Integrating environmental and genetic effects to predict responses of tree populations to climate.

Science.gov (United States)

Wang, Tongli; O'Neill, Gregory A; Aitken, Sally N

2010-01-01

Climate is a major environmental factor affecting the phenotype of trees and is also a critical agent of natural selection that has molded among-population genetic variation. Population response functions describe the environmental effect of planting site climates on the performance of a single population, whereas transfer functions describe among-population genetic variation molded by natural selection for climate. Although these approaches are widely used to predict the responses of trees to climate change, both have limitations. We present a novel approach that integrates both genetic and environmental effects into a single "universal response function" (URF) to better predict the influence of climate on phenotypes. Using a large lodgepole pine (Pinus contorta Dougl. ex Loud.) field transplant experiment composed of 140 populations planted on 62 sites to demonstrate the methodology, we show that the URF makes full use of data from provenance trials to: (1) improve predictions of climate change impacts on phenotypes; (2) reduce the size and cost of future provenance trials without compromising predictive power; (3) more fully exploit existing, less comprehensive provenance tests; (4) quantify and compare environmental and genetic effects of climate on population performance; and (5) predict the performance of any population growing in any climate. Finally, we discuss how the last attribute allows the URF to be used as a mechanistic model to predict population and species ranges for the future and to guide assisted migration of seed for reforestation, restoration, or afforestation and genetic conservation in a changing climate.

A probabilistic model of ecosystem response to climate change

International Nuclear Information System (INIS)

Shevliakova, E.; Dowlatabadi, H.

1994-01-01

Anthropogenic activities are leading to rapid changes in land cover and emissions of greenhouse gases into the atmosphere. These changes can bring about climate change typified by average global temperatures rising by 1--5 C over the next century. Climate change of this magnitude is likely to alter the distribution of terrestrial ecosystems on a large scale. Options available for dealing with such change are abatement of emissions, adaptation, and geoengineering. The integrated assessment of climate change demands that frameworks be developed where all the elements of the climate problem are present (from economic activity to climate change and its impacts on market and non-market goods and services). Integrated climate assessment requires multiple impact metrics and multi-attribute utility functions to simulate the response of different key actors/decision-makers to the actual physical impacts (rather than a dollar value) of the climate-damage vs. policy-cost debate. This necessitates direct modeling of ecosystem impacts of climate change. The authors have developed a probabilistic model of ecosystem response to global change. This model differs from previous efforts in that it is statistically estimated using actual ecosystem and climate data yielding a joint multivariate probability of prevalence for each ecosystem, given climatic conditions. The authors expect this approach to permit simulation of inertia and competition which have, so far, been absent in transfer models of continental-scale ecosystem response to global change. Thus, although the probability of one ecotype will dominate others at a given point, others would have the possibility of establishing an early foothold

Climate engineering research : A precautionary response to climate change?

NARCIS (Netherlands)

Reynolds, J.L.; Fleurke, F.M.

2013-01-01

In the face of dire forecasts for anthropogenic climate change, climate engineering is increasingly discussed as a possible additional set of responses to reduce climate change’s threat. These proposals have been controversial, in part because they – like climate change itself – pose uncertain risks

The response of soil processes to climate change

DEFF Research Database (Denmark)

Emmett, B.A.; Beier, C.; Estiarte, M.

2004-01-01

Predicted changes in climate may affect key soil processes such as respiration and net nitrogen (N) mineralization and thus key ecosystem functions such as carbon (C) storage and nutrient availability. To identify the sensitivity of shrubland soils to predicted climate changes, we have carried out...... the environmental gradient with the results from the manipulation experiments provides evidence for strong climate controls on soil respiration, net N mineralization and nitrification, and litter decomposition. Trends of 0%-19% increases of soil respiration in response to warming and decreases of 3%-29% in response...... to drought were observed. Across the environmental gradient and below soil temperatures of 20degreesC at a depth of 5-10 cm, a mean Q(10) of 4.1 in respiration rates was observed although this varied from 2.4 to 7.0 between sites. Highest Q(10), values were observed in Spain and the UK and were therefore...

Climate Response of Tree Radial Growth at Different Timescales in the Qinling Mountains.

Directory of Open Access Journals (Sweden)

Changfeng Sun

Full Text Available The analysis of the tree radial growth response to climate is crucial for dendroclimatological research. However, the response relationships between tree-ring indices and climatic factors at different timescales are not yet clear. In this study, the tree-ring width of Huashan pine (Pinus armandii from Huashan in the Qinling Mountains, north-central China, was used to explore the response differences of tree growth to climatic factors at daily, pentad (5 days, dekad (10 days and monthly timescales. Correlation function and linear regression analysis were applied in this paper. The tree-ring width showed a more sensitive response to daily and pentad climatic factors. With the timescale decreasing, the absolute value of the maximum correlation coefficient between the tree-ring data and precipitation increases as well as temperature (mean, minimum and maximum temperature. Compared to the other three timescales, pentad was more suitable for analysing the response of tree growth to climate. Relative to the monthly climate data, the association between the tree-ring data and the pentad climate data was more remarkable and accurate, and the reconstruction function based on the pentad climate was also more reliable and stable. We found that the major climatic factor limiting Huashan pine growth was the precipitation of pentads 20-35 (from April 6 to June 24 rather than the well-known April-June precipitation. The pentad was also proved to be a better timescale for analysing the climate and tree growth in the western and eastern Qinling Mountains. The formation of the earlywood density of Chinese pine (Pinus tabulaeformis from Shimenshan in western Qinling was mainly affected by the maximum temperature of pentads 28-32 (from May 16 to June 9. The maximum temperature of pentads 28-33 (from May 16 to June 14 was the major factor affecting the ring width of Chinese pine from Shirenshan in eastern Qinling.

Climate variability slows evolutionary responses of Colias butterflies to recent climate change.

Science.gov (United States)

Kingsolver, Joel G; Buckley, Lauren B

2015-03-07

How does recent climate warming and climate variability alter fitness, phenotypic selection and evolution in natural populations? We combine biophysical, demographic and evolutionary models with recent climate data to address this question for the subalpine and alpine butterfly, Colias meadii, in the southern Rocky Mountains. We focus on predicting patterns of selection and evolution for a key thermoregulatory trait, melanin (solar absorptivity) on the posterior ventral hindwings, which affects patterns of body temperature, flight activity, adult and egg survival, and reproductive success in Colias. Both mean annual summer temperatures and thermal variability within summers have increased during the past 60 years at subalpine and alpine sites. At the subalpine site, predicted directional selection on wing absorptivity has shifted from generally positive (favouring increased wing melanin) to generally negative during the past 60 years, but there is substantial variation among years in the predicted magnitude and direction of selection and the optimal absorptivity. The predicted magnitude of directional selection at the alpine site declined during the past 60 years and varies substantially among years, but selection has generally been positive at this site. Predicted evolutionary responses to mean climate warming at the subalpine site since 1980 is small, because of the variability in selection and asymmetry of the fitness function. At both sites, the predicted effects of adaptive evolution on mean population fitness are much smaller than the fluctuations in mean fitness due to climate variability among years. Our analyses suggest that variation in climate within and among years may strongly limit evolutionary responses of ectotherms to mean climate warming in these habitats. © 2015 The Author(s) Published by the Royal Society. All rights reserved.

Climate change and functional traits affect population dynamics of a long-lived seabird.

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Jenouvrier, Stéphanie; Desprez, Marine; Fay, Remi; Barbraud, Christophe; Weimerskirch, Henri; Delord, Karine; Caswell, Hal

2018-07-01

Recent studies unravelled the effect of climate changes on populations through their impact on functional traits and demographic rates in terrestrial and freshwater ecosystems, but such understanding in marine ecosystems remains incomplete. Here, we evaluate the impact of the combined effects of climate and functional traits on population dynamics of a long-lived migratory seabird breeding in the southern ocean: the black-browed albatross (Thalassarche melanophris, BBA). We address the following prospective question: "Of all the changes in the climate and functional traits, which would produce the biggest impact on the BBA population growth rate?" We develop a structured matrix population model that includes the effect of climate and functional traits on the complete BBA life cycle. A detailed sensitivity analysis is conducted to understand the main pathway by which climate and functional trait changes affect the population growth rate. The population growth rate of BBA is driven by the combined effects of climate over various seasons and multiple functional traits with carry-over effects across seasons on demographic processes. Changes in sea surface temperature (SST) during late winter cause the biggest changes in the population growth rate, through their effect on juvenile survival. Adults appeared to respond to changes in winter climate conditions by adapting their migratory schedule rather than by modifying their at-sea foraging activity. However, the sensitivity of the population growth rate to SST affecting BBA migratory schedule is small. BBA foraging activity during the pre-breeding period has the biggest impact on population growth rate among functional traits. Finally, changes in SST during the breeding season have little effect on the population growth rate. These results highlight the importance of early life histories and carry-over effects of climate and functional traits on demographic rates across multiple seasons in population response to climate

Soil ecosystem functioning under climate change: plant species and community effects

Energy Technology Data Exchange (ETDEWEB)

Kardol, Paul [ORNL; Cregger, Melissa [ORNL; Campany, Courtney E [ORNL; Classen, Aimee T [ORNL

2010-01-01

Feedbacks of terrestrial ecosystems to climate change depend on soil ecosystem dynamics. Soil ecosystems can directly and indirectly respond to climate change. For example, warming directly alters microbial communities by increasing their activity. Climate change may also alter plant community composition, thus indirectly altering the microbial communities that feed on their inputs. To better understand how climate change may directly and indirectly alter soil ecosystem functioning, we investigated old-field plant community and soil ecosystem responses to single and combined effects of elevated [CO2], warming, and water availability. Specifically, we collected soils at the plot level (plant community soils), and beneath dominant plant species (plant-specific soils). We used microbial enzyme activities and soil nematodes as indicators for soil ecosystem functioning. Our study resulted in two main findings: 1) Overall, while there were some interactions, water, relative to increases in [CO2] and warming, had the largest impact on plant community composition, soil enzyme activities, and soil nematodes. Multiple climate change factors can interact to shape ecosystems, but in this case, those interactions were largely driven by changes in water availability. 2) Indirect effects of climate change, via changes in plant communities, had a significant impact on soil ecosystem functioning and this impact was not obvious when looking at plant community soils. Climate change effects on enzyme activities and soil nematode abundance and community structure strongly differed between plant community soils and plant-specific soils, but also within plant-specific soils. In sum, these results indicate that accurate assessments of climate change impacts on soil ecosystem functioning require incorporating the concurrent changes in plant function and plant community composition. Climate change-induced shifts in plant community composition will likely modify or counteract the direct

Ecological response of Cedrus atlantica to climate variability in the Massif of Guetiane (Algeria

Directory of Open Access Journals (Sweden)

Said Slimani

2014-12-01

Full Text Available Aim of the study: The study analyzes the long-term response of Atlas cedar, Cedrus atlantica (Manneti, to climate variability. Area of study: Atlas cedar forest of Guetiane (Batna, Algeria.Material and methods: The dendrochronological approach was adopted. An Atlas cedar tree-ring chronology was established from twenty trees. The response of the species to climate variability was assessed through the pointer years (PYs, the common climate signal among the individual chronologies, expressed by the first component (PC1, the mean sensitivity (msx, and response function and correlations analysis involving the tree-ring index and climate data (monthly mean temperature and total precipitation.Results: The highest growth variability was registered from the second half of the 20th century. The lower than the mean PYs, the PC1, and the msx increased markedly during the studied period. Dramatic increases in the PC1 and msx were detected at the end of the 1970s, reflecting a shift towards drier conditions enhancing an increasing trend towards more synchronous response of trees to climate conditions. The response function and correlations analysis showed that tree growth was mainly influenced by precipitation variability.Research highlights: Our findings provide baseline knowledge concerning the ecological response of Atlas cedar to climate variability in in its southern distribution limit, where a high level of tree mortality has been observed during recent decades, coinciding with the driest period Algeria has ever experienced. This information is vital to support ongoing ecosystem management efforts in the region. Keywords: Atlas cedar; annual growth variability; dieback; dendrochronology. 

Plant community responses to climate change

Energy Technology Data Exchange (ETDEWEB)

Kongstad, J.

2012-07-01

Climate change is expected to affect terrestrial ecosystems across the globe with increased atmospheric CO{sub 2} concentration, higher temperatures and changes in precipitation patterns. These environmental factors are drivers of many important ecosystem processes, and changes in ecosystem function are therefore expected in the future. The aim of this PhD-thesis was to examine the effects of climate change on aboveground plant growth, plant composition and plant phenology in Danish heathland ecosystems. Two sites were investigated in large-scale field experiments: 1) the CLIMAITE site, 'Brandbjerg' and 2) the INCREASE site at Mols. Field manipulations lasted years and included: Warming, summer drought and (CLIMAITE only) elevated CO{sub 2} concentrations. The treatments were applied individually and in all possible combinations. Further, at Brandbjerg, but outside the treatment plots, a study was performed on the effects nitrogen and phosphorus addition on phenology, chemistry and growth of the dominant grass Deschampsia flexuosa (Wavy Hairgrass). In general, the aboveground vegetation responded less than expected to changing climatic conditions; even though Calluna vulgaris (Heather) increased in biomass over the study period, the biomass was not affected by the manipulations, indicating that C. vulgaris, has a strong resistance to changes in climate. Also, the grass biomass (primarily D. flexuosa) was not affected and was relatively constant over the period. I argue that the resilience of D. flexuosa towards the climatic treatments came from the plants ability to let the tissue die back, and then quickly recover once conditions again became favourable. That gave the plant a high resilience to changes in climatic factors. Calluna vulgaris, on the other hand, showed a resistance to changes by constantly maintaining the growth during the whole season, probably because of its evergreen status. Together, the two different strategies made the heathland

Long-term ecophysiological responses to climate change

DEFF Research Database (Denmark)

Boesgaard, Kristine Stove; Ro-Poulsen, Helge

Plant physiology is affected by climate change. Acclimations of photosynthetic processes are induced by short-term changes in climatic conditions. Further acclimation can be caused by longterm adjustments to climate change due to ecosystem-feedbacks. The aim of this PhD was to investigate plant...... term responses of plant physiology to the climate change factors were investigated. In the CLIMAITE-experiment it has been shown that 2 years of treatment altered physiological responses in Deschampsiaand Calluna. In the work of this PhD similar responses were observed after 6 years of treatment...... physiological responses to climate change in a seasonal and long-term perspective. The effects of elevated CO2, passive night time warming and periodic summer drought as single factor and in combination, on plant physiology were investigated in the long-term multifactorial field experiment CLIMAITE in a Danish...

Climate-driven changes in functional biogeography of Arctic marine fish communities.

Science.gov (United States)

Frainer, André; Primicerio, Raul; Kortsch, Susanne; Aune, Magnus; Dolgov, Andrey V; Fossheim, Maria; Aschan, Michaela M

2017-11-14

Climate change triggers poleward shifts in species distribution leading to changes in biogeography. In the marine environment, fish respond quickly to warming, causing community-wide reorganizations, which result in profound changes in ecosystem functioning. Functional biogeography provides a framework to address how ecosystem functioning may be affected by climate change over large spatial scales. However, there are few studies on functional biogeography in the marine environment, and none in the Arctic, where climate-driven changes are most rapid and extensive. We investigated the impact of climate warming on the functional biogeography of the Barents Sea, which is characterized by a sharp zoogeographic divide separating boreal from Arctic species. Our unique dataset covered 52 fish species, 15 functional traits, and 3,660 stations sampled during the recent warming period. We found that the functional traits characterizing Arctic fish communities, mainly composed of small-sized bottom-dwelling benthivores, are being rapidly replaced by traits of incoming boreal species, particularly the larger, longer lived, and more piscivorous species. The changes in functional traits detected in the Arctic can be predicted based on the characteristics of species expected to undergo quick poleward shifts in response to warming. These are the large, generalist, motile species, such as cod and haddock. We show how functional biogeography can provide important insights into the relationship between species composition, diversity, ecosystem functioning, and environmental drivers. This represents invaluable knowledge in a period when communities and ecosystems experience rapid climate-driven changes across biogeographical regions. Copyright © 2017 the Author(s). Published by PNAS.

Species interactions reverse grassland responses to changing climate.

Science.gov (United States)

Suttle, K B; Thomsen, Meredith A; Power, Mary E

2007-02-02

Predictions of ecological response to climate change are based largely on direct climatic effects on species. We show that, in a California grassland, species interactions strongly influence responses to changing climate, overturning direct climatic effects within 5 years. We manipulated the seasonality and intensity of rainfall over large, replicate plots in accordance with projections of leading climate models and examined responses across several trophic levels. Changes in seasonal water availability had pronounced effects on individual species, but as precipitation regimes were sustained across years, feedbacks and species interactions overrode autecological responses to water and reversed community trajectories. Conditions that sharply increased production and diversity through 2 years caused simplification of the food web and deep reductions in consumer abundance after 5 years. Changes in these natural grassland communities suggest a prominent role for species interactions in ecosystem response to climate change.

Climate change response framework overview: Chapter 1

Science.gov (United States)

Chris Swanston; Maria Janowiak; Patricia Butler

2012-01-01

Managers currently face the immense challenge of anticipating the effects of climate change on forest ecosystems and then developing and applying management responses for adapting forests to future conditions. The Climate Change Response Framework (CCRF) is a highly collaborative approach to helping land managers understand the potential effects of climate change on...

Choice of baseline climate data impacts projected species' responses to climate change.

Science.gov (United States)

Baker, David J; Hartley, Andrew J; Butchart, Stuart H M; Willis, Stephen G

2016-07-01

Climate data created from historic climate observations are integral to most assessments of potential climate change impacts, and frequently comprise the baseline period used to infer species-climate relationships. They are often also central to downscaling coarse resolution climate simulations from General Circulation Models (GCMs) to project future climate scenarios at ecologically relevant spatial scales. Uncertainty in these baseline data can be large, particularly where weather observations are sparse and climate dynamics are complex (e.g. over mountainous or coastal regions). Yet, importantly, this uncertainty is almost universally overlooked when assessing potential responses of species to climate change. Here, we assessed the importance of historic baseline climate uncertainty for projections of species' responses to future climate change. We built species distribution models (SDMs) for 895 African bird species of conservation concern, using six different climate baselines. We projected these models to two future periods (2040-2069, 2070-2099), using downscaled climate projections, and calculated species turnover and changes in species-specific climate suitability. We found that the choice of baseline climate data constituted an important source of uncertainty in projections of both species turnover and species-specific climate suitability, often comparable with, or more important than, uncertainty arising from the choice of GCM. Importantly, the relative contribution of these factors to projection uncertainty varied spatially. Moreover, when projecting SDMs to sites of biodiversity importance (Important Bird and Biodiversity Areas), these uncertainties altered site-level impacts, which could affect conservation prioritization. Our results highlight that projections of species' responses to climate change are sensitive to uncertainty in the baseline climatology. We recommend that this should be considered routinely in such analyses. © 2016 John Wiley

IN SITU COMPARISON OF TREE-RING RESPONSES TO CLIMATE AND POPULATION GENETICS: THE NEED TO CONTROL FOR LOCAL CLIMATE AND SITE VARIABLES

Directory of Open Access Journals (Sweden)

Johann Mathias Housset

2016-10-01

Full Text Available Tree species responses to climate change will be greatly influenced by their evolutionary potential and their phenotypic plasticity. Investigating tree-rings responses to climate and population genetics at the regional scale is therefore crucial in assessing the tree behaviour to climate change. This study combined in situ dendroclimatology and population genetics over a latitudinal gradient and compared the variations between the two at the intra- and inter-population levels. This approach was applied on the northern marginal populations of Thuja occidentalis (eastern white-cedar in the Canadian boreal forest. We aimed first to assess the radial growth variability (response functional trait within populations across the gradient and to compare it with the genetic diversity (microsatellites. Second, we investigated the variability in the growth response to climate at the regional scale through the radial growth-climate relationships, and tested its correlation with environmental variables and population genetic structure. Model selection based on the Akaike Information Criteria revealed that the growth synchronicity between pairs of trees of a population covariates with both the genetic diversity of this population and the amount of precipitation (inverse correlation, although these variables only explained a small fraction of the observed variance. At the regional scale, variance partitioning and partial redundancy analysis indicate that the growth response to climate was greatly modulated by stand environmental variables, suggesting predominant plastic variations in growth-response to climate. Combining in situ dendroclimatology and population genetics is a promising way to investigate species’ response capacity to climate change in natural stands. We stress the need to control for local climate and site conditions effects on dendroclimatic response to climate to avoid misleading conclusions regarding the associations with genetic variables.

Climate extremes drive changes in functional community structure.

Science.gov (United States)

Boucek, Ross E; Rehage, Jennifer S

2014-06-01

The response of communities to climate extremes can be quite variable. Much of this variation has been attributed to differences in community-specific functional trait diversity, as well as community composition. Yet, few if any studies have explicitly tested the response of the functional trait structure of communities following climate extremes (CEs). Recently in South Florida, two independent, but sequential potential CEs took place, a 2010 cold front, followed by a 2011 drought, both of which had profound impacts on a subtropical estuarine fish community. These CEs provided an opportunity to test whether the structure of South Florida fish communities following each extreme was a result of species-specific differences in functional traits. From historical temperature (1927-2012) and freshwater inflows records into the estuary (1955-2012), we determined that the cold front was a statistically extreme disturbance, while the drought was not, but rather a decadal rare disturbance. The two disturbances predictably affected different parts of functional community structure and thus different component species. The cold front virtually eliminated tropical species, including large-bodied snook, mojarra species, nonnative cichlids, and striped mullet, while having little affect on temperate fishes. Likewise, the drought severely impacted freshwater fishes including Florida gar, bowfin, and two centrarchids, with little effect on euryhaline species. Our findings illustrate the ability of this approach to predict and detect both the filtering effects of different types of disturbances and the implications of the resulting changes in community structure. Further, we highlight the value of this approach to developing predictive frameworks for better understanding community responses to global change. © 2014 John Wiley & Sons Ltd.

Role of population genetics in guiding ecological responses to climate.

Science.gov (United States)

Rehfeldt, Gerald E; Leites, Laura P; Joyce, Dennis G; Weiskittel, Aaron R

2018-02-01

Population responses to climate were assessed using 3-7 years height growth data gathered for 266 populations growing in 12 common gardens established in the 1980s as part of five disparate studies of Pinus contorta var. latifolia. Responses are interpreted according to three concepts: the ecological optimum, the climate where a population is competitively exclusive and in which, therefore, it occurs naturally; the physiological optimum, the climate where a population grows best but is most often competitively excluded; and growth potential, the innate capacity for growth at the physiological optimum. Statistical analyses identified winter cold, measured by the square root of negative degree-days calculated from the daily minimum temperature (MINDD0 1/2 ), as the climatic effect most closely related to population growth potential; the colder the winter inhabited by a population, the lower its growth potential, a relationship presumably molded by natural selection. By splitting the data into groups based on population MINDD0 1/2 and using a function suited to skewed normal distributions, regressions were developed for predicting growth from the distance in climate space (MINDD0 1/2 ) populations had been transferred from their native location to a planting site. The regressions were skewed, showing that the ecological optimum of most populations is colder than the physiological optimum and that the discrepancy between the two increases as the ecological optimum becomes colder. Response to climate change is dependent on innate growth potential and the discrepancy between the two optima and, therefore, is population-specific, developing out of genotype-environment interactions. Response to warming in the short-term can be either positive or negative, but long term responses will be negative for all populations, with the timing of the demise dependent on the amount of skew. The results pertain to physiological modeling, species distribution models, and climate

America's Climate Choices: Informing an Effective Response to Climate Change (Invited)

Science.gov (United States)

Liverman, D. M.; McConnell, M. C.; Raven, P.

2010-12-01

At the request of Congress, the National Academy of Sciences convened a series of coordinated activities to provide advice on actions and strategies that the nation can take to respond to climate change. As part of this suite of activities, this study examines information needs and recommends ways the federal government can better inform responses by enhancing climate change and greenhouse gas information and reporting systems and by improving climate communication and education. Demand for better information to support climate-related decisions has grown rapidly as people, organizations, and governments have moved ahead with plans and actions to reduce greenhouse gas emissions and to adapt to the impacts of climate change. To meet this demand, good information systems and services are needed. Without such systems, decision makers cannot evaluate whether particular policies and actions are achieving their goals or should be modified. Although the many non-federal efforts to reduce emissions and/or adapt to future climate changes carry considerable potential to reduce risks related to climate change, there is currently no comprehensive way to assess the effectiveness of those efforts. In addition, the diverse climate change responses to date have resulted in a patchwork of regional, state, and local policies that has prompted many state and business leaders to call for the development of a more predictable and coherent policy environment at the federal level. This report demonstrates that the nation lacks comprehensive, robust, and credible information and reporting systems to inform climate choices and evaluate their effectiveness. This report also argues that decision makers can benefit from a systematic and iterative framework for responding to climate change, in which decisions and policies can be revised in light of new information and experience and that improved information and reporting systems allow for ongoing evaluation of responses to climate risks. The

Eco-theological Responses to Climate Change in Oceania

DEFF Research Database (Denmark)

Rubow, Cecilie; Bird, Cliff

2016-01-01

to reform classical theologies and church practices. Secondly, we identify challenges facing the contextual theologies, among them recent claims about climate-change-denying responses by Biblicist Christians in the Pacific region. These challenges apart, we suggest, thirdly, that the churches are important......This paper explores eco-theological responses to climate change in Oceania. First, we review central texts in the contextual theological tradition in Oceania, focusing on recent responses to climate change. This points to a body of theological texts integrating climate change into a broader effort...

National policy response to climate change in South Africa

CSIR Research Space (South Africa)

Garland, Rebecca M

2014-08-01

Full Text Available The South African government has taken several steps in response to climate change and its associated threats to human health. The National Climate Change Response Plan White Paper defines government's vision for effective climate change response...

Climate-responsive design : A framework for an energy concept design-decision support tool for architects using principles of climate-responsive design

NARCIS (Netherlands)

Looman, R.H.J.

2017-01-01

In climate-responsive design the building becomes an intermediary in its own energy housekeeping, forming a link between the harvest of climate resources and low-energy provision of comfort. Essential here is the employment of climate-responsive building elements; structural and architectural

Herbivory and eutrophication mediate grassland plant nutrient responses across a global climatic gradient

Science.gov (United States)

Anderson, T. Michael; Griffith, Daniel M.; Grace, James B.; Lind, Eric M.; Adler, Peter B.; Biederman, Lori A.; Blumenthal, Dana M.; Daleo, Pedro; Firn, Jennifer; Hagenah, Nicole; Harpole, W. Stanley; MacDougall, Andrew S.; McCulley, Rebecca L.; Prober, Suzanne M.; Risch, Anita C.; Sankaran, Mahesh; Schütz, Martin; Seabloom, Eric W.; Stevens, Carly J.; Sullivan, Lauren; Wragg, Peter; Borer, Elizabeth T.

2018-01-01

Plant stoichiometry, the relative concentration of elements, is a key regulator of ecosystem functioning and is also being altered by human activities. In this paper we sought to understand the global drivers of plant stoichiometry and compare the relative contribution of climatic vs. anthropogenic effects. We addressed this goal by measuring plant elemental (C, N, P and K) responses to eutrophication and vertebrate herbivore exclusion at eighteen sites on six continents. Across sites, climate and atmospheric N deposition emerged as strong predictors of plot‐level tissue nutrients, mediated by biomass and plant chemistry. Within sites, fertilization increased total plant nutrient pools, but results were contingent on soil fertility and the proportion of grass biomass relative to other functional types. Total plant nutrient pools diverged strongly in response to herbivore exclusion when fertilized; responses were largest in ungrazed plots at low rainfall, whereas herbivore grazing dampened the plant community nutrient responses to fertilization. Our study highlights (1) the importance of climate in determining plant nutrient concentrations mediated through effects on plant biomass, (2) that eutrophication affects grassland nutrient pools via both soil and atmospheric pathways and (3) that interactions among soils, herbivores and eutrophication drive plant nutrient responses at small scales, especially at water‐limited sites.

The Science of Climate Responsibility

Science.gov (United States)

Mitchell, D.; Frumhoff, P. C.; Sparrow, S.; Allen, M. R.

2015-12-01

Extreme events linked with human induced climate change have now been reported around the globe. Among the most troublesome impacts are increased wild fires, failed crop yields, extreme flooding and increase human mortality (Hansen and Cramer, 2015). Many of these impacts are predicted to increase into the future. Non-industrialised communities around the world will be the least capable of adapting, while the industrial communities, who are often responsible for historical carbon emissions, will find adaptation easier. Such a situation lends itself to the issue of responsibility. In order to assess responsibility, it must first be established where the major carbon and methane emissions are originating. It must then be estimated how these emissions project onto localised climate, which is often the primary indicator behind impacts on society. In this study, we address this question using a 25 km regional climate model capable of simulating climate thousands of times under the Weather@home citizen science project. The use of this framework allows us to generate huge data sample sizes, which can be put in the context of very low sample sizes of observational data. We concentrate on the 2003 heat wave over Europe, but show how this method could be applied to less data rich regions, including the Middle East and the Horn of Africa.

The Response of Ice Sheets to Climate Variability

Science.gov (United States)

Snow, K.; Goldberg, D. N.; Holland, P. R.; Jordan, J. R.; Arthern, R. J.; Jenkins, A.

2017-12-01

West Antarctic Ice Sheet loss is a significant contributor to sea level rise. While the ice loss is thought to be triggered by fluctuations in oceanic heat at the ice shelf bases, ice sheet response to ocean variability remains poorly understood. Using a synchronously coupled ice-ocean model permitting grounding line migration, this study evaluates the response of an ice sheet to periodic variations in ocean forcing. Resulting oscillations in grounded ice volume amplitude is shown to grow as a nonlinear function of ocean forcing period. This implies that slower oscillations in climatic forcing are disproportionately important to ice sheets. The ice shelf residence time offers a critical time scale, above which the ice response amplitude is a linear function of ocean forcing period and below which it is quadratic. These results highlight the sensitivity of West Antarctic ice streams to perturbations in heat fluxes occurring at decadal time scales.

Using climate response functions in analyzing electricity production variables. A case study from Norway.

Science.gov (United States)

Tøfte, Lena S.; Martino, Sara; Mo, Birger

2016-04-01

representation of hydropower is included and total hydro power production for each area is calculated, and the production is distributed among all available plants within each area. During simulation, the demand is affected by prices and temperatures. 6 different infrastructure scenarios of wind and power line development are analyzed. The analyses are done by running EMPS calibrated for today's situation for 11*11*8 different combinations of altered weather variables (temperature, precipitation and wind) describing different climate change scenarios, finding the climate response function for every EMPS-variable according the electricity production, such as prices and income, energy balances (supply, consumption and trade), overflow losses, probability of curtailment etc .

Rapid adjustment of bird community compositions to local climatic variations and its functional consequences.

Science.gov (United States)

Gaüzère, Pierre; Jiguet, Frédéric; Devictor, Vincent

2015-09-01

The local spatial congruence between climate changes and community changes has rarely been studied over large areas. We proposed one of the first comprehensive frameworks tracking local changes in community composition related to climate changes. First, we investigated whether and how 12 years of changes in the local composition of bird communities were related to local climate variations. Then, we tested the consequences of this climate-induced adjustment of communities on Grinnellian (habitat-related) and Eltonian (function-related) homogenization. A standardized protocol monitoring spatial and temporal trends of birds over France from 2001 to 2012 was used. For each plot and each year, we used the spring temperature and the spring precipitations and calculated three indices reflecting the thermal niche, the habitat specialization, and the functional originality of the species within a community. We then used a moving-window approach to estimate the spatial distribution of the temporal trends in each of these indices and their congruency with local climatic variations. Temperature fluctuations and community dynamics were found to be highly variable in space, but their variations were finely congruent. More interestingly, the community adjustment to temperature variations was nonmonotonous. Instead, unexplained fluctuations in community composition were observed up to a certain threshold of climate change intensity, above which a change in community composition was observed. This shift corresponded to a significant decrease in the relative abundance of habitat specialists and functionally original species within communities, regardless of the direction of temperature change. The investigation of variations in climate and community responses appears to be a central step toward a better understanding of climate change effects on biodiversity. Our results suggest a fine-scale and short-term adjustment of community composition to temperature changes. Moreover

Evolution of plasticity and adaptive responses to climate change along climate gradients.

Science.gov (United States)

Kingsolver, Joel G; Buckley, Lauren B

2017-08-16

The relative contributions of phenotypic plasticity and adaptive evolution to the responses of species to recent and future climate change are poorly understood. We combine recent (1960-2010) climate and phenotypic data with microclimate, heat balance, demographic and evolutionary models to address this issue for a montane butterfly, Colias eriphyle , along an elevational gradient. Our focal phenotype, wing solar absorptivity, responds plastically to developmental (pupal) temperatures and plays a central role in thermoregulatory adaptation in adults. Here, we show that both the phenotypic and adaptive consequences of plasticity vary with elevation. Seasonal changes in weather generate seasonal variation in phenotypic selection on mean and plasticity of absorptivity, especially at lower elevations. In response to climate change in the past 60 years, our models predict evolutionary declines in mean absorptivity (but little change in plasticity) at high elevations, and evolutionary increases in plasticity (but little change in mean) at low elevation. The importance of plasticity depends on the magnitude of seasonal variation in climate relative to interannual variation. Our results suggest that selection and evolution of both trait means and plasticity can contribute to adaptive response to climate change in this system. They also illustrate how plasticity can facilitate rather than retard adaptive evolutionary responses to directional climate change in seasonal environments. © 2017 The Author(s).

A dampened land use change climate response towards the tropics

NARCIS (Netherlands)

Molen, van der M.K.; Hurk, van den B.J.J.M.; Hazeleger, W.

2011-01-01

In climate simulations we find a pronounced meridional (equator to pole) gradient of climate response to land cover change. Climate response approaches zero in the tropics, and increases towards the poles. The meridional gradient in climate response to land cover change results from damping

National policy response to climate change in South Africa | Garland ...

African Journals Online (AJOL)

The South African government has taken several steps in response to climate change and its associated threats to human health. The National Climate Change Response Plan White Paper defines government's vision for effective climate change response and transitioning to a climate-resilient, low-carbon economy.

Climate change, responsibility, and justice.

Science.gov (United States)

Jamieson, Dale

2010-09-01

In this paper I make the following claims. In order to see anthropogenic climate change as clearly involving moral wrongs and global injustices, we will have to revise some central concepts in these domains. Moreover, climate change threatens another value ("respect for nature") that cannot easily be taken up by concerns of global justice or moral responsibility.

How light competition between plants affects their response to climate change.

Science.gov (United States)

van Loon, Marloes P; Schieving, Feike; Rietkerk, Max; Dekker, Stefan C; Sterck, Frank; Anten, Niels P R

2014-09-01

How plants respond to climate change is of major concern, as plants will strongly impact future ecosystem functioning, food production and climate. Here, we investigated how vegetation structure and functioning may be influenced by predicted increases in annual temperatures and atmospheric CO2 concentration, and modeled the extent to which local plant-plant interactions may modify these effects. A canopy model was developed, which calculates photosynthesis as a function of light, nitrogen, temperature, CO2 and water availability, and considers different degrees of light competition between neighboring plants through canopy mixing; soybean (Glycine max) was used as a reference system. The model predicts increased net photosynthesis and reduced stomatal conductance and transpiration under atmospheric CO2 increase. When CO2 elevation is combined with warming, photosynthesis is increased more, but transpiration is reduced less. Intriguingly, when competition is considered, the optimal response shifts to producing larger leaf areas, but with lower stomatal conductance and associated vegetation transpiration than when competition is not considered. Furthermore, only when competition is considered are the predicted effects of elevated CO2 on leaf area index (LAI) well within the range of observed effects obtained by Free air CO2 enrichment (FACE) experiments. Together, our results illustrate how competition between plants may modify vegetation responses to climate change. © 2014 The Authors. New Phytologist © 2014 New Phytologist Trust.

A climate response function explaining most of the variation in the forest floor needle mass and the needle decomposition in pine forests across Europe

DEFF Research Database (Denmark)

Kurz-Besson, C.; Coûteaux, M.M.; Berg, Bjørn

2006-01-01

The forest floor needle mass and the decomposition rates of pine needle litter in a European climate transect were studied in order to estimate the impact of climate change on forest soil carbon sequestration. Eight pine forests preserved from fire were selected along a climatic latitudinal...... gradient from 40° to 60° N, from Spain and Portugal to Sweden. The forest floor (Oi and Oe layers) was sorted into five categories of increasing decomposition level according to morphological criteria. The needle mass loss in each category was determined using a linear mass density method. The needle...... and a recalcitrant one. NF was correlated with actual evapotranspiration (AET) whereas the decomposition parameters (decomposition rate of the decomposable fraction, first year mass loss, forest floor needle mass, age of the most-decomposed category) were related to a combined response function to climate (CRF...

If climate action becomes urgent: The importance of response times for various climate strategies

NARCIS (Netherlands)

van Vuuren, D.P.; Stehfest, E.

2013-01-01

Most deliberations on climate policy are based on a mitigation response that assumes a gradually increasing reduction over time. However, situations may occur where a more urgent response is needed. A key question for climate policy in general, but even more in the case a rapid response is needed,

Climate change adapatation response at local government level

CSIR Research Space (South Africa)

Mambo, Julia

2018-03-01

Full Text Available The climate change response policy gives the mandate to all municipalities and other levels of government to develop and implement climate chnage adaptation response. The availability of appropriate information is essential for this process...

A dampened land use change climate response towards the tropics

Energy Technology Data Exchange (ETDEWEB)

Molen, M.K. van der [Royal Netherlands Meteorological Institute, De Bilt (Netherlands); Wageningen University and Research Centre (WUR), Department of Meteorology and Air Quality, Wageningen (Netherlands); Hurk, B.J.J.M. van den; Hazeleger, W. [Royal Netherlands Meteorological Institute, De Bilt (Netherlands)

2011-11-15

In climate simulations we find a pronounced meridional (equator to pole) gradient of climate response to land cover change. Climate response approaches zero in the tropics, and increases towards the poles. The meridional gradient in climate response to land cover change results from damping feedbacks in the tropics, rather than from polar amplification. The main cause for the damping in the tropics is the decrease in cloud cover after deforestation, resulting in increased incoming radiation at the surface and a lower planetary albedo, both counteracting the increase in surface albedo with deforestation. In our simulations, deforestation was also associated with a decrease in sensible heat flux but not a clear signal in evaporation. Meridional differences in climate response have implications for attribution of observed climate change, as well as for climate change mitigation strategies. (orig.)

