the climate model of intermediate complexity IAP RAS CM. The model is forced by the historical+SRES A1B anthropogenic greenhouse gases+tropospheric sulphates scenario for 1860-2100 with additional sulphur emissions in the stratosphere in the twenty-first century. Different ensemble members are constructed by varying values of the parameters governing mass, horizontal distribution and radiative forcing of the stratospheric sulphates. It is obtained that, given a global loading of the sulphates in the stratosphere, among those studied in this paper latitudinal distributions of geoengineering aerosols, the most efficient one at the global basis is that peaked between 50° N and 70° N and with a somewhat smaller burden in the tropics. Uniform latitudinal distribution of stratospheric sulphates is a little less efficient. Sulphur emissions in the stratosphere required to stop the global temperature at the level corresponding to the mean value for 2000-2010 amount to more than 10 TgS/year in the year 2100. These emissions may be reduced if some warming is allowed to occur in the twenty-first century. For instance, if the global temperature trend S g in every decade of this century is limited not to exceed 0.10 K/decade (0.15 K/decade), geoengineering emissions of 4-14 TgS/year (2-7 TgS/year) would be sufficient. Even if the global warming is stopped, temperature changes in different regions still occur with a magnitude up to 1 K. Their horizontal pattern depends on implied latitudinal distribution of stratospheric sulphates. In addition, for the stabilised global mean surface air temperature, global precipitation decreases by about 10%. If geoengineering emissions are stopped after several decades of implementation, their climatic effect is removed within a few decades. In this period, surface air

  6. Ocean acidification ameliorates harmful effects of warming in primary consumer.

    Science.gov (United States)

    Pedersen, Sindre Andre; Hanssen, Anja Elise

    2018-01-01

    Climate change-induced warming and ocean acidification are considered two imminent threats to marine biodiversity and current ecosystem structures. Here, we have for the first time examined an animal's response to a complete life cycle of exposure to co-occurring warming (+3°C) and ocean acidification (+1,600 μatm CO 2 ), using the key subarctic planktonic copepod, Calanus finmarchicus , as a model species. The animals were generally negatively affected by warming, which significantly reduced the females' energy status and reproductive parameters (respectively, 95% and 69%-87% vs. control). Unexpectedly, simultaneous acidification partially offset the negative effect of warming in an antagonistic manner, significantly improving reproductive parameters and hatching success (233%-340% improvement vs. single warming exposure). The results provide proof of concept that ocean acidification may partially offset negative effects caused by warming in some species. Possible explanations and ecological implications for the observed antagonistic effect are discussed.

  7. Microbial communities respond to experimental warming, but site matters.

    Science.gov (United States)

    Cregger, Melissa A; Sanders, Nathan J; Dunn, Robert R; Classen, Aimée T

    2014-01-01

    Because microorganisms are sensitive to temperature, ongoing global warming is predicted to influence microbial community structure and function. We used large-scale warming experiments established at two sites near the northern and southern boundaries of US eastern deciduous forests to explore how microbial communities and their function respond to warming at sites with differing climatic regimes. Soil microbial community structure and function responded to warming at the southern but not the northern site. However, changes in microbial community structure and function at the southern site did not result in changes in cellulose decomposition rates. While most global change models rest on the assumption that taxa will respond similarly to warming across sites and their ranges, these results suggest that the responses of microorganisms to warming may be mediated by differences across the geographic boundaries of ecosystems.

  8. [Startup mechanism of moxibustion warming and dredging function].

    Science.gov (United States)

    Huang, Kaiyu; Liang, Shuang; Sun, Zheng; Zhang, Jianbin

    2017-09-12

    With "moxibustion" and "warm stimulation" as the keywords, the literature on moxibustion mechanism of warming and dredging from June 1st, 1995 to June 1st, 2016 was collected from PubMed, China National Knowledge Infrastructure (CNKI) and Wanfang database. The startup mechanism of moxibustion warming and dredging function was analyzed in terms of moxibustion warming stimulation. The results were found that moxibustion was based on local rising temperature of acupoint. It activated local specific receptors, heat sensitive immune cells, heat shock proteins and so on to start the warming and dredging function and produce various local effects. The warming stimulation signals as well as subsequent effects through nerve and body fluid pathways induced the effects of further specific target organs and body systems.

  9. Microbial communities respond to experimental warming, but site matters

    Directory of Open Access Journals (Sweden)

    Melissa A. Cregger

    2014-04-01

    Full Text Available Because microorganisms are sensitive to temperature, ongoing global warming is predicted to influence microbial community structure and function. We used large-scale warming experiments established at two sites near the northern and southern boundaries of US eastern deciduous forests to explore how microbial communities and their function respond to warming at sites with differing climatic regimes. Soil microbial community structure and function responded to warming at the southern but not the northern site. However, changes in microbial community structure and function at the southern site did not result in changes in cellulose decomposition rates. While most global change models rest on the assumption that taxa will respond similarly to warming across sites and their ranges, these results suggest that the responses of microorganisms to warming may be mediated by differences across the geographic boundaries of ecosystems.