Defining response capacity to enhance climate change policy

International Nuclear Information System (INIS)

Tompkins, Emma L.; Neil Adger, W.

2005-01-01

Climate change adaptation and mitigation decisions made by governments are usually taken in different policy domains. At the individual level however, adaptation and mitigation activities are undertaken together as part of the management of risk and resources. We propose that a useful starting point to develop a national climate policy is to understand what societal response might mean in practice. First we frame the set of responses at the national policy level as a trade off between investment in the development and diffusion of new technology, and investment in encouraging and enabling society to change its behaviour and or adopt the new technology. We argue that these are the pertinent trade-offs, rather than those usually posited between climate change mitigation and adaptation. The preference for a policy response that focuses more on technological innovation rather than one that focuses on changing social behaviour will be influenced by the capacity of different societies to change their greenhouse gas emissions; by perceived vulnerability to climate impacts; and by capacity to modify social behaviour and physical environment. Starting with this complete vision of response options should enable policy makers to re-evaluate the risk environment and the set of response options available to them. From here, policy makers should consider who is responsible for making climate response decisions and when actions should be taken. Institutional arrangements dictate social and political acceptability of different policies, they structure worldviews, and they determine the provision of resources for investment in technological innovation and social change. The importance of focussing on the timing of the response is emphasised to maximise the potential for adjustments through social learning and institutional change at different policy scales. We argue that the ability to respond to climate change is both enabled and constrained by social and technological conditions

The role of plant functional trade-offs for biodiversity changes and biome shifts under scenarios of global climatic change

Directory of Open Access Journals (Sweden)

B. Reu

2011-05-01

Full Text Available The global geographic distribution of biodiversity and biomes is determined by species-specific physiological tolerances to climatic constraints. Current vegetation models employ empirical bioclimatic relationships to predict present-day vegetation patterns and to forecast biodiversity changes and biome shifts under climatic change. In this paper, we consider trade-offs in plant functioning and their responses under climatic changes to forecast and explain changes in plant functional richness and shifts in biome geographic distributions.

The Jena Diversity model (JeDi simulates plant survival according to essential plant functional trade-offs, including ecophysiological processes such as water uptake, photosynthesis, allocation, reproduction and phenology. We use JeDi to quantify changes in plant functional richness and biome shifts between present-day and a range of possible future climates from two SRES emission scenarios (A2 and B1 and seven global climate models using metrics of plant functional richness and functional identity.

Our results show (i a significant loss of plant functional richness in the tropics, (ii an increase in plant functional richness at mid and high latitudes, and (iii a pole-ward shift of biomes. While these results are consistent with the findings of empirical approaches, we are able to explain them in terms of the plant functional trade-offs involved in the allocation, metabolic and reproduction strategies of plants. We conclude that general aspects of plant physiological tolerances can be derived from functional trade-offs, which may provide a useful process- and trait-based alternative to bioclimatic relationships. Such a mechanistic approach may be particularly relevant when addressing vegetation responses to climatic changes that encounter novel combinations of climate parameters that do not exist under contemporary climate.

Functional diversity supports the physiological tolerance hypothesis for plant species richness along climatic gradients

Science.gov (United States)

Spasojevic, Marko J.; Grace, James B.; Harrison, Susan; Damschen, Ellen Ingman

2013-01-01

1. The physiological tolerance hypothesis proposes that plant species richness is highest in warm and/or wet climates because a wider range of functional strategies can persist under such conditions. Functional diversity metrics, combined with statistical modeling, offer new ways to test whether diversity-environment relationships are consistent with this hypothesis. 2. In a classic study by R. H. Whittaker (1960), herb species richness declined from mesic (cool, moist, northerly) slopes to xeric (hot, dry, southerly) slopes. Building on this dataset, we measured four plant functional traits (plant height, specific leaf area, leaf water content and foliar C:N) and used them to calculate three functional diversity metrics (functional richness, evenness, and dispersion). We then used a structural equation model to ask if ‘functional diversity’ (modeled as the joint responses of richness, evenness, and dispersion) could explain the observed relationship of topographic climate gradients to species richness. We then repeated our model examining the functional diversity of each of the four traits individually. 3. Consistent with the physiological tolerance hypothesis, we found that functional diversity was higher in more favorable climatic conditions (mesic slopes), and that multivariate functional diversity mediated the relationship of the topographic climate gradient to plant species richness. We found similar patterns for models focusing on individual trait functional diversity of leaf water content and foliar C:N. 4. Synthesis. Our results provide trait-based support for the physiological tolerance hypothesis, suggesting that benign climates support more species because they allow for a wider range of functional strategies.

Ecological responses to recent climate change

Energy Technology Data Exchange (ETDEWEB)

Walther, Gian-Reto [Hannover Univ., Inst. of Geobotany, Hannover (Germany); Post, Eric [Pennsylvania State Univ., Dept. of Biology, University Park, PA (United States); Convey, Peter [British Antarctic Survey, Natural Environment Research Council, Cambridge (United Kingdom); Menzel, Annette [Technical Univ. Munich, Dept. of Ecology, Freising (Germany); Parmesan, Camille [Texas Univ., Patterson Labs., Integrative Biology Dept., Austin, TX (United States); Beebee, Trevor J.C. [Sussex Univ., School of Biological Sciences, Brighton (United Kingdom); Fromentin, Jean-Marc [IFREMER, Centre Halieutique Mediterraneen et Tropical, Sete, 34 (France); Hoegh-Guldberg, Ove [Queensland Univ., Centre for Marine Studies, St Lucia, QLD (Australia); Bairlein, Franz [Institute for Avian Research ' Vogelwarte Helgoland' , Wilhelmshaven (Germany)

2002-03-28

There is now ample evidence of the ecological impacts of recent climate change, from polar terrestrial to tropical marine environments. The responses of both flora and fauna span an array of ecosystems and organisational hierarchies, from the species to the community levels. Despite continued uncertainty as to community and ecosystem trajectories under global change, our review exposes a coherent pattern of ecological change across systems. Although we are only at an early stage in the projected trends of global warming, ecological responses to recent climate change are already clearly visible. (Author)

China's response to climate change issues after Paris Climate Change Conference

Directory of Open Access Journals (Sweden)

Yun Gao

2016-12-01

Full Text Available The Paris Climate Change Conference was successfully concluded with the Paris Agreement, which is a milestone for the world in collectively combating climate change. By participating in IPCC assessments and conducting national climate change assessments, China has been increasing its understanding of the issue. For the first time, China's top leader attended the Conference of the Parties, which indicates the acknowledgement of the rationality and necessity of climate change response by China at different levels. Moreover, this participation reflects China's commitment to including climate change in its ecology improvement program and pursuing a low-carbon society and economy. In order to ensure the success of the Paris Conference, China has contributed significantly. China's constructive participation in global governance shows that China is a responsible power. These principles such as the creation of a future of win–win cooperation with each country contributing to the best of its ability; a future of the rule of law, fairness, and justice; and a future of inclusiveness, mutual learning, and common development will serve as China's guidelines in its efforts to facilitate the implementation of the Paris Agreement and participate in the design of international systems.

China's response to climate change issues after Paris Climate Change Conference

Institute of Scientific and Technical Information of China (English)

GAO Yun

2016-01-01

The Paris Climate Change Conference was successfully concluded with the Paris Agreement, which is a milestone for the world in collectively combating climate change. By participating in IPCC assessments and conducting national climate change assessments, China has been increasing its understanding of the issue. For the first time, China's top leader attended the Conference of the Parties, which indicates the acknowledgement of the rationality and necessity of climate change response by China at different levels. Moreover, this participation reflects China's commitment to including climate change in its ecology improvement program and pursuing a low-carbon society and economy. In order to ensure the success of the Paris Conference, China has contributed significantly. China's constructive participation in global governance shows that China is a responsible power. These principles such as the creation of a future of winewin cooperation with each country contributing to the best of its ability;a future of the rule of law, fairness, and justice;and a future of inclusiveness, mutual learning, and common development will serve as China's guidelines in its efforts to facilitate the implementation of the Paris Agreement and participate in the design of international systems.

Responsibility for private sector adaptation to climate change

Directory of Open Access Journals (Sweden)

Tina Schneider

2014-06-01

Full Text Available The Intergovernmental Panel on Climate Change (2007 indicates that vulnerable industries should adapt to the increasing likelihood of extreme weather events along with slowly shifting mean annual temperatures and precipitation patterns, to prevent major damages or periods of inoperability in the future. Most articles in the literature on business management frame organizational adaptation to climate change as a private action. This makes adaptation the sole responsibility of a company, for its sole benefit, and overlooks the fact that some companies provide critical goods and services such a food, water, electricity, and medical care, that are so vital to society that even a short-term setback in operations could put public security at risk. This raises the following questions: (1 Who is responsible for climate change adaptation by private-sector suppliers of critical infrastructure? (2 How can those who are identified to be responsible, actually be held to assume their responsibility for adapting to climate change? These questions will be addressed through a comprehensive review of the literature on business management, complemented by a review of specialized literature on public management. This review leads to several conclusions. Even though tasks that formerly belonged to the state have been taken over by private companies, the state still holds ultimate responsibility in the event of failure of private-sector owned utilities, insofar as they are "critical infrastructure." Therefore, it remains the state's responsibility to foster adaptation to climate change with appropriate action. In theory, effective ways of assuming this responsibility, while enabling critical infrastructure providers the flexibility adapt to climate change, would be to delegate adaptation to an agency, or to conduct negotiations with stakeholders. In view of this theory, Germany will be used as a case study to demonstrate how private-sector critical infrastructure

Climate model diversity in the Northern Hemisphere Polar vortex response to climate change.

Science.gov (United States)

Simpson, I.; Seager, R.; Hitchcock, P.; Cohen, N.

2017-12-01

Global climate models vary widely in their predictions of the future of the Northern Hemisphere stratospheric polar vortex, with some showing a significant strengthening of the vortex, some showing a significant weakening and others displaying a response that is not outside of the range expected from internal variability alone. This inter-model spread in stratospheric predictions may account for some inter-model spread in tropospheric predictions with important implications for the storm tracks and regional climate change, particularly for the North Atlantic sector. Here, our current state of understanding of this model spread and its tropospheric impacts will be reviewed. Previous studies have proposed relationships between a models polar vortex response to climate change and its present day vortex climatology while others have demonstrated links between a models polar vortex response and changing wave activity coming up from the troposphere below under a warming climate. The extent to which these mechanisms can account for the spread in polar vortex changes exhibited by the Coupled Model Intercomparison Project, phase 5 models will be assessed. In addition, preliminary results from a series of idealized experiments with the Community Atmosphere Model will be presented. In these experiments, nudging of the stratospheric zonal mean state has been imposed to mimic the inter-model spread in the polar vortex response to climate change so that the downward influence of the spread in zonal mean stratospheric responses on the tropospheric circulation can be assessed within one model.

Interpreting the Climatic Effects on Xylem Functional Traits in Two Mediterranean Oak Species: The Role of Extreme Climatic Events.

Science.gov (United States)

Rita, Angelo; Borghetti, Marco; Todaro, Luigi; Saracino, Antonio

2016-01-01

In the Mediterranean region, the widely predicted rise in temperature, change in the precipitation pattern, and increase in the frequency of extreme climatic events are expected to alter the shape of ecological communities and to affect plant physiological processes that regulate ecosystem functioning. Although change in the mean values are important, there is increasing evidence that plant distribution, survival, and productivity respond to extremes rather than to the average climatic condition. The present study aims to assess the effects of both mean and extreme climatic conditions on radial growth and functional anatomical traits using long-term tree-ring time series of two co-existing Quercus spp. from a drought-prone site in Southern Italy. In particular, this is the first attempt to apply the Generalized Additive Model for Location, Scale, and Shape (GAMLSS) technique and Bayesian modeling procedures to xylem traits data set, with the aim of (i) detecting non-linear long-term responses to climate and (ii) exploring relationships between climate extreme and xylem traits variability in terms of probability of occurrence. This study demonstrates the usefulness of long-term xylem trait chronologies as records of environmental conditions at annual resolution. Statistical analyses revealed that most of the variability in tree-ring width and specific hydraulic conductivity might be explained by cambial age. Additionally, results highlighted appreciable relationships between xylem traits and climate variability more than tree-ring width, supporting also the evidence that the plant hydraulic traits are closely linked to local climate extremes rather than average climatic conditions. We reported that the probability of extreme departure in specific hydraulic conductivity (Ks) rises at extreme values of Standardized Precipitation Index (SPI). Therefore, changing frequency or intensity of extreme events might overcome the adaptive limits of vascular transport, resulting

Interpreting the climatic effects on xylem functional traits in two Mediterranean oak species: the role of extreme climatic events

Directory of Open Access Journals (Sweden)

Angelo Rita

2016-08-01

Full Text Available In the Mediterranean region, the widely predicted rise in temperature, change in the precipitation pattern and increase in the frequency of extreme climatic events are expected to alter the shape of ecological communities and to affect plant physiological processes that regulate ecosystem functioning. Although change in the mean values are important, there is increasing evidence that plant distribution, survival and productivity respond to extremes rather than to the average climatic condition. The present study aims to assess the effects of both mean and extreme climatic conditions on radial growth and functional anatomical traits using long-term tree-ring time series of two co-existing Quercus spp. from a drought-prone site in Southern Italy. In particular, this is the first attempt to apply the Generalized Additive Model for Location, Scale and Shape (GAMLSS technique and Bayesian modeling procedures to xylem traits data set, with the aim of i detecting non-linear long-term responses to climate and ii exploring relationships between climate extreme and xylem traits variability in terms of probability of occurrence. This study demonstrates the usefulness of long-term xylem trait chronologies as records of environmental conditions at annual resolution. Statistical analyses revealed that most of the variability in tree-ring width and specific hydraulic conductivity might be explained by cambial age. Additionally, results highlighted appreciable relationships between xylem traits and climate variability more than tree-ring width, supporting also the evidence that the plant hydraulic traits are closely linked to local climate extremes rather than average climatic conditions. We reported that the probability of extreme departure in specific hydraulic conductivity (Ks rises at extreme values of Standardized Precipitation Index (SPI. Therefore, changing frequency or intensity of extreme events might overcome the adaptive limits of vascular transport

Responses of mycorrhizal fungi and other rootassociated fungi to climate change

DEFF Research Database (Denmark)

Merrild, Marie Porret

Climate change is expected to affect many terrestrial ecosystem processes. Mycorrhizal fungi are important to soil carbon (C) and nutrient cycling thus changes in abundance of mycorrhizal fungi could alter ecosystem functioning. The aim of the present thesis was therefore to investigate responses...... of mycorrhizal fungi to climate change in a seasonal and long-term perspective. Effects of elevated CO2 (510 ppm), night-time warming and extended summer drought were investigated in the long-term field experiment CLIMAITE located in a Danish semi-natural heathland. Mycorrhizal colonization was investigated...... levels. Colonization by arbuscular mycorrhizal (AM) fungi increased under elevated CO2 and warming in spring while ericoid mycorrhiza (ErM) colonisation decreased in response to drought and warming. Increased AM colonization correlated with higher phosphorus and nitrogen root pools. Dark septate...

Climate Change Effects on Agriculture: Economic Responses to Biophysical Shocks

Science.gov (United States)

Nelson, Gerald C.; Valin, Hugo; Sands, Ronald D.; Havlik, Petr; Ahammad, Helal; Deryng, Delphine; Elliott, Joshua; Fujimori, Shinichiro; Hasegawa, Tomoko; Heyhoe, Edwina

2014-01-01

Agricultural production is sensitive to weather and thus directly affected by climate change. Plausible estimates of these climate change impacts require combined use of climate, crop, and economic models. Results from previous studies vary substantially due to differences in models, scenarios, and data. This paper is part of a collective effort to systematically integrate these three types of models. We focus on the economic component of the assessment, investigating how nine global economic models of agriculture represent endogenous responses to seven standardized climate change scenarios produced by two climate and five crop models. These responses include adjustments in yields, area, consumption, and international trade. We apply biophysical shocks derived from the Intergovernmental Panel on Climate Change's representative concentration pathway with end-of-century radiative forcing of 8.5 W/m(sup 2). The mean biophysical yield effect with no incremental CO2 fertilization is a 17% reduction globally by 2050 relative to a scenario with unchanging climate. Endogenous economic responses reduce yield loss to 11%, increase area of major crops by 11%, and reduce consumption by 3%. Agricultural production, cropland area, trade, and prices show the greatest degree of variability in response to climate change, and consumption the lowest. The sources of these differences include model structure and specification; in particular, model assumptions about ease of land use conversion, intensification, and trade. This study identifies where models disagree on the relative responses to climate shocks and highlights research activities needed to improve the representation of agricultural adaptation responses to climate change.

Carbon Dynamics in Heathlands in Response to a Changing Climate

DEFF Research Database (Denmark)

Nielsen, Pia Lund

Climate is changing, and more adverse changes are expected in the future. Changes, caused by continuously rising atmospheric concentrations of greenhouse gasses as CO2, will affect ecosystem processes and functions in the future and hence the cycling of carbon. The vaste amount of studies have...... layers showed much slower decomposition than fine root from top layer. Higher roots biomass and allocation of carbon deeper down in the soil profile in response to elevated CO2 combined with the slower decomposition of deep roots could affect future carbon cycling, but soil carbon sequestration depends...... focused on effects of climate change on aboveground biomass, less have been conducted on belowground biomass, and the thesis is one of few studies comprising both above- and belowground biomass and take interactions of climate change factors into account. To follow the fate of carbon in the ecosystem we...

Crop responses to climatic variation

DEFF Research Database (Denmark)

Porter, John R.; Semenov, Mikhail A.

2005-01-01

The yield and quality of food crops is central to the well being of humans and is directly affected by climate and weather. Initial studies of climate change on crops focussed on effects of increased carbon dioxide (CO2) level and/or global mean temperature and/or rainfall and nutrition on crop...... production. However, crops can respond nonlinearly to changes in their growing conditions, exhibit threshold responses and are subject to combinations of stress factors that affect their growth, development and yield. Thus, climate variability and changes in the frequency of extreme events are important...... for yield, its stability and quality. In this context, threshold temperatures for crop processes are found not to differ greatly for different crops and are important to define for the major food crops, to assist climate modellers predict the occurrence of crop critical temperatures and their temporal...

Multi-Wheat-Model Ensemble Responses to Interannual Climate Variability

Science.gov (United States)

Ruane, Alex C.; Hudson, Nicholas I.; Asseng, Senthold; Camarrano, Davide; Ewert, Frank; Martre, Pierre; Boote, Kenneth J.; Thorburn, Peter J.; Aggarwal, Pramod K.; Angulo, Carlos

2016-01-01

We compare 27 wheat models' yield responses to interannual climate variability, analyzed at locations in Argentina, Australia, India, and The Netherlands as part of the Agricultural Model Intercomparison and Improvement Project (AgMIP) Wheat Pilot. Each model simulated 1981e2010 grain yield, and we evaluate results against the interannual variability of growing season temperature, precipitation, and solar radiation. The amount of information used for calibration has only a minor effect on most models' climate response, and even small multi-model ensembles prove beneficial. Wheat model clusters reveal common characteristics of yield response to climate; however models rarely share the same cluster at all four sites indicating substantial independence. Only a weak relationship (R2 0.24) was found between the models' sensitivities to interannual temperature variability and their response to long-termwarming, suggesting that additional processes differentiate climate change impacts from observed climate variability analogs and motivating continuing analysis and model development efforts.

Modeling dynamics of tundra plant communities on the Yamal Peninsula, Russia, in response to climate change and grazing pressure

International Nuclear Information System (INIS)

Yu, Q; Epstein, H E; Frost, G V; Walker, D A; Forbes, B C

2011-01-01

Understanding the responses of the arctic tundra biome to a changing climate requires knowledge of the complex interactions among the climate, soils and biological system. This study investigates the individual and interaction effects of climate change and reindeer grazing across a variety of climate zones and soil texture types on tundra vegetation community dynamics using an arctic vegetation model that incorporates the reindeer diet, where grazing is a function of both foliar nitrogen concentration and reindeer forage preference. We found that grazing is important, in addition to the latitudinal climate gradient, in controlling tundra plant community composition, explaining about 13% of the total variance in model simulations for all arctic tundra subzones. The decrease in biomass of lichen, deciduous shrub and graminoid plant functional types caused by grazing is potentially dampened by climate warming. Moss biomass had a nonlinear response to increased grazing intensity, and such responses were stronger when warming was present. Our results suggest that evergreen shrubs may benefit from increased grazing intensity due to their low palatability, yet a growth rate sensitivity analysis suggests that changes in nutrient uptake rates may result in different shrub responses to grazing pressure. Heavy grazing caused plant communities to shift from shrub tundra toward moss, graminoid-dominated tundra in subzones C and D when evergreen shrub growth rates were decreased in the model. The response of moss, lichen and forbs to warming varied across the different subzones. Initial vegetation responses to climate change during transient warming are different from the long term equilibrium responses due to shifts in the controlling mechanisms (nutrient limitation versus competition) within tundra plant communities.

A statistical mechanical approach for the computation of the climatic response to general forcings

Directory of Open Access Journals (Sweden)

V. Lucarini

2011-01-01

Full Text Available The climate belongs to the class of non-equilibrium forced and dissipative systems, for which most results of quasi-equilibrium statistical mechanics, including the fluctuation-dissipation theorem, do not apply. In this paper we show for the first time how the Ruelle linear response theory, developed for studying rigorously the impact of perturbations on general observables of non-equilibrium statistical mechanical systems, can be applied with great success to analyze the climatic response to general forcings. The crucial value of the Ruelle theory lies in the fact that it allows to compute the response of the system in terms of expectation values of explicit and computable functions of the phase space averaged over the invariant measure of the unperturbed state. We choose as test bed a classical version of the Lorenz 96 model, which, in spite of its simplicity, has a well-recognized prototypical value as it is a spatially extended one-dimensional model and presents the basic ingredients, such as dissipation, advection and the presence of an external forcing, of the actual atmosphere. We recapitulate the main aspects of the general response theory and propose some new general results. We then analyze the frequency dependence of the response of both local and global observables to perturbations having localized as well as global spatial patterns. We derive analytically several properties of the corresponding susceptibilities, such as asymptotic behavior, validity of Kramers-Kronig relations, and sum rules, whose main ingredient is the causality principle. We show that all the coefficients of the leading asymptotic expansions as well as the integral constraints can be written as linear function of parameters that describe the unperturbed properties of the system, such as its average energy. Some newly obtained empirical closure equations for such parameters allow to define such properties as an explicit function of the unperturbed forcing

What plant hydraulics can tell us about responses to climate-change droughts.

Science.gov (United States)

Sperry, John S; Love, David M

2015-07-01

Climate change exposes vegetation to unusual drought, causing declines in productivity and increased mortality. Drought responses are hard to anticipate because canopy transpiration and diffusive conductance (G) respond to drying soil and vapor pressure deficit (D) in complex ways. A growing database of hydraulic traits, combined with a parsimonious theory of tree water transport and its regulation, may improve predictions of at-risk vegetation. The theory uses the physics of flow through soil and xylem to quantify how canopy water supply declines with drought and ceases by hydraulic failure. This transpiration 'supply function' is used to predict a water 'loss function' by assuming that stomatal regulation exploits transport capacity while avoiding failure. Supply-loss theory incorporates root distribution, hydraulic redistribution, cavitation vulnerability, and cavitation reversal. The theory efficiently defines stomatal responses to D, drying soil, and hydraulic vulnerability. Driving the theory with climate predicts drought-induced loss of plant hydraulic conductance (k), canopy G, carbon assimilation, and productivity. Data lead to the 'chronic stress hypothesis' wherein > 60% loss of k increases mortality by multiple mechanisms. Supply-loss theory predicts the climatic conditions that push vegetation over this risk threshold. The theory's simplicity and predictive power encourage testing and application in large-scale modeling. © 2015 The Authors. New Phytologist © 2015 New Phytologist Trust.

Science, Ethics and the Climate Responsibilities of Industrial Carbon Producers

Science.gov (United States)

Frumhoff, P. C.

2014-12-01

The question of responsibility for climate change lies at the heart of societal debate over actions to curb greenhouse gas emissions and prepare for now unavoidable climate impacts. The UN Framework Convention on Climate Change established the principle of "common but differentiated responsibilities" among nations, signaling the recognition that industrialized nations who had produced the lion's share of historic emissions bore particular responsibility for avoiding dangerous interference with the climate system. But climate responsibilities can be distributed in other ways as well. This talk focuses on the scientific, historical and ethical basis for considering the climate responsibilities of the major fossil energy companies that have produced and marketed the coal, oil and natural gas whose use largely drives global warming, often while investing in efforts to discredit the scientific evidence and prevent policies that would encourage a transition to low-carbon energy. Earth scientists and scientific societies who rely on financial support from these companies have an opportunity to consider what ethical stance they might take to align their research, scientific understanding and values.

Climate Change: Ethics and Collective Responsibility

Science.gov (United States)

Peacock, K.; Brown, M. B.; Mann, M. E.; Lewandowsky, S.

2014-12-01

Climate change poses grave risks for societies and people all around the earth. Though details of the risks remain uncertain, they include accelerating sea level rise and ocean acidification, regional drought, floods and heat waves, crop failures and more: dangerous changes are already occurring, while GHG emissions continue to grow, ice melts, water expands, temperature rises, and weather patterns shift. Our roles as individuals and nations in producing the emissions of GHGs responsible for this episode of climate change, and the actions that could be taken to mitigate it, raise difficult ethical questions. When we are responsible for putting others in danger, we have a duty to mitigate that danger. But our sense of responsibility is diluted here: each individual act contributes only minutely to the overall risks, and the links between individual acts and the harms they produce are complex, indirect and involve many other agents. In these circumstances, our sense of personal responsibility is diminished and uncoordinated, individual responses to the risks become ineffective. We propose a view of the ethics of climate change that begins with the tragedy of the commons: Free use of a shared, indispensable resource can lead to catastrophe as the resource is overrun, and the destruction of the commons arises from choices that are individuallyrational, if each person's choice is made independently of others'. Finally, individuals often fail to make ethical choices when the links between individual actions and their negative outcomes are obscure, when individual choices are made separately and privately, and when special interests stand to gain from actions that are generally harmful. Philosophical work in ethics has emphasized the role of ethics in enabling cooperation between individuals and coordinating group responses to problems, while recent work on social rules has modeled them as generalized forbiddings, taught and enforced by 'blocking' behaviours which

Non-climatic thermal adaptation: implications for species' responses to climate warming.

Science.gov (United States)

Marshall, David J; McQuaid, Christopher D; Williams, Gray A

2010-10-23

There is considerable interest in understanding how ectothermic animals may physiologically and behaviourally buffer the effects of climate warming. Much less consideration is being given to how organisms might adapt to non-climatic heat sources in ways that could confound predictions for responses of species and communities to climate warming. Although adaptation to non-climatic heat sources (solar and geothermal) seems likely in some marine species, climate warming predictions for marine ectotherms are largely based on adaptation to climatically relevant heat sources (air or surface sea water temperature). Here, we show that non-climatic solar heating underlies thermal resistance adaptation in a rocky-eulittoral-fringe snail. Comparisons of the maximum temperatures of the air, the snail's body and the rock substratum with solar irradiance and physiological performance show that the highest body temperature is primarily controlled by solar heating and re-radiation, and that the snail's upper lethal temperature exceeds the highest climatically relevant regional air temperature by approximately 22°C. Non-climatic thermal adaptation probably features widely among marine and terrestrial ectotherms and because it could enable species to tolerate climatic rises in air temperature, it deserves more consideration in general and for inclusion into climate warming models.

Regional climate response collaboratives: Multi-institutional support for climate resilience

Science.gov (United States)

Averyt, Kristen; Derner, Justin D.; Dilling, Lisa; Guerrero, Rafael; Joyce, Linda A.; McNeeley, Shannon; McNie, Elizabeth; Morisette, Jeffrey T.; Ojima, Dennis; O'Malley, Robin; Peck, Dannele; Ray, Andrea J.; Reeves, Matt; Travis, William

2018-01-01

Federal investments by U.S. agencies to enhance climate resilience at regional scales grew over the past decade (2010s). To maximize efficiency and effectiveness in serving multiple sectors and scales, it has become critical to leverage existing agency-specific research, infrastructure, and capacity while avoiding redundancy. We discuss lessons learned from a multi-institutional “regional climate response collaborative” that comprises three different federally-supported climate service entities in the Rocky Mountain west and northern plains region. These lessons include leveraging different strengths of each partner, creating deliberate mechanisms to increase cross-entity communication and joint ownership of projects, and placing a common priority on stakeholder-relevant research and outcomes. We share the conditions that fostered successful collaboration, which can be transferred elsewhere, and suggest mechanisms for overcoming potential barriers. Synergies are essential for producing actionable research that informs climate-related decisions for stakeholders and ultimately enhances climate resilience at regional scales.

Functional approach to exploring climatic and landscape controls of runoff generation: 1. Behavioral constraints on runoff volume

Science.gov (United States)

Li, Hong-Yi; Sivapalan, Murugesu; Tian, Fuqiang; Harman, Ciaran

2014-12-01

Inspired by the Dunne diagram, the climatic and landscape controls on the partitioning of annual runoff into its various components (Hortonian and Dunne overland flow and subsurface stormflow) are assessed quantitatively, from a purely theoretical perspective. A simple distributed hydrologic model has been built sufficient to simulate the effects of different combinations of climate, soil, and topography on the runoff generation processes. The model is driven by a sequence of simple hypothetical precipitation events, for a large combination of climate and landscape properties, and hydrologic responses at the catchment scale are obtained through aggregation of grid-scale responses. It is found, first, that the water balance responses, including relative contributions of different runoff generation mechanisms, could be related to a small set of dimensionless similarity parameters. These capture the competition between the wetting, drying, storage, and drainage functions underlying the catchment responses, and in this way, provide a quantitative approximation of the conceptual Dunne diagram. Second, only a subset of all hypothetical catchment/climate combinations is found to be "behavioral," in terms of falling sufficiently close to the Budyko curve, describing mean annual runoff as a function of climate aridity. Furthermore, these behavioral combinations are mostly consistent with the qualitative picture presented in the Dunne diagram, indicating clearly the commonality between the Budyko curve and the Dunne diagram. These analyses also suggest clear interrelationships amongst the "behavioral" climate, soil, and topography parameter combinations, implying these catchment properties may be constrained to be codependent in order to satisfy the Budyko curve.

Climate modelling, uncertainty and responses to predictions of change

International Nuclear Information System (INIS)

Henderson-Sellers, A.

1996-01-01

Article 4.1(F) of the Framework Convention on Climate Change commits all parties to take climate change considerations into account, to the extent feasible, in relevant social, economic and environmental policies and actions and to employ methods such as impact assessments to minimize adverse effects of climate change. This could be achieved by, inter alia, incorporating climate change risk assessment into development planning processes, i.e. relating climatic change to issues of habitability and sustainability. Adaptation is an ubiquitous and beneficial natural and human strategy. Future adaptation (adjustment) to climate is inevitable at the least to decrease the vulnerability to current climatic impacts. An urgent issue is the mismatch between the predictions of global climatic change and the need for information on local to regional change in order to develop adaptation strategies. Mitigation efforts are essential since the more successful mitigation activities are, the less need there will be for adaptation responses. And, mitigation responses can be global (e.g. a uniform percentage reduction in greenhouse gas emissions) while adaptation responses will be local to regional in character and therefore depend upon confident predictions of regional climatic change. The dilemma facing policymakers is that scientists have considerable confidence in likely global climatic changes but virtually zero confidence in regional changes. Mitigation and adaptation strategies relevant to climatic change can most usefully be developed in the context of sound understanding of climate, especially the near-surface continental climate, permitting discussion of societally relevant issues. But, climate models can't yet deliver this type of regionally and locationally specific prediction and some aspects of current research even seem to indicate increased uncertainty. These topics are explored in this paper using the specific example of the prediction of land-surface climate changes

National Forest management options in response to climate change

Science.gov (United States)

Forest Service U.S. Department of Agriculture

2009-01-01

The effect of climate change on ecosystem structure, function, and services will depend on the ecosystem's degree of sensitivity to climate change, the natural ability of plants and animals to adapt, and the availability of effective management options. Sensitivity to climate change is a function of ecosystem health and environmental stresses such as air pollution...

Fraternities and Sororities Shaping the Campus Climate of Personal and Social Responsibility

Science.gov (United States)

Barnhardt, Cassie L.

2014-01-01

Data from 9,760 college students on 20 campuses were used to explore the extent to which fraternity and sorority organizations assert an influence over the manner in which students experience the climate for personal and social responsibility while in college. Results demonstrated greater exposure to fraternities and sororities can function to…

Plasticity and genetic adaptation mediate amphibian and reptile responses to climate change

Science.gov (United States)

Urban, Mark C; Richardson, Jonathan L; Freidenfelds, Nicole A

2014-01-01

Phenotypic plasticity and genetic adaptation are predicted to mitigate some of the negative biotic consequences of climate change. Here, we evaluate evidence for plastic and evolutionary responses to climate variation in amphibians and reptiles via a literature review and meta-analysis. We included studies that either document phenotypic changes through time or space. Plasticity had a clear and ubiquitous role in promoting phenotypic changes in response to climate variation. For adaptive evolution, we found no direct evidence for evolution of amphibians or reptiles in response to climate change over time. However, we found many studies that documented adaptive responses to climate along spatial gradients. Plasticity provided a mixture of adaptive and maladaptive responses to climate change, highlighting that plasticity frequently, but not always, could ameliorate climate change. Based on our review, we advocate for more experiments that survey genetic changes through time in response to climate change. Overall, plastic and genetic variation in amphibians and reptiles could buffer some of the formidable threats from climate change, but large uncertainties remain owing to limited data. PMID:24454550

The response of glaciers to climate change

NARCIS (Netherlands)

Klok, Elisabeth Jantina

2003-01-01

The research described in this thesis addresses two aspects of the response of glaciers to climate change. The first aspect deals with the physical processes that govern the interaction between glaciers and climate change and was treated by (1) studying the spatial and temporal variation of the

Multi-wheat-model ensemble responses to interannual climatic variability

DEFF Research Database (Denmark)

Ruane, A C; Hudson, N I; Asseng, S

2016-01-01

We compare 27 wheat models' yield responses to interannual climate variability, analyzed at locations in Argentina, Australia, India, and The Netherlands as part of the Agricultural Model Intercomparison and Improvement Project (AgMIP) Wheat Pilot. Each model simulated 1981–2010 grain yield, and ......-term warming, suggesting that additional processes differentiate climate change impacts from observed climate variability analogs and motivating continuing analysis and model development efforts.......We compare 27 wheat models' yield responses to interannual climate variability, analyzed at locations in Argentina, Australia, India, and The Netherlands as part of the Agricultural Model Intercomparison and Improvement Project (AgMIP) Wheat Pilot. Each model simulated 1981–2010 grain yield, and we...... evaluate results against the interannual variability of growing season temperature, precipitation, and solar radiation. The amount of information used for calibration has only a minor effect on most models' climate response, and even small multi-model ensembles prove beneficial. Wheat model clusters reveal...

How weather impacts the forced climate response

Energy Technology Data Exchange (ETDEWEB)

Kirtman, Ben P. [University of Miami, Division of Meteorology and Physical Oceanography, Rosenstiel School for Atmospheric and Marine Science, Miami, FL (United States); Center for Ocean-Land-Atmosphere Studies, Calverton, MD (United States); Schneider, Edwin K.; Straus, David M. [George Mason University, Department of Atmospheric, Oceanic and Earth Sciences, Fairfax, VA (United States); Center for Ocean-Land-Atmosphere Studies, Calverton, MD (United States); Min, Dughong; Burgman, Robert [University of Miami, Division of Meteorology and Physical Oceanography, Rosenstiel School for Atmospheric and Marine Science, Miami, FL (United States)

2011-12-15

The new interactive ensemble modeling strategy is used to diagnose how noise due to internal atmospheric dynamics impacts the forced climate response during the twentieth century (i.e., 1870-1999). The interactive ensemble uses multiple realizations of the atmospheric component model coupled to a single realization of the land, ocean and ice component models in order to reduce the noise due to internal atmospheric dynamics in the flux exchange at the interface of the component models. A control ensemble of so-called climate of the twentieth century simulations of the Community Climate Simulation Model version 3 (CCSM3) are compared with a similar simulation with the interactive ensemble version of CCSM3. Despite substantial differences in the overall mean climate, the global mean trends in surface temperature, 500 mb geopotential and precipitation are largely indistinguishable between the control ensemble and the interactive ensemble. Large differences in the forced response; however, are detected particularly in the surface temperature of the North Atlantic. Associated with the forced North Atlantic surface temperature differences are local differences in the forced precipitation and a substantial remote rainfall response in the deep tropical Pacific. We also introduce a simple variance analysis to separately compare the variance due to noise and the forced response. We find that the noise variance is decreased when external forcing is included. In terms of the forced variance, we find that the interactive ensemble increases this variance relative to the control. (orig.)

The radiative heating response to climate change

Science.gov (United States)

Maycock, Amanda

2016-04-01

The structure and magnitude of radiative heating rates in the atmosphere can change markedly in response to climate forcings; diagnosing the causes of these changes can aid in understanding parts of the large-scale circulation response to climate change. This study separates the relative drivers of projected changes in longwave and shortwave radiative heating rates over the 21st century into contributions from radiatively active gases, such as carbon dioxide, ozone and water vapour, and from changes in atmospheric and surface temperatures. Results are shown using novel radiative diagnostics applied to timeslice experiments from the UM-UKCA chemistry-climate model; these online estimates are compared to offline radiative transfer calculations. Line-by-line calculations showing spectrally-resolved changes in heating rates due to different gases will also be presented.

A plant's perspective of extremes: terrestrial plant responses to changing climatic variability.

Science.gov (United States)

Reyer, Christopher P O; Leuzinger, Sebastian; Rammig, Anja; Wolf, Annett; Bartholomeus, Ruud P; Bonfante, Antonello; de Lorenzi, Francesca; Dury, Marie; Gloning, Philipp; Abou Jaoudé, Renée; Klein, Tamir; Kuster, Thomas M; Martins, Monica; Niedrist, Georg; Riccardi, Maria; Wohlfahrt, Georg; de Angelis, Paolo; de Dato, Giovanbattista; François, Louis; Menzel, Annette; Pereira, Marízia

2013-01-01

We review observational, experimental, and model results on how plants respond to extreme climatic conditions induced by changing climatic variability. Distinguishing between impacts of changing mean climatic conditions and changing climatic variability on terrestrial ecosystems is generally underrated in current studies. The goals of our review are thus (1) to identify plant processes that are vulnerable to changes in the variability of climatic variables rather than to changes in their mean, and (2) to depict/evaluate available study designs to quantify responses of plants to changing climatic variability. We find that phenology is largely affected by changing mean climate but also that impacts of climatic variability are much less studied, although potentially damaging. We note that plant water relations seem to be very vulnerable to extremes driven by changes in temperature and precipitation and that heat-waves and flooding have stronger impacts on physiological processes than changing mean climate. Moreover, interacting phenological and physiological processes are likely to further complicate plant responses to changing climatic variability. Phenological and physiological processes and their interactions culminate in even more sophisticated responses to changing mean climate and climatic variability at the species and community level. Generally, observational studies are well suited to study plant responses to changing mean climate, but less suitable to gain a mechanistic understanding of plant responses to climatic variability. Experiments seem best suited to simulate extreme events. In models, temporal resolution and model structure are crucial to capture plant responses to changing climatic variability. We highlight that a combination of experimental, observational, and/or modeling studies have the potential to overcome important caveats of the respective individual approaches. © 2012 Blackwell Publishing Ltd.

Range position and climate sensitivity: The structure of among-population demographic responses to climatic variation

Science.gov (United States)

Amburgey, Staci M.; Miller, David A. W.; Grant, Evan H. Campbell; Rittenhouse, Tracy A. G.; Benard, Michael F.; Richardson, Jonathan L.; Urban, Mark C.; Hughson, Ward; Brand, Adrianne B,; Davis, Christopher J.; Hardin, Carmen R.; Paton, Peter W. C.; Raithel, Christopher J.; Relyea, Rick A.; Scott, A. Floyd; Skelly, David K.; Skidds, Dennis E.; Smith, Charles K.; Werner, Earl E.

2018-01-01

Species’ distributions will respond to climate change based on the relationship between local demographic processes and climate and how this relationship varies based on range position. A rarely tested demographic prediction is that populations at the extremes of a species’ climate envelope (e.g., populations in areas with the highest mean annual temperature) will be most sensitive to local shifts in climate (i.e., warming). We tested this prediction using a dynamic species distribution model linking demographic rates to variation in temperature and precipitation for wood frogs (Lithobates sylvaticus) in North America. Using long-term monitoring data from 746 populations in 27 study areas, we determined how climatic variation affected population growth rates and how these relationships varied with respect to long-term climate. Some models supported the predicted pattern, with negative effects of extreme summer temperatures in hotter areas and positive effects on recruitment for summer water availability in drier areas. We also found evidence of interacting temperature and precipitation influencing population size, such as extreme heat having less of a negative effect in wetter areas. Other results were contrary to predictions, such as positive effects of summer water availability in wetter parts of the range and positive responses to winter warming especially in milder areas. In general, we found wood frogs were more sensitive to changes in temperature or temperature interacting with precipitation than to changes in precipitation alone. Our results suggest that sensitivity to changes in climate cannot be predicted simply by knowing locations within the species’ climate envelope. Many climate processes did not affect population growth rates in the predicted direction based on range position. Processes such as species-interactions, local adaptation, and interactions with the physical landscape likely affect the responses we observed. Our work highlights the

How does complex terrain influence responses of carbon and water cycle processes to climate variability and climate change? (Invited)

Science.gov (United States)

Bond, B. J.; Peterson, K.; McKane, R.; Lajtha, K.; Quandt, D. J.; Allen, S. T.; Sell, S.; Daly, C.; Harmon, M. E.; Johnson, S. L.; Spies, T.; Sollins, P.; Abdelnour, A. G.; Stieglitz, M.

2010-12-01

We are pursuing the ambitious goal of understanding how complex terrain influences the responses of carbon and water cycle processes to climate variability and climate change. Our studies take place in H.J. Andrews Experimental Forest, an LTER (Long Term Ecological Research) site situated in Oregon’s central-western Cascade Range. Decades of long-term measurements and intensive research have revealed influences of topography on vegetation patterns, disturbance history, and hydrology. More recent research has shown surprising interactions between microclimates and synoptic weather patterns due to cold air drainage and pooling in mountain valleys. Using these data and insights, in addition to a recent LiDAR (Light Detection and Ranging) reconnaissance and a small sensor network, we are employing process-based models, including “SPA” (Soil-Plant-Atmosphere, developed by Mathew Williams of the University of Edinburgh), and “VELMA” (Visualizing Ecosystems for Land Management Alternatives, developed by Marc Stieglitz and colleagues of the Georgia Institute of Technology) to focus on two important features of mountainous landscapes: heterogeneity (both spatial and temporal) and connectivity (atmosphere-canopy-hillslope-stream). Our research questions include: 1) Do fine-scale spatial and temporal heterogeneity result in emergent properties at the basin scale, and if so, what are they? 2) How does connectivity across ecosystem components affect system responses to climate variability and change? Initial results show that for environmental drivers that elicit non-linear ecosystem responses on the plot scale, such as solar radiation, soil depth and soil water content, fine-scale spatial heterogeneity may produce unexpected emergent properties at larger scales. The results from such modeling experiments are necessarily a function of the supporting algorithms. However, comparisons based on models such as SPA and VELMA that operate at much different spatial scales

Individualized responsibility: 'if climate protection becomes everyone's responsibility, does it end up being no-one's?'

Directory of Open Access Journals (Sweden)

Jennifer Kent

2009-09-01

Full Text Available Whereas global compacts, such as the Kyoto Protocol, have yet to consolidate action from governments on climate change, there has been increasing emphasis and acknowledgement of the role of individuals (as citizens and consumers as contributors to climate change and as responsible agents in mitigating greenhouse gas emissions. Recently, along with the acknowledgement of the threat that anthropogenic climate change presents to the planet, governments and non-government organizations have focused on personal responsibility campaigns targeting individuals and households with a view to stemming the growth of greenhouse gas emissions. The Australian Government, for example, spent $25 million in 2007 on the climate change information campaign targeted to every Australian household, ‘Be Climate Clever: “I can do that”. Such measures centre on “personal, private-sphere ….. behaviour” (Stern 2005: 10786 that focuses on the “choice of goods, services and lifestyles” (WWF-UK 2008: 10 and imply that global greenhouse gas emission reduction targets can be met through the actions of individuals. There is growing concern in some quarters about climate change programs that emphasize individual behaviour change strategies that use “simple and painless steps” (WWF-UK 2008 and “small steps add up” (Accountability and Consumers International 2007 approaches. The emergent fear is that given the urgency of the climate change problem that such approaches will mean important opportunities for citizen-led action will be lost. This paper will explore how notions of individual responsibility have arisen and what the trend towards individualized responsibility may mean for active citizenship on climate change.

Cultural responses to climate change during the late Holocene.

Science.gov (United States)

deMenocal, P B

2001-04-27

Modern complex societies exhibit marked resilience to interannual-to- decadal droughts, but cultural responses to multidecadal-to-multicentury droughts can only be addressed by integrating detailed archaeological and paleoclimatic records. Four case studies drawn from New and Old World civilizations document societal responses to prolonged drought, including population dislocations, urban abandonment, and state collapse. Further study of past cultural adaptations to persistent climate change may provide valuable perspective on possible responses of modern societies to future climate change.

Regional and Global Climate Response to Anthropogenic SO2 Emissions from China in Three Climate Models

Science.gov (United States)

Kasoar, M.; Voulgarakis, Apostolos; Lamarque, Jean-Francois; Shindell, Drew T.; Bellouin, Nicholas; Collins, William J.; Faluvegi, Greg; Tsigaridis, Kostas

2016-01-01

We use the HadGEM3-GA4, CESM1, and GISS ModelE2 climate models to investigate the global and regional aerosol burden, radiative flux, and surface temperature responses to removing anthropogenic sulfur dioxide (SO2) emissions from China. We find that the models differ by up to a factor of 6 in the simulated change in aerosol optical depth (AOD) and shortwave radiative flux over China that results from reduced sulfate aerosol, leading to a large range of magnitudes in the regional and global temperature responses. Two of the three models simulate a near-ubiquitous hemispheric warming due to the regional SO2 removal, with similarities in the local and remote pattern of response, but overall with a substantially different magnitude. The third model simulates almost no significant temperature response. We attribute the discrepancies in the response to a combination of substantial differences in the chemical conversion of SO2 to sulfate, translation of sulfate mass into AOD, cloud radiative interactions, and differences in the radiative forcing efficiency of sulfate aerosol in the models. The model with the strongest response (HadGEM3-GA4) compares best with observations of AOD regionally, however the other two models compare similarly (albeit poorly) and still disagree substantially in their simulated climate response, indicating that total AOD observations are far from sufficient to determine which model response is more plausible. Our results highlight that there remains a large uncertainty in the representation of both aerosol chemistry as well as direct and indirect aerosol radiative effects in current climate models, and reinforces that caution must be applied when interpreting the results of modelling studies of aerosol influences on climate. Model studies that implicate aerosols in climate responses should ideally explore a range of radiative forcing strengths representative of this uncertainty, in addition to thoroughly evaluating the models used against

A plant’s perspective of extremes: Terrestrial plant responses to changing climatic variability

Science.gov (United States)

Reyer, C.; Leuzinger, S.; Rammig, A.; Wolf, A.; Bartholomeus, R. P.; Bonfante, A.; de Lorenzi, F.; Dury, M.; Gloning, P.; Abou Jaoudé, R.; Klein, T.; Kuster, T. M.; Martins, M.; Niedrist, G.; Riccardi, M.; Wohlfahrt, G.; de Angelis, P.; de Dato, G.; François, L.; Menzel, A.; Pereira, M.

2013-01-01

We review observational, experimental and model results on how plants respond to extreme climatic conditions induced by changing climatic variability. Distinguishing between impacts of changing mean climatic conditions and changing climatic variability on terrestrial ecosystems is generally underrated in current studies. The goals of our review are thus (1) to identify plant processes that are vulnerable to changes in the variability of climatic variables rather than to changes in their mean, and (2) to depict/evaluate available study designs to quantify responses of plants to changing climatic variability. We find that phenology is largely affected by changing mean climate but also that impacts of climatic variability are much less studied but potentially damaging. We note that plant water relations seem to be very vulnerable to extremes driven by changes in temperature and precipitation and that heatwaves and flooding have stronger impacts on physiological processes than changing mean climate. Moreover, interacting phenological and physiological processes are likely to further complicate plant responses to changing climatic variability. Phenological and physiological processes and their interactions culminate in even more sophisticated responses to changing mean climate and climatic variability at the species and community level. Generally, observational studies are well suited to study plant responses to changing mean climate, but less suitable to gain a mechanistic understanding of plant responses to climatic variability. Experiments seem best suited to simulate extreme events. In models, temporal resolution and model structure are crucial to capture plant responses to changing climatic variability. We highlight that a combination of experimental, observational and /or modeling studies have the potential to overcome important caveats of the respective individual approaches. PMID:23504722

Effects of global climate change on the US forest sector: response functions derived from a dynamic resource and market simulator.

Science.gov (United States)

Bruce A. McCarl; Darius M. Adams; Ralph J. Alig; Diana Burton; Chi-Chung. Chen

2000-01-01

A multiperiod, regional, mathematical programming economic model is used to evaluate the potential economic impacts of global climatic change on the US forest sector. A wide range of scenarios for the biological response of forests to climate change are developed, ranging from small to large changes in forest growth rates. These scenarios are simulated in the economic...

Trophic level responses differ as climate warms in Ireland

Science.gov (United States)

Donnelly, Alison; Yu, Rong; Liu, Lingling

2015-08-01

Effective ecosystem functioning relies on successful species interaction. However, this delicate balance may be disrupted if species do not respond to environmental change at a similar rate. Here we examine trends in the timing of spring phenophases of groups of species occupying three trophic levels as a potential indicator of ecosystem response to climate warming in Ireland. The data sets were of varying length (1976-2009) and from varying locations: (1) timing of leaf unfolding and May Shoot of a range of broadleaf and conifer tree species, (2) first appearance dates of a range of moth species, and (3) first arrival dates of a range of spring migrant birds. All three groups revealed a statistically significant ( Pphenology that was driven by rising spring temperature ( P<0.05; 0.45 °C /decade). However, the rate of advance was greater for moths (1.8 days/year), followed by birds (0.37 days/year) and trees (0.29 days/year). In addition, the length of time between (1) moth emergence and leaf unfolding and (2) moth emergence and bird arrival decreased significantly ( P<0.05 and P<0.001, respectively), indicating a decrease in the timing between food supply and demand. These differing trophic level response rates demonstrate the potential for a mismatch in the timing of interdependent phenophases as temperatures rise. Even though these data were not specifically collected to examine climate warming impacts, we conclude that such data may be used as an early warning indicator and as a means to monitor the potential for future ecosystem disruption to occur as climate warms.

Climate Science and the Responsibilities of Fossil Fuel Companies for Climate Damages and Adaptation

Science.gov (United States)

Frumhoff, P. C.; Ekwurzel, B.

2017-12-01

Policymakers in several jurisdictions are now considering whether fossil fuel companies might bear some legal responsibility for climate damages and the costs of adaptation to climate change potentially traceable to the emissions from their marketed products. Here, we explore how scientific research, outreach and direct engagement with industry leaders and shareholders have informed and may continue to inform such developments. We present the results of new climate model research quantifying the contribution of carbon dioxide and methane emissions traced to individual fossil fuel companies to changes in global temperature and sea level; explore the impact of such research and outreach on both legal and broader societal consideration of company responsibility; and discuss the opportunities and challenges for scientists to engage in further work in this area.

Climate change damage functions in LCA

DEFF Research Database (Denmark)

Callesen, Ingeborg; Beier, Claus; Bagger Jørgensen, Rikke

, their properties, goods and services. In: Climate change 2007. Cambridge, Cambridge University Press, p. 211-272. [2] Mikkelsen TN, Beier C, et al. (2008) Experimental design of multifactor climate change experiments with elevated CO2, warming and drought – the CLIMAITE project. Functional Ecology, 22, 185-195. [3...... will be variable (2). Modeling exercises suggest large-scale range shifts of the major biomes of the world (1). The unknown magnitude of future GHG emissions and the complexity of the climate-carbon system induce large uncertainties in the projected changes. A changed climate may result in new interactions and new...... directions of ecosystem change due to differing adaptive capacities and new species assemblages. Within the framework ‘ecosystem services’ both marketed and non-marketed utilities of the natural environment are formulated (3). Provisioning, cultural, supporting, and regulating ecosystem services have been...

Contrasted demographic responses facing future climate change in Southern Ocean seabirds.

Science.gov (United States)

Barbraud, Christophe; Rivalan, Philippe; Inchausti, Pablo; Nevoux, Marie; Rolland, Virginie; Weimerskirch, Henri

2011-01-01

1. Recent climate change has affected a wide range of species, but predicting population responses to projected climate change using population dynamics theory and models remains challenging, and very few attempts have been made. The Southern Ocean sea surface temperature and sea ice extent are projected to warm and shrink as concentrations of atmospheric greenhouse gases increase, and several top predator species are affected by fluctuations in these oceanographic variables. 2. We compared and projected the population responses of three seabird species living in sub-tropical, sub-Antarctic and Antarctic biomes to predicted climate change over the next 50 years. Using stochastic population models we combined long-term demographic datasets and projections of sea surface temperature and sea ice extent for three different IPCC emission scenarios (from most to least severe: A1B, A2, B1) from general circulation models of Earth's climate. 3. We found that climate mostly affected the probability to breed successfully, and in one case adult survival. Interestingly, frequent nonlinear relationships in demographic responses to climate were detected. Models forced by future predicted climatic change provided contrasted population responses depending on the species considered. The northernmost distributed species was predicted to be little affected by a future warming of the Southern Ocean, whereas steep declines were projected for the more southerly distributed species due to sea surface temperature warming and decrease in sea ice extent. For the most southerly distributed species, the A1B and B1 emission scenarios were respectively the most and less damaging. For the two other species, population responses were similar for all emission scenarios. 4. This is among the first attempts to study the demographic responses for several populations with contrasted environmental conditions, which illustrates that investigating the effects of climate change on core population dynamics

Functional Resilience against Climate-Driven Extinctions - Comparing the Functional Diversity of European and North American Tree Floras.

Directory of Open Access Journals (Sweden)

Mario Liebergesell

Full Text Available Future global change scenarios predict a dramatic loss of biodiversity for many regions in the world, potentially reducing the resistance and resilience of ecosystem functions. Once before, during Plio-Pleistocene glaciations, harsher climatic conditions in Europe as compared to North America led to a more depauperate tree flora. Here we hypothesize that this climate driven species loss has also reduced functional diversity in Europe as compared to North America. We used variation in 26 traits for 154 North American and 66 European tree species and grid-based co-occurrences derived from distribution maps to compare functional diversity patterns of the two continents. First, we identified similar regions with respect to contemporary climate in the temperate zone of North America and Europe. Second, we compared the functional diversity of both continents and for the climatically similar sub-regions using the functional dispersion-index (FDis and the functional richness index (FRic. Third, we accounted in these comparisons for grid-scale differences in species richness, and, fourth, investigated the associated trait spaces using dimensionality reduction. For gymnosperms we find similar functional diversity on both continents, whereas for angiosperms functional diversity is significantly greater in Europe than in North America. These results are consistent across different scales, for climatically similar regions and considering species richness patterns. We decomposed these differences in trait space occupation into differences in functional diversity vs. differences in functional identity. We show that climate-driven species loss on a continental scale might be decoupled from or at least not linearly related to changes in functional diversity. This might be important when analyzing the effects of climate-driven biodiversity change on ecosystem functioning.

Mangroves Response to Climate Change: A Review of Recent Findings on Mangrove Extension and Distribution

Directory of Open Access Journals (Sweden)

Mario D.P. Godoy

2015-06-01

Full Text Available Mangroves function as a natural coastline protection for erosion and inundation, providing important environmental services. Due to their geographical distribution at the continent-ocean interface, the mangrove habitat may suffer heavy impacts from global climate change, maximized by local human activities occurring in a given coastal region. This review analyzed the literature published over the last 25 years, on the documented response of mangroves to environmental change caused by global climate change, taking into consideration 104 case studies and predictive modeling, worldwide. Most studies appeared after the year 2000, as a response to the 1997 IPCC report. Although many reports showed that the world's mangrove area is decreasing due to direct anthropogenic pressure, several others, however, showed that in a variety of habitats mangroves are expanding as a response to global climate change. Worldwide, pole ward migration is extending the latitudinal limits of mangroves due to warmer winters and decreasing the frequency of extreme low temperatures, whereas in low-lying coastal plains, mangroves are migrating landward due to sea level rise, as demonstrated for the NE Brazilian coast. Taking into consideration climate change alone, mangroves in most areas will display a positive response. In some areas however, such as low-lying oceanic islands, such as in the Pacific and the Caribbean, and constrained coastlines, such as the SE Brazilian coast, mangroves will most probably not survive.

Adaptive and plastic responses of Quercus petraea populations to climate across Europe.

Science.gov (United States)

Sáenz-Romero, Cuauhtémoc; Lamy, Jean-Baptiste; Ducousso, Alexis; Musch, Brigitte; Ehrenmann, François; Delzon, Sylvain; Cavers, Stephen; Chałupka, Władysław; Dağdaş, Said; Hansen, Jon Kehlet; Lee, Steve J; Liesebach, Mirko; Rau, Hans-Martin; Psomas, Achilleas; Schneck, Volker; Steiner, Wilfried; Zimmermann, Niklaus E; Kremer, Antoine

2017-07-01

How temperate forests will respond to climate change is uncertain; projections range from severe decline to increased growth. We conducted field tests of sessile oak (Quercus petraea), a widespread keystone European forest tree species, including more than 150 000 trees sourced from 116 geographically diverse populations. The tests were planted on 23 field sites in six European countries, in order to expose them to a wide range of climates, including sites reflecting future warmer and drier climates. By assessing tree height and survival, our objectives were twofold: (i) to identify the source of differential population responses to climate (genetic differentiation due to past divergent climatic selection vs. plastic responses to ongoing climate change) and (ii) to explore which climatic variables (temperature or precipitation) trigger the population responses. Tree growth and survival were modeled for contemporary climate and then projected using data from four regional climate models for years 2071-2100, using two greenhouse gas concentration trajectory scenarios each. Overall, results indicated a moderate response of tree height and survival to climate variation, with changes in dryness (either annual or during the growing season) explaining the major part of the response. While, on average, populations exhibited local adaptation, there was significant clinal population differentiation for height growth with winter temperature at the site of origin. The most moderate climate model (HIRHAM5-EC; rcp4.5) predicted minor decreases in height and survival, while the most extreme model (CCLM4-GEM2-ES; rcp8.5) predicted large decreases in survival and growth for southern and southeastern edge populations (Hungary and Turkey). Other nonmarginal populations with continental climates were predicted to be severely and negatively affected (Bercé, France), while populations at the contemporary northern limit (colder and humid maritime regions; Denmark and Norway) will

Climate-related environmental stress in intertidal grazers: scaling-up biochemical responses to assemblage-level processes

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Elena Maggi

2016-10-01

Full Text Available Background Organisms are facing increasing levels of environmental stress under climate change that may severely affect the functioning of biological systems at different levels of organization. Growing evidence suggests that reduction in body size is a universal response of organisms to global warming. However, a clear understanding of whether extreme climate events will impose selection directly on phenotypic plastic responses and how these responses affect ecological interactions has remained elusive. Methods We experimentally investigated the effects of extreme desiccation events on antioxidant defense mechanisms of a rocky intertidal gastropod (Patella ulyssiponensis, and evaluated how these effects scaled-up at the population and assemblage levels. Results With increasing levels of desiccation stress, limpets showed significant lower levels of total glutathione, tended to grow less and had reduced per capita interaction strength on their resources. Discussion Results suggested that phenotypic plasticity (i.e., reduction in adults’ body size allowed buffering biochemical responses to stress to scale-up at the assemblage level. Unveiling the linkages among different levels of biological organization is key to develop indicators that can anticipate large-scale ecological impacts of climate change.

Production functions for climate policy modeling. An empirical analysis

International Nuclear Information System (INIS)

Van der Werf, Edwin

2008-01-01

Quantitative models for climate policy modeling differ in the production structure used and in the sizes of the elasticities of substitution. The empirical foundation for both is generally lacking. This paper estimates the parameters of 2-level CES production functions with capital, labour and energy as inputs, and is the first to systematically compare all nesting structures. Using industry-level data from 12 OECD countries, we find that the nesting structure where capital and labour are combined first, fits the data best, but for most countries and industries we cannot reject that all three inputs can be put into one single nest. These two nesting structures are used by most climate models. However, while several climate policy models use a Cobb-Douglas function for (part of the) production function, we reject elasticities equal to one, in favour of considerably smaller values. Finally we find evidence for factor-specific technological change. With lower elasticities and with factor-specific technological change, some climate policy models may find a bigger effect of endogenous technological change on mitigating the costs of climate policy. (author)

Response of switchgrass yield to future climate change

International Nuclear Information System (INIS)

Tulbure, Mirela G; Wimberly, Michael C; Owens, Vance N

2012-01-01

A climate envelope approach was used to model the response of switchgrass, a model bioenergy species in the United States, to future climate change. The model was built using general additive models (GAMs), and switchgrass yields collected at 45 field trial locations as the response variable. The model incorporated variables previously shown to be the main determinants of switchgrass yield, and utilized current and predicted 1 km climate data from WorldClim. The models were run with current WorldClim data and compared with results of predicted yield obtained using two climate change scenarios across three global change models for three time steps. Results did not predict an increase in maximum switchgrass yield but showed an overall shift in areas of high switchgrass productivity for both cytotypes. For upland cytotypes, the shift in high yields was concentrated in northern and north-eastern areas where there were increases in average growing season temperature, whereas for lowland cultivars the areas where yields were projected to increase were associated with increases in average early growing season precipitation. These results highlight the fact that the influences of climate change on switchgrass yield are spatially heterogeneous and vary depending on cytotype. Knowledge of spatial distribution of suitable areas for switchgrass production under climate change should be incorporated into planning of current and future biofuel production. Understanding how switchgrass yields will be affected by future changes in climate is important for achieving a sustainable biofuels economy. (letter)

Modeling maize response to climate modification in Hungary

OpenAIRE

Angela Anda

2006-01-01

Modeling provides a tool for a better understanding of the modified plant behaviour that results from various climatic differences. The present study provides new information about the physiological processes in maize (Zea mays L.) in response to climatic changes. The aim was to help local farmers adapt to climate modifications in Hungary and mitigate the future consequences of these changes. A simulation model was applied to estimate the possible feedback on crop properties and elevated CO2....

Eyewitness Accounts on Climate Variability and the Responses: Perspectives from Farmers

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Jiban Mani Poudel

2012-06-01

Full Text Available People with different socio-cultural arrangements havedifferent experiences and responses to climatic variability. The place specific experiences and responses at community level still remain a little explored issue in the discourse of climate change research. This paper deals with local experiences of climatic variability which have been monitoring by locals in their lifetime, on the one hand, and, on the other, explore their responses or coping mechanisms which they have been practicing to mitigate with climatic risks. Moreover, farmers’ experiences were documented in term of observed climatic variability in their lifetime focusing on qualitative data. I have used eyewitness accounts and hearsays to document their experiences of climatic variability. Moreover, farmers have developed various coping mechanisms such as indigenous knowledge, utilize kinship based social network, environment friendly cropping practices, and use of alternative sources of water (water-tanker, well-water for irrigation, arrange rain-making ritual to cope with climatic uncertainty in their lifetime.DOI: http://dx.doi.org/10.3126/dsaj.v5i0.6362Dhaulagiri Journal of Sociology and Anthropology Vol. 5, 2011: 171-90

Catchment Classification: Connecting Climate, Structure and Function

Science.gov (United States)

Sawicz, K. A.; Wagener, T.; Sivapalan, M.; Troch, P. A.; Carrillo, G. A.

2010-12-01

Hydrology does not yet possess a generally accepted catchment classification framework. Such a classification framework needs to: [1] give names to things, i.e. the main classification step, [2] permit transfer of information, i.e. regionalization of information, [3] permit development of generalizations, i.e. to develop new theory, and [4] provide a first order environmental change impact assessment, i.e., the hydrologic implications of climate, land use and land cover change. One strategy is to create a catchment classification framework based on the notion of catchment functions (partitioning, storage, and release). Results of an empirical study presented here connects climate and structure to catchment function (in the form of select hydrologic signatures), based on analyzing over 300 US catchments. Initial results indicate a wide assortment of signature relationships with properties of climate, geology, and vegetation. The uncertainty in the different regionalized signatures varies widely, and therefore there is variability in the robustness of classifying ungauged basins. This research provides insight into the controls of hydrologic behavior of a catchment, and enables a classification framework applicable to gauged and ungauged across the study domain. This study sheds light on what we can expect to achieve in mapping climate, structure and function in a top-down manner. Results of this study complement work done using a bottom-up physically-based modeling framework to generalize this approach (Carrillo et al., this session).

A global model of malaria climate sensitivity: comparing malaria response to historic climate data based on simulation and officially reported malaria incidence

Directory of Open Access Journals (Sweden)

Edlund Stefan

2012-09-01

Full Text Available Abstract Background The role of the Anopheles vector in malaria transmission and the effect of climate on Anopheles populations are well established. Models of the impact of climate change on the global malaria burden now have access to high-resolution climate data, but malaria surveillance data tends to be less precise, making model calibration problematic. Measurement of malaria response to fluctuations in climate variables offers a way to address these difficulties. Given the demonstrated sensitivity of malaria transmission to vector capacity, this work tests response functions to fluctuations in land surface temperature and precipitation. Methods This study of regional sensitivity of malaria incidence to year-to-year climate variations used an extended Macdonald Ross compartmental disease model (to compute malaria incidence built on top of a global Anopheles vector capacity model (based on 10 years of satellite climate data. The predicted incidence was compared with estimates from the World Health Organization and the Malaria Atlas. The models and denominator data used are freely available through the Eclipse Foundation’s Spatiotemporal Epidemiological Modeller (STEM. Results Although the absolute scale factor relating reported malaria to absolute incidence is uncertain, there is a positive correlation between predicted and reported year-to-year variation in malaria burden with an averaged root mean square (RMS error of 25% comparing normalized incidence across 86 countries. Based on this, the proposed measure of sensitivity of malaria to variations in climate variables indicates locations where malaria is most likely to increase or decrease in response to specific climate factors. Bootstrapping measures the increased uncertainty in predicting malaria sensitivity when reporting is restricted to national level and an annual basis. Results indicate a potential 20x improvement in accuracy if data were available at the level ISO 3166–2

Tourists’ Environmentally Responsible Behavior in Response to Climate Change and Tourist Experiences in Nature-Based Tourism

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Ju Hyoung Han

2016-07-01

Full Text Available Nature-based tourism destinations—locations in which economic viability and environmental responsibility are sought—are sensitive to climate change and its effects on important environmental components of the tourism areas. To meet the dual roles, it is important for destination marketers and resources managers to provide quality experiences for tourists and to induce tourists’ environmentally responsible behavior in such destinations. This study documents the importance of perceptions toward climate change and tourist experiences in determining tourists’ environmentally responsible behavior while enjoying holidays at nature-based tourism destinations in Jeju Island, South Korea. Two hundred and eleven Korean and 204 Chinese tourists marked dominant tourist arrivals to the island, and responded to the survey questionnaire. Results showed that perceptions toward climate change and tourist experiences affect Korean tourists’ environmentally responsible behavior intentions, whereas tourist experiences—not perceptions toward climate change—only significantly affect Chinese tourists’ behavior intention. In a nature-based tourism context under the pressure of climate change and adverse environmental effects as consequences of tourism activities, resources managers and destination marketers need to develop environmental campaigns or informative tourist programs to formulate environmentally responsible behavior as well as to increase tourist quality experiences among domestic and international tourists.

Predicting species-specific responses of fungi to climatic variation using historical records.

Science.gov (United States)

Diez, Jeffrey M; James, Timothy Y; McMunn, Marshall; Ibáñez, Inés

2013-10-01

Although striking changes have been documented in plant and animal phenology over the past century, less is known about how the fungal kingdom's phenology has been changing. A few recent studies have documented changes in fungal fruiting in Europe in the last few decades, but the geographic and taxonomic extent of these changes, the mechanisms behind these changes, and their relationships to climate are not well understood. Here, we analyzed herbarium data of 274 species of fungi from Michigan to test the hypotheses that fruiting times of fungi depend on annual climate and that responses depend on taxonomic and functional groups. We show that the fungal community overall fruits later in warmer and drier years, which has led to a shift toward later fruiting dates for autumn-fruiting species, consistent with existing evidence. However, we also show that these effects are highly variable among species and are partly explained by basic life-history characteristics. Resulting differences in climate sensitivities are expected to affect community structure as climate changes. This study provides a unique picture of the climate dependence of fungal phenology in North America and an approach for quantifying how individual species and broader fungal communities will respond to ongoing climate change. © 2013 John Wiley & Sons Ltd.

Atmospheric CO2 and climate: Importance of the transient response

International Nuclear Information System (INIS)

Schneider, S.H.; Thompson, S.L.

1981-01-01

Preliminary studies suggest that the thermal inertia of the upper layers of the oceans, combined with vertical mixing of deeper oceanic waters, could delay the response of the globally averaged surface temperature to an increasing atmospheric CO 2 concentration by a decade or so relative to equilibrium calculations. This study extends the global analysis of the transient response to zonal averages, using a hierarchy of simple energy balance models and vertical mixing assumptions for water exchange between upper and deeper oceanic layers. It is found that because of the latitudinal dependence of both thermal inertia and radiative and dynamic energy exchange mechanisms, the approach toward equilibrium of the surface temperature of various regions of the earth will be significantly different from the global average approach. This suggests that the actual time evolution of the horizontal surface temperature gradients--and any associated regional climatic anomalies-may well be significantly different from that suggested by equilibrium climatic modeling simulations (or those computed with a highly unrealistic geographic distribution of ocean thermal capacity). Also, the transient response as a function of latitude is significantly different between globally equivalent CO 2 and solar constant focusing runs. It is suggested that the nature of the transient response is a major uncertainty in characterizing the CO 2 problem and that study of this topic should become a major priority for future research. An appendix puts this issue in the context of the overall CO 2 problem

77 FR 76034 - National Water Program 2012 Strategy: Response to Climate Change

Science.gov (United States)

2012-12-26

... Strategy: Response to Climate Change AGENCY: Environmental Protection Agency (EPA). ACTION: Notice of... Program 2012 Strategy: Response to Climate Change'' (2012 Strategy). The Strategy describes a set of long-term visions and goals for the management of water resources in light of climate change and charts key...

Climate change and our responsibilities as chemists

Directory of Open Access Journals (Sweden)

Bassam Z. Shakhashiri

2014-01-01

Full Text Available For almost all of 4.5 billion years, natural forces have shaped Earth’s environment. But, during the past century, as a result of the Industrial Revolution, which has had enormous benefits for humans, the effects of human activities have become the main driver for climate change. The increase of atmospheric carbon dioxide caused by burning fossil fuels for energy to power the revolution causes an energy imbalance between incoming solar radiation and outgoing planetary emission. The imbalance is warming the planet and causing the atmosphere and oceans to warm, ice to melt, sea level to rise, and weather extremes to increase. In addition, dissolution of part of the carbon dioxide in the oceans is causing them to acidify, with possible negative effects on marine biota. As citizens of an interconnected global society and scientists who have the background to understand climate change, we have a responsibility first to understand the science. One resource that is available to help is the American Chemical Society Climate Science Toolkit, www.acs.org/climatescience. With this understanding our further responsibility as citizen scientists is to engage others in deliberative discussions on the science, to take actions ourselves to adapt to and mitigate human-caused climate change, and urge others to follow our example.

Modelling exploratio of the future of European beech (Fagus sylvatica L.) under climate change - Range, abundance, genetic diversity and adaptive response

NARCIS (Netherlands)

Kramer, K.; Degen, B.; Buschbom, J.; Hickler, T.; Thuiller, W.; Sykes, M.T.; Winter, de W.P.

2010-01-01

We explored impacts of climate change on the geographic distribution of European beech by applying state of the art statistical and process-based models, and assessed possible climate change impacts on both adaptive capacity in the centre of its distribution and adaptive responses of functional

Bridging the Divide: Linking Genomics to Ecosystem Responses to Climate Change: Final Report

Energy Technology Data Exchange (ETDEWEB)

Smith, Melinda D.

2014-03-15

Over the project period, we have addressed the following objectives: 1) assess the effects of altered precipitation patterns (i.e., increased variability in growing season precipitation) on genetic diversity of the dominant C4 grass species, Andropogon gerardii, and 2) experimentally assess the impacts of extreme climatic events (heat wave, drought) on responses of the dominant C4 grasses, A. gerardii and Sorghastrum nutans, and the consequences of these response for community and ecosystem structure and function. Below is a summary of how we have addressed these objectives. Objective 1 After ten years of altered precipitation, we found the number of genotypes of A. gerardii was significantly reduced compared to the ambient precipitation treatments (Avolio et al., 2013a). Although genotype number was reduced, the remaining genotypes were less related to one another indicating that the altered precipitation treatment was selecting for increasingly dissimilar genomes (based on mean pairwise Dice distance among individuals). For the four key genotypes that displayed differential abundances depending on the precipitation treatment (G1, G4, and G11 in the altered plots and G2 in the ambient plots), we identified phenotypic differences in the field that could account for ecological sorting (Avolio & Smith, 2013a). The three altered rainfall genotypes also have very different phenotypic traits in the greenhouse in response to different soil moisture availabilities (Avolio and Smith, 2013c). Two of the genotypes that increased in abundance in the altered precipitation plots had greater allocation to root biomass (G4 and G11), while G1 allocated more biomass aboveground. These phenotypic differences among genotypes suggests that changes in genotypic structure between the altered and the ambient treatments has likely occurred via niche differentiation, driven by changes in soil moisture dynamics (reduced mean, increased variability and changes in the depth distribution of

Implications for Climate Sensitivity from the Response to Individual Forcings

Science.gov (United States)

Marvel, Kate; Schmidt, Gavin A.; Miller, Ron L.; Nazarenko, Larissa

2015-01-01

Climate sensitivity to doubled CO2 is a widely-used metric of the large-scale response to external forcing. Climate models predict a wide range for two commonly used definitions: the transient climate response (TCR: the warming after 70 years of CO2 concentrations that riseat 1 per year), and the equilibrium climate sensitivity (ECS: the equilibrium temperature change following a doubling of CO2 concentrations). Many observational datasets have been used to constrain these values, including temperature trends over the recent past 16, inferences from paleo-climate and process-based constraints from the modern satellite eras. However, as the IPCC recently reported different classes of observational constraints produce somewhat incongruent ranges. Here we show that climate sensitivity estimates derived from recent observations must account for the efficacy of each forcing active during the historical period. When we use single forcing experiments to estimate these efficacies and calculate climate sensitivity from the observed twentieth-century warming, our estimates of both TCR and ECS are revised upward compared to previous studies, improving the consistency with independent constraints.

Relevant climate response tests for stratospheric aerosol injection: A combined ethical and scientific analysis

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Lenferna, Georges Alexandre; Russotto, Rick D.; Tan, Amanda; Gardiner, Stephen M.; Ackerman, Thomas P.

2017-06-01

In this paper, we focus on stratospheric sulfate injection as a geoengineering scheme, and provide a combined scientific and ethical analysis of climate response tests, which are a subset of outdoor tests that would seek to impose detectable and attributable changes to climate variables on global or regional scales. We assess the current state of scientific understanding on the plausibility and scalability of climate response tests. Then, we delineate a minimal baseline against which to consider whether certain climate response tests would be relevant for a deployment scenario. Our analysis shows that some climate response tests, such as those attempting to detect changes in regional climate impacts, may not be deployable in time periods relevant to realistic geoengineering scenarios. This might pose significant challenges for justifying stratospheric sulfate aerosol injection deployment overall. We then survey some of the major ethical challenges that proposed climate response tests face. We consider what levels of confidence would be required to ethically justify approving a proposed test; whether the consequences of tests are subject to similar questions of justice, compensation, and informed consent as full-scale deployment; and whether questions of intent and hubris are morally relevant for climate response tests. We suggest further research into laboratory-based work and modeling may help to narrow the scientific uncertainties related to climate response tests, and help inform future ethical debate. However, even if such work is pursued, the ethical issues raised by proposed climate response tests are significant and manifold.