  10. Effects of Warming on Tree Species’ Recruitment in Deciduous Forests of the Eastern United States

    Energy Technology Data Exchange (ETDEWEB)

    Melillo, Jerry M. [Marine Biological Lab., Woods Hole, MA (United States); Clark, James S. [Duke Univ., Durham, NC (United States); Mohan, Jacqueline [Univ. of Georgia, Athens, GA (United States)

    2015-03-25

    Climate change is restructuring forests of the United States, although the details of this restructuring are currently uncertain. Rising temperatures of 2 to 8oC and associated changes in soil moisture will shift the competitive balance between species that compete for light and water, and so change their abilities to produce seed, germinate, grow, and survive. We have used large-scale experiments to determine the effects of warming on the most sensitive stage of species distributions, i.e., recruitment, in mixed deciduous forests in southern New England and in the Piedmont region of North Carolina. Two questions organized our research: (1) Might temperate tree species near the “warm” end of their range in the eastern United States decline in abundance during the coming century due to projected warming? and (2) Might trees near the “cool” end of their range in the eastern United States increase in abundance, or extend their range, during the coming 100 years because of projected warming? To explore these questions, we exposed seedlings to air and soil warming experiments in two eastern deciduous forest sites; one at the Harvard Forest (HF) in central Massachusetts, and the other at the Duke Forest (DF) in the Piedmont region of North Carolina. We focused on tree species common to both Harvard and Duke Forests (such as red, black, and white oaks), those near northern range limits (black oak, flowing dogwood, tulip poplar), and those near southern range limits (yellow birch, sugar maple, Virginia pine). At each site, we planted seeds and seedlings in common gardens established in temperature-controlled, open-top chambers. The experimental design was replicated and fully factorial and involved three temperature regimes (ambient, +3oC and +5oC) and two light regimes (closed forest canopy (low light) and gap conditions (high light)). Measured variables included Winter/Spring responses to temperature and mid-Summer responses to low soil moisture. This research

  11. Observed changes in seasonal heat waves and warm temperature extremes in the Romanian Carpathians

    Science.gov (United States)

    Micu, Dana; Birsan, Marius-Victor; Dumitrescu, Alexandru; Cheval, Sorin

    2015-04-01

    Extreme high temperature have a large impact on environment and human activities, especially in high elevation areas particularly sensitive to the recent climate warming. The climate of the Romanian Carpathians became warmer particularly in winter, spring and summer, exibiting a significant increasing frequency of warm extremes. The paper investigates the seasonal changes in the frequency, duration and intensity of heat waves in relation to the shifts in the daily distribution of maximum temperatures over a 50-year period of meteorological observations (1961-2010). The paper uses the heat wave definition recommended by the Expert Team on Climate Change Detection and Indices (ETCCDI) and exploits the gridded daily dataset of maximum temperature at 0.1° resolution (~10 km) developed in the framework of the CarpatClim project (www.carpatclim.eu). The seasonal changes in heat waves behavior were identified using the Mann-Kendall non-parametric trend test. The results suggest an increase in heat wave frequency and a lengthening of intervals affected by warm temperature extremes all over the study region, which are explained by the shifts in the upper (extreme) tail of the daily maximum temperature distribution in most seasons. The trends are consistent across the region and are well correlated to the positive phases of the East Atlantic Oscillation. Our results are in good agreement with the previous temperature-related studies concerning the Carpathian region. This study was realized within the framework of the project GENCLIM, financed by UEFISCDI, code PN-II 151/2014.

  12. Response of snow-dependent hydrologic extremes to continued global warming.

    Science.gov (United States)

    Diffenbaugh, Noah S; Scherer, Martin; Ashfaq, Moetasim

    2013-04-01

    Snow accumulation is critical for water availability in the northern hemisphere 1,2, raising concern that global warming could have important impacts on natural and human systems in snow-dependent regions 1,3. Although regional hydrologic changes have been observed (e.g., 1,3-5), the time of emergence of extreme changes in snow accumulation and melt remains a key unknown for assessing climate change impacts 3,6,7. We find that the CMIP5 global climate model ensemble exhibits an imminent shift towards low snow years in the northern hemisphere, with areas of western North America, northeastern Europe, and the Greater Himalaya showing the strongest emergence during the near-term decades and at 2°C global warming. The occurrence of extremely low snow years becomes widespread by the late-21st century, as do the occurrence of extremely high early-season snowmelt and runoff (implying increasing flood risk), and extremely low late-season snowmelt and runoff (implying increasing water stress). Our results suggest that many snow-dependent regions of the northern hemisphere are likely to experience increasing stress from low snow years within the next three decades, and from extreme changes in snow-dominated