Climate Change Impacts and Responses: Societal Indicators for the National Climate Assessment

Science.gov (United States)

Kenney, Melissa A.; Chen, Robert S.; Maldonado, Julie; Quattrochi, Dale

2011-01-01

The Climate Change Impacts and Responses: Societal Indicators for the National Climate Assessment workshop, sponsored by the National Aeronautics and Space Administration (NASA) for the National Climate Assessment (NCA), was held on April 28-29, 2011 at The Madison Hotel in Washington, DC. A group of 56 experts (see list in Appendix B) convened to share their experiences. Participants brought to bear a wide range of disciplinary expertise in the social and natural sciences, sector experience, and knowledge about developing and implementing indicators for a range of purposes. Participants included representatives from federal and state government, non-governmental organizations, tribes, universities, and communities. The purpose of the workshop was to assist the NCA in developing a strategic framework for climate-related physical, ecological, and socioeconomic indicators that can be easily communicated with the U.S. population and that will support monitoring, assessment, prediction, evaluation, and decision-making. The NCA indicators are envisioned as a relatively small number of policy-relevant integrated indicators designed to provide a consistent, objective, and transparent overview of major variations in climate impacts, vulnerabilities, adaptation, and mitigation activities across sectors, regions, and timeframes. The workshop participants were asked to provide input on a number of topics, including: (1) categories of societal indicators for the NCA; (2) alternative approaches to constructing indicators and the better approaches for NCA to consider; (3) specific requirements and criteria for implementing the indicators; and (4) sources of data for and creators of such indicators. Socioeconomic indicators could include demographic, cultural, behavioral, economic, public health, and policy components relevant to impacts, vulnerabilities, and adaptation to climate change as well as both proactive and reactive responses to climate change. Participants provided

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.

Holocene Substrate Influences on Plant and Fire Response to Climate Change

Science.gov (United States)

Briles, C.; Whitlock, C. L.

2011-12-01

The role of substrates in facilitating plant responses to climate change in the past has received little attention. Ecological studies, documenting the relative role of fertile and infertile substrates in mediating the effects of climate change, lack the temporal information that paleoecological lake studies provide on how plants have responded under equal, larger and more rapid past climate events than today. In this paper, pollen and macroscopic charcoal preserved in the sediments of eight lakes surrounded by infertile ultramafic soils and more fertile soils in the Klamath Mountains of northern California were analyzed. Comparison of late-Quaternary paleoecological sites suggests that infertile and fertile substrates supported distinctly different plant communities. Trees and shrubs on infertile substrates were less responsive to climate change than those on fertile substrates, with the only major compositional change occurring at the glacial/interglacial transition (~11.5ka), when temperature rose 5oC. Trees and shrubs on fertile substrates were more responsive to climate changes, and tracked climate by moving along elevational gradients, including during more recent climate events such as the Little Ice Age and Medieval Climate Anomaly. Fire regimes were similar until 4ka on both substrate types. After 4ka, understory fuels on infertile substrates became sparse and fire activity decreased, while on fertile substrates forests became increasingly denser and fire activity increased. The complacency of plant communities on infertile sites to climate change contrasts with the individualistic and rapid adjustments of species on fertile sites. The findings differ from observations on shorter time scales that show the most change in herb cover and richness in the last 60 years on infertile substrates. Thus, the paleorecord provides unique long-term ecological data necessary to evaluate the response of plants to future climate change under different levels of soil

A climate responsive urban design tool: a platform to improve energy efficiency in a dry hot climate

Science.gov (United States)

El Dallal, Norhan; Visser, Florentine

2017-09-01

In the Middle East and North Africa (MENA) region, new urban developments should address the climatic conditions to improve outdoor comfort and to reduce the energy consumption of buildings. This article describes a design tool that supports climate responsive design for a dry hot climate. The approach takes the climate as an initiator for the conceptual urban form with a more energy-efficient urban morphology. The methodology relates the different passive strategies suitable for major climate conditions in MENA region (dry-hot) to design parameters that create the urban form. This parametric design approach is the basis for a tool that generates conceptual climate responsive urban forms so as to assist the urban designer early in the design process. Various conceptual scenarios, generated by a computational model, are the results of the proposed platform. A practical application of the approach is conducted on a New Urban Community in Aswan (Egypt), showing the economic feasibility of the resulting urban form and morphology, and the proposed tool.

Historical precipitation predictably alters the shape and magnitude of microbial functional response to soil moisture.

Science.gov (United States)

Averill, Colin; Waring, Bonnie G; Hawkes, Christine V

2016-05-01

Soil moisture constrains the activity of decomposer soil microorganisms, and in turn the rate at which soil carbon returns to the atmosphere. While increases in soil moisture are generally associated with increased microbial activity, historical climate may constrain current microbial responses to moisture. However, it is not known if variation in the shape and magnitude of microbial functional responses to soil moisture can be predicted from historical climate at regional scales. To address this problem, we measured soil enzyme activity at 12 sites across a broad climate gradient spanning 442-887 mm mean annual precipitation. Measurements were made eight times over 21 months to maximize sampling during different moisture conditions. We then fit saturating functions of enzyme activity to soil moisture and extracted half saturation and maximum activity parameter values from model fits. We found that 50% of the variation in maximum activity parameters across sites could be predicted by 30-year mean annual precipitation, an indicator of historical climate, and that the effect is independent of variation in temperature, soil texture, or soil carbon concentration. Based on this finding, we suggest that variation in the shape and magnitude of soil microbial response to soil moisture due to historical climate may be remarkably predictable at regional scales, and this approach may extend to other systems. If historical contingencies on microbial activities prove to be persistent in the face of environmental change, this approach also provides a framework for incorporating historical climate effects into biogeochemical models simulating future global change scenarios. © 2016 John Wiley & Sons Ltd.

Relating climate change signals and physiographic catchment properties to clustered hydrological response types

Directory of Open Access Journals (Sweden)

N. Köplin

2012-07-01

Full Text Available We propose an approach to reduce a comprehensive set of 186 mesoscale catchments in Switzerland to fewer response types to climate change and to name sensitive regions as well as catchment characteristics that govern hydrological change. We classified the hydrological responses of our study catchments through an agglomerative-hierarchical cluster analysis, and we related the dominant explanatory variables, i.e. the determining catchment properties and climate change signals, to the catchments' hydrological responses by means of redundancy analysis. All clusters except for one exhibit clearly decreasing summer runoff and increasing winter runoff. This seasonal shift was observed for the near future period (2025–2046 but is particularly obvious in the far future period (2074–2095. Within a certain elevation range (between 1000 and 2500 m a.s.l., the hydrological change is basically a function of elevation, because the latter governs the dominant hydro-climatological processes associated with temperature, e.g. the ratio of liquid to solid precipitation and snow melt processes. For catchments below the stated range, hydrological change is mainly a function of precipitation change, which is not as pronounced as the temperature signal is. Future impact studies in Switzerland can be conducted on a reduced sample of catchments representing the sensitive regions or covering a range of altitudes.

Corporate responses to climate change: the role of partnerships

NARCIS (Netherlands)

Kolk, A.; Pinkse, J.; Hull van Houten, L.; Martens, P.; Chang, C.T.

2010-01-01

This chapter relates to the NWO-funded research project "‘Getting down to business’: Economic responses to climate change," which studied the (potential) contribution of business to climate change mitigation and adaptation. After an introductory overview of the overall project and its main findings,

Taxonomic and functional diversity provides insight into microbial pathways and stress responses in the saline Qinghai Lake, China.

Directory of Open Access Journals (Sweden)

Qiuyuan Huang

Full Text Available Microbe-mediated biogeochemical cycles contribute to the global climate system and have sensitive responses and feedbacks to environmental stress caused by climate change. Yet, little is known about the effects of microbial biodiversity (i.e., taxonmic and functional diversity on biogeochemical cycles in ecosytems that are highly sensitive to climate change. One such sensitive ecosystem is Qinghai Lake, a high-elevation (3196 m saline (1.4% lake located on the Tibetan Plateau, China. This study provides baseline information on the microbial taxonomic and functional diversity as well as the associated stress response genes. Illumina metagenomic and metatranscriptomic datasets were generated from lake water samples collected at two sites (B and E. Autotrophic Cyanobacteria dominated the DNA samples, while heterotrophic Proteobacteria dominated the RNA samples at both sites. Photoheterotrophic Loktanella was also present at both sites. Photosystem II was the most active pathway at site B; while, oxidative phosphorylation was most active at site E. Organisms that expressed photosystem II or oxidative phosphorylation also expressed genes involved in photoprotection and oxidative stress, respectively. Assimilatory pathways associated with the nitrogen cycle were dominant at both sites. Results also indicate a positive relationship between functional diversity and the number of stress response genes. This study provides insight into the stress resilience of microbial metabolic pathways supported by greater taxonomic diversity, which may affect the microbial community response to climate change.

Biocrust spectral response as affected by changing climatic conditions

Science.gov (United States)

Rodriguez-Caballero, Emilio; Guirado, Emilio; Escribano, Paula; Reyes, Andres; Weber, Bettina

2017-04-01

Drylands are characterized by scarce vegetation coverage and low rates of biological activity, both constrained by water scarcity. Under these conditions, biocrusts form key players of ecosystem functioning. They comprise complex poikilohydric communities of cyanobacteria, algae, lichens and bryophytes together with heterotrophic bacteria, archaea and fungi, which cover the uppermost soil layer. Biocrusts can cope with prolonged phases of drought, being rapidly re-activated when water becomes available again. Upon reactivation, biocrusts almost immediately turn green, fixing atmospheric carbon and nitrogen and increasing ecosystem productivity. However, due to their inconspicuous growth they have only rarely been analysed and spatially and temporally continuous information on their response to water pulses is missing. These data are particularly important under changing climatic conditions predicting an increase in aridity and variations in precipitation patterns within most of the dryland regions. In the present study, we used multi-temporal series of NDVI obtained from LANDSAT images to analyze biocrust and vegetation response to water pulses within the South African Succulent Karoo and we predicted their future response under different climate change scenarios. The results showed that biocrust and vegetation greenness are controlled by aridity, solar radiation and soil water content, showing similar annual patterns, with minimum values during dry periods that increased within the rainy season and decreased again after the onset of drought. However, biocrusts responded faster to water availability and turned green almost immediately after small rains, producing a small NDVI peak only few days after rainfall, whereas more time was needed for vegetation to grow new green tissue. However, once the photosynthetic tissue of vegetation was restored, it caused the highest increase of NDVI values after the rain. Predicted changes in precipitation patterns and aridity

Separating the role of biotic interactions and climate in determining adaptive response of plants to climate change.

Science.gov (United States)

Tomiolo, Sara; Van der Putten, Wim H; Tielbörger, Katja

2015-05-01

Altered rainfall regimes will greatly affect the response of plant species to climate change. However, little is known about how direct effects of changing precipitation on plant performance may depend on other abiotic factors and biotic interactions. We used reciprocal transplants between climatically very different sites with simultaneous manipulation of soil, plant population origin, and neighbor conditions to evaluate local adaptation and possible adaptive response of four Eastern Mediterranean annual plant species to climate change. The effect of site on plant performance was negligible, but soil origin had a strong effect on fecundity, most likely due to differential water retaining ability. Competition by neighbors strongly reduced fitness. We separated the effects of the abiotic and biotic soil properties on plant performance by repeating the field experiment in a greenhouse under homogenous environmental conditions and including a soil biota manipulation treatment. As in the field, plant performance differed among soil origins and neighbor treatments. Moreover, we found plant species-specific responses to soil biota that may be best explained by the differential sensitivity to negative and positive soil biota effects. Overall, under the conditions of our experiment with two contrasting sites, biotic interactions had a strong effect on plant fitness that interacted with and eventually overrode climate. Because climate and biotic interactions covary, reciprocal transplants and climate gradient studies should consider soil biotic interactions and abiotic conditions when evaluating climate change effects on plant performance.

[Evolution of maize climate productivity and its response to climate change in Heilongjiang Province, China.

Science.gov (United States)

Li, Xiu Fen; Zhao, Hui Ying; Zhu, Hai Xia; Wang, Ping; Wang, Qiu Jing; Wang, Ming; Li, Yu Guang

2016-08-01

Under the background of climate change, revealing the change trend and spatial diffe-rence of maize climate productivity in-depth and understanding the regularity of maize climatic resources utilization can provide scientific basis for the macro-decision of agricultural production in Heilongjiang Province. Based on the 1981-2014 meteorological data of 72 weather stations and the corresponding maize yield data in Heilongjiang Province, by the methods of step by step revisal, spatial interpolation and linear trend analysis, this paper studied the photosynthetic productivity (PP), light-temperature productivity (LTP), and climatic productivity (CP) of spring maize, and their temporal and spatial variation characteristics, main influencing factors and light energy utilization efficiency, and evaluated the maize climate productivities under different climate scenarios in the future. The results showed that during the study period, the mean PP, LTP and CP in Heilongjiang Province were 26558, 19953, 18742 kg·hm -2 , respectively. Maize PP, LTP and CP were high in plains and low in mountains, and gradually decreased from southwest to northeast. PP, LTP and CP presented significantly increasing trends, and the increase rates were 378, 723 and 560 kg·hm -2 ·(10 a) -1 , respectively. The increase of radiation and temperature had positive effect on maize production in Heilongjiang Province. The potential productivity of maize presented significant response to climate change. The decrease of solar radiation led to the decline of PP in western Songnen Plain, but the increased temperature compensated the negative effect of solar radiation, so the downward trend of LTP was slowed. The response to climate warming was particularly evident in North and East, and LTP was significantly increased, which was sensitive to the change of precipitation in southwest of Songnen Plain and part of Sanjiang Plain. The average ratio of maize actual yield to its climate productivity was only 24

Natural responses to Quaternary climatic change in the Nevada Test Site region

International Nuclear Information System (INIS)

Gibson, J.D.

1993-01-01

Migration of hazardous contaminants within geologic settings depends on natural processes. Climatic fluctuations can affect the magnitudes and rates of many of these processes. In any long-term environmental evaluation of natural processes, responses to climatic change must be considered. Four generalized categories of natural responses to Quaternary climatic change are recognized for the Nevada Test Site (NTS) region of southwestern Nevada and adjacent California: (1) biologic, (2) geomorphic, (3) hydrologic (including surface and subsurface) and (4) pedologic/diagenetic. Specific examples that correspond to the four categories illustrate the broad range of complex natural processes the are affected by climatic change. These responses dictate the potential effects of climatic change on contaminant transport, effects that are being examined by existing and planned environmental-restoration and waste-management programs within the region. Regulatory requirements for many of these programs include long-term (>10,000-year) waste isolation because of radiologic components. The purpose here is not to be exhaustive in documenting all known natural responses to climatic change in the NTS region, but rather to give a flavor of the scope of interdisciplinary and interrelated fields of Quaternary science that must be considered in evaluating the possible effects of climatic change on long-term environmental programs

Livelihood responses to climate change in the Niger-delta ...

African Journals Online (AJOL)

Today, climatic changes coupled with oil exploration activeities in the region have negatively impacted on the environment. This has resulted in the alteration of habitats, biodiversity los and pollution of water bodies. This paper assesses livelihood responses of local people to climate change and the implications for food ...

Transgenerational plasticity as an important mechanism affecting response of clonal species to changing climate.

Science.gov (United States)

Münzbergová, Zuzana; Hadincová, Věroslava

2017-07-01

In spite of the increasing number of studies on the importance of transgenerational plasticity for species response to novel environments, its effects on species ability to respond to climate change are still largely unexplored. We study the importance of transgenerational plasticity for response of a clonal species Festuca rubra . Individuals from four natural populations representing two levels of temperature and two levels of precipitation were cultivated in four growth chambers that simulate the temperature and precipitation of origin of the populations (maternal phase). Each population was represented in each growth chamber. After 6 months, single young ramets of these plants were reshuffled among the growth chambers and let to grow for additional 2 months (offspring phase). The results show that transgenerational effects (i.e., maternal phase conditions) significantly modify species response to novel climates, and the direction and intensity of the response depend on the climate of origin of the plants. For traits related to recourse acquisition, the conditions of maternal phase, either alone or in interaction mainly with climate of origin, had stronger effect than the conditions of cultivation. Overall, the maternal climate interacted more intensively with the climate of origin than with the offspring climate. The direction of the effect of the maternal climate was of different directions and intensities depending on plant origin and trait studied. The data demonstrated strong significant effects of conditions during maternal phase on species response to novel climates. These transgenerational affects were, however, not adaptive. Still, transgenerational plasticity may be an important driver of species response to novel conditions across clonal generations. These effects thus need to be carefully considered in future studies exploring species response to novel climates. This will also have strong effects on species performance under increasingly variable

Predicting ecological responses of the Florida Everglades to possible future climate scenarios: Introduction

Science.gov (United States)

Aumen, Nicholas G.; Havens, Karl E; Best, G. Ronnie; Berry, Leonard

2015-01-01

Florida’s Everglades stretch from the headwaters of the Kissimmee River near Orlando to Florida Bay. Under natural conditions in this flat landscape, water flowed slowly downstream as broad, shallow sheet flow. The ecosystem is markedly different now, altered by nutrient pollution and construction of canals, levees, and water control structures designed for flood control and water supply. These alterations have resulted in a 50 % reduction of the ecosystem’s spatial extent and significant changes in ecological function in the remaining portion. One of the world’s largest restoration programs is underway to restore some of the historic hydrologic and ecological functions of the Everglades, via a multi-billion dollar Comprehensive Everglades Restoration Plan. This plan, finalized in 2000, did not explicitly consider climate change effects, yet today we realize that sea level rise and future changes in rainfall (RF), temperature, and evapotranspiration (ET) may have system-wide impacts. This series of papers describes results of a workshop where a regional hydrologic model was used to simulate the hydrology expected in 2060 with climate changes including increased temperature, ET, and sea level, and either an increase or decrease in RF. Ecologists with expertise in various areas of the ecosystem evaluated the hydrologic outputs, drew conclusions about potential ecosystem responses, and identified research needs where projections of response had high uncertainty. Resource managers participated in the workshop, and they present lessons learned regarding how the new information might be used to guide Everglades restoration in the context of climate change.

A new climate dataset for systematic assessments of climate change impacts as a function of global warming

Directory of Open Access Journals (Sweden)

J. Heinke

2013-10-01

Full Text Available In the ongoing political debate on climate change, global mean temperature change (ΔTglob has become the yardstick by which mitigation costs, impacts from unavoided climate change, and adaptation requirements are discussed. For a scientifically informed discourse along these lines, systematic assessments of climate change impacts as a function of ΔTglob are required. The current availability of climate change scenarios constrains this type of assessment to a narrow range of temperature change and/or a reduced ensemble of climate models. Here, a newly composed dataset of climate change scenarios is presented that addresses the specific requirements for global assessments of climate change impacts as a function of ΔTglob. A pattern-scaling approach is applied to extract generalised patterns of spatially explicit change in temperature, precipitation and cloudiness from 19 Atmosphere–Ocean General Circulation Models (AOGCMs. The patterns are combined with scenarios of global mean temperature increase obtained from the reduced-complexity climate model MAGICC6 to create climate scenarios covering warming levels from 1.5 to 5 degrees above pre-industrial levels around the year 2100. The patterns are shown to sufficiently maintain the original AOGCMs' climate change properties, even though they, necessarily, utilise a simplified relationships between ΔTglob and changes in local climate properties. The dataset (made available online upon final publication of this paper facilitates systematic analyses of climate change impacts as it covers a wider and finer-spaced range of climate change scenarios than the original AOGCM simulations.

Climate change and irrigation. An Australian response

International Nuclear Information System (INIS)

Pigram, J.J.

1995-01-01

Climatic changes on a global or regional scale, resulting from human activities, and the likely effects of such changes on Australia were discussed. Irrigation concerns of the Murray-Darling Basin in southeast Australia associated with global climate were described. Potential risks for regional economies and communities (agriculture in this instance) which may be significant, were assessed. Restructuring of the irrigation industry, and appropriate policy initiatives were urged now, while there is still some time to prepare. Application of the 'Precautionary Principle' to reduce global climate change effects was recommended. (This principle states that in areas threatened by severe climatic change lack of full scientific certainty should not be used as an excuse to delay decisive measures designed to mitigate environmental degradation). Bold policy adjustments and the creation of a new institutional framework to promote sustainable resource management were called for. It was suggested that the region could become a 'laboratory' for the whole world for assessing the effectiveness of managerial responses to environmental changes

Convergence in the temperature response of leaf respiration across biomes and plant functional types.

Science.gov (United States)

Heskel, Mary A; O'Sullivan, Odhran S; Reich, Peter B; Tjoelker, Mark G; Weerasinghe, Lasantha K; Penillard, Aurore; Egerton, John J G; Creek, Danielle; Bloomfield, Keith J; Xiang, Jen; Sinca, Felipe; Stangl, Zsofia R; Martinez-de la Torre, Alberto; Griffin, Kevin L; Huntingford, Chris; Hurry, Vaughan; Meir, Patrick; Turnbull, Matthew H; Atkin, Owen K

2016-04-05

Plant respiration constitutes a massive carbon flux to the atmosphere, and a major control on the evolution of the global carbon cycle. It therefore has the potential to modulate levels of climate change due to the human burning of fossil fuels. Neither current physiological nor terrestrial biosphere models adequately describe its short-term temperature response, and even minor differences in the shape of the response curve can significantly impact estimates of ecosystem carbon release and/or storage. Given this, it is critical to establish whether there are predictable patterns in the shape of the respiration-temperature response curve, and thus in the intrinsic temperature sensitivity of respiration across the globe. Analyzing measurements in a comprehensive database for 231 species spanning 7 biomes, we demonstrate that temperature-dependent increases in leaf respiration do not follow a commonly used exponential function. Instead, we find a decelerating function as leaves warm, reflecting a declining sensitivity to higher temperatures that is remarkably uniform across all biomes and plant functional types. Such convergence in the temperature sensitivity of leaf respiration suggests that there are universally applicable controls on the temperature response of plant energy metabolism, such that a single new function can predict the temperature dependence of leaf respiration for global vegetation. This simple function enables straightforward description of plant respiration in the land-surface components of coupled earth system models. Our cross-biome analyses shows significant implications for such fluxes in cold climates, generally projecting lower values compared with previous estimates.

How light competition between plants affects their response to climate change

NARCIS (Netherlands)

Loon, van M.P.; Schieving, F.; Rietkerk, M.; Dekker, S.C.; Sterck, F.J.; Anten, N.P.R.

2014-01-01

How plants respond to climate change is of major concern, as plants will strongly impact future ecosystem functioning, food production and climate. Here, we investigated how vegetation structure and functioning may be influenced by predicted increases in annual temperatures and atmospheric CO2

Behavioural, ecological and evolutionary responses to extreme climatic events: challenges and directions.

Science.gov (United States)

van de Pol, Martijn; Jenouvrier, Stéphanie; Cornelissen, Johannes H C; Visser, Marcel E

2017-06-19

More extreme climatic events (ECEs) are among the most prominent consequences of climate change. Despite a long-standing recognition of the importance of ECEs by paleo-ecologists and macro-evolutionary biologists, ECEs have only recently received a strong interest in the wider ecological and evolutionary community. However, as with many rapidly expanding fields, it lacks structure and cohesiveness, which strongly limits scientific progress. Furthermore, due to the descriptive and anecdotal nature of many ECE studies it is still unclear what the most relevant questions and long-term consequences are of ECEs. To improve synthesis, we first discuss ways to define ECEs that facilitate comparison among studies. We then argue that biologists should adhere to more rigorous attribution and mechanistic methods to assess ECE impacts. Subsequently, we discuss conceptual and methodological links with climatology and disturbance-, tipping point- and paleo-ecology. These research fields have close linkages with ECE research, but differ in the identity and/or the relative severity of environmental factors. By summarizing the contributions to this theme issue we draw parallels between behavioural, ecological and evolutionary ECE studies, and suggest that an overarching challenge is that most empirical and theoretical evidence points towards responses being highly idiosyncratic, and thus predictability being low. Finally, we suggest a roadmap based on the proposition that an increased focus on the mechanisms behind the biological response function will be crucial for increased understanding and predictability of the impacts of ECE.This article is part of the themed issue 'Behavioural, ecological and evolutionary responses to extreme climatic events'. © 2017 The Author(s).

Integrating Climate and Ecosystem-Response Sciences in Temperate Western North American Mountains: The CIRMOUNT Initiative

Science.gov (United States)

Millar, C. I.; Fagre, D. B.

2004-12-01

Mountain regions are uniquely sensitive to changes in climate, vulnerable to climate effects on biotic and physical factors of intense social concern, and serve as critical early-warning systems of climate impacts. Escalating demands on western North American (WNA) mountain ecosystems increasingly stress both natural resources and rural community capacities; changes in mountain systems cascade to issues of national concern. Although WNA has long been a focus for climate- and climate-related environmental research, these efforts remain disciplinary and poorly integrated, hindering interpretation into policy and management. Knowledge is further hampered by lack of standardized climate monitoring stations at high-elevations in WNA. An initiative is emerging as the Consortium for Integrated Climate Research in Western Mountains (CIRMOUNT) whose primary goal is to improve knowledge of high-elevation climate systems and to better integrate physical, ecological, and social sciences relevant to climate change, ecosystem response, and natural-resource policy in WNA. CIRMOUNT seeks to focus research on climate variability and ecosystem response (progress in understanding synoptic scale processes) that improves interpretation of linkages between ecosystem functions and human processing (progress in understanding human-environment integration), which in turn would yield applicable information and understanding on key societal issues such as mountains as water towers, biodiversity, carbon forest sinks, and wildland hazards such as fire and forest dieback (progress in understanding ecosystem services and key thresholds). Achieving such integration depends first on implementing a network of high-elevation climate-monitoring stations, and linking these with integrated ecosystem-response studies. Achievements since 2003 include convening the 2004 Mountain Climate Sciences Symposium (1, 2) and several special sessions at technical conferences; initiating a biennial mountain climate

Anthropogenic nitrogen deposition alters growth responses of European beech (Fagus sylvativa L.) to climate change.

Science.gov (United States)

Hess, Carsten; Niemeyer, Thomas; Fichtner, Andreas; Jansen, Kirstin; Kunz, Matthias; Maneke, Moritz; von Wehrden, Henrik; Quante, Markus; Walmsley, David; von Oheimb, Goddert; Härdtle, Werner

2018-02-01

Global change affects the functioning of forest ecosystems and the services they provide, but little is known about the interactive effects of co-occurring global change drivers on important functions such as tree growth and vitality. In the present study we quantified the interactive (i.e. synergistic or antagonistic) effects of atmospheric nitrogen (N) deposition and climatic variables (temperature, precipitation) on tree growth (in terms of tree-ring width, TRW), taking forest ecosystems with European beech (Fagus sylvatica L.) as an example. We hypothesised that (i) N deposition and climatic variables can evoke non-additive responses of the radial increment of beech trees, and (ii) N loads have the potential to strengthen the trees' sensitivity to climate change. In young stands, we found a synergistic positive effect of N deposition and annual mean temperature on TRW, possibly linked to the alleviation of an N shortage in young stands. In mature stands, however, high N deposition significantly increased the trees' sensitivity to increasing annual mean temperatures (antagonistic effect on TRW), possibly due to increased fine root dieback, decreasing mycorrhizal colonization or shifts in biomass allocation patterns (aboveground vs. belowground). Accordingly, N deposition and climatic variables caused both synergistic and antagonistic effects on the radial increment of beech trees, depending on tree age and stand characteristics. Hence, the nature of interactions could mediate the long-term effects of global change drivers (including N deposition) on forest carbon sequestration. In conclusion, our findings illustrate that interaction processes between climatic variables and N deposition are complex and have the potential to impair growth and performance of European beech. This in turn emphasises the importance of multiple-factor studies to foster an integrated understanding and models aiming at improved projections of tree growth responses to co-occurring drivers

Changing Climate Drives Lagging and Accelerating Glacier Responses and Accelerating Adjustments of the Hazard Regime

Science.gov (United States)

Kargel, Jeffrey

2013-04-01

It is virtually universally recognized among climate and cryospheric scientists that climate and greenhouse gas abundances are closely correlated. Disagreements mainly pertain to the fundamental triggers for large fluctuations in climate and greenhouse gases during the pre-industrial era, and exactly how coupling is achieved amongst the dynamic solid Earth, the Sun, orbital and rotational dynamics, greenhouse gas abundances, and climate. Also unsettled is the climate sensitivity defined as the absolute linkage between the magnitude of climate warming/cooling and greenhouse gas increase/decrease. Important questions concern lagging responses (either greenhouse gases lagging climate fluctuations, or vice versa) and the causes of the lags. In terms of glacier and ice sheet responses to climate change, there also exist several processes causing lagging responses to climate change inputs. The simplest parameterization giving a glacier's lagging response time, τ, is that given by Jóhanneson et al. (1989), modified slightly here as τ = b/h, where b is a measure of ablation rate and h is a measure of glacier thickness. The exact definitions of τ, b, and h are subject to some interpretive license, but for a back-of-the-envelope approximation, we may take b as the magnitude of the mean ablation rate over the whole ablation area, and h as the mean glacier thickness in the glacier ablation zone. τ remains a bit ambiguous but may be considered as an exponential time scale for a decreasing response of b to a climatic step change. For some climate changes, b and h can be taken as the values prior to the climate change, but for large climatic shifts, this parameterization must be iterated. The actual response of a glacier at any time is the sum of exponentially decreasing responses from past changes. (Several aspects of glacier dynamics cause various glacier responses to differ from this idealized glacier-response theory.) Some important details relating to the retreat (or

Modeling the Effects of Drought Events on Forest Ecosystem Functioning Historically and Under Scenarios of Climate Change

Science.gov (United States)

Ren, J.; Hanan, E. J.; Kolden, C.; Abatzoglou, J. T.; Tague, C.; Liu, M.; Adam, J. C.

2017-12-01

Drought events have been increasing across the western United States in recent years. Many studies have shown that, in the context of climate change, droughts will continue to be stronger, more frequent, and prolonged in the future. However, the response of forest ecosystems to droughts, particularly multi-year droughts, is not well understood. The objectives of this study are to examine how drought events of varying characteristics (e.g. intensity, duration, frequency, etc.) have affected the functioning of forest ecosystems historically, and how changing drought characteristics (including multi-year droughts) may affect forest functioning in a future climate. We utilize the Regional Hydro-Ecological Simulation System (RHESSys) to simulate impacts of both historical droughts and scenarios of future droughts on forest ecosystems. RHESSys is a spatially-distributed and process-based model that captures the interactions between coupled biogeochemical and hydrologic cycles at catchment scales. Here our case study is the Trail Creek catchment of the Big Wood River basin in Idaho, the Northwestern USA. For historical simulations, we use the gridded meteorological data of 1979 to 2016; for future climate scenarios, we utilize downscaled data from GCMs that have been demonstrated to capture drought events in the Northwest of the USA. From these climate projections, we identify various types of drought in intensity and duration, including multi-year drought events. We evaluate the following responses of ecosystems to these events: 1) evapotranspiration and streamflow; 2) gross primary productivity; 3) the post-drought recovery of plant biomass; and 4) the forest functioning and recovery after multi-year droughts. This research is part of an integration project to examine the roles of drought, insect outbreak, and forest management activities on wildfire activity and its impacts. This project will provide improved information for forest managers and communities in the wild

Is Dealing with Climate Change a Corporation's Responsibility? A Social Contract Perspective.

Science.gov (United States)

Unsworth, Kerrie L; Russell, Sally V; Davis, Matthew C

2016-01-01

In this paper, we argue that individuals - as members of society - play an important role in the expectations of whether or not companies are responsible for addressing environmental issues, and whether or not governments should regulate them. From this perspective of corporate social responsibility as a social contract we report the results of a survey of 1066 individuals. The aim of the survey was to assess participants' belief in anthropogenic climate change, free-market ideology, and beliefs around who is responsible for dealing with climate change. Results showed that both climate change views and free market ideology have a strong effect on beliefs that companies are responsible for dealing with climate change and on support for regulatory policy to that end. Furthermore, we found that free market ideology is a barrier in the support of corporate regulatory policy. The implications of these findings for research, policy, and practice are discussed.

Co-evolutionary organisational response development model (CORD): a case study of an Australian energy company climate change responses

OpenAIRE

Mishra, Kirti

2016-01-01

The thesis reports an investigation of the effects of the complex, evolving relationships between organisations and their environments. This examination is a case study of the responses of an Australian energy company to effects of climate change, and aims to enhance understanding of how organisational responses to climate change develop and evolve over time.    The impact of climate change on the contemporary organisational environment has multiple aspects – natural, ec...

Functional consequences of climate change-induced plant species loss in a tallgrass prairie.

Science.gov (United States)

Craine, Joseph M; Nippert, Jesse B; Towne, E Gene; Tucker, Sally; Kembel, Steven W; Skibbe, Adam; McLauchlan, Kendra K

2011-04-01

Future climate change is likely to reduce the floristic diversity of grasslands. Yet the potential consequences of climate-induced plant species losses for the functioning of these ecosystems are poorly understood. We investigated how climate change might alter the functional composition of grasslands for Konza Prairie, a diverse tallgrass prairie in central North America. With species-specific climate envelopes, we show that a reduction in mean annual precipitation would preferentially remove species that are more abundant in the more productive lowland positions at Konza. As such, decreases in precipitation could reduce productivity not only by reducing water availability but by also removing species that inhabit the most productive areas and respond the most to climate variability. In support of this prediction, data on species abundance at Konza over 16 years show that species that are more abundant in lowlands than uplands are preferentially reduced in years with low precipitation. Climate change is likely to also preferentially remove species from particular functional groups and clades. For example, warming is forecast to preferentially remove perennials over annuals as well as Cyperaceae species. Despite these predictions, climate change is unlikely to unilaterally alter the functional composition of the tallgrass prairie flora, as many functional traits such as physiological drought tolerance and maximum photosynthetic rates showed little relationship with climate envelope parameters. In all, although climatic drying would indirectly alter grassland productivity through species loss patterns, the insurance afforded by biodiversity to ecosystem function is likely to be sustained in the face of climate change.

Forest responses to tropospheric ozone and global climate change: an analysis.

Science.gov (United States)

Kickert, R N; Krupa, S V

1990-01-01

In this paper an analysis is provided on: what we know, what we need to know, and what we need to do, to further our understanding of the relationships between tropospheric ozone (O(3)), global climate change and forest responses. The relationships between global geographic distributions of forest ecosystems and potential geographic regions of high photochemical smog by the year 2025 AD are described. While the emphasis is on the effects of tropospheric O(3) on forest ecosystems, discussion is presented to understand such effects in the context of global climate change. One particular strong point of this paper is the audit of published surface O(3) data by photochemical smog region that reveals important forest/woodland geographic regions where little or no O(3) data exist even though the potential threat to forests in those regions appears to be large. The concepts and considerations relevant to the examination of ecosystem responses as a whole, rather than simply tree stands alone are reviewed. A brief argument is provided to stimulate the modification of the concept of simple cause and effect relationships in viewing total ecosystems. Our knowledge of O(3) exposure and its effects on the energy, nutrient and hydrological flow within the ecosystem are described. Modeling strategies for such systems are reviewed. A discussion of responses of forests to potential multiple climatic changes is provided. An important concept in this paper is that changes in water exchange processes throughout the hydrological cycle can be used as early warning indicators of forest responses to O(3). Another strength of this paper is the integration of information on structural and functional processes of ecosystems and their responses to O(3). An admitted weakness of this analysis is that the information on integrated ecosystem responses is based overwhelmingly on the San Bernardino Forest ecosystem research program of the 1970s because of a lack of similar studies. In the final

Adaptive and plastic responses of Quercus petraea populations to climate across Europe

DEFF Research Database (Denmark)

Sáenz-Romero, Cuauhtémoc; Lamy, Jean-Baptiste; Ducousso, Alexis

2017-01-01

geographically diverse populations. The tests were planted on 23 field sites in six European countries, in order to expose them to a wide range of climates, including sites reflecting future warmer and drier climates. By assessing tree height and survival, our objectives were twofold: (i) to identify the source......How temperate forests will respond to climate change is uncertain; projections range from severe decline to increased growth. We conducted field tests of sessile oak (Quercus petraea), a widespread keystone European forest tree species, including more than 150 000 trees sourced from 116...... of differential population responses to climate (genetic differentiation due to past divergent climatic selection vs. plastic responses to ongoing climate change) and (ii) to explore which climatic variables (temperature or precipitation) trigger the population responses. Tree growth and survival were modeled...

America's Climate Choices: Cross-Cutting Research Themes to Support Effective Responses to Climate Change

Science.gov (United States)

Moser, S. C.; America'S Climate Choices Science Panel

2010-12-01

The Science Panel of the America’s Climate Choices project concluded that the climate science research enterprise has to make substantial shifts to better meet the needs of the emerging policy and decision landscape in the US. While much scientific attention in the past necessarily and to great success focused on the physical and biogeochemical aspects of understanding the climate-Earth system, much greater focus is now needed in also developing a science of responses to climate change. To that end, the ACC Science report recommended seven cross-cutting themes, three of which will be highlighted in this talk as they touch on topics the physical science community tends to be less familiar with: (1) vulnerability and adaptation analyses of coupled human-environment systems; (2) research on strategies for limiting climate change; and (3) effective information and decision support systems. The presentation will define and sketch out the potential scope of each of these areas and provide examples from various sectors highlighted in the Science panel report.

Dose-response functions and corrosion mapping for a small geographical area

International Nuclear Information System (INIS)

Haagenrud, S.E.; Henriksen, J.F.; Gram, F.

1985-01-01

Detailed corrosion and environmental measurements have been used to develop dose response (D/R) functions for carbon steel, zinc, copper, and aluminum for a 26 x 31 km urban/rural area with approximately homogeneous climate. The D/R functions, expressed in terms of SO 2 and time of wetness, were of the same type for all four metals. The SO 2 contribution to the total corrosion dominates in the centers of towns and around an industrial plant. Corrosion maps for the whole area were established

Ecological and methodological drivers of species’ distribution and phenology responses to climate change

KAUST Repository

Brown, Christopher J.

2015-12-10

Climate change is shifting species’ distribution and phenology. Ecological traits, such as mobility or reproductive mode, explain variation in observed rates of shift for some taxa. However, estimates of relationships between traits and climate responses could be influenced by how responses are measured. We compiled a global dataset of 651 published marine species’ responses to climate change, from 47 papers on distribution shifts and 32 papers on phenology change. We assessed the relative importance of two classes of predictors of the rate of change, ecological traits of the responding taxa and methodological approaches for quantifying biological responses. Methodological differences explained 22% of the variation in range shifts, more than the 7.8% of the variation explained by ecological traits. For phenology change, methodological approaches accounted for 4% of the variation in measurements, whereas 8% of the variation was explained by ecological traits. Our ability to predict responses from traits was hindered by poor representation of species from the tropics, where temperature isotherms are moving most rapidly. Thus, the mean rate of distribution change may be underestimated by this and other global syntheses. Our analyses indicate that methodological approaches should be explicitly considered when designing, analysing and comparing results among studies. To improve climate impact studies, we recommend that: (1) re-analyses of existing time-series state how the existing datasets may limit the inferences about possible climate responses; (2) qualitative comparisons of species’ responses across different studies be limited to studies with similar methodological approaches; (3) meta-analyses of climate responses include methodological attributes as covariates and; (4) that new time series be designed to include detection of early warnings of change or ecologically relevant change. Greater consideration of methodological attributes will improve the

Younger Dryas cooling and the Greenland climate response to CO2.

Science.gov (United States)

Liu, Zhengyu; Carlson, Anders E; He, Feng; Brady, Esther C; Otto-Bliesner, Bette L; Briegleb, Bruce P; Wehrenberg, Mark; Clark, Peter U; Wu, Shu; Cheng, Jun; Zhang, Jiaxu; Noone, David; Zhu, Jiang

2012-07-10

Greenland ice-core δ(18)O-temperature reconstructions suggest a dramatic cooling during the Younger Dryas (YD; 12.9-11.7 ka), with temperatures being as cold as the earlier Oldest Dryas (OD; 18.0-14.6 ka) despite an approximately 50 ppm rise in atmospheric CO(2). Such YD cooling implies a muted Greenland climate response to atmospheric CO(2), contrary to physical predictions of an enhanced high-latitude response to future increases in CO(2). Here we show that North Atlantic sea surface temperature reconstructions as well as transient climate model simulations suggest that the YD over Greenland should be substantially warmer than the OD by approximately 5 °C in response to increased atmospheric CO(2). Additional experiments with an isotope-enabled model suggest that the apparent YD temperature reconstruction derived from the ice-core δ(18)O record is likely an artifact of an altered temperature-δ(18)O relationship due to changing deglacial atmospheric circulation. Our results thus suggest that Greenland climate was warmer during the YD relative to the OD in response to rising atmospheric CO(2), consistent with sea surface temperature reconstructions and physical predictions, and has a sensitivity approximately twice that found in climate models for current climate due to an enhanced albedo feedback during the last deglaciation.

Semi-arid vegetation response to antecedent climate and water balance windows

Science.gov (United States)

Thoma, David P.; Munson, Seth M.; Irvine, Kathryn M.; Witwicki, Dana L.; Bunting, Erin

2016-01-01

Questions Can we improve understanding of vegetation response to water availability on monthly time scales in semi-arid environments using remote sensing methods? What climatic or water balance variables and antecedent windows of time associated with these variables best relate to the condition of vegetation? Can we develop credible near-term forecasts from climate data that can be used to prepare for future climate change effects on vegetation? Location Semi-arid grasslands in Capitol Reef National Park, Utah, USA. Methods We built vegetation response models by relating the normalized difference vegetation index (NDVI) from MODIS imagery in Mar–Nov 2000–2013 to antecedent climate and water balance variables preceding the monthly NDVI observations. We compared how climate and water balance variables explained vegetation greenness and then used a multi-model ensemble of climate and water balance models to forecast monthly NDVI for three holdout years. Results Water balance variables explained vegetation greenness to a greater degree than climate variables for most growing season months. Seasonally important variables included measures of antecedent water input and storage in spring, switching to indicators of drought, input or use in summer, followed by antecedent moisture availability in autumn. In spite of similar climates, there was evidence the grazed grassland showed a response to drying conditions 1 mo sooner than the ungrazed grassland. Lead times were generally short early in the growing season and antecedent window durations increased from 3 mo early in the growing season to 1 yr or more as the growing season progressed. Forecast accuracy for three holdout years using a multi-model ensemble of climate and water balance variables outperformed forecasts made with a naïve NDVI climatology. Conclusions We determined the influence of climate and water balance on vegetation at a fine temporal scale, which presents an opportunity to forecast vegetation

Deconstructing the climate change response of the Northern Hemisphere wintertime storm tracks

OpenAIRE

Harvey, B. J.; Shaffrey, L. C.; Woollings, T. J.

2015-01-01

There are large uncertainties in the circulation response of the atmosphere to climate change. One manifestation of this is the substantial spread in projections for the extratropical storm tracks made by different state-of-the-art climate models. In this study we perform a series of sensitivity experiments, with the atmosphere component of a single climate model, in order to identify the causes of the differences between storm track responses in different models. In particular, the Northern ...

Tropical rainforest response to marine sky brightening climate engineering

Science.gov (United States)

Muri, Helene; Niemeier, Ulrike; Kristjánsson, Jón Egill

2015-04-01

Tropical forests represent a major atmospheric carbon dioxide sink. Here the gross primary productivity (GPP) response of tropical rainforests to climate engineering via marine sky brightening under a future scenario is investigated in three Earth system models. The model response is diverse, and in two of the three models, the tropical GPP shows a decrease from the marine sky brightening climate engineering. Partial correlation analysis indicates precipitation to be important in one of those models, while precipitation and temperature are limiting factors in the other. One model experiences a reversal of its Amazon dieback under marine sky brightening. There, the strongest partial correlation of GPP is to temperature and incoming solar radiation at the surface. Carbon fertilization provides a higher future tropical rainforest GPP overall, both with and without climate engineering. Salt damage to plants and soils could be an important aspect of marine sky brightening.

Climate Change and Roads

DEFF Research Database (Denmark)

Chinowsky, P.; Arndt, Channing

2012-01-01

to estimate the impact of individual climate stressors on road infrastructure in Mozambique. Through these models, stressor–response functions are introduced that quantify the cost impact of a specific stressor based on the intensity of the stressor and the type of infrastructure it is affecting. Utilizing...... four climate projection scenarios, the paper details how climate change response decisions may cost the Mozambican government in terms of maintenance costs and long-term roadstock inventory reduction. Through this approach the paper details how a 14% reduction in inventory loss can be achieved through...

Effects of climate variability and functional changes on the interannual variation of the carbon balance in a temperate deciduous forest

DEFF Research Database (Denmark)

Wu, Jian; van der Linden, Leon; Lasslop, G.

2012-01-01

scale, direct climatic variability and changes in ecosystem functional properties regulated the IAV of the carbon balance at this site. Correlation analysis showed that the sensitivity of carbon fluxes to climatic variability was significantly higher at shorter than at longer time scales and changed...... seasonally. Ecosystem response anomalies implied that changes in the distribution of climate anomalies during the vegetation period will have stronger impacts on future ecosystem carbon balances than changes in average climate. We improved a published modelling approach which distinguishes the direct....... At the annual time scale as much as 80% of the IAV in NEE was attributed to the variation in photosynthesis and respiration related model parameters. Our results suggest that the observed decadal NEE trend at the investigated site was dominated by changes in ecosystem functioning. In general this study showed...

Climate response to changes in atmospheric carbon dioxide and solar irradiance on the time scale of days to weeks

International Nuclear Information System (INIS)

Cao Long; Bala, Govindasamy; Caldeira, Ken

2012-01-01

Recent studies show that fast climate response on time scales of less than a month can have important implications for long-term climate change. In this study, we investigate climate response on the time scale of days to weeks to a step-function quadrupling of atmospheric CO 2 and contrast this with the response to a 4% increase in solar irradiance. Our simulations show that significant climate effects occur within days of a stepwise increase in both atmospheric CO 2 content and solar irradiance. Over ocean, increased atmospheric CO 2 warms the lower troposphere more than the surface, increasing atmospheric stability, moistening the boundary layer, and suppressing evaporation and precipitation. In contrast, over ocean, increased solar irradiance warms the lower troposphere to a much lesser extent, causing a much smaller change in evaporation and precipitation. Over land, both increased CO 2 and increased solar irradiance cause rapid surface warming that tends to increase both evaporation and precipitation. However, the physiological effect of increased atmospheric CO 2 on plant stomata reduces plant transpiration, drying the boundary layer and decreasing precipitation. This effect does not occur with increased solar irradiance. Therefore, differences in climatic effects from CO 2 versus solar forcing are manifested within days after the forcing is imposed. (letter)

Plant responses, climate pivot points, and trade-offs in water-limited ecosystems

Science.gov (United States)

Munson, S. M.; Bunting, E.

2017-12-01

Ecosystem transitions and thresholds are conceptually well-defined and have become a framework to address vegetation response to climate change and land-use intensification, yet there are few approaches to define the environmental conditions which can lead to them. We demonstrate a novel climate pivot point approach using long-term monitoring data from a broad network of permanent plots, satellite imagery, and experimental treatments across the southwestern U.S. The climate pivot point identifies conditions that lead to decreased plant performance and serves as an early warning sign of increased vulnerability of crossing a threshold into an altered ecosystem state. Plant responses and climate pivot points aligned with the lifespan and structural characteristics of species, were modified by soil and landscape attributes of a site, and had non-linear dynamics in some cases. Species with strong increases in abundance when water was available were most susceptible to losses during water shortages, reinforcing plant energetic and physiological tradeoffs. Future research to uncover the heterogeneity of plant responses and climate pivot points at multiple scales can lead to greater understanding of shifts in ecosystem productivity and vulnerability to climate change.

Phylogenetic conservatism and trait correlates of spring phenological responses to climate change in northeast China.

Science.gov (United States)

Du, Yanjun; Chen, Jingru; Willis, Charles G; Zhou, Zhiqiang; Liu, Tong; Dai, Wujun; Zhao, Yuan; Ma, Keping

2017-09-01

Climate change has resulted in major changes in plant phenology across the globe that includes leaf-out date and flowering time. The ability of species to respond to climate change, in part, depends on their response to climate as a phenological cue in general. Species that are not phenologically responsive may suffer in the face of continued climate change. Comparative studies of phenology have found phylogeny to be a reliable predictor of mean leaf-out date and flowering time at both the local and global scales. This is less true for flowering time response (i.e., the correlation between phenological timing and climate factors), while no study to date has explored whether the response of leaf-out date to climate factors exhibits phylogenetic signal. We used a 52-year observational phenological dataset for 52 woody species from the Forest Botanical Garden of Heilongjiang Province, China, to test phylogenetic signal in leaf-out date and flowering time, as well as, the response of these two phenological traits to both temperature and winter precipitation. Leaf-out date and flowering time were significantly responsive to temperature for most species, advancing, on average, 3.11 and 2.87 day/°C, respectively. Both leaf-out and flowering, and their responses to temperature exhibited significant phylogenetic signals. The response of leaf-out date to precipitation exhibited no phylogenetic signal, while flowering time response to precipitation did. Native species tended to have a weaker flowering response to temperature than non-native species. Earlier leaf-out species tended to have a greater response to winter precipitation. This study is the first to assess phylogenetic signal of leaf-out response to climate change, which suggests, that climate change has the potential to shape the plant communities, not only through flowering sensitivity, but also through leaf-out sensitivity.

Biodiversity as a solution to mitigate climate change impacts on the functioning of forest ecosystems.

Science.gov (United States)

Hisano, Masumi; Searle, Eric B; Chen, Han Y H

2018-02-01

Forest ecosystems are critical to mitigating greenhouse gas emissions through carbon sequestration. However, climate change has affected forest ecosystem functioning in both negative and positive ways, and has led to shifts in species/functional diversity and losses in plant species diversity which may impair the positive effects of diversity on ecosystem functioning. Biodiversity may mitigate climate change impacts on (I) biodiversity itself, as more-diverse systems could be more resilient to climate change impacts, and (II) ecosystem functioning through the positive relationship between diversity and ecosystem functioning. By surveying the literature, we examined how climate change has affected forest ecosystem functioning and plant diversity. Based on the biodiversity effects on ecosystem functioning (B→EF), we specifically address the potential for biodiversity to mitigate climate change impacts on forest ecosystem functioning. For this purpose, we formulate a concept whereby biodiversity may reduce the negative impacts or enhance the positive impacts of climate change on ecosystem functioning. Further B→EF studies on climate change in natural forests are encouraged to elucidate how biodiversity might influence ecosystem functioning. This may be achieved through the detailed scrutiny of large spatial/long temporal scale data sets, such as long-term forest inventories. Forest management strategies based on B→EF have strong potential for augmenting the effectiveness of the roles of forests in the mitigation of climate change impacts on ecosystem functioning. © 2017 Cambridge Philosophical Society.

Human Responses to Climate Variability: The Case of South Africa

Science.gov (United States)

Oppenheimer, M.; Licker, R.; Mastrorillo, M.; Bohra-Mishra, P.; Estes, L. D.; Cai, R.

2014-12-01

Climate variability has been associated with a range of societal and individual outcomes including migration, violent conflict, changes in labor productivity, and health impacts. Some of these may be direct responses to changes in mean temperature or precipitation or extreme events, such as displacement of human populations by tropical cyclones. Others may be mediated by a variety of biological, social, or ecological factors such as migration in response to long-term changes in crops yields. Research is beginning to elucidate and distinguish the many channels through which climate variability may influence human behavior (ranging from the individual to the collective, societal level) in order to better understand how to improve resilience in the face of current variability as well as future climate change. Using a variety of data sets from South Africa, we show how climate variability has influenced internal (within country) migration in recent history. We focus on South Africa as it is a country with high levels of internal migration and dramatic temperature and precipitation changes projected for the 21st century. High poverty rates and significant levels of rain-fed, smallholder agriculture leave large portions of South Africa's population base vulnerable to future climate change. In this study, we utilize two complementary statistical models - one micro-level model, driven by individual and household level survey data, and one macro-level model, driven by national census statistics. In both models, we consider the effect of climate on migration both directly (with gridded climate reanalysis data) and indirectly (with agricultural production statistics). With our historical analyses of climate variability, we gain insights into how the migration decisions of South Africans may be influenced by future climate change. We also offer perspective on the utility of micro and macro level approaches in the study of climate change and human migration.

Structural and functional responses of plant communities to climate change-mediated alterations in the hydrology of riparian areas in temperate Europe.

Science.gov (United States)

Baattrup-Pedersen, Annette; Garssen, Annemarie; Göthe, Emma; Hoffmann, Carl Christian; Oddershede, Andrea; Riis, Tenna; van Bodegom, Peter M; Larsen, Søren E; Soons, Merel

2018-04-01

The hydrology of riparian areas changes rapidly these years because of climate change-mediated alterations in precipitation patterns. In this study, we used a large-scale in situ experimental approach to explore effects of drought and flooding on plant taxonomic diversity and functional trait composition in riparian areas in temperate Europe. We found significant effects of flooding and drought in all study areas, the effects being most pronounced under flooded conditions. In near-stream areas, taxonomic diversity initially declined in response to both drought and flooding (although not significantly so in all years) and remained stable under drought conditions, whereas the decline continued under flooded conditions. For most traits, we found clear indications that the functional diversity also declined under flooded conditions, particularly in near-stream areas, indicating that fewer strategies succeeded under flooded conditions. Consistent changes in community mean trait values were also identified, but fewer than expected. This can have several, not mutually exclusive, explanations. First, different adaptive strategies may coexist in a community. Second, intraspecific variability was not considered for any of the traits. For example, many species can elongate shoots and petioles that enable them to survive shallow, prolonged flooding but such abilities will not be captured when applying mean trait values. Third, we only followed the communities for 3 years. Flooding excludes species intolerant of the altered hydrology, whereas the establishment of new species relies on time-dependent processes, for instance the dispersal and establishment of species within the areas. We expect that altered precipitation patterns will have profound consequences for riparian vegetation in temperate Europe. Riparian areas will experience loss of taxonomic and functional diversity and, over time, possibly also alterations in community trait responses that may have cascading effects

Hydrological response to climate change in a glaciated catchment in the Himalayas

NARCIS (Netherlands)

Immerzeel, W.W.; Beek, L.P.H. van; Konz, M.; Shresta, A.B.; Bierkens, M.F.P.

2012-01-01

The analysis of climate change impact on the hydrology of high altitude glacierized catchments in the Himalayas is complex due to the high variability in climate, lack of data, large uncertainties in climate change projection and uncertainty about the response of glaciers. Therefore a high

A global synthesis of animal phenological responses to climate change

Science.gov (United States)

Cohen, Jeremy M.; Lajeunesse, Marc J.; Rohr, Jason R.

2018-03-01

Shifts in phenology are already resulting in disruptions to the timing of migration and breeding, and asynchronies between interacting species1-5. Recent syntheses have concluded that trophic level1, latitude6 and how phenological responses are measured7 are key to determining the strength of phenological responses to climate change. However, researchers still lack a comprehensive framework that can predict responses to climate change globally and across diverse taxa. Here, we synthesize hundreds of published time series of animal phenology from across the planet to show that temperature primarily drives phenological responses at mid-latitudes, with precipitation becoming important at lower latitudes, probably reflecting factors that drive seasonality in each region. Phylogeny and body size are associated with the strength of phenological shifts, suggesting emerging asynchronies between interacting species that differ in body size, such as hosts and parasites and predators and prey. Finally, although there are many compelling biological explanations for spring phenological delays, some examples of delays are associated with short annual records that are prone to sampling error. Our findings arm biologists with predictions concerning which climatic variables and organismal traits drive phenological shifts.

Tributaries affect the thermal response of lakes to climate change

Science.gov (United States)

Råman Vinnå, Love; Wüest, Alfred; Zappa, Massimiliano; Fink, Gabriel; Bouffard, Damien

2018-01-01

Thermal responses of inland waters to climate change varies on global and regional scales. The extent of warming is determined by system-specific characteristics such as fluvial input. Here we examine the impact of ongoing climate change on two alpine tributaries, the Aare River and the Rhône River, and their respective downstream peri-alpine lakes: Lake Biel and Lake Geneva. We propagate regional atmospheric temperature effects into river discharge projections. These, together with anthropogenic heat sources, are in turn incorporated into simple and efficient deterministic models that predict future water temperatures, river-borne suspended sediment concentration (SSC), lake stratification and river intrusion depth/volume in the lakes. Climate-induced shifts in river discharge regimes, including seasonal flow variations, act as positive and negative feedbacks in influencing river water temperature and SSC. Differences in temperature and heating regimes between rivers and lakes in turn result in large seasonal shifts in warming of downstream lakes. The extent of this repressive effect on warming is controlled by the lakes hydraulic residence time. Previous studies suggest that climate change will diminish deep-water oxygen renewal in lakes. We find that climate-related seasonal variations in river temperatures and SSC shift deep penetrating river intrusions from summer towards winter. Thus potentially counteracting the otherwise negative effects associated with climate change on deep-water oxygen content. Our findings provide a template for evaluating the response of similar hydrologic systems to on-going climate change.

Tributaries affect the thermal response of lakes to climate change

Directory of Open Access Journals (Sweden)

L. Råman Vinnå

2018-01-01

Full Text Available Thermal responses of inland waters to climate change varies on global and regional scales. The extent of warming is determined by system-specific characteristics such as fluvial input. Here we examine the impact of ongoing climate change on two alpine tributaries, the Aare River and the Rhône River, and their respective downstream peri-alpine lakes: Lake Biel and Lake Geneva. We propagate regional atmospheric temperature effects into river discharge projections. These, together with anthropogenic heat sources, are in turn incorporated into simple and efficient deterministic models that predict future water temperatures, river-borne suspended sediment concentration (SSC, lake stratification and river intrusion depth/volume in the lakes. Climate-induced shifts in river discharge regimes, including seasonal flow variations, act as positive and negative feedbacks in influencing river water temperature and SSC. Differences in temperature and heating regimes between rivers and lakes in turn result in large seasonal shifts in warming of downstream lakes. The extent of this repressive effect on warming is controlled by the lakes hydraulic residence time. Previous studies suggest that climate change will diminish deep-water oxygen renewal in lakes. We find that climate-related seasonal variations in river temperatures and SSC shift deep penetrating river intrusions from summer towards winter. Thus potentially counteracting the otherwise negative effects associated with climate change on deep-water oxygen content. Our findings provide a template for evaluating the response of similar hydrologic systems to on-going climate change.

Carbon dioxide and climate impulse response functions for the computation of greenhouse gas metrics: a multi-model analysis

Directory of Open Access Journals (Sweden)

F. Joos

2013-03-01

Full Text Available The responses of carbon dioxide (CO2 and other climate variables to an emission pulse of CO2 into the atmosphere are often used to compute the Global Warming Potential (GWP and Global Temperature change Potential (GTP, to characterize the response timescales of Earth System models, and to build reduced-form models. In this carbon cycle-climate model intercomparison project, which spans the full model hierarchy, we quantify responses to emission pulses of different magnitudes injected under different conditions. The CO2 response shows the known rapid decline in the first few decades followed by a millennium-scale tail. For a 100 Gt-C emission pulse added to a constant CO2 concentration of 389 ppm, 25 ± 9% is still found in the atmosphere after 1000 yr; the ocean has absorbed 59 ± 12% and the land the remainder (16 ± 14%. The response in global mean surface air temperature is an increase by 0.20 ± 0.12 °C within the first twenty years; thereafter and until year 1000, temperature decreases only slightly, whereas ocean heat content and sea level continue to rise. Our best estimate for the Absolute Global Warming Potential, given by the time-integrated response in CO2 at year 100 multiplied by its radiative efficiency, is 92.5 × 10−15 yr W m−2 per kg-CO2. This value very likely (5 to 95% confidence lies within the range of (68 to 117 × 10−15 yr W m−2 per kg-CO2. Estimates for time-integrated response in CO2 published in the IPCC First, Second, and Fourth Assessment and our multi-model best estimate all agree within 15% during the first 100 yr. The integrated CO2 response, normalized by the pulse size, is lower for pre-industrial conditions, compared to present day, and lower for smaller pulses than larger pulses. In contrast, the response in temperature, sea level and ocean heat content is less sensitive to these choices. Although, choices in pulse size, background concentration, and model lead to uncertainties, the most important and

Nonlinear dynamics in ecosystem response to climatic change: Case studies and policy implications

Science.gov (United States)

Burkett, Virginia R.; Wilcox, Douglas A.; Stottlemyer, Robert; Barrow, Wylie; Fagre, Dan; Baron, Jill S.; Price, Jeff; Nielsen, Jennifer L.; Allen, Craig D.; Peterson, David L.; Ruggerone, Greg; Doyle, Thomas

2005-01-01

Many biological, hydrological, and geological processes are interactively linked in ecosystems. These ecological phenomena normally vary within bounded ranges, but rapid, nonlinear changes to markedly different conditions can be triggered by even small differences if threshold values are exceeded. Intrinsic and extrinsic ecological thresholds can lead to effects that cascade among systems, precluding accurate modeling and prediction of system response to climate change. Ten case studies from North America illustrate how changes in climate can lead to rapid, threshold-type responses within ecological communities; the case studies also highlight the role of human activities that alter the rate or direction of system response to climate change. Understanding and anticipating nonlinear dynamics are important aspects of adaptation planning since responses of biological resources to changes in the physical climate system are not necessarily proportional and sometimes, as in the case of complex ecological systems, inherently nonlinear.

[Prediction of the suitable distribution and responses to climate change of Elaeagnus mollis in Shanxi Province, China].

Science.gov (United States)

Zhang, Yin Bo; Gao, Chen Hong; Qin, Hao

2018-04-01

Understanding the responses of the habitats of endangered species to climate change is of great significance for biodiversity conservation and the maintenance of the integrity of ecosystem function. In this study, the potential suitable distribution habitats of Elaeagnus mollis in Shanxi Province was simulated by the maximum entropy model, based on 73 occurrence field records and 35 environmental factors under the current climate condition. Moreover, with the Fifth Assessment Report of Intergovernmental Panel on Climate Change, the dynamics of distribution pattern was analyzed for E. mollis under different climate scenarios. The results showed that the area under the receiver operating characteristic curve (AUC) value was 0.987, indicating that the data fitted the model very well and that the prediction was highly reliable. Results from the Jackknife test showed that the main environmental variables affecting the E. mollis distribution were the precipitation seasonality, the range of annual temperature, annual mean temperature, isothermality, annual precipitation, and pH of topsoil, with the cumulative contribution reaching 94.8%. At present, the potential suitable habitats of E. mollis are mainly located in two regions, the southern of Lyuliang Mountain and Zhongtiao Mountain in Shanxi Province. Under different climate scenarios, the total suitable area of E. mollis would shrink in 2070s. In RCP 2.6 the suitable area would firstly increase and then decrease, while in RCP 4.5 and RCP 8.5 it would response sensitively and first decrease and then increase. Its spatial distribution in two suitable regions would show divergent responses to climate change. The distribution in southern Lyuliang Mountain would fluctuate slightly in latitudinal direction, while that in Zhongtiao Mountain would migrate along elevation.

Climate and terrain factors explaining streamflow response and recession in Australian catchments

Directory of Open Access Journals (Sweden)

A. I. J. M. van Dijk

2010-01-01

Full Text Available Daily streamflow data were analysed to assess which climate and terrain factors best explain streamflow response in 183 Australian catchments. Assessed descriptors of catchment response included the parameters of fitted baseflow models, and baseflow index (BFI, average quick flow and average baseflow derived by baseflow separation. The variation in response between catchments was compared with indicators of catchment climate, morphology, geology, soils and land use. Spatial coherence in the residual unexplained variation was investigated using semi-variogram techniques. A linear reservoir model (one parameter; recession coefficient produced baseflow estimates as good as those obtained using a non-linear reservoir (two parameters and for practical purposes was therefore considered an appropriate balance between simplicity and explanatory performance. About a third (27–34% of the spatial variation in recession coefficients and BFI was explained by catchment climate indicators, with another 53% of variation being spatially correlated over distances of 100–150 km, probably indicative of substrate characteristics not captured by the available soil and geology data. The shortest recession half-times occurred in the driest catchments and were attributed to intermittent occurrence of fast-draining (possibly perched groundwater. Most (70–84% of the variation in average baseflow and quick flow was explained by rainfall and climate characteristics; another 20% of variation was spatially correlated over distances of 300–700 km, possibly reflecting a combination of terrain and climate factors. It is concluded that catchment streamflow response can be predicted quite well on the basis of catchment climate alone. The prediction of baseflow recession response should be improved further if relevant substrate properties were identified and measured.

Predicting the Response of Electricity Load to Climate Change

Energy Technology Data Exchange (ETDEWEB)

Sullivan, Patrick [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Colman, Jesse [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Kalendra, Eric [National Renewable Energy Laboratory (NREL), Golden, CO (United States)

2015-07-28

Our purpose is to develop a methodology to quantify the impact of climate change on electric loads in the United States. We perform simple linear regression, assisted by geospatial smoothing, on paired temperature and load time-series to estimate the heating- and coolinginduced sensitivity to temperature across 300 transmission zones and 16 seasonal and diurnal time periods. The estimated load sensitivities can be coupled with climate scenarios to quantify the potential impact of climate change on load, with a primary application being long-term electricity scenarios. The method allows regional and seasonal differences in climate and load response to be reflected in the electricity scenarios. While the immediate product of this analysis was designed to mesh with the spatial and temporal resolution of a specific electricity model to enable climate change scenarios and analysis with that model, we also propose that the process could be applied for other models and purposes.

The influence of a motivational climate intervention on participants' salivary cortisol and psychological responses.

Science.gov (United States)

Hogue, Candace M; Fry, Mary D; Fry, Andrew C; Pressman, Sarah D

2013-02-01

Research in achievement goal perspective theory suggests that the creation of a caring/task-involving (C/TI) climate results in more advantageous psychological and behavioral responses relative to an ego-involving (EI) climate; however, research has not yet examined the physiological consequences associated with psychological stress in relation to climate. Given the possible health and fitness implications of certain physiological stress responses, it is critical to understand this association. Thus, the purpose of this study was to examine whether an EI climate procures increases in the stress-responsive hormone cortisol, as well as negative psychological changes, following the learning of a new skill, compared with a C/TI climate. Participants (n = 107) were randomized to a C/TI or an EI climate in which they learned how to juggle for 30 min over the course of 2 hr. Seven salivary cortisol samples were collected during this period. Results indicated that EI participants experienced greater cortisol responses after the juggling session and significantly greater anxiety, stress, shame, and self-consciousness relative to C/TI participants. In contrast, the C/TI participants reported greater enjoyment, effort, self-confidence, and interest and excitement regarding future juggling than the EI participants. These findings indicate that motivational climates may have a significant impact on both the physiological and psychological responses of participants.

Climate Change and the Concept of Shared Responsibility

DEFF Research Database (Denmark)

Martinsen, Franziska; Seibt, Johanna

2013-01-01

the spatial to the temporal dimension of such wide-scope results of individual actions. This shift from ‘global ethics’ to ‘intergenerational ethics’ and, in particular, ‘climate ethics’ requires some new analytical concepts, however. In this paper we provide a definition of wide-scope responsibility geared...... to articulate our moral concerns about emergent effects in complex systems, such as climate change. Working from Iris Marion Young’s “social connection model of responsibility”, we present a notion of shared ecological responsibility with global and intergenerational scope. We show that our account...... is not affected by the so-called non-identity objection to intergenerational ethics. Since we work from an action-theoretic rather than normative perspective, our account is ‘ethically parametrized’ in the sense that it can be combined with different conceptions of structural and intergenerational justice...

Is Dealing with Climate Change a Corporation’s Responsibility? A Social Contract Perspective

Science.gov (United States)

Unsworth, Kerrie L.; Russell, Sally V.; Davis, Matthew C.

2016-01-01

In this paper, we argue that individuals – as members of society – play an important role in the expectations of whether or not companies are responsible for addressing environmental issues, and whether or not governments should regulate them. From this perspective of corporate social responsibility as a social contract we report the results of a survey of 1066 individuals. The aim of the survey was to assess participants’ belief in anthropogenic climate change, free-market ideology, and beliefs around who is responsible for dealing with climate change. Results showed that both climate change views and free market ideology have a strong effect on beliefs that companies are responsible for dealing with climate change and on support for regulatory policy to that end. Furthermore, we found that free market ideology is a barrier in the support of corporate regulatory policy. The implications of these findings for research, policy, and practice are discussed. PMID:27588009

Heterogeneous responses of temperate-zone amphibian populations to climate change complicates conservation planning

Science.gov (United States)

Muths, Erin L.; Chambert, Thierry A.; Schmidt, B. R.; Miller, D. A. W.; Hossack, Blake R.; Joly, P.; Grolet, O.; Green, D. M.; Pilliod, David S.; Cheylan, M.; Fisher, Robert N.; McCaffery, R. M.; Adams, M. J.; Palen, W. J.; Arntzen, J. W.; Garwood, J.; Fellers, Gary M.; Thirion, J. M.; Grant, Evan H. Campbell; Besnard, A.

2017-01-01

The pervasive and unabated nature of global amphibian declines suggests common demographic responses to a given driver, and quantification of major drivers and responses could inform broad-scale conservation actions. We explored the influence of climate on demographic parameters (i.e., changes in the probabilities of survival and recruitment) using 31 datasets from temperate zone amphibian populations (North America and Europe) with more than a decade of observations each. There was evidence for an influence of climate on population demographic rates, but the direction and magnitude of responses to climate drivers was highly variable among taxa and among populations within taxa. These results reveal that climate drivers interact with variation in life-history traits and population-specific attributes resulting in a diversity of responses. This heterogeneity complicates the identification of conservation ‘rules of thumb’ for these taxa, and supports the notion of local focus as the most effective approach to overcome global-scale conservation challenges.

Future vegetation ecosystem response to warming climate over the Tibetan Plateau

Science.gov (United States)

Bao, Y.; Gao, Y.; Wang, Y.

2017-12-01

The amplified vegetation response to climate variability has been found over the Tibetan Plateau (TP) in recent decades. In this study, the potential impacts of 21st century climate change on the vegetation ecosystem over the TP are assessed based on the dynamic vegetation outputs of models from Coupled Model Intercomparison Project Phase 5 (CMIP5), and the sensitivity of the TP vegetation in response to warming climate was investigated. Models project a continuous and accelerating greening in future, especially in the eastern TP, which closely associates with the plant type upgrade due to the pronouncing warming in growing season.Vegetation leaf area index (LAI) increase well follows the global warming, suggesting the warming climate instead of co2 fertilization controlls the future TP plant growth. The warming spring may advance the start of green-up day and extend the growing season length. More carbon accumulation in vegetation and soil will intensify the TP carbon cycle and will keep it as a carbon sink in future. Keywords: Leaf Area Index (LAI), Climate Change, Global Dynamic Vegetation Models (DGVMs), CMIP5, Tibetan Plateau (TP)

Effective and responsible teaching of climate change in Earth Science-related disciplines

Science.gov (United States)

Robinson, Z. P.; Greenhough, B. J.

2009-04-01

Climate change is a core topic within Earth Science-related courses. This vast topic covers a wide array of different aspects that could be covered, from past climatic change across a vast range of scales to environmental (and social and economic) impacts of future climatic change and strategies for reducing anthropogenic climate change. The Earth Science disciplines play a crucial role in our understanding of past, present and future climate change and the Earth system in addition to understanding leading to development of strategies and technological solutions to achieve sustainability. However, an increased knowledge of the occurrence and causes of past (natural) climate changes can lead to a lessened concern and sense of urgency and responsibility amongst students in relation to anthropogenic causes of climatic change. Two concepts integral to the teaching of climate change are those of scientific uncertainty and complexity, yet an emphasis on these concepts can lead to scepticism about future predictions and a further loss of sense of urgency. The requirement to understand the nature of scientific uncertainty and think and move between different scales in particular relating an increased knowledge of longer timescale climatic change to recent (industrialised) climate change, are clearly areas of troublesome knowledge that affect students' sense of responsibility towards their role in achieving a sustainable society. Study of the attitudes of university students in a UK HE institution on a range of Earth Science-related programmes highlights a range of different attitudes in the student body towards the subject of climate change. Students express varied amounts of ‘climate change saturation' resulting from both media and curriculum coverage, a range of views relating to the significance of humans to the global climate and a range of opinions about the relevance of environmental citizenship to their degree programme. Climate change is therefore a challenging

OPEC's response to international climate agreements

International Nuclear Information System (INIS)

Braaten, J.; Golombek, R.

1998-01-01

This paper studies a game between a group of countries that have agreed to participate in an international climate agreement (the signatories) and OPEC. The purpose of the signatories is to design carbon taxes that maximize their total net income, given a goal on global carbon emissions. As a response to the climate agreement, OPEC imposes an oil tax on its member states that maximizes OPEC's profits. Within a numerical model we find the subgame-perfect equilibrium of a game in which each player chooses when to fix his decision variables. It is shown that in equilibrium the group of signatories chooses to be the leader and OPEC chooses to be the follower. It is demonstrated, however, that for both agents the order of move is of minor (numerical) importance. Hence, the players have limited incentives for strategic behaviour. 17 refs

International climate protection legislation. The way towards a global climate agreement in the sense of common but differentiated responsibility

International Nuclear Information System (INIS)

Jahrmarkt, Lena

2016-01-01

Climate Change is one of the most important issues in the 21st century. Its extensive impacts regarding society, policy, economy and environment and its threats require an effective reaction at the international level. But does the newly adopted Paris Agreement comply to the expectations? Or how could an effective Climate Agreement be achieved to meet climate effectiveness and climate justice? To answer these questions this study analyses the development of international climate change law in a comprehensive way. In combination with analysing the principle of common, but differentiated responsibility it is possible to present new aspects for a climate Agreement by learning from failures of the past and embracing the raising threat brought about by climate change.

Watershed scale response to climate change--Trout Lake Basin, Wisconsin

Science.gov (United States)

Walker, John F.; Hunt, Randall J.; Hay, Lauren E.; Markstrom, Steven L.

2012-01-01

General Circulation Model simulations of future climate through 2099 project a wide range of possible scenarios. To determine the sensitivity and potential effect of long-term climate change on the freshwater resources of the United States, the U.S. Geological Survey Global Change study, "An integrated watershed scale response to global change in selected basins across the United States" was started in 2008. The long-term goal of this national study is to provide the foundation for hydrologically based climate change studies across the nation.

How can streamflow and climate-landscape data be used to estimate baseflow mean response time?

Science.gov (United States)

Zhang, Runrun; Chen, Xi; Zhang, Zhicai; Soulsby, Chris; Gao, Man

2018-02-01

Mean response time (MRT) is a metric describing the propagation of catchment hydraulic behavior that reflects both hydro-climatic conditions and catchment characteristics. To provide a comprehensive understanding of catchment response over a longer-time scale for hydraulic processes, the MRT function for baseflow generation was derived using an instantaneous unit hydrograph (IUH) model that describes the subsurface response to effective rainfall inputs. IUH parameters were estimated based on the "match test" between the autocorrelation function (ACFs) derived from the filtered base flow time series and from the IUH parameters, under the GLUE framework. Regionalization of MRT was conducted using estimates and hydroclimate-landscape indices in 22 sub-basins of the Jinghe River Basin (JRB) in the Loess Plateau of northwest China. Results indicate there is strong equifinality in determination of the best parameter sets but the median values of the MRT estimates are relatively stable in the acceptable range of the parameters. MRTs vary markedly over the studied sub-basins, ranging from tens of days to more than a year. Climate, topography and geomorphology were identified as three first-order controls on recharge-baseflow response processes. Human activities involving the cultivation of permanent crops may elongate the baseflow MRT and hence increase the dynamic storage. Cross validation suggests the model can be used to estimate MRTs in ungauged catchments in similar regions of throughout the Loess Plateau. The proposed method provides a systematic approach for MRT estimation and regionalization in terms of hydroclimate and catchment characteristics, which is helpful in the sustainable water resources utilization and ecological protection in the Loess Plateau.

Functional group, biomass, and climate change effects on ecological drought in semiarid grasslands

Science.gov (United States)

Wilson, Scott D.; Schlaepfer, Daniel R.; Bradford, John B.; Lauenroth, William K.; Duniway, Michael C.; Hall, Sonia A.; Jamiyansharav, Khishigbayar; Jia, Gensuo; Lkhagva, Ariuntsetseg; Munson, Seth M.; Pyke, David A.; Tietjen, Britta

2018-01-01

Water relations in plant communities are influenced both by contrasting functional groups (grasses, shrubs) and by climate change via complex effects on interception, uptake and transpiration. We modelled the effects of functional group replacement and biomass increase, both of which can be outcomes of invasion and vegetation management, and climate change on ecological drought (soil water potential below which photosynthesis stops) in 340 semiarid grassland sites over 30‐year periods. Relative to control vegetation (climate and site‐determined mixes of functional groups), the frequency and duration of drought were increased by shrubs and decreased by annual grasses. The rankings of shrubs, control vegetation, and annual grasses in terms of drought effects were generally consistent in current and future climates, suggesting that current differences among functional groups on drought effects predict future differences. Climate change accompanied by experimentally‐increased biomass (i.e. the effects of invasions that increase community biomass, or management that increases productivity through fertilization or respite from grazing) increased drought frequency and duration, and advanced drought onset. Our results suggest that the replacement of perennial temperate semiarid grasslands by shrubs, or increased biomass, can increase ecological drought both in current and future climates.

High-latitude tree-ring data: Records of climatic change and ecological response

International Nuclear Information System (INIS)

Graumlich, L.J.

1991-01-01

Tree-ring data provide critical information regarding two fundamental questions as to the role of the polar regions in global change: (1) what is the nature of climatic variability? and (2) what is the response of vegetation to climatic variability? Tree-ring-based climatic reconstructions document the variability of the climate system on time scales of years to centuries. Dendroclimatic reconstructions indicate that the climatic episodes defined on the basis of documentary evidence in western Europe (i.e., Medieval Warm Episode, ca. A.D. 1000-1300; Little Ice Age, ca. A.D. 1550-1850) can be observed at some high-latitude sites (ex., Polar Urals). Spatial variation in long-term temperature trends (ex., northern Fennoscandia vs. Polar Urals) demonstrates the importance of regional-scale climatic controls. When collated into global networks, proxy-based climatic reconstructions can be used to test hypotheses as to the relative importance of external forcing vs. internal variation in governing climatic variation. Specifically, such a global network would allow the quantification of the climatic response to various permutations of factors thought to be important in governing decadal- to centennial-scale climatic variation. Tree populations respond to annual- to centennial-scale climatic variation through changes in rates of growth, establishment, and mortality. Tree-ring studies that document multiple aspects of high-latitude treeline dynamics (i.e., the timing of tree establishment, mortality, and changes from krummholz to upright growth) indicate a complex interaction between growth form, population processes, and environmental variability. Such interactions result in varying sensitivities of high-latitude trees to climatic change

Studies on climate change problems and response measures in China

Energy Technology Data Exchange (ETDEWEB)

Ruqiu, Y. [China National Environmental Protection Agency, Beijing (China)

1995-06-01

Climate has substantial influence on the development of human society. At the same time, the global climate is being affected by human activities. Since industrial revolution large amount of CO{sub 2} and other greenhouse gases have been emitted to the atmosphere, causing significant change in its composition. It is recognized that this change might be sufficient to cause change in global climate. Because of the importance of climate change issues, the Chinese government pays great attention to them. As climate change concerns almost all aspects of the social and economic development, in order to coordinate ministries and agencies of the government in their efforts to deal with climate change problems, the Coordinating Group on Climate Change under the Environmental Protection Committee of the State Council was established in February 1990. There are four working groups under the Coordinating Group, working on scientific assessment, impact assessment and response strategies, economic implication and international convention matters of climate change. A number of research and technological development projects related to climate change issues have been organized, including bilateral cooperation projects and projects supported by GEF, UNEP, UNDP, the World Bank, the Asian Development Bank and other international organizations. (EG) 11 refs.

Studies on climate change problems and response measures in China

International Nuclear Information System (INIS)

Ruqiu, Y.

1995-01-01

Climate has substantial influence on the development of human society. At the same time, the global climate is being affected by human activities. Since industrial revolution large amount of CO 2 and other greenhouse gases have been emitted to the atmosphere, causing significant change in its composition. It is recognized that this change might be sufficient to cause change in global climate. Because of the importance of climate change issues, the Chinese government pays great attention to them. As climate change concerns almost all aspects of the social and economic development, in order to coordinate ministries and agencies of the government in their efforts to deal with climate change problems, the Coordinating Group on Climate Change under the Environmental Protection Committee of the State Council was established in February 1990. There are four working groups under the Coordinating Group, working on scientific assessment, impact assessment and response strategies, economic implication and international convention matters of climate change. A number of research and technological development projects related to climate change issues have been organized, including bilateral cooperation projects and projects supported by GEF, UNEP, UNDP, the World Bank, the Asian Development Bank and other international organizations. (EG) 11 refs

A model of the responses of ecotones to climate change

Energy Technology Data Exchange (ETDEWEB)

Noble, I.R. (Australian National University, Canberra, ACT (Australia). Research School of Biological Sciences, Ecosystem Dynamics Group)

1993-08-01

It has been suggested that global climatic change may be detected by monitoring the positions of ecotones. The author built a model of the dynamics of ecotones similar to those found in altitudinal or latitudinal treelines, where a slow tendency for the ecotone to advance is counterbalanced by disturbances such as fire or landslides. The model showed that the response of such ecotones to a wide range of simulated climate changes was slow and that the ecotone front was dissected. It would appear that such ecotones would not make suitable sites for monitoring climate change.

77 FR 19661 - Draft National Water Program 2012 Strategy: Response to Climate Change

Science.gov (United States)

2012-04-02

... 2012 Strategy: Response to Climate Change AGENCY: Environmental Protection Agency (EPA). ACTION: Notice... change challenges to its mission of protecting human health and the environment. Climate change alters... even temporal nature of effects, climate change will pose challenges to various aspects of water...

Community responses to extreme climatic conditions

Directory of Open Access Journals (Sweden)

Frédéric JIGUET, Lluis BROTONS, Vincent DEVICTOR

2011-06-01

Full Text Available Species assemblages and natural communities are increasingly impacted by changes in the frequency and severity of extreme climatic events. Here we propose a brief overview of expected and demonstrated direct and indirect impacts of extreme events on animal communities. We show that differential impacts on basic biological parameters of individual species can lead to strong changes in community composition and structure with the potential to considerably modify the functional traits of the community. Sudden disequilibria have even been shown to induce irreversible shifts in marine ecosystems, while cascade effects on various taxonomic groups have been highlighted in Mediterranean forests. Indirect effects of extreme climatic events are expected when event-induced habitat changes (e.g. soil stability, vegetation composition, water flows altered by droughts, floods or hurricanes have differential consequences on species assembled within the communities. Moreover, in increasing the amplitude of trophic mismatches, extreme events are likely to turn many systems into ecological traps under climate change. Finally, we propose a focus on the potential impacts of an extreme heat wave on local assemblages as an empirical case study, analysing monitoring data on breeding birds collected in France. In this example, we show that despite specific populations were differently affected by local temperature anomalies, communities seem to be unaffected by a sudden heat wave. These results suggest that communities are tracking climate change at the highest possible rate [Current Zoology 57 (3: 406–413, 2011].

Lags in the response of mountain plant communities to climate change.

Science.gov (United States)

Alexander, Jake M; Chalmandrier, Loïc; Lenoir, Jonathan; Burgess, Treena I; Essl, Franz; Haider, Sylvia; Kueffer, Christoph; McDougall, Keith; Milbau, Ann; Nuñez, Martin A; Pauchard, Aníbal; Rabitsch, Wolfgang; Rew, Lisa J; Sanders, Nathan J; Pellissier, Loïc

2018-02-01

Rapid climatic changes and increasing human influence at high elevations around the world will have profound impacts on mountain biodiversity. However, forecasts from statistical models (e.g. species distribution models) rarely consider that plant community changes could substantially lag behind climatic changes, hindering our ability to make temporally realistic projections for the coming century. Indeed, the magnitudes of lags, and the relative importance of the different factors giving rise to them, remain poorly understood. We review evidence for three types of lag: "dispersal lags" affecting plant species' spread along elevational gradients, "establishment lags" following their arrival in recipient communities, and "extinction lags" of resident species. Variation in lags is explained by variation among species in physiological and demographic responses, by effects of altered biotic interactions, and by aspects of the physical environment. Of these, altered biotic interactions could contribute substantially to establishment and extinction lags, yet impacts of biotic interactions on range dynamics are poorly understood. We develop a mechanistic community model to illustrate how species turnover in future communities might lag behind simple expectations based on species' range shifts with unlimited dispersal. The model shows a combined contribution of altered biotic interactions and dispersal lags to plant community turnover along an elevational gradient following climate warming. Our review and simulation support the view that accounting for disequilibrium range dynamics will be essential for realistic forecasts of patterns of biodiversity under climate change, with implications for the conservation of mountain species and the ecosystem functions they provide. © 2017 John Wiley & Sons Ltd.

Lags in the response of mountain plant communities to climate change

Science.gov (United States)

Alexander, Jake M.; Chalmandrier, Loïc; Lenoir, Jonathan; Burgess, Treena I.; Essl, Franz; Haider, Sylvia; Kueffer, Christoph; McDougall, Keith; Milbau, Ann; Nuñez, Martin A.; Pauchard, Aníbal; Rabitsch, Wolfgang; Rew, Lisa J.; Sanders, Nathan J.; Pellissier, Loïc

2018-01-01

Rapid climatic changes and increasing human influence at high elevations around the world will have profound impacts on mountain biodiversity. However, forecasts from statistical models (e.g. species distribution models) rarely consider that plant community changes could substantially lag behind climatic changes, hindering our ability to make temporally realistic projections for the coming century. Indeed, the magnitudes of lags, and the relative importance of the different factors giving rise to them, remain poorly understood. We review evidence for three types of lag: “dispersal lags” affecting plant species’ spread along elevational gradients, “establishment lags” following their arrival in recipient communities, and “extinction lags” of resident species. Variation in lags is explained by variation among species in physiological and demographic responses, by effects of altered biotic interactions, and by aspects of the physical environment. Of these, altered biotic interactions could contribute substantially to establishment and extinction lags, yet impacts of biotic interactions on range dynamics are poorly understood. We develop a mechanistic community model to illustrate how species turnover in future communities might lag behind simple expectations based on species’ range shifts with unlimited dispersal. The model shows a combined contribution of altered biotic interactions and dispersal lags to plant community turnover along an elevational gradient following climate warming. Our review and simulation support the view that accounting for disequilibrium range dynamics will be essential for realistic forecasts of patterns of biodiversity under climate change, with implications for the conservation of mountain species and the ecosystem functions they provide. PMID:29112781

A replicated climate change field experiment reveals rapid evolutionary response in an ecologically important soil invertebrate

DEFF Research Database (Denmark)

Bataillon, Thomas; Galtier, Nicolas; Bernard, Aurelien

2016-01-01

to climate change in a common annelid worm using a controlled replicated experiment where climatic conditions were manipulated in a natural setting. Analyzing the transcribed genome of 15 local populations, we found that about 12% of the genetic polymorphisms exhibit differences in allele frequencies......Whether species can respond evolutionarily to current climate change is crucial for the persistence of many species. Yet, very few studies have examined genetic responses to climate change in manipulated experiments carried out innatural field conditions. We examined the evolutionary response...... associated to changes in soil temperature and soil moisture. This shows an evolutionaryresponse to realistic climate change happening over short-time scale, and calls for incorporating evolution into modelspredicting future response of species to climate change. It also shows that designed climate change...

Exploiting temporal variability to understand tree recruitment response to climate change

Science.gov (United States)

Ines Ibanez; James S. Clark; Shannon LaDeau; Janneke Hill Ris Lambers

2007-01-01

Predicting vegetation shifts under climate change is a challenging endeavor, given the complex interactions between biotic and abiotic variables that influence demographic rates. To determine how current trends and variation in climate change affect seedling establishment, we analyzed demographic responses to spatiotemporal variation to temperature and soil moisture in...

Assessing the implications of human land-use change for the transient climate response to cumulative carbon emissions

International Nuclear Information System (INIS)

Simmons, C T; Matthews, H D

2016-01-01

Recent research has shown evidence of a linear climate response to cumulative CO 2 emissions, which implies that the source, timing, and amount of emissions does not significantly influence the climate response per unit emission. Furthermore, these analyses have generally assumed that the climate response to land-use CO 2 emissions is equivalent to that of fossil fuels under the assumption that, once in the atmosphere, the radiative forcing induced by CO 2 is not sensitive to the emissions source. However, land-cover change also affects surface albedo and the strength of terrestrial carbon sinks, both of which have an additional climate effect. In this study, we use a coupled climate-carbon cycle model to assess the climate response to historical and future cumulative land-use CO 2 emissions, in order to compare it to the response to fossil fuel CO 2 . We find that when we isolate the CO 2 -induced (biogeochemical) temperature changes associated with land-use change, then the climate response to cumulative land-use emissions is equivalent to that of fossil fuel CO 2 . We show further that the globally-averaged albedo-induced biophysical cooling from land-use change is non-negligible and may be of comparable magnitude to the biogeochemical warming, with the result that the net climate response to land-use change is substantially different from a linear response to cumulative emissions. However, our new simulations suggest that the biophysical cooling from land-use change follows its own independent (negative) linear response to cumulative net land-use CO 2 emissions, which may provide a useful scaling factor for certain applications when evaluating the full transient climate response to emissions. (letter)

Financial market response to extreme events indicating climatic change

Science.gov (United States)

Anttila-Hughes, J. K.

2016-05-01

A variety of recent extreme climatic events are considered to be strong evidence that the climate is warming, but these incremental advances in certainty often seem ignored by non-scientists. I identify two unusual types of events that are considered to be evidence of climate change, announcements by NASA that the global annual average temperature has set a new record, and the sudden collapse of major polar ice shelves, and then conduct an event study to test whether news of these events changes investors' valuation of energy companies, a subset of firms whose future performance is closely tied to climate change. I find evidence that both classes of events have influenced energy stock prices since the 1990s, with record temperature announcements on average associated with negative returns and ice shelf collapses associated with positive returns. I identify a variety of plausible mechanisms that may be driving these differential responses, discuss implications for energy markets' views on long-term regulatory risk, and conclude that investors not only pay attention to scientifically significant climate events, but discriminate between signals carrying different information about the nature of climatic change.

Testing For The Linearity of Responses To Multiple Anthropogenic Climate Forcings

Science.gov (United States)

Forest, C. E.; Stone, P. H.; Sokolov, A. P.

To test whether climate forcings are additive, we compare climate model simulations in which anthropogenic forcings are applied individually and in combination. Tests are performed with different values for climate system properties (climate sensitivity and rate of heat uptake by the deep ocean) as well as for different strengths of the net aerosol forcing, thereby testing for the dependence of linearity on these properties. The MIT 2D Land-Ocean Climate Model used in this study consists of a zonally aver- aged statistical-dynamical atmospheric model coupled to a mixed-layer Q-flux ocean model, with heat anomalies diffused into the deep ocean. Following our previous stud- ies, the anthropogenic forcings are the changes in concentrations of greenhouse gases (1860-1995), sulfate aerosol (1860-1995), and stratospheric and tropospheric ozone (1979-1995). The sulfate aerosol forcing is applied as a surface albedo change. For an aerosol forcing of -1.0 W/m2 and an effective ocean diffusitivity of 2.5 cm2/s, the nonlinearity of the response of global-mean surface temperatures to the combined forcing shows a strong dependence on climate sensitivity. The fractional change in decadal averages ([(TG + TS + TO) - TGSO]/TGSO) for the 1986-1995 period compared to pre-industrial times are 0.43, 0.90, and 1.08 with climate sensitiv- ities of 3.0, 4.5, and 6.2 C, respectively. The values of TGSO for these three cases o are 0.52, 0.62, and 0.76 C. The dependence of linearity on climate system properties, o the role of climate system feedbacks, and the implications for the detection of climate system's response to individual forcings will be presented. Details of the model and forcings can be found at http://web.mit.edu/globalchange/www/.

The ocean's role in polar climate change: asymmetric Arctic and Antarctic responses to greenhouse gas and ozone forcing.

Science.gov (United States)

Marshall, John; Armour, Kyle C; Scott, Jeffery R; Kostov, Yavor; Hausmann, Ute; Ferreira, David; Shepherd, Theodore G; Bitz, Cecilia M

2014-07-13

In recent decades, the Arctic has been warming and sea ice disappearing. By contrast, the Southern Ocean around Antarctica has been (mainly) cooling and sea-ice extent growing. We argue here that interhemispheric asymmetries in the mean ocean circulation, with sinking in the northern North Atlantic and upwelling around Antarctica, strongly influence the sea-surface temperature (SST) response to anthropogenic greenhouse gas (GHG) forcing, accelerating warming in the Arctic while delaying it in the Antarctic. Furthermore, while the amplitude of GHG forcing has been similar at the poles, significant ozone depletion only occurs over Antarctica. We suggest that the initial response of SST around Antarctica to ozone depletion is one of cooling and only later adds to the GHG-induced warming trend as upwelling of sub-surface warm water associated with stronger surface westerlies impacts surface properties. We organize our discussion around 'climate response functions' (CRFs), i.e. the response of the climate to 'step' changes in anthropogenic forcing in which GHG and/or ozone-hole forcing is abruptly turned on and the transient response of the climate revealed and studied. Convolutions of known or postulated GHG and ozone-hole forcing functions with their respective CRFs then yield the transient forced SST response (implied by linear response theory), providing a context for discussion of the differing warming/cooling trends in the Arctic and Antarctic. We speculate that the period through which we are now passing may be one in which the delayed warming of SST associated with GHG forcing around Antarctica is largely cancelled by the cooling effects associated with the ozone hole. By mid-century, however, ozone-hole effects may instead be adding to GHG warming around Antarctica but with diminished amplitude as the ozone hole heals. The Arctic, meanwhile, responding to GHG forcing but in a manner amplified by ocean heat transport, may continue to warm at an accelerating rate.

The response of the southwest Western Australian wave climate to Indian Ocean climate variability

Science.gov (United States)

Wandres, Moritz; Pattiaratchi, Charitha; Hetzel, Yasha; Wijeratne, E. M. S.

2018-03-01

Knowledge of regional wave climates is critical for coastal planning, management, and protection. In order to develop a regional wave climate, it is important to understand the atmospheric systems responsible for wave generation. This study examines the variability of the southwest Western Australian (SWWA) shelf and nearshore wind wave climate and its relationship to southern hemisphere climate variability represented by various atmospheric indices: the southern oscillation index (SOI), the Southern Annular Mode (SAM), the Indian Ocean Dipole Mode Index (DMI), the Indian Ocean Subtropical Dipole (IOSD), the latitudinal position of the subtropical high-pressure ridge (STRP), and the corresponding intensity of the subtropical ridge (STRI). A 21-year wave hindcast (1994-2014) of the SWWA continental shelf was created using the third generation wave model Simulating WAves Nearshore (SWAN), to analyse the seasonal and inter-annual wave climate variability and its relationship to the atmospheric regime. Strong relationships between wave heights and the STRP and the STRI, a moderate correlation between the wave climate and the SAM, and no significant correlation between SOI, DMI, and IOSD and the wave climate were found. Strong spatial, seasonal, and inter-annual variability, as well as seasonal longer-term trends in the mean wave climate were studied and linked to the latitudinal changes in the subtropical high-pressure ridge and the Southern Ocean storm belt. As the Southern Ocean storm belt and the subtropical high-pressure ridge shifted southward (northward) wave heights on the SWWA shelf region decreased (increased). The wave height anomalies appear to be driven by the same atmospheric conditions that influence rainfall variability in SWWA.

Climate of origin affects tick (Ixodes ricinus) host-seeking behavior in response to temperature: implications for resilience to climate change?

Science.gov (United States)

Gilbert, Lucy; Aungier, Jennifer; Tomkins, Joseph L

2014-04-01

Climate warming is changing distributions and phenologies of many organisms and may also impact on vectors of disease-causing pathogens. In Europe, the tick Ixodes ricinus is the primary vector of medically important pathogens (e.g., Borrelia burgdorferi sensu lato, the causative agent of Lyme borreliosis). How might climate change affect I. ricinus host-seeking behavior (questing)? We hypothesize that, in order to maximize survival, I. ricinus have adapted their questing in response to temperature in accordance with local climates. We predicted that ticks from cooler climates quest at cooler temperatures than those from warmer climates. This would suggest that I. ricinus can adapt and therefore have the potential to be resilient to climate change. I. ricinus were collected from a cline of climates using a latitudinal gradient (northeast Scotland, North Wales, South England, and central France). Under laboratory conditions, ticks were subjected to temperature increases of 1°C per day, from 6 to 15°C. The proportion of ticks questing was recorded five times per temperature (i.e., per day). The theoretical potential to quest was then estimated for each population over the year for future climate change projections. As predicted, more ticks from cooler climates quested at lower temperatures than did ticks from warmer climates. The proportion of ticks questing was strongly associated with key climate parameters from each location. Our projections, based on temperature alone, suggested that populations could advance their activity season by a month under climate change, which has implications for exposure periods of hosts to tick-borne pathogens. Our findings suggest that I. ricinus have adapted their behavior in response to climate, implying some potential to adapt to climate change. Predictive models of I. ricinus dynamics and disease risk over continental scales would benefit from knowledge of these differences between populations.

Pleistocene climate, phylogeny, and climate envelope models: an integrative approach to better understand species' response to climate change.

Directory of Open Access Journals (Sweden)

A Michelle Lawing

Full Text Available Mean annual temperature reported by the Intergovernmental Panel on Climate Change increases at least 1.1°C to 6.4°C over the next 90 years. In context, a change in climate of 6°C is approximately the difference between the mean annual temperature of the Last Glacial Maximum (LGM and our current warm interglacial. Species have been responding to changing climate throughout Earth's history and their previous biological responses can inform our expectations for future climate change. Here we synthesize geological evidence in the form of stable oxygen isotopes, general circulation paleoclimate models, species' evolutionary relatedness, and species' geographic distributions. We use the stable oxygen isotope record to develop a series of temporally high-resolution paleoclimate reconstructions spanning the Middle Pleistocene to Recent, which we use to map ancestral climatic envelope reconstructions for North American rattlesnakes. A simple linear interpolation between current climate and a general circulation paleoclimate model of the LGM using stable oxygen isotope ratios provides good estimates of paleoclimate at other time periods. We use geologically informed rates of change derived from these reconstructions to predict magnitudes and rates of change in species' suitable habitat over the next century. Our approach to modeling the past suitable habitat of species is general and can be adopted by others. We use multiple lines of evidence of past climate (isotopes and climate models, phylogenetic topology (to correct the models for long-term changes in the suitable habitat of a species, and the fossil record, however sparse, to cross check the models. Our models indicate the annual rate of displacement in a clade of rattlesnakes over the next century will be 2 to 3 orders of magnitude greater (430-2,420 m/yr than it has been on average for the past 320 ky (2.3 m/yr.

Adaptation responses of crops to climate change

Energy Technology Data Exchange (ETDEWEB)

Seino, Hiroshi [National Inst. of Agro-Environmental Sciences, Tsukuba, Ibaraki (Japan)

1993-12-31

Appreciable global climatic responses to increasing levels of atmospheric CO{sub 2} and other trace gases are expected to take place over the next 50 to 80 years. Increasing atmospheric concentrations of carbon dioxide and other greenhouse gases are producing or will produce changes in the climate of the Earth. In particular, numerous efforts of climate modeling project very substantial increase of surface air temperature. In addition to a general warming of the atmosphere, the possibility of increased summer dryness in the continental mid-latitudes has been suggested on the basis of both historical analogues and some General Circulation Model (GCM) studies. There are three types of effect of climatic change on agriculture: (1) the physiological (direct) effect of elevated levels of atmospheric CO{sub 2} on crop plants and weeds, (2) the effect of changes in parameters of climate (e.g., temperature, precipitation, and solar radiation) on plants and animals, and (3) the effects of climate-related rises in sea-level on land use. The direct effects of elevated CO{sub 2} are on photosynthesis and respiration and thereby on growth, and there are additional effects of increased CO{sub 2} on development, yield quality and stomatal aperture and water use. A doubling of CO{sub 2} increases the instantaneous photosynthetic rate by 30% to 100%, depending on the other environmental conditions, and reduce water requirements of plants by reducing transpiration (per unit leaf area) through reductions in stomatal aperture. A doubling of CO{sub 2} causes partial stomatal closure on both C{sub 3} and C{sub 4} plants (approximately a 40% decrease in aperture). In many experiments this results in reductions of transpiration of about 23% to 46%. However. there is considerable uncertainty over the magnitude of this in natural conditions.

Climate Policy: Stop Wanting to Pay to Evade Our Responsibilities

International Nuclear Information System (INIS)

Billette de Villemeur, Etienne; Leroux, Justin

2016-01-01

We explore an alternative to existing economic instruments to tackle climate change: carbon liabilities. Such liabilities would hold countries responsible for future climate damage to the tune of their emissions over time. The prospect of having to repay this carbon debt over time is enough to discipline emitters, leading to the efficient emissions level. Contrary to existing instruments, our scheme does not rest on a consensus regarding the discount factor nor about climate forecasts; this, together with its reliance on observed damage, allows for better international participation and leads to a fairer division of costs and risks

Response of a multi-stressed Mediterranean river to future climate and socio-economic scenarios.

Science.gov (United States)

Stefanidis, Konstantinos; Panagopoulos, Yiannis; Mimikou, Maria

2018-06-15

Streams and rivers are among the most threatened ecosystems in Europe due to the combined effects of multiple pressures related to anthropogenic activities. Particularly in the Mediterranean region, changes in hydromorphology along with increased nutrient loadings are known to affect the ecological functions and ecosystem services of streams and rivers with the anticipated climate change being likely to further impair their functionality and structure. In this study, we investigated the combined effects of agricultural driven stressors on the ecology and delivered services of the Pinios river basin in Greece under three future world scenarios developed within the EU funded MARS project. Scenarios are based on combinations of Representative Concentration Pathways and Shared Socioeconomic Pathways and refer to early century (2030) and mid-century (2060) representing future climate worlds with particular socioeconomic characteristics. To assess the responses of ecological and ecosystem service indicators to the scenarios we first simulated hydrology and water quality in Pinios with a process-based model. Simulated abiotic stressor parameters (predictors) were linked to two biotic indicators, the macroinvertebrate indicators ASPT and EPT, with empirical modelling based on boosted regression trees and general linear models. Our results showed that the techno world scenario driven by fast economic growth and intensive exploitation of energy resources had the largest impact on both the abiotic status (nutrient loads and concentrations in water) and the biotic indicators. In contrast, the predicted changes under the other two future worlds, consensus and fragmented, were more diverse and were mostly dictated by the projected climate. This work showed that the future scenarios, especially the mid-century ones, had significant impact on both abiotic status and biotic responses underpinning the need for implementing catchment management practices able to mitigate the

Diverging responses of tropical Andean biomes under future climate conditions.

Directory of Open Access Journals (Sweden)

Carolina Tovar

Full Text Available Observations and projections for mountain regions show a strong tendency towards upslope displacement of their biomes under future climate conditions. Because of their climatic and topographic heterogeneity, a more complex response is expected for biodiversity hotspots such as tropical mountain regions. This study analyzes potential changes in the distribution of biomes in the Tropical Andes and identifies target areas for conservation. Biome distribution models were developed using logistic regressions. These models were then coupled to an ensemble of 8 global climate models to project future distribution of the Andean biomes and their uncertainties. We analysed projected changes in extent and elevational range and identified regions most prone to change. Our results show a heterogeneous response to climate change. Although the wetter biomes exhibit an upslope displacement of both the upper and the lower boundaries as expected, most dry biomes tend to show downslope expansion. Despite important losses being projected for several biomes, projections suggest that between 74.8% and 83.1% of the current total Tropical Andes will remain stable, depending on the emission scenario and time horizon. Between 3.3% and 7.6% of the study area is projected to change, mostly towards an increase in vertical structure. For the remaining area (13.1%-17.4%, there is no agreement between model projections. These results challenge the common believe that climate change will lead to an upslope displacement of biome boundaries in mountain regions. Instead, our models project diverging responses, including downslope expansion and large areas projected to remain stable. Lastly, a significant part of the area expected to change is already affected by land use changes, which has important implications for management. This, and the inclusion of a comprehensive uncertainty analysis, will help to inform conservation strategies in the Tropical Andes, and to guide similar

Decadal phytoplankton dynamics in response to episodic climatic disturbances in a subtropical deep freshwater ecosystem.

Science.gov (United States)

Ko, Chia-Ying; Lai, Chao-Chen; Hsu, Huang-Hsiung; Shiah, Fuh-Kwo

2017-02-01

Information of the decadal timescale effects of episodic climatic disturbances (i.e., typhoons) on phytoplankton in freshwater ecosystems have received less attention and fewer seasonal evaluations partly due to the lack of long-term time-series monitoring data in typhoon prevailing areas. Through field observations of a total 36 typhoon cases in a subtropical deep freshwater ecosystem in the period of 2005-2014, we quantified phytoplankton biomass, production and growth rate in response to meteorological and hydrological changes in the weeks before, during and after typhoons between summer and autumn, and also investigated the effects of typhoon characteristics on the aforementioned phytoplankton responses. The results showed that phytoplankton exposed to typhoon disturbances generally exhibited an increasing trend over the weeks before, during and after typhoons in summer but varied in autumn. The correlations and multivariate regressions showed different contributions of meteorological and hydrological variables to individual phytoplankton responses before, during and after typhoons between seasons. The post-typhoon weeks (i.e., within two weeks after a typhoon had passed) were especially important for the timeline of phytoplankton increases and with a detectable seasonal variation that the chlorophyll a concentration significantly increased in autumn whereas both primary production and growth rate were associated with significant changes in summer. Additionally, phytoplankton responses during the post-typhoon weeks were significantly different between discrete or continuous types of typhoon events. Our work illustrated the fact that typhoons did influence phytoplankton responses in the subtropical deep freshwater ecosystem and typhoon passages in summer and autumn affected the phytoplankton dynamics differently. Nevertheless, sustained and systematic monitoring in order to advance our understanding of the role of typhoons between seasons in the modulation of

Climate and vegetation in a semi-arid savanna: Development of a climate–vegetation response model linking plant metabolic performance to climate and the effects on forage availability for large herbivores

Directory of Open Access Journals (Sweden)

Armin H. Seydack

2012-02-01

Developing the climate–vegetation response model involved three main components, namely (1 defining indicators of forage availability to herbivores (nitrogen productivity, nitrogen quality, carbon-nutrient quality, (2 identifying herbivore species guilds of similar nutritional requirements with respect to these indicators [bulk feeders with tolerance to fibrous herbage (buffalo, waterbuck, bulk feeders with preference for high nitrogen quality forage (short grass preference grazers: blue wildebeest and zebra and selective feeders where dietary items of relatively high carbon-nutrient quality represented key forage resources (selective grazers: sable antelope, roan antelope, tsessebe, eland] and (3 developing a process model where the expected effects of plant metabolic responses to climate on key forage resources were made explicit. According to the climate–vegetation response model both shorter-term transient temperature acclimation pulses and longer-term shifts in plant metabolic functionality settings were predicted to have occurred in response to temperature trends over the past century. These temperature acclimation responses were expected to have resulted in transient pulses of increased forage availability (increased nitrogen- and carbon-nutrient quality, as well as the progressive long-term decline of the carbon-nutrient quality of forage. Conservation implications: The climate–vegetation response model represents a research framework for further studies contributing towards the enhanced understanding of landscape-scale functioning of savanna systems with reference to the interplay between climate, vegetation and herbivore population dynamics. Gains in such understanding can support sound conservation management.

Responses of the ocean carbon cycle to climate change: Results from an earth system climate model simulation

Institute of Scientific and Technical Information of China (English)

WANG Shuang-Jing; CAO Long; LI Na

2014-01-01

Based on simulations using the University of Victoria’s Earth System Climate Model, we analyzed the responses of the ocean carbon cycle to increasing atmospheric CO2 levels and climate change from 1800 to 2500 following the RCP 8.5 scenario and its extension. Compared to simulations without climate change, the simulation with a climate sensitivity of 3.0 K shows that in 2100, due to increased atmospheric CO2 concentrations, the simulated sea surface temperature increases by 2.7 K, the intensity of the North Atlantic deep water formation reduces by4.5 Sv, and the oceanic uptake of anthropogenic CO2 decreases by 0.8 Pg C. Climate change is also found to have a large effect on the North Atlantic’s ocean column inventory of anthropogenic CO2. Between the years 1800 and 2500, compared with the simulation with no climate change, the simulation with climate change causes a reduction in the total anthropogenic CO2 column inventory over the entire ocean and in North Atlantic by 23.1% and 32.0%, respectively. A set of simulations with climate sensitivity variations from 0.5 K to 4.5 K show that with greater climate sensitivity climate change would have a greater effect in reducing the ocean’s ability to absorb CO2 from the atmosphere.

The effects of climate downscaling technique and observational data set on modeled ecological responses

Science.gov (United States)

Afshin Pourmokhtarian; Charles T. Driscoll; John L. Campbell; Katharine Hayhoe; Anne M. K. Stoner

2016-01-01

Assessments of future climate change impacts on ecosystems typically rely on multiple climate model projections, but often utilize only one downscaling approach trained on one set of observations. Here, we explore the extent to which modeled biogeochemical responses to changing climate are affected by the selection of the climate downscaling method and training...

Understanding Farmers' Response to Climate Variability in Nigeria ...

African Journals Online (AJOL)

In this study, farmers 'response to climate variability was examined. Primary and secondary data were used. A multi-stage sampling procedure was adopted in the collection of the primary data using structured questionnaires. Four vegetation zones out of seven where farming is mainly carried out were selected for the study.

Predicting athletes' functional and dysfunctional emotions: The role of the motivational climate and motivation regulations.

Science.gov (United States)

Ruiz, Montse C; Haapanen, Saara; Tolvanen, Asko; Robazza, Claudio; Duda, Joan L

2017-08-01

This study examined the relationships between perceptions of the motivational climate, motivation regulations, and the intensity and functionality levels of athletes' pleasant and unpleasant emotional states. Specifically, we examined the hypothesised mediational role of motivation regulations in the climate-emotion relationship. We also tested a sequence in which emotions were assumed to be predicted by the motivational climate dimensions and then served as antecedents to variability in motivation regulations. Participants (N = 494) completed a multi-section questionnaire assessing targeted variables. Structural equation modelling (SEM) revealed that a perceived task-involving climate was a positive predictor of autonomous motivation and of the impact of functional anger, and a negative predictor of the intensity of anxiety and dysfunctional anger. Autonomous motivation was a partial mediator of perceptions of a task-involving climate and the impact of functional anger. An ego-involving climate was a positive predictor of controlled motivation, and of the intensity and impact of functional anger and the intensity of dysfunctional anger. Controlled motivation partially mediated the relationship between an ego-involving climate and the intensity of dysfunctional anger. Good fit to the data also emerged for the motivational climate, emotional states, and motivation regulations sequence. Findings provide support for the consideration of hedonic tone and functionality distinctions in the assessment of athletes' emotional states.

Flood risk and climate change in the Rotterdam area, The Netherlands: Enhancing citizen's climate risk perceptions and prevention responses despite skepticism

OpenAIRE

de Boer, J.; Botzen, W.J.W.; Terpstra, T.

2016-01-01

Effective communication about climate change and related risks is complicated by the polarization between “climate alarmists” and “skeptics.” This paper provides insights for the design of climate risk communication strategies by examining how the interplay between climate change and flood risk communication affects citizens’ risk perceptions and responses. The study is situated in a delta area with substantial geographic variations in the occurrence and potential impact of flood risk, which ...

Climate and carbon-cycle response to astronomical forcing over the last 35 Ma.

Science.gov (United States)

De Vleeschouwer, D.; Palike, H.; Vahlenkamp, M.; Crucifix, M.

2017-12-01

On a million-year time scale, the characteristics of insolation forcing caused by cyclical variations in the astronomical parameters of the Earth remain stable. Nevertheless, Earth's climate responded very differently to this forcing during different parts of the Cenozoic. The recently-published ∂18Obenthic megasplice (De Vleeschouwer et al., 2017) allowed for a clear visualization of these changes in global climate response to astronomical forcing. However, many open questions remain regarding how carbon-cycle dynamics influence Earth's climate sensitivity to astronomical climate forcing. To provide insight into the interaction between the carbon cycle and astronomical insolation forcing, we built a benthic carbon isotope (∂13Cbenthic) megasplice for the last 35 Ma, employing the same technique used to build the ∂18Obenthic megasplice. The ∂13Cbenthic megasplice exhibits a strong imprint of the 405 and 100-kyr eccentricity cycles throughout the last 35 Ma. This is intriguing, as the oxygen isotope megasplice looses its eccentricity imprint after the mid-Miocene climatic transition (MMCT; see Fig. 1 in De Vleeschouwer et al., 2017). In other words, the carbon cycle responded completely differently to astronomical forcing, compared to global climate during the late Miocene. We visualize this difference in response by the application of a Gaussian process, which renders the dependence of one variable (here ∂18Obenthic or ∂13Cbenthic) in a multidimensional space (here precession, obliquity and eccentricity). Together, the ∂13Cbenthic and ∂18Obenthic megasplices thus provide a unique tool for paleoclimatology, allowing for the quantification and visualization of the changing paleoclimate and carbon-cycle response to astronomical forcing throughout geologic time. References De Vleeschouwer, D., Vahlenkamp, M., Crucifix, M., Pälike, H., 2017. Alternating Southern and Northern Hemisphere climate response to astronomical forcing during the past 35 m

Biotic interactions overrule plant responses to climate, depending on the species' biogeography.

Directory of Open Access Journals (Sweden)

Astrid Welk

Full Text Available This study presents an experimental approach to assess the relative importance of climatic and biotic factors as determinants of species' geographical distributions. We asked to what extent responses of grassland plant species to biotic interactions vary with climate, and to what degree this variation depends on the species' biogeography. Using a gradient from oceanic to continental climate represented by nine common garden transplant sites in Germany, we experimentally tested whether congeneric grassland species of different geographic distribution (oceanic vs. continental plant range type responded differently to combinations of climate, competition and mollusc herbivory. We found the relative importance of biotic interactions and climate to vary between the different components of plant performance. While survival and plant height increased with precipitation, temperature had no effect on plant performance. Additionally, species with continental plant range type increased their growth in more benign climatic conditions, while those with oceanic range type were largely unable to take a similar advantage of better climatic conditions. Competition generally caused strong reductions of aboveground biomass and growth. In contrast, herbivory had minor effects on survival and growth. Against expectation, these negative effects of competition and herbivory were not mitigated under more stressful continental climate conditions. In conclusion we suggest variation in relative importance of climate and biotic interactions on broader scales, mediated via species-specific sensitivities and factor-specific response patterns. Our results have important implications for species distribution models, as they emphasize the large-scale impact of biotic interactions on plant distribution patterns and the necessity to take plant range types into account.

N cycling in SPRUCE (Spruce Peatlands Response Under Climatic and Environmental Changes)

Science.gov (United States)

Peatlands located in boreal regions make up a third of global wetland area and are expected to have the highest temperature increases in response to climate change. As climate warms, we expect peat decomposition may accelerate, altering the cycling of nitrogen. Alterations in th...

Association between females' perceptions of college aerobic class motivational climates and their responses.

Science.gov (United States)

Brown, Theresa C; Fry, Mary D

2013-01-01

The aim of this study was to examine the relationship between female college students' perceptions of the motivational climate in their aerobics classes to their adaptive exercise responses. Data were collected from university group exercise classes in spring 2008. The participants (N = 213) responded to a questionnaire measuring perceptions of the climate (i.e., caring, task-, and ego-involving), correlates of intrinsic motivation (i.e., interest/enjoyment, perceived competence, effort/importance, and tension/pressure), commitment to exercise, and reasons for exercising. Canonical correlation analyses revealed that participants who perceived a predominately caring, task-involving climate reported higher interest/enjoyment, perceived competence, effort/importance, and commitment to exercise, as well as lower tension/pressure. Further, those who perceived a high caring, task-involving, and low ego-involving climate were also more likely to report more health-related reasons for exercise versus appearance-focused reasons. Results suggested that important motivational benefits might exist when women perceive caring, task-involving climates in their aerobics class settings. Aerobics class instructors who intentionally create caring, task-involving climates may promote more adaptive motivational responses among their female participants.

Response and adaptation of grapevine cultivars to hydrological conditions forced by a changing climate in a complex landscape

Science.gov (United States)

De Lorenzi, Francesca; Bonfante, Antonello; Alfieri, Silvia Maria; Monaco, Eugenia; De Mascellis, Roberto; Manna, Piero; Menenti, Massimo

2014-05-01

Soil water availability is one of the main components of the terroir concept, influencing crop yield and fruit composition in grapes. The aim of this work is to analyze some elements of the "natural environment" of terroir (climate and soil) in combination with the intra-specific biodiversity of yield responses of grapevine to water availability. From a reference (1961-90) to a future (2021-50) climate case, the effects of climate evolution on soil water availability are assessed and, regarding soil water regime as a predictor variable, the potential spatial distribution of wine-producing cultivars is determined. In a region of Southern Italy (Valle Telesina, 20,000 ha), where a terroir classification has been produced (Bonfante et al., 2011), we applied an agro-hydrological model to determine water availability indicators. Simulations were performed in 60 soil typological units, over the entire study area, and water availability (= hydrological) indicators were determined. Two climate cases were considered: reference (1961-90) and future (2021-2050), the former from climatic statistics on observed variables, and the latter from statistical downscaling of predictions by general circulation models (AOGCM) under A1B SRES scenario. Climatic data consist of daily time series of maximum and minimum temperature, and daily rainfall on a grid with a spatial resolution of 35 km. Spatial and temporal variability of hydrological indicators was addressed. With respect to temporal variability, both inter-annual and intra-annual (i.e. at different stages of crop cycle) variability were analyzed. Some cultivar-specific relations between hydrological indicators and characteristics of must quality were established. Moreover, for several wine-producing cultivars, hydrological requirements were determined by means of yield response functions to soil water availability, through the re-analysis of experimental data derived from scientific literature. The standard errors of estimated

Forests, fire, floods and fish: nonlinear biophysical responses to changing climate

Science.gov (United States)

Pierce, J. L.; Baxter, C.; Yager, E. M.; Fremier, A. K.; Crosby, B. T.; Smith, A. M.; Kennedy, B.; Hicke, J. A.; Feris, K.

2009-12-01

consequences for organisms, and 6) how hypothesized shifts in climate-related forces alter the function and resiliency of the Salmon River ecosystem. Integrated approaches include the application of legacy datasets, the exploration of historic chemical and physical records of ecosystem change, intensive stream, riparian and forest monitoring, the use of paired experimental watershed approaches, and the development of spatial analysis tools. If feedbacks among geomorphic, hydrologic and ecologic systems are positive this suggests a possible state change in response to a changing climate.

A Hydrological Response Analysis Considering Climatic Variability: Case Study of Hunza Catchment

Directory of Open Access Journals (Sweden)

A. N. Laghari

2018-06-01

Full Text Available The hydrological response of mountainous catchments particularly dependent on melting runoff is very vulnerable to climatic variability. This study is an attempt to assess hydrological response towards climatic variability of the Hunza catchment located in the mountainous chain of greater Hindu Kush-Himalaya (HKH region. The hydrological response is analyzed through changes in snowmelt, ice melt and total runoff simulated through the application of the hydrological modeling system PREVAH under hypothetically developed climate change scenarios. The developed scenarios are based on changes in precipitation (Prp and temperature (Tmp and their combination. Under all the warmer scenarios, the increase in temperature systematically decreases the mean annual snow melt and increases significantly glacier melt volume. Temperature changes from 1°C to 4°C produce a large increase in spring and summer runoff, while no major variation was observed in the winter and autumn runoff. The maximum seasonal changes recorded under the Tmp+4°C, Prp+10% scenario.

State responsibility and compensation for climate change damages - a legal and economic assessment

International Nuclear Information System (INIS)

Tol, R.S.J.; Institute for Environmental Studies, Amsterdam; Carnegie Mellon University, Pittsburgh, PA; Verheyen, R.

2004-01-01

Customary international law has that countries may do each other no harm. A country violates this rule if an activity under its control does damage to another country, and if this is done on purpose or due to carelessness. Impacts of climate change fall under this rule, which is reinforced by many declarations and treaties,including the UNFCCC. Compensation for the harm done depends on many parameters, such as emission scenarios, climate change, climate change impacts and its accounting. The compensation paid by the OECD may run up to 4% of its GDP, far exceeding the costs of climate change to the OECD directly. However, the most crucial issues are, first, from when countries can be held responsible and, second, which emissions are acceptable and which careless. This may even be interpreted such that the countries of the OECD are entitled to compensation, rather than be obliged to pay. State responsibility could substantially change international climate policy. (author)

Educational climate seems unrelated to leadership skills of clinical consultants responsible of postgraduate medical education in clinical departments.

Science.gov (United States)

Malling, Bente; Mortensen, Lene S; Scherpbier, Albert J J; Ringsted, Charlotte

2010-09-21

The educational climate is crucial in postgraduate medical education. Although leaders are in the position to influence the educational climate, the relationship between leadership skills and educational climate is unknown. This study investigates the relationship between the educational climate in clinical departments and the leadership skills of clinical consultants responsible for education. The study was a trans-sectional correlation study. The educational climate was investigated by a survey among all doctors (specialists and trainees) in the departments. Leadership skills of the consultants responsible for education were measured by multi-source feedback scores from heads of departments, peer consultants, and trainees. Doctors from 42 clinical departments representing 21 specialties participated. The response rate of the educational climate investigation was moderate 52% (420/811), Response rate was high in the multisource-feedback process 84.3% (420/498). The educational climate was scored quite high mean 3.9 (SD 0.3) on a five-point Likert scale. Likewise the leadership skills of the clinical consultants responsible for education were considered good, mean 5.4 (SD 0.6) on a seven-point Likert scale. There was no significant correlation between the scores concerning the educational climate and the scores on leadership skills, r = 0.17 (p = 0.29). This study found no relation between the educational climate and the leadership skills of the clinical consultants responsible for postgraduate medical education in clinical departments with the instruments used. Our results indicate that consultants responsible for education are in a weak position to influence the educational climate in the clinical department. Further studies are needed to explore, how heads of departments and other factors related to the clinical organisation could influence the educational climate.

Streamflow response to climate and landuse changes in a coastal watershed in North Carolina

Science.gov (United States)

S. Qi; G. Sun; Y. Wang; S.G. McNulty; J.A. Moore Myers

2009-01-01

It is essential to examine the sensitivity of hydrologic responses to climate and landuse change across different physiographic regions in order to formulate sound water management policies for local response to projected global change. This study used the a simulation model to examine the potential impacts of climate and landuse changes on streamflow of the...

Modeling Climate Responses to Spectral Solar Forcing on Centennial and Decadal Time Scales

Science.gov (United States)

Wen, G.; Cahalan, R.; Rind, D.; Jonas, J.; Pilewskie, P.; Harder, J.

2012-01-01

We report a series of experiments to explore clima responses to two types of solar spectral forcing on decadal and centennial time scales - one based on prior reconstructions, and another implied by recent observations from the SORCE (Solar Radiation and Climate Experiment) SIM (Spectral 1rradiance Monitor). We apply these forcings to the Goddard Institute for Space Studies (GISS) Global/Middle Atmosphere Model (GCMAM). that couples atmosphere with ocean, and has a model top near the mesopause, allowing us to examine the full response to the two solar forcing scenarios. We show different climate responses to the two solar forCing scenarios on decadal time scales and also trends on centennial time scales. Differences between solar maximum and solar minimum conditions are highlighted, including impacts of the time lagged reSponse of the lower atmosphere and ocean. This contrasts with studies that assume separate equilibrium conditions at solar maximum and minimum. We discuss model feedback mechanisms involved in the solar forced climate variations.

Mangrove ecosystems under climate change

Science.gov (United States)

Jennerjahn, T.C.; Gilman, E.; Krauss, Ken W.; Lacerda, L.D.; Nordhaus, I.; Wolanski, E.

2017-01-01

This chapter assesses the response of mangrove ecosystems to possible outcomes of climate change, with regard to the following categories: (i) distribution, diversity, and community composition, (ii) physiology of flora and fauna, (iii) water budget, (iv) productivity and remineralization, (v) carbon storage in biomass and sediments, and (vi) the filter function for elements beneficial or harmful to life. These categories are then used to identify the regions most vulnerable to climate change. The four most important factors determining the response of mangrove ecosystems to climate change are sea level rise, an increase in frequency and/or intensity of storms, increases in temperature, and aridity. While these changes may be beneficial for some mangrove forests at latitudinal distribution limits, they will threaten forest structure and functions and related ecosystem services in most cases. The interaction of climate change with human interventions is discussed, as well as the effects on ecosystem services including possible adaptation and management options. The chapter closes with an outlook on knowledge gaps and priority research needed to fill these gaps.

Phenological sensitivity to climate across taxa and trophic levels

DEFF Research Database (Denmark)

Thackeray, Stephen J.; Henrys, Peter; Hemming, Deborah

2016-01-01

Differences in phenological responses to climate change among species can desynchronise ecological interactions and thereby threaten ecosystem function. To assess these threats, we must quantify the relative impact of climate change on species at different trophic levels. Here, we apply a Climate...

Social implications of residential demand response in cool temperate climates

International Nuclear Information System (INIS)

Darby, Sarah J.; McKenna, Eoghan

2012-01-01

Residential electrical demand response (DR) offers the prospect of reducing the environmental impact of electricity use, and also the supply costs. However, the relatively small loads and numerous actors imply a large effort: response ratio. Residential DR may be an essential part of future smart grids, but how viable is it in the short to medium term? This paper reviews some DR concepts, then evaluates the propositions that households in cool temperate climates will be in a position to contribute to grid flexibility within the next decade, and that that they will allow some automated load control. Examples of demand response from around the world are discussed in order to assess the main considerations for cool climates. Different tariff types and forms of control are assessed in terms of what is being asked of electricity users, with a focus on real-time pricing and direct load control in energy systems with increasingly distributed resources. The literature points to the significance of thermal loads, supply mix, demand-side infrastructure, market regulation, and the framing of risks and opportunities associated with DR. In concentrating on social aspects of residential demand response, the paper complements the body of work on technical and economic potential. - Highlights: ► Demand response implies major change in governance of electricity systems. ► Households in cool temperate climates can be flexible, mainly with thermal loads. ► DR requires simple tariffs, appropriate enabling technology, education, and feedback. ► Need to test consumer acceptance of DR in specific conditions. ► Introduce tariffs with technologies e.g., TOU tariff plus DLC with electric vehicles.

Orbital forcing of Arctic climate: mechanisms of climate response and implications for continental glaciation

Energy Technology Data Exchange (ETDEWEB)

Jackson, C S [Program in Atmospheric and Oceanic Sciences, Princeton University, NJ 08542, Princeton (United States); Institute for Geophysics, The John A. and Katherine G. Jackson School of Geosciences, The University of Texas at Austin, 4412 Spicewood Springs Rd., Bldg 600, TX 78759, Austin (United States); Broccoli, A J [NOAA/Geophysical Fluid Dynamics Laboratory, NJ 08542, Princeton (United States); Department of Environmental Sciences, Rutgers University, NJ 08903, New Brunswick (United States)

2003-12-01

Progress in understanding how terrestrial ice volume is linked to Earth's orbital configuration has been impeded by the cost of simulating climate system processes relevant to glaciation over orbital time scales (10{sup 3}-10{sup 5} years). A compromise is usually made to represent the climate system by models that are averaged over one or more spatial dimensions or by three-dimensional models that are limited to simulating particular ''snapshots'' in time. We take advantage of the short equilibration time ({proportional_to}10 years) of a climate model consisting of a three-dimensional atmosphere coupled to a simple slab ocean to derive the equilibrium climate response to accelerated variations in Earth's orbital configuration over the past 165,000 years. Prominent decreases in ice melt and increases in snowfall are simulated during three time intervals near 26, 73, and 117 thousand years ago (ka) when aphelion was in late spring and obliquity was low. There were also significant decreases in ice melt and increases in snowfall near 97 and 142 ka when eccentricity was relatively large, aphelion was in late spring, and obliquity was high or near its long term mean. These ''glaciation-friendly'' time intervals correspond to prominent and secondary phases of terrestrial ice growth seen within the marine {delta}{sup 18}O record. Both dynamical and thermal effects contribute to the increases in snowfall during these periods, through increases in storm activity and the fraction of precipitation falling as snow. The majority of the mid- to high latitude response to orbital forcing is organized by the properties of sea ice, through its influence on radiative feedbacks that nearly double the size of the orbital forcing as well as its influence on the seasonal evolution of the latitudinal temperature gradient. (orig.)

Wave climate change, coastline response and hazard prediction in New South Wales, Australia

International Nuclear Information System (INIS)

Goodwin, Ian D.; Verdon, Danielle; Cowell, Peter

2007-01-01

Full text: Full text: Considerable research effort has been directed towards understanding and the gross prediction of shoreline response to sea level rise (eg. Cowell ef a/. 2003a, b). In contrast, synoptic prediction of changes in the planform configuration of shorelines in response to changes in wind and wave climates over many decades has been limited by the lack of geohistorical data on shoreline alignment evolution and long time series of wave climate. This paper presents new data sets on monthly mean wave direction variability based on: a. Waverider buoy data; b. a reconstruction of monthly mid-shelf wave direction, 1877 to 2002 AD from historical MSLP data (Goodwin 2005); and c. a multi-decadal reconstruction of wave direction, in association with the Interdecadal Pacific Oscillation and the Southern Annular Mode of climate variability, covering the past millennium. A model of coastline response to the wave climate variability is presented for northern and central New South Wales (NSW) for decadal to multi-decadal time scales, and is based on instrumental and geohistorical data. The sensitivity of the coastline position and alignment, and beach state to mean and extreme wave climate changes is demonstrated (e.g. Goodwin et al. 2006). State changes in geometric shoreline alignment rotation, sand volume (progradation/recession) for NSW and mean wave direction, are shown to be in agreement with the low-frequency change in Pacific-wide climate. Synoptic typing of climate patterns using Self Organised Mapping methods is used to downscale CSIRO GCM output for this century. The synoptic types are correlated to instrumental wave climate data and coastal behaviour. The shifts in downscaled synoptic types for 2030 and 2070 AD are then used as the basis for predicting mean wave climate changes, coastal behaviour and hazards along the NSW coastline. The associated coastal hazards relate to the definition of coastal land loss through rising sea levels and shoreline

Seven Steps in Identifying Local Climate Change Responses for Agriculture in Vietnam

NARCIS (Netherlands)

Bosma, R.H.; Ngo, An T.; Huynh, Chuong V.; Le, Huong T.; Dang, Nhan K.; Van, Tri P.D.; Halsema, van G.E.

2016-01-01

This study presents a seven-step approach to identify and support local climate change (CC) responses in agriculture. The following seven steps comprise this approach: 1. Analyse past trends on the climatic factors and model the future trends. 2. Simulate the possible impacts of CC on the selected

Climate change and environmentally responsible behavior on the Great Barrier Reef, Australia

Science.gov (United States)

Jee In Yoon; Gerard Kyle; Carena J. vanRiper; Stephen G. Sutton

2012-01-01

This study explored the relationship between Australians' perceptions of climate change, its impact on the Great Barrier Reef (GBR), and predictors of environmentally responsible behavior (ERB). Our hypothesized model suggested that general attitudes toward climate change, social pressure for engaging in ERBs (subjective norms), and perceived behavioral control (...

Understanding the varied response of the extratropical storm tracks to climate change.

Science.gov (United States)

O'Gorman, Paul A

2010-11-09

Transient eddies in the extratropical storm tracks are a primary mechanism for the transport of momentum, energy, and water in the atmosphere, and as such are a major component of the climate system. Changes in the extratropical storm tracks under global warming would impact these transports, the ocean circulation and carbon cycle, and society through changing weather patterns. I show that the southern storm track intensifies in the multimodel mean of simulations of 21st century climate change, and that the seasonal cycle of storm-track intensity increases in amplitude in both hemispheres. I use observations of the present-day seasonal cycle to confirm the relationship between storm-track intensity and the mean available potential energy of the atmosphere, and show how this quantitative relationship can be used to account for much of the varied response in storm-track intensity to global warming, including substantially different responses in simulations with different climate models. The results suggest that storm-track intensity is not related in a simple way to global-mean surface temperature, so that, for example, a stronger southern storm track in response to present-day global warming does not imply it was also stronger in hothouse climates of the past.

Climate-suitable planting as a strategy for maintaining forest productivity and functional diversity.

Science.gov (United States)

Duveneck, Matthew J; Scheller, Robert M

2015-09-01

Within the time frame of the longevity of tree species, climate change will change faster than the ability of natural tree migration. Migration lags may result in reduced productivity and reduced diversity in forests under current management and climate change. We evaluated the efficacy of planting climate-suitable tree species (CSP), those tree species with current or historic distributions immediately south of a focal landscape, to maintain or increase aboveground biomass productivity, and species and functional diversity. We modeled forest change with the LANDIS-II forest simulation model for 100 years (2000-2100) at a 2-ha cell resolution and five-year time steps within two landscapes in the Great Lakes region (northeastern Minnesota and northern lower Michigan, USA). We compared current climate to low- and high-emission futures. We simulated a low-emission climate future with the Intergovernmental Panel on Climate Change (IPCC) 2007 B1 emission scenario and the Parallel Climate Model Global Circulation Model (GCM). We simulated a high-emission climate future with the IPCC A1FI emission scenario and the Geophysical Fluid Dynamics Laboratory (GFDL) GCM. We compared current forest management practices (business-as-usual) to CSP management. In the CSP scenario, we simulated a target planting of 5.28% and 4.97% of forested area per five-year time step in the Minnesota and Michigan landscapes, respectively. We found that simulated CSP species successfully established in both landscapes under all climate scenarios. The presence of CSP species generally increased simulated aboveground biomass. Species diversity increased due to CSP; however, the effect on functional diversity was variable. Because the planted species were functionally similar to many native species, CSP did not result in a consistent increase nor decrease in functional diversity. These results provide an assessment of the potential efficacy and limitations of CSP management. These results have

Climate change adaptation : planning for BC

International Nuclear Information System (INIS)

Harford, D.; Vanderwill, C.; Church, A.

2008-11-01

This paper explored climate change challenges facing British Columbia in the context of 9 topical issues, notably biodiversity, extreme events, energy, water supply, crop adaptation, health risks, sea level rise, population dynamics and new technologies. Each issue was summarized in terms of threats, current responses in British Columbia and precedents being set in Canada. The key principles of adaptation to climate change were also reviewed. In addition, the paper explored ways to adopt smart adaptation strategies-policy responses to climate change that cut across all major government functions, such as infrastructure, energy, water, economic development, resource management and agriculture. The paper emphasized that strategies that respond to the climate challenge should acknowledge the links between adaptation and mitigation, or emissions reduction. Both concepts need major investment in research, education and infrastructure to support comprehensive, effective responses. refs., tabs., figs

Evaluation of the regional climate response in Australia to large-scale climate modes in the historical NARCliM simulations

Science.gov (United States)

Fita, L.; Evans, J. P.; Argüeso, D.; King, A.; Liu, Y.

2017-10-01

NARCliM (New South Wales (NSW)/Australian Capital Territory (ACT) Regional Climate Modelling project) is a regional climate modeling project for the Australian area. It is providing a comprehensive dynamically downscaled climate dataset for the CORDEX-AustralAsia region at 50-km resolution, and south-East Australia at a resolution of 10 km. The first phase of NARCliM produced 60-year long reanalysis driven regional simulations to allow evaluation of the regional model performance. This long control period (1950-2009) was used so that the model ability to capture the impact of large scale climate modes on Australian climate could be examined. Simulations are evaluated using a gridded observational dataset. Results show that using model independence as a criteria for choosing atmospheric model configuration from different possible sets of parameterizations may contribute to the regional climate models having different overall biases. The regional models generally capture the regional climate response to large-scale modes better than the driving reanalysis, though no regional model improves on all aspects of the simulated climate.

Allowable CO2 concentrations under the United Nations Framework Convention on Climate Change as a function of the climate sensitivity probability distribution function

International Nuclear Information System (INIS)

Harvey, L D Danny

2007-01-01

Article 2 of the United Nations Framework Convention on Climate Change (UNFCCC) calls for stabilization of greenhouse gas (GHG) concentrations at levels that prevent dangerous anthropogenic interference (DAI) in the climate system. Until recently, the consensus viewpoint was that the climate sensitivity (the global mean equilibrium warming for a doubling of atmospheric CO 2 concentration) was 'likely' to fall between 1.5 and 4.5 K. However, a number of recent studies have generated probability distribution functions (pdfs) for climate sensitivity with the 95th percentile of the expected climate sensitivity as large as 10 K, while some studies suggest that the climate sensitivity is likely to fall in the lower half of the long-standing 1.5-4.5 K range. This paper examines the allowable CO 2 concentration as a function of the 95th percentile of the climate sensitivity pdf (ranging from 2 to 8 K) and for the following additional assumptions: (i) the 50th percentile for the pdf of the minimum sustained global mean warming that causes unacceptable harm equal to 1.5 or 2.5 K; and (ii) 1%, 5% or 10% allowable risks of unacceptable harm. For a 1% risk tolerance and the more stringent harm-threshold pdf, the allowable CO 2 concentration ranges from 323 to 268 ppmv as the 95th percentile of the climate sensitivity pdf increases from 2 to 8 K, while for a 10% risk tolerance and the less stringent harm-threshold pdf, the allowable CO 2 concentration ranges from 531 to 305 ppmv. In both cases it is assumed that non-CO 2 GHG radiative forcing can be reduced to half of its present value, otherwise; the allowable CO 2 concentration is even smaller. Accounting for the fact that the CO 2 concentration will gradually fall if emissions are reduced to zero, and that peak realized warming will then be less than the peak equilibrium warming (related to peak radiative forcing) allows the CO 2 concentration to peak at 10-40 ppmv higher than the limiting values given above for a climate

Estuarine Response to River Flow and Sea-Level Rise under Future Climate Change and Human Development

Energy Technology Data Exchange (ETDEWEB)

Yang, Zhaoqing; Wang, Taiping; Voisin, Nathalie; Copping, Andrea E.

2015-04-01

Understanding the response of river flow and estuarine hydrodynamics to climate change, land-use/land-cover change (LULC), and sea-level rise is essential to managing water resources and stress on living organisms under these changing conditions. This paper presents a modeling study using a watershed hydrology model and an estuarine hydrodynamic model, in a one-way coupling, to investigate the estuarine hydrodynamic response to sea-level rise and change in river flow due to the effect of future climate and LULC changes in the Snohomish River estuary, Washington, USA. A set of hydrodynamic variables, including salinity intrusion points, average water depth, and salinity of the inundated area, were used to quantify the estuarine response to river flow and sea-level rise. Model results suggest that salinity intrusion points in the Snohomish River estuary and the average salinity of the inundated areas are a nonlinear function of river flow, although the average water depth in the inundated area is approximately linear with river flow. Future climate changes will shift salinity intrusion points further upstream under low flow conditions and further downstream under high flow conditions. In contrast, under the future LULC change scenario, the salinity intrusion point will shift downstream under both low and high flow conditions, compared to present conditions. The model results also suggest that the average water depth in the inundated areas increases linearly with sea-level rise but at a slower rate, and the average salinity in the inundated areas increases linearly with sea-level rise; however, the response of salinity intrusion points in the river to sea-level rise is strongly nonlinear.

Development and testing of transfer functions for generating quantitative climatic estimates from Australian pollen data

Science.gov (United States)

Cook, Ellyn J.; van der Kaars, Sander

2006-10-01

We review attempts to derive quantitative climatic estimates from Australian pollen data, including the climatic envelope, climatic indicator and modern analogue approaches, and outline the need to pursue alternatives for use as input to, or validation of, simulations by models of past, present and future climate patterns. To this end, we have constructed and tested modern pollen-climate transfer functions for mainland southeastern Australia and Tasmania using the existing southeastern Australian pollen database and for northern Australia using a new pollen database we are developing. After testing for statistical significance, 11 parameters were selected for mainland southeastern Australia, seven for Tasmania and six for northern Australia. The functions are based on weighted-averaging partial least squares regression and their predictive ability evaluated against modern observational climate data using leave-one-out cross-validation. Functions for summer, annual and winter rainfall and temperatures are most robust for southeastern Australia, while in Tasmania functions for minimum temperature of the coldest period, mean winter and mean annual temperature are the most reliable. In northern Australia, annual and summer rainfall and annual and summer moisture indexes are the strongest. The validation of all functions means all can be applied to Quaternary pollen records from these three areas with confidence. Copyright

Isolating the atmospheric circulation response to Arctic sea-ice loss in the coupled climate system

Science.gov (United States)

Kushner, Paul; Blackport, Russell

2017-04-01

In the coupled climate system, projected global warming drives extensive sea-ice loss, but sea-ice loss drives warming that amplifies and can be confounded with the global warming process. This makes it challenging to cleanly attribute the atmospheric circulation response to sea-ice loss within coupled earth-system model (ESM) simulations of greenhouse warming. In this study, many centuries of output from coupled ocean/atmosphere/land/sea-ice ESM simulations driven separately by sea-ice albedo reduction and by projected greenhouse-dominated radiative forcing are combined to cleanly isolate the hemispheric scale response of the circulation to sea-ice loss. To isolate the sea-ice loss signal, a pattern scaling approach is proposed in which the local multidecadal mean atmospheric response is assumed to be separately proportional to the total sea-ice loss and to the total low latitude ocean surface warming. The proposed approach estimates the response to Arctic sea-ice loss with low latitude ocean temperatures fixed and vice versa. The sea-ice response includes a high northern latitude easterly zonal wind response, an equatorward shift of the eddy driven jet, a weakening of the stratospheric polar vortex, an anticyclonic sea level pressure anomaly over coastal Eurasia, a cyclonic sea level pressure anomaly over the North Pacific, and increased wintertime precipitation over the west coast of North America. Many of these responses are opposed by the response to low-latitude surface warming with sea ice fixed. However, both sea-ice loss and low latitude surface warming act in concert to reduce storm track strength throughout the mid and high latitudes. The responses are similar in two related versions of the National Center for Atmospheric Research earth system models, apart from the stratospheric polar vortex response. Evidence is presented that internal variability can easily contaminate the estimates if not enough independent climate states are used to construct them

Making sense of climate change risks and responses at the community level: A cultural-political lens

Directory of Open Access Journals (Sweden)

Ainka A. Granderson

2014-01-01

Full Text Available How to better assess, communicate and respond to risks from climate change at the community level have emerged as key questions within climate risk management. Recent research to address these questions centres largely on psychological factors, exploring how cognition and emotion lead to biases in risk assessment. Yet, making sense of climate change and its responses at the community level demands attention to the cultural and political processes that shape how risk is conceived, prioritized and managed. I review the emergent literature on risk perceptions and responses to climate change using a cultural-political lens. This lens highlights how knowledge, meaning and power are produced and negotiated across multiple stakeholders at the community level. It draws attention to the different ways of constructing climate change risks and suggests an array of responses at the community level. It further illustrates how different constructions of risk intersect with agency and power to shape the capacity for response and collective action. What matters are whose constructions of risk, and whose responses, count in decision-making. I argue for greater engagement with the interpretive social sciences in research, practice and policy. The interpretive social sciences offer theories and tools for capturing and problematising the ways of knowing, sense-making and mobilising around risks from climate change. I also highlight the importance of participatory approaches in incorporating the multiplicity of interests at the community level into climate risk management in fair, transparent and culturally appropriate ways.

The American Climate Prospectus: a risk-centered analysis of the economic impacts of climate change

Science.gov (United States)

Jina, A.; Houser, T.; Hsiang, S. M.; Kopp, R. E., III; Delgado, M.; Larsen, K.; Mohan, S.; Rasmussen, D.; Rising, J.; Wilson, P. S.; Muir-Wood, R.

2014-12-01

The American Climate Prospectus (ACP), the analysis underlying the Risky Business project, quantitatively assessed the climate risks posed to the United States' economy in six sectors - crop yields, energy demand, coastal property, crime, labor productivity, and mortality [1]. The ACP is unique in its characterization of the full probability distribution of economic impacts of climate change throughout the 21st century, making it an extremely useful basis for risk assessments. Three key innovations allow for this characterization. First, climate projections from CMIP5 models are scaled to a temperature probability distribution derived from a coarser climate model (MAGICC). This allows a more accurate representation of the whole distribution of future climates (in particular the tails) than a simple ensemble average. These are downscaled both temporally and spatially. Second, a set of local sea level rise and tropical cyclone projections are used in conjunction with the most detailed dataset of coastal property in the US in order to capture the risks of rising seas and storm surge. Third, we base many of our sectors on empirically-derived responses to temperature and precipitation. Each of these dose-response functions is resampled many times to populate a statistical distribution. Combining these with uncertainty in emissions scenario, climate model, and weather, we create the full probability distribution of climate impacts from county up to national levels, as well as model the effects upon the economy as a whole. Results are presented as likelihood ranges, as well as changes to return intervals of extreme events. The ACP analysis allows us to compare between sectors to understand the magnitude of required policy responses, and also to identify risks through time. Many sectors displaying large impacts at the end of the century, like those of mortality, have smaller changes in the near-term, due to non-linearities in the response functions. Other sectors, like

OPEC`s response to international climate agreements

Energy Technology Data Exchange (ETDEWEB)

Braaten, J.; Golombek, R.

1996-03-01

This publication studies a game between a group of countries that have agreed to participate in an international climate agreement (the signatories) and OPEC. The task of the signatories is to design carbon taxes that maximize their total net income, given a goal on global carbon emissions. In response to the climate agreement, OPEC imposes an oil tax on its member states that maximizes OPEC`s profits. Within a numerical model, the subgame-perfect equilibrium of a game is found in which each player chooses when to fix his decision variables. It is shown that, in equilibrium, the group of signatories chooses to be the leader and OPEC chooses to be the follower. It is demonstrated, however, that for both agents the order of move is of minor (numerical) importance. Hence, the players have limited incentives for strategic behaviour. 15 refs., 2 figs., 5 tabs.

Do responses to different anthropogenic forcings add linearly in climate models?

International Nuclear Information System (INIS)

Marvel, Kate; Schmidt, Gavin A; LeGrande, Allegra N; Nazarenko, Larissa; Shindell, Drew; Bonfils, Céline; Tsigaridis, Kostas

2015-01-01

Many detection and attribution and pattern scaling studies assume that the global climate response to multiple forcings is additive: that the response over the historical period is statistically indistinguishable from the sum of the responses to individual forcings. Here, we use the NASA Goddard Institute for Space Studies (GISS) and National Center for Atmospheric Research Community Climate System Model (CCSM4) simulations from the CMIP5 archive to test this assumption for multi-year trends in global-average, annual-average temperature and precipitation at multiple timescales. We find that responses in models forced by pre-computed aerosol and ozone concentrations are generally additive across forcings. However, we demonstrate that there are significant nonlinearities in precipitation responses to different forcings in a configuration of the GISS model that interactively computes these concentrations from precursor emissions. We attribute these to differences in ozone forcing arising from interactions between forcing agents. Our results suggest that attribution to specific forcings may be complicated in a model with fully interactive chemistry and may provide motivation for other modeling groups to conduct further single-forcing experiments. (letter)

Interactive effects of climate change and biodiversity loss on ecosystem functioning.

Science.gov (United States)

Pires, Aliny P F; Srivastava, Diane S; Marino, Nicholas A C; MacDonald, A Andrew M; Figueiredo-Barros, Marcos Paulo; Farjalla, Vinicius F

2018-05-01

Climate change and biodiversity loss are expected to simultaneously affect ecosystems, however research on how each driver mediates the effect of the other has been limited in scope. The multiple stressor framework emphasizes non-additive effects, but biodiversity may also buffer the effects of climate change, and climate change may alter which mechanisms underlie biodiversity-function relationships. Here, we performed an experiment using tank bromeliad ecosystems to test the various ways that rainfall changes and litter diversity may jointly determine ecological processes. Litter diversity and rainfall changes interactively affected multiple functions, but how depends on the process measured. High litter diversity buffered the effects of altered rainfall on detritivore communities, evidence of insurance against impacts of climate change. Altered rainfall affected the mechanisms by which litter diversity influenced decomposition, reducing the importance of complementary attributes of species (complementarity effects), and resulting in an increasing dependence on the maintenance of specific species (dominance effects). Finally, altered rainfall conditions prevented litter diversity from fueling methanogenesis, because such changes in rainfall reduced microbial activity by 58%. Together, these results demonstrate that the effects of climate change and biodiversity loss on ecosystems cannot be understood in isolation and interactions between these stressors can be multifaceted. © 2018 by the Ecological Society of America.

The dependence of wintertime Mediterranean precipitation on the atmospheric circulation response to climate change

Science.gov (United States)

Zappa, Giuseppe; Hoskins, Brian; Shepherd, Ted

2016-04-01

Climate models indicate a future wintertime precipitation reduction in the Mediterranean region which may have large socio-economic impacts. However, there is large uncertainty in the amplitude of the projected precipitation reduction and this limits the possibility to inform effective adaptation planning. We analyse CMIP5 climate model output to quantify the role of atmospheric circulation in the precipitation change and the time of emergence of the Mediterranean precipitation response. It is found that a simple circulation index, i.e. the 850 hPa zonal wind (U850) in North Africa, well describes the year to year fluctuations in the area-averaged Mediterranean precipitation, with positive (i.e. westerly) U850 anomalies in North Africa being associated with positive precipitation anomalies. Under climate change, U850 in North Africa and the Mediterranean precipitation are both projected to decrease consistently with the relationship found in the inter-annual variability. This enables us to estimate that about 85% of the CMIP5 mean precipitation response and 80% of the variance in the inter-model spread are related to changes in the atmospheric circulation. In contrast, there is no significant correlation between the mean precipitation response and the global-mean surface warming across the models. We also find that the precipitation response to climate change might already emerge from internal variability by 2025 relative to 1960-1990 according to the climate models with a large circulation response. This implies that it might soon be possible to test model projections using observations. Finally, some of the mechanisms which are important for the Mediterranean circulation response in the CMIP5 models are discussed.

Dynamics of the flood response to slow-fast landscape-climate feedbacks

Directory of Open Access Journals (Sweden)

R. A. P. Perdigão

2015-06-01

Full Text Available The dynamical evolution of the flood response to landscape-climate feedbacks is evaluated in a joint nonlinear statistical-dynamical approach. For that purpose, a spatiotemporal sensitivity analysis is conducted on hydrological data from 1976–2008 over 804 catchments throughout Austria, and a general, data-independent nonlinear dynamical model is built linking floods with climate (via precipitation, landscape (via elevation and their feedbacks. These involve nonlinear scale interactions, with landform evolution processes taking place at the millennial scale (slow dynamics, and climate adjusting in years to decades (fast dynamics. The results show that floods are more responsive to spatial (regional than to temporal (decadal variability. Catchments from dry lowlands and high wetlands exhibit similarity between the spatial and temporal sensitivities (spatiotemporal symmetry and low landscape-climate codependence, suggesting they are not coevolving significantly. However, intermediate regions show differences between those sensitivities (symmetry breaks and higher landscape-climate codependence, suggesting undergoing coevolution. The break of symmetry is an emergent behaviour from nonlinear feedbacks within the system. A new coevolution index is introduced relating spatiotemporal symmetry with relative characteristic celerities, which need to be taken into account in hydrological space-time trading. Coevolution is expressed here by the interplay between slow and fast dynamics, represented respectively by spatial and temporal characteristics. The dynamical model captures emerging features of the flood dynamics and nonlinear landscape-climate feedbacks, supporting the nonlinear statistical assessment of spatiotemporally asymmetric flood change. Moreover, it enables the dynamical estimation of flood changes in space and time from the given knowledge at different spatiotemporal conditions. This study ultimately brings to light emerging signatures of

Recent climate warming forces contrasting growth responses of white spruce at treeline in Alaska through temperature thresholds

Science.gov (United States)

Martin Wilmking; Glenn P. Juday; Valerie A. Barber; Harold S.J. Zald

2004-01-01

Northern and high-latitude alpine treelines are generally thought to be limited by available warmth. Most studies of tree-growth-climate interaction at treeline as well as climate reconstructions using dendrochronology report positive growth response of treeline trees to warmer temperatures. However, population-wide responses of treeline trees to climate remain largely...

Thermal reactionomes reveal divergent responses to thermal extremes in warm and cool-climate ant species

DEFF Research Database (Denmark)

Stanton-Geddes, John; Nguyen, Andrew; Chick, Lacy

2016-01-01

across an experimental gradient. We characterized thermal reactionomes of two common ant species in the eastern U.S, the northern cool-climate Aphaenogaster picea and the southern warm-climate Aphaenogaster carolinensis, across 12 temperatures that spanned their entire thermal breadth.......The distributions of species and their responses to climate change are in part determined by their thermal tolerances. However, little is known about how thermal tolerance evolves. To test whether evolutionary extension of thermal limits is accomplished through enhanced cellular stress response...

Response of seasonal soil freeze depth to climate change across China

Science.gov (United States)

Peng, Xiaoqing; Zhang, Tingjun; Frauenfeld, Oliver W.; Wang, Kang; Cao, Bin; Zhong, Xinyue; Su, Hang; Mu, Cuicui

2017-05-01

The response of seasonal soil freeze depth to climate change has repercussions for the surface energy and water balance, ecosystems, the carbon cycle, and soil nutrient exchange. Despite its importance, the response of soil freeze depth to climate change is largely unknown. This study employs the Stefan solution and observations from 845 meteorological stations to investigate the response of variations in soil freeze depth to climate change across China. Observations include daily air temperatures, daily soil temperatures at various depths, mean monthly gridded air temperatures, and the normalized difference vegetation index. Results show that soil freeze depth decreased significantly at a rate of -0.18 ± 0.03 cm yr-1, resulting in a net decrease of 8.05 ± 1.5 cm over 1967-2012 across China. On the regional scale, soil freeze depth decreases varied between 0.0 and 0.4 cm yr-1 in most parts of China during 1950-2009. By investigating potential climatic and environmental driving factors of soil freeze depth variability, we find that mean annual air temperature and ground surface temperature, air thawing index, ground surface thawing index, and vegetation growth are all negatively associated with soil freeze depth. Changes in snow depth are not correlated with soil freeze depth. Air and ground surface freezing indices are positively correlated with soil freeze depth. Comparing these potential driving factors of soil freeze depth, we find that freezing index and vegetation growth are more strongly correlated with soil freeze depth, while snow depth is not significant. We conclude that air temperature increases are responsible for the decrease in seasonal freeze depth. These results are important for understanding the soil freeze-thaw dynamics and the impacts of soil freeze depth on ecosystem and hydrological process.

Two decades of climate driving the dynamics of functional and taxonomic diversity of a tropical small mammal community in western Mexico.

Science.gov (United States)

Mason-Romo, Edgard David; Farías, Ariel A; Ceballos, Gerardo

2017-01-01

Understanding the effects of global climate disruption on biodiversity is important to future conservation efforts. While taxonomic diversity is widely studied, functional diversity of plants, and recently animals, is receiving increasing attention. Most studies of mammals are short-term, focus on temperate habitats, and rely on traits described in the literature rather than generating traits from observations. Unlike previous studies, this long-term field study assessed the factors driving the functional and taxonomic diversity of small-mammal assemblages in dry tropical forests using both traits recorded from literature and a demographic database. We assessed the drivers (abundance and biomass, temperature and rainfall) of taxonomic richness and functional diversity for two rain-driven seasons in two adjacent but distinct forests-upland and lowland (arroyo or riparian) forests. Our analysis found that rainfall, both seasonal and atypical, was the primary factor driving functional and taxonomic diversity of small-mammal assemblages. Functional responses differed between the two types of forests, however, with effects being stronger in the harsher conditions of the upland forests than in the less severe conditions prevailing in the arroyo (riparian) forest. The latter also supports a richer, more diverse, and more stable small-mammal assemblage. These findings highlight the importance of climate to tropical biological diversity, as extreme climate events (hurricanes, droughts and floods) and disruption of rainfall patterns were shown to decrease biodiversity. They also support the need to preserve these habitats, as their high taxonomic diversity and functional redundancy makes them resilient against global climate disruption and local extreme events. Tropical dry forests constitute a potential reservoir for biodiversity and the ecosystem services they provide. Unfortunately, these forests are among the most endangered terrestrial ecosystems because of

Two decades of climate driving the dynamics of functional and taxonomic diversity of a tropical small mammal community in western Mexico.

Directory of Open Access Journals (Sweden)

Edgard David Mason-Romo

Full Text Available Understanding the effects of global climate disruption on biodiversity is important to future conservation efforts. While taxonomic diversity is widely studied, functional diversity of plants, and recently animals, is receiving increasing attention. Most studies of mammals are short-term, focus on temperate habitats, and rely on traits described in the literature rather than generating traits from observations. Unlike previous studies, this long-term field study assessed the factors driving the functional and taxonomic diversity of small-mammal assemblages in dry tropical forests using both traits recorded from literature and a demographic database. We assessed the drivers (abundance and biomass, temperature and rainfall of taxonomic richness and functional diversity for two rain-driven seasons in two adjacent but distinct forests-upland and lowland (arroyo or riparian forests. Our analysis found that rainfall, both seasonal and atypical, was the primary factor driving functional and taxonomic diversity of small-mammal assemblages. Functional responses differed between the two types of forests, however, with effects being stronger in the harsher conditions of the upland forests than in the less severe conditions prevailing in the arroyo (riparian forest. The latter also supports a richer, more diverse, and more stable small-mammal assemblage. These findings highlight the importance of climate to tropical biological diversity, as extreme climate events (hurricanes, droughts and floods and disruption of rainfall patterns were shown to decrease biodiversity. They also support the need to preserve these habitats, as their high taxonomic diversity and functional redundancy makes them resilient against global climate disruption and local extreme events. Tropical dry forests constitute a potential reservoir for biodiversity and the ecosystem services they provide. Unfortunately, these forests are among the most endangered terrestrial ecosystems because

Treeline dynamics in response to climate change in the Min Mountains, southwestern China.

Science.gov (United States)

Zhao, Zhi-Jiang; Shen, Guo-Zhen; Tan, Liu-Yi; Kang, Dong-Wei; Wang, Meng-Jun; Kang, Wen; Guo, Wen-Xia; Zeppel, Melanie Jb; Yu, Qiang; Li, Jun-Qing

2013-12-01

Abies faxoniana is the dominant plant species of the forest ecosystem on the eastern edge of Qinghai-Tibet Plateau, where the treeline is strongly defined by climate. The tree-ring chronologies and age structure of Abies faxoniana were developed in the treeline ecotones on the northwestern and southeastern aspects of the Min Mountains in the Wanglang Nature Reserve to examine the treeline dynamics of recent decades in response to climate change. On the northwestern aspect, correlation analysis showed that the radial growth was significantly and positively correlated with precipitation in current January and monthly mean temperature in current April, but significantly and negatively correlated with monthly mean temperature in previous August. On the southeastern aspect, the radial growth was significantly negatively correlated with monthly mean temperature in previous July and August. The different responses of radial growth to climatic variability on both the aspects might be mainly due to the micro-environmental conditions. The recruitment benefited from the warm temperature in current April, July and September on the northwestern aspect. The responses of radial growth and recruitment to climatic variability were similar on the northwestern slope. Recruitment was greatly restricted by competition with dense bamboos on the southeastern aspect.

On the brink of change: plant responses to climate on the Colorado Plateau

Science.gov (United States)

Munson, Seth M.; Belnap, Jayne; Schelz, Charles D.; Moran, Mary; Carolin, Tara W.

2011-01-01

The intensification of aridity due to anthropogenic climate change in the southwestern U.S. is likely to have a large impact on the growth and survival of plant species that may already be vulnerable to water stress. To make accurate predictions of plant responses to climate change, it is essential to determine the long-term dynamics of plant species associated with past climate conditions. Here we show how the plant species and functional types across a wide range of environmental conditions in Colorado Plateau national parks have changed with climate variability over the last twenty years. During this time, regional mean annual temperature increased by 0.18°C per year from 1989–1995, 0.06°C per year from 1995–2003, declined by 0.14°C from 2003–2008, and there was high interannual variability in precipitation. Non-metric multidimensional scaling of plant species at long-term monitoring sites indicated five distinct plant communities. In many of the communities, canopy cover of perennial plants was sensitive to mean annual temperature occurring in the previous year, whereas canopy cover of annual plants responded to cool season precipitation. In the perennial grasslands, there was an overall decline of C3 perennial grasses, no change of C4 perennial grasses, and an increase of shrubs with increasing temperature. In the shrublands, shrubs generally showed no change or slightly increased with increasing temperature. However, certain shrub species declined where soil and physical characteristics of a site limited water availability. In the higher elevation woodlands, Juniperus osteosperma and shrub canopy cover increased with increasing temperature, while Pinus edulis at the highest elevation sites was unresponsive to interannual temperature variability. These results from well-protected national parks highlight the importance of temperature to plant responses in a water-limited region and suggest that projected increases in aridity are likely to promote

Subtropical Low Cloud Response to a Warmer Climate in an Superparameterized Climate Model: Part I. Regime Sorting and Physical Mechanisms

Directory of Open Access Journals (Sweden)

Peter N Blossey

2009-07-01

Full Text Available The subtropical low cloud response to a climate with SST uniformly warmed by 2 K is analyzed in the SP- CAM superparameterized climate model, in which each grid column is replaced by a two-dimensional cloud-resolving model (CRM. Intriguingly, SP-CAM shows substantial low cloud increases over the subtropical oceans in the warmer climate. The paper aims to understand the mechanism for these increases. The subtropical low cloud increase is analyzed by sorting grid-column months of the climate model into composite cloud regimes using percentile ranges of lower tropospheric stability (LTS. LTS is observed to be well correlated to subtropical low cloud amount and boundary layer vertical structure. The low cloud increase in SP-CAM is attributed to boundary-layer destabilization due to increased clear-sky radiative cooling in the warmer climate. This drives more shallow cumulus convection and a moister boundary layer, inducing cloud increases and further increasing the radiative cooling. The boundary layer depth does not change substantially, due to compensation between increased radiative cooling (which promotes more turbulent mixing and boundary-layer deepening and slight strengthening of the boundary-layer top inversion (which inhibits turbulent entrainment and promotes a shallower boundary layer. The widespread changes in low clouds do not appear to be driven by changes in mean subsidence.
In a companion paper we use column-mode CRM simulations based on LTS-composite profiles to further study the low cloud response mechanisms and to explore the sensitivity of low cloud response to grid resolution in SP-CAM.

Response of corn markets to climate volatility under alternative energy futures.

Science.gov (United States)

Diffenbaugh, Noah S; Hertel, Thomas W; Scherer, Martin; Verma, Monika

2012-07-01

Recent price spikes(1,2) have raised concern that climate change could increase food insecurity by reducing grain yields in the coming decades(3,4). However, commodity price volatility is also influenced by other factors(5,6), which may either exacerbate or buffer the effects of climate change. Here we show that US corn price volatility exhibits higher sensitivity to near-term climate change than to energy policy influences or agriculture-energy market integration, and that the presence of a biofuels mandate enhances the sensitivity to climate change by more than 50%. The climate change impact is driven primarily by intensification of severe hot conditions in the primary corn-growing region of the US, which causes US corn price volatility to increase sharply in response to global warming projected over the next three decades. Closer integration of agriculture and energy markets moderates the effects of climate change, unless the biofuels mandate becomes binding, in which case corn price volatility is instead exacerbated. However, in spite of the substantial impact on US corn price volatility, we find relatively small impact on food prices. Our findings highlight the critical importance of interactions between energy policies, energy-agriculture linkages, and climate change.

Linking models of human behaviour and climate alters projected climate change

Science.gov (United States)

Beckage, Brian; Gross, Louis J.; Lacasse, Katherine; Carr, Eric; Metcalf, Sara S.; Winter, Jonathan M.; Howe, Peter D.; Fefferman, Nina; Franck, Travis; Zia, Asim; Kinzig, Ann; Hoffman, Forrest M.

2018-01-01

Although not considered in climate models, perceived risk stemming from extreme climate events may induce behavioural changes that alter greenhouse gas emissions. Here, we link the C-ROADS climate model to a social model of behavioural change to examine how interactions between perceived risk and emissions behaviour influence projected climate change. Our coupled climate and social model resulted in a global temperature change ranging from 3.4-6.2 °C by 2100 compared with 4.9 °C for the C-ROADS model alone, and led to behavioural uncertainty that was of a similar magnitude to physical uncertainty (2.8 °C versus 3.5 °C). Model components with the largest influence on temperature were the functional form of response to extreme events, interaction of perceived behavioural control with perceived social norms, and behaviours leading to sustained emissions reductions. Our results suggest that policies emphasizing the appropriate attribution of extreme events to climate change and infrastructural mitigation may reduce climate change the most.

Climate change in the oceans: Human impacts and responses.

Science.gov (United States)

Allison, Edward H; Bassett, Hannah R

2015-11-13

Although it has far-reaching consequences for humanity, attention to climate change impacts on the ocean lags behind concern for impacts on the atmosphere and land. Understanding these impacts, as well as society's diverse perspectives and multiscale responses to the changing oceans, requires a correspondingly diverse body of scholarship in the physical, biological, and social sciences and humanities. This can ensure that a plurality of values and viewpoints is reflected in the research that informs climate policy and may enable the concerns of maritime societies and economic sectors to be heard in key adaptation and mitigation discussions. Copyright © 2015, American Association for the Advancement of Science.

Potential for a hazardous geospheric response to projected future climate changes.

Science.gov (United States)

McGuire, B

2010-05-28

Periods of exceptional climate change in Earth history are associated with a dynamic response from the geosphere, involving enhanced levels of potentially hazardous geological and geomorphological activity. The response is expressed through the adjustment, modulation or triggering of a broad range of surface and crustal phenomena, including volcanic and seismic activity, submarine and subaerial landslides, tsunamis and landslide 'splash' waves, glacial outburst and rock-dam failure floods, debris flows and gas-hydrate destabilization. In relation to anthropogenic climate change, modelling studies and projection of current trends point towards increased risk in relation to a spectrum of geological and geomorphological hazards in a warmer world, while observations suggest that the ongoing rise in global average temperatures may already be eliciting a hazardous response from the geosphere. Here, the potential influences of anthropogenic warming are reviewed in relation to an array of geological and geomorphological hazards across a range of environmental settings. A programme of focused research is advocated in order to: (i) understand better those mechanisms by which contemporary climate change may drive hazardous geological and geomorphological activity; (ii) delineate those parts of the world that are most susceptible; and (iii) provide a more robust appreciation of potential impacts for society and infrastructure.

Changes in potential habitat of 147 North American breeding bird species in response to redistribution of trees and climate following predicted climate change

Science.gov (United States)

Stephen N. Matthews; Louis R. Iverson; Anantha M. Prasad; Matthew P. Peters

2011-01-01

Mounting evidence shows that organisms have already begun to respond to global climate change. Advances in our knowledge of how climate shapes species distributional patterns has helped us better understand the response of birds to climate change. However, the distribution of birds across the landscape is also driven by biotic and abiotic components, including habitat...

Climate change, uncertainty, and resilient fisheries: Institutional responses through integrative science

DEFF Research Database (Denmark)

Miller, K.; Charles, A.; Barange, M.

2010-01-01

This paper explores the importance of a focus on the fundamental goals of resilience and adaptive capacity in the governance of uncertain fishery systems, particularly in the context of climate change. Climate change interacts strongly with fishery systems, and adds to the inherent uncertainty...... that understanding these aspects of fishery systems and fishery governance is valuable even in the absence of climate-induced processes of change, but that attention to climate change both reinforces the need for, and facilitates the move toward, implementation of integrative science for improved fishery governance....... and processes – to support suitable institutional responses, a broader planning perspective, and development of suitable resilience-building strategies. The paper explores how synergies between institutional change and integrative science can facilitate the development of more effective fisheries policy...

Changing climate response in near-treeline bristlecone pine with elevation and aspect

International Nuclear Information System (INIS)

Salzer, Matthew W; Hughes, Malcolm K; Larson, Evan R; Bunn, Andrew G

2014-01-01

In the White Mountains of California, eight bristlecone pine (Pinus longaeva) tree-ring width chronologies were developed from trees at upper treeline and just below upper treeline along North- and South-facing elevational transects from treeline to ∼90 m below. There is evidence for a climate-response threshold between approximately 60–80 vertical m below treeline, above which trees have shown a positive growth-response to temperature and below which they do not. Chronologies from 80 m or more below treeline show a change in climate response and do not correlate strongly with temperature-sensitive chronologies developed from trees growing at upper treeline. Rather, they more closely resemble lower elevation precipitation-sensitive chronologies. At the highest sites, trees on South-facing slopes grow faster than trees on North-facing slopes. High growth rates in the treeline South-facing trees have declined since the mid-1990s. This suggests the possibility that the climate-response of the highest South-facing trees may have changed and that temperature may no longer be the main limiting factor for growth on the South aspect. These results indicate that increasing warmth may lead to a divergence between tree growth and temperature at previously temperature-limited sites. (letter)

Investigate the plant biomass response to climate warming in permafrost ecosystem using matrix-based data assimilation

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Lu, X.; Du, Z.; Schuur, E.; Luo, Y.

2017-12-01

Permafrost is one of the most vulnerable regions on the earth with over 40% world soil C represented in this region. Future climate warming potentially has a great impact on this region. On one hand, rising temperature accelerates permafrost soil thaw and release more C from land. On the other hand, warming may also increase the plant growing season length and therefore negatively feedback to climate change by increasing annual land C uptake. However, whether permafrost vegetation biomass change in response to warming can sequester more C has not been well understood. Manipulated air warming experiments reported that air warming has very limited impacts on grass land productivity and biomass growth in permafrost region [Mauritz et al., 2017]. It is hard to reveal the mechanisms behind the limited air warming response directly from experiment data. We employ a vegetation C cycle matrix model based on Community land model 4.5 (CLM4.5) and data assimilation technique to investigate how much do phenology and physiology processes contribute to the response respectively. Our results indicate phenology contributes the most in response to warming. The shift of vegetation parameter distributions after 2012 indicate vegetation acclimation may explain the modest response in plant biomass to air warming. The results suggest future model development need to take vegetation acclimation more seriously. The novel matrix-based model allows data assimilation to be conducted more efficiently. It provides more functional understanding of the models as well as the mechanism behind experiment data.

An exploration of options and functions of climate technology centres and networks. Discussion paper

International Nuclear Information System (INIS)

De Coninck, H.C.; Wuertenberger, L.; Cochran, J.; Cox, S.; Benioff, R.

2010-11-01

This paper responds to a request to UNEP from the UNFCCC Expert Group on Technology Transfer to examine operational modalities for climate technology centres and networks. The paper first discusses possible dimensions for the climate technology centre and network, and it reviews a number of existing networks and centres. It then distinguishes five options for the organizational structure and describes potential operational characteristics for each of these options. All options examined seek to build from existing climate and non-climate-related public and private technology centres, networks, and initiatives. Consistent with the UNFCCC negotiating text and draft technology decision, the paper evaluates potential implementation options and outcomes for each of the functions tentatively assigned to the climate technology centre and network, as well as selected functions of the technology executive committee. Approaches are offered for integrating delivery of these functions through coordinated programmes, and hypothetical examples are given to explain how the technology mechanism might add value in practice. The options presented in this paper are not an exhaustive treatment of potential structures or implementation approaches, and other approaches can be considered.

Climate change as a three-part ethical problem: a response to Jamieson and Gardiner.

Science.gov (United States)

Kingston, Ewan

2014-12-01

Dale Jamieson has claimed that conventional human-directed ethical concepts are an inadequate means for accurately understanding our duty to respond to climate change. Furthermore, he suggests that a responsibility to respect nature can instead provide the appropriate framework with which to understand such a duty. Stephen Gardiner has responded by claiming that climate change is a clear case of ethical responsibility, but the failure of institutions to respond to it creates a (not unprecedented) political problem. In assessing the debate between Gardiner and Jamieson, I develop an analysis which shows a three-part structure to the problem of climate change, in which the problem Gardiner identifies is only one of three sub-problems of climate change. This analysis highlights difficulties with Jamieson's argument that the duty of respect for nature is necessary for a full understanding of climate ethics, and suggests how a human-directed approach based on the three-part analysis can avoid Jamieson's charge of inadequacy.

Creating and Assessing Campus Climates That Support Personal and Social Responsibility

Science.gov (United States)

Reason, Robert D.

2013-01-01

In this article, Robert D. Reason defines personal and social responsibility as a five-component outcome of college, presents a case for thinking about educating for personal and social responsibility through the lens of campus climate that eschews the hunt for a single intervention, and encourages the marshaling of multiple resources in multiple…

Climate Intervention as an Optimization Problem

Science.gov (United States)

Caldeira, Ken; Ban-Weiss, George A.

2010-05-01

Typically, climate models simulations of intentional intervention in the climate system have taken the approach of imposing a change (eg, in solar flux, aerosol concentrations, aerosol emissions) and then predicting how that imposed change might affect Earth's climate or chemistry. Computations proceed from cause to effect. However, humans often proceed from "What do I want?" to "How do I get it?" One approach to thinking about intentional intervention in the climate system ("geoengineering") is to ask "What kind of climate do we want?" and then ask "What pattern of radiative forcing would come closest to achieving that desired climate state?" This involves defining climate goals and a cost function that measures how closely those goals are attained. (An important next step is to ask "How would we go about producing these desired patterns of radiative forcing?" However, this question is beyond the scope of our present study.) We performed a variety of climate simulations in NCAR's CAM3.1 atmospheric general circulation model with a slab ocean model and thermodynamic sea ice model. We then evaluated, for a specific set of climate forcing basis functions (ie, aerosol concentration distributions), the extent to which the climate response to a linear combination of those basis functions was similar to a linear combination of the climate response to each basis function taken individually. We then developed several cost functions (eg, relative to the 1xCO2 climate, minimize rms difference in zonal and annual mean land temperature, minimize rms difference in zonal and annual mean runoff, minimize rms difference in a combination of these temperature and runoff indices) and then predicted optimal combinations of our basis functions that would minimize these cost functions. Lastly, we produced forward simulations of the predicted optimal radiative forcing patterns and compared these with our expected results. Obviously, our climate model is much simpler than reality and

Inter- and intra-specific responses to elevated ozone and chamber climate in northern birches

International Nuclear Information System (INIS)

Manninen, S.; Huttunen, S.; Vanhatalo, M.; Pakonen, T.; Haemaelaeinen, A.

2009-01-01

We studied the responses of micropropagated, northern provenances of downy, mountain and silver birches to elevated ozone (O 3 ) and changing climate using open-top chambers (OTCs). Contrary to our hypothesis, northern birches were sensitive to O 3 , i.e. O 3 levels of 31-36 ppb reduced the leaf and root biomasses by -10%, whereas wood biomass was affected to a lesser extent. The warmer and drier OTC climate enhanced growth in general, though there were differences among the species and clones, e.g. in bud burst and biomass production. Inter- and intra-specific responses to O 3 and changing climate relate to traits such as allocation patterns between the above- and belowground parts (i.e. root/shoot ratio), which further relate to nutrient and water economy. Our experiments may have mimicked future conditions quite well, but only long-term field studies can yield the information needed to forecast responses at both tree and ecosystem levels. - Northern birches are responsive to ambient ozone levels.

Key ecological responses to nitrogen are altered by climate change

Science.gov (United States)

Greaver, T.L.; Clark, C.M.; Compton, J.E.; Vallano, D.; Talhelm, A. F.; Weaver, C.P.; Band, L.E.; Baron, Jill S.; Davidson, E.A.; Tague, C.L.; Felker-Quinn, E.; Lynch, J.A.; Herrick, J.D.; Liu, L.; Goodale, C.L.; Novak, K. J.; Haeuber, R. A.

2016-01-01

Climate change and anthropogenic nitrogen deposition are both important ecological threats. Evaluating their cumulative effects provides a more holistic view of ecosystem vulnerability to human activities, which would better inform policy decisions aimed to protect the sustainability of ecosystems. Our knowledge of the cumulative effects of these stressors is growing, but we lack an integrated understanding. In this Review, we describe how climate change alters key processes in terrestrial and freshwater ecosystems related to nitrogen cycling and availability, and the response of ecosystems to nitrogen addition in terms of carbon cycling, acidification and biodiversity.

Iterative functionalism and climate management regimes: From intergovernmental panel on climate change to intergovernmental negotiating committee

International Nuclear Information System (INIS)

Feldman, D.L.; Tennessee Univ., Knoxville, TN

1992-01-01

This paper contends that an iterative ''functionalist'' regime -- comprised of international organizations that monitor the global climate and perform scientific and policy research on prevention, mitigation, and adaptation strategies for response to possible global warming -- has developed over the past decade. A common global effort by scientists, diplomats, and others to negotiate a framework convention that would reduce emissions of carbon dioxide and other ''greenhouse gases'' has been brought about by this regime. Individuals that participate in this regime are engaged in several cooperative activities including: (1) international research on the causes and consequences of global change; (2) global environmental monitoring and standard-setting for analyses of climate data; and (3) negotiating a framework convention that places limits on greenhouse gas emissions by countries. The implications of this iterative approach for successful implementation of a treaty to forestall global climate change are discussed

Net root growth and nutrient acquisition in response to predicted climate change in two contrasting heathland species

DEFF Research Database (Denmark)

Arndal, M.F.; Merrild, M.P.; Michelsen, A.

2013-01-01

Accurate predictions of nutrient acquisition by plant roots and mycorrhizas are critical in modelling plant responses to climate change.We conducted a field experiment with the aim to investigate root nutrient uptake in a future climate and studied root production by ingrowth cores, mycorrhizal...... to elevated CO2. The species-specific response to the treatments suggests different sensitivity to global change factors, which could result in changed plant competitive interactions and belowground nutrient pool sizes in response to future climate change....

Climate risk management information, sources and responses in a pastoral region in East Africa

Directory of Open Access Journals (Sweden)

Anthony Egeru

2016-01-01

Full Text Available Pastoralists in East Africa face a range of stressors, climate variability and change being one of them. Effective climate risk management involves managing the full range of variability and balancing hazard management with efforts to capitalise on opportunity; climate risk management information is central in this process. In this study, pastoralists’ perceptions of climate change, climate risk management information types, sources and attendant responses in a pastoral region in East Africa are examined. Through a multi-stage sampling process, a total of 198 heads of households in three districts were selected and interviewed using a semi-structured questionnaire. In addition, 29 focus group discussions and 10 key informant interviews were conducted to generate qualitative information to supplement survey data. Descriptive and thematic analysis were utilised in summarizing the data. Ninety-nine percent of the pastoralists noted that the climate had changed evidenced by high but erratic rainfall, occurrence of floods and variation in rainfall onset and cessation among other indicators. This change in climate had led to emergence of ‘new’ livestock and crop diseases, crop failure and low yields leading to frequent food shortages, water shortages, poor market access, and variation in pasture availability among other effects. Climate risk management information was received from multiple sources including; radio, diviners, community meetings, shrine elders, humanitarian agencies, and Uganda People’s defence forces (UPDF. Community meetings were however perceived as most accessible, reliable and dependable sources of information. Shifting livestock to dry season grazing and watering areas, selling firewood and charcoal, seeking for military escorts to grazing areas, purchasing veterinary drugs, shifting livestock to disease ‘free’ areas, and performing rituals (depending on the perceived risk constituted a set of responses undertaken in

Crop yield response to climate change varies with cropping intensity.

Science.gov (United States)

Challinor, Andrew J; Parkes, Ben; Ramirez-Villegas, Julian

2015-04-01

Projections of the response of crop yield to climate change at different spatial scales are known to vary. However, understanding of the causes of systematic differences across scale is limited. Here, we hypothesize that heterogeneous cropping intensity is one source of scale dependency. Analysis of observed global data and regional crop modelling demonstrate that areas of high vs. low cropping intensity can have systematically different yields, in both observations and simulations. Analysis of global crop data suggests that heterogeneity in cropping intensity is a likely source of scale dependency for a number of crops across the globe. Further crop modelling and a meta-analysis of projected tropical maize yields are used to assess the implications for climate change assessments. The results show that scale dependency is a potential source of systematic bias. We conclude that spatially comprehensive assessments of climate impacts based on yield alone, without accounting for cropping intensity, are prone to systematic overestimation of climate impacts. The findings therefore suggest a need for greater attention to crop suitability and land use change when assessing the impacts of climate change. © 2015 John Wiley & Sons Ltd.

Interactions of Mean Climate Change and Climate Variability on Food Security Extremes

Science.gov (United States)

Ruane, Alexander C.; McDermid, Sonali; Mavromatis, Theodoros; Hudson, Nicholas; Morales, Monica; Simmons, John; Prabodha, Agalawatte; Ahmad, Ashfaq; Ahmad, Shakeel; Ahuja, Laj R.

2015-01-01

Recognizing that climate change will affect agricultural systems both through mean changes and through shifts in climate variability and associated extreme events, we present preliminary analyses of climate impacts from a network of 1137 crop modeling sites contributed to the AgMIP Coordinated Climate-Crop Modeling Project (C3MP). At each site sensitivity tests were run according to a common protocol, which enables the fitting of crop model emulators across a range of carbon dioxide, temperature, and water (CTW) changes. C3MP can elucidate several aspects of these changes and quantify crop responses across a wide diversity of farming systems. Here we test the hypothesis that climate change and variability interact in three main ways. First, mean climate changes can affect yields across an entire time period. Second, extreme events (when they do occur) may be more sensitive to climate changes than a year with normal climate. Third, mean climate changes can alter the likelihood of climate extremes, leading to more frequent seasons with anomalies outside of the expected conditions for which management was designed. In this way, shifts in climate variability can result in an increase or reduction of mean yield, as extreme climate events tend to have lower yield than years with normal climate.C3MP maize simulations across 126 farms reveal a clear indication and quantification (as response functions) of mean climate impacts on mean yield and clearly show that mean climate changes will directly affect the variability of yield. Yield reductions from increased climate variability are not as clear as crop models tend to be less sensitive to dangers on the cool and wet extremes of climate variability, likely underestimating losses from water-logging, floods, and frosts.

Temporal response of the tiger salamander (Ambystoma tigrinum to 3,000 years of climatic variation

Directory of Open Access Journals (Sweden)

Long Webb

2005-09-01

Full Text Available Abstract Background Amphibians are sensitive indicators of environmental conditions and show measurable responses, such as changes in phenology, abundance and range limits to local changes in precipitation and temperature regimes. Amphibians offer unique opportunities to study the important ecological and evolutionary implications of responses in life history characteristics to climatic change. We analyzed a late-Holocene fossil record of the Tiger Salamander (Ambystoma tigrinum for evidence of population-level changes in body size and paedomorphosis to climatic change over the last 3000 years. Results We found a significant difference in body size index between paedomorphic and metamorphic individuals during the time interval dominated by the Medieval Warm Period. There is a consistent ratio of paedomorphic to metamorphic specimens through the entire 3000 years, demonstrating that not all life history characteristics of the population were significantly altered by changes in climate on this timescale. Conclusion The fossil record of Ambystoma tigrinum we used spans an ecologically relevant timescale appropriate for understanding population and community response to projected climatic change. The population-level responses we documented are concordant with expectations based on modern environmental studies, and yield insight into population-level patterns across hundreds of generations, especially the independence of different life history characteristics. These conclusions lead us to offer general predictions about the future response of this species based on likely scenarios of climatic warming in the Rocky Mountain region.

Responses of Montane Forest to Climate Variability in the Central Himalayas of Nepal

Directory of Open Access Journals (Sweden)

Janardan Mainali

2015-02-01

Full Text Available Climate changes are having dramatic ecological impacts in mid- to high-latitude mountain ranges where growth conditions are limited by climatic variables such as duration of growing season, moisture, and ambient temperature. We document patterns of forest vegetative response for 5 major alpine forest communities to current climate variability in the central Himalayas of Nepal to provide a baseline for assessment of future changes, as well as offer some insight into the trajectory of these changes over time. We used mean monthly surface air temperature and rainfall and the monthly averaged normalized difference vegetation index (NDVI to compare relative vegetation productivity among forest types and in relation to both climatic variables. Because changes in temperature and precipitation are directly manifested as changes in phenology, we examined current vegetative responses to climate variability in an effort to determine which climate variable is most critical for different alpine forest types. Our results show that correlations differ according to vegetation type and confirm that both precipitation and temperature affect monthly NDVI values, though more significant correlations were found with temperature data. The temperature response was more consistent because at the maximum increased temperatures, there was still an ongoing increase in vegetative vigor. This indicates that temperature is still the major limiting factor for plant growth at higher-elevation sites. This part of the Himalayas has abundant moisture, and some forest types are already saturated in terms of growth in relation to precipitation. Clear increases in productivity are documented on the upper treeline ecotones, and these systems are likely to continue to have increasing growth rates.

Simulating changes in ecosystem structure and composition in response to climate change: a case study focused on tropical nitrogen-fixing trees (Invited)

Science.gov (United States)

Medvigy, D.; Levy, J.; Xu, X.; Batterman, S. A.; Hedin, L.

2013-12-01

Ecosystems, by definition, involve a community of organisms. These communities generally exhibit heterogeneity in their structure and composition as a result of local variations in climate, soil, topography, disturbance history, and other factors. Climate-driven shifts in ecosystems will likely include an internal re-organization of community structure and composition and as well as the introduction of novel species. In terms of vegetation, this ecosystem heterogeneity can occur at relatively small scales, sometimes of the order of tens of meters or even less. Because this heterogeneous landscape generally has a variable and nonlinear response to environmental perturbations, it is necessary to carefully aggregate the local competitive dynamics between individual plants to the large scales of tens or hundreds of kilometers represented in climate models. Accomplishing this aggregation in a computationally efficient way has proven to be an extremely challenging task. To meet this challenge, the Ecosystem Demography 2 (ED2) model statistically characterizes a distribution of local resource environments, and then simulates the competition between individuals of different sizes and species (or functional groupings). Within this framework, it is possible to explicitly simulate the impacts of climate change on ecosystem structure and composition, including both internal re-organization and the introduction of novel species or functional groups. This presentation will include several illustrative applications of the evolution of ecosystem structure and composition under climate change. One application pertains to the role of nitrogen-fixing species in tropical forests. Will increasing CO2 concentrations increase the demand for nutrients and perhaps give a competitive edge to nitrogen-fixing species? Will potentially warmer and drier conditions make some tropical forests more water-limited, reducing the demand for nitrogen, thereby giving a competitive advantage to non

Plant response to climate change along the forest-tundra ecotone in northeastern Siberia.

Science.gov (United States)

Berner, Logan T; Beck, Pieter S A; Bunn, Andrew G; Goetz, Scott J

2013-11-01

Russia's boreal (taiga) biome will likely contract sharply and shift northward in response to 21st century climatic change, yet few studies have examined plant response to climatic variability along the northern margin. We quantified climate dynamics, trends in plant growth, and growth-climate relationships across the tundra shrublands and Cajander larch (Larix cajanderi Mayr.) woodlands of the Kolyma river basin (657 000 km(2) ) in northeastern Siberia using satellite-derived normalized difference vegetation indices (NDVI), tree ring-width measurements, and climate data. Mean summer temperatures (Ts ) increased 1.0 °C from 1938 to 2009, though there was no trend (P > 0.05) in growing year precipitation or climate moisture index (CMIgy ). Mean summer NDVI (NDVIs ) increased significantly from 1982 to 2010 across 20% of the watershed, primarily in cold, shrub-dominated areas. NDVIs positively correlated (P  0.05), which significantly correlated with NDVIs (r = 0.44, P < 0.05, 1982-2007). Both satellite and tree-ring analyses indicated that plant growth was constrained by both low temperatures and limited moisture availability and, furthermore, that warming enhanced growth. Impacts of future climatic change on forests near treeline in Arctic Russia will likely be influenced by shifts in both temperature and moisture, which implies that projections of future forest distribution and productivity in this area should take into account the interactions of energy and moisture limitations. © 2013 John Wiley & Sons Ltd.

Assessing Forest Carbon Response to Climate Change and Disturbances Using Long-term Hydro-climatic Observations and Simulations

Science.gov (United States)

Trettin, C.; Dai, Z.; Amatya, D. M.

2014-12-01

Long-term climatic and hydrologic observations on the Santee Experimental Forest in the lower coastal plain of South Carolina were used to estimate long-term changes in hydrology and forest carbon dynamics for a pair of first-order watersheds. Over 70 years of climate data indicated that warming in this forest area in the last decades was faster than the global mean; 35+ years of hydrologic records showed that forest ecosystem succession three years following Hurricane Hugo caused a substantial change in the ratio of runoff to precipitation. The change in this relationship between the paired watersheds was attributed to altered evapotranspiration processes caused by greater abundance of pine in the treatment watershed and regeneration of the mixed hardwood-pine forest on the reference watershed. The long-term records and anomalous observations are highly valuable for reliable calibration and validation of hydrological and biogeochemical models capturing the effects of climate variability. We applied the hydrological model MIKESHE that showed that runoff and water table level are sensitive to global warming, and that the sustained warming trends can be expected to decrease stream discharge and lower the mean water table depth. The spatially-explicit biogeochemical model Forest-DNDC, validated using biomass measurements from the watersheds, was used to assess carbon dynamics in response to high resolution hydrologic observation data and simulation results. The simulations showed that the long-term spatiotemporal carbon dynamics, including biomass and fluxes of soil carbon dioxide and methane were highly regulated by disturbance regimes, climatic conditions and water table depth. The utility of linked-modeling framework demonstrated here to assess biogeochemical responses at the watershed scale suggests applications for assessing the consequences of climate change within an urbanizing forested landscape. The approach may also be applicable for validating large

Development of ecological indicators of climate change based on lichen functional diversity

OpenAIRE

Matos, Paula Sofia Antunes

2016-01-01

Growing evidence shows us that climate has changed in the recent decades, and the scenario for the future will most likely worsen. A set of climate variables is being developed to monitor climate change, but this is not enough to keep track its effects on ecosystems. It’s imperative to understand and quantify how ecosystems functioning are affected by and respond to these changes, and ecological indicators based on biodiversity metrics are one of the tools to do this. The...

Climate change negotiation simulations for students: responses across gender and age.A case study: San Francisco State University World Climate Exercises

Science.gov (United States)

Rasheva, E. A.

2015-12-01

For decades, role-play and simulation exercises have been utilized for learning and policy decision making. While the power of Model UN simulations in building first-person experience and understanding of complex international issues is well known, the effectiveness of simulations for inspiring citizen engagement in scientific public-policy issues is little studied. My work hypothesizes that climate-change negotiation simulations can enhance students' scientific literacy and policy advocacy. It aims to determine how age and gender influence the responsiveness of students to such simulations. During the 2015 fall semester, I am conducting World Climate exercises for fellow graduate and undergraduate students at San Francisco State University. At the end of the exercise, I will have collected the responses to an anonymous questionnaire in which the participants indicate age and gender. The questionnaire asks participants to describe their hopes and fears for the future and to propose public and personal actions for achieving a strong climate change agreement. I am tracking differences to determine whether participants' age and gender correlate with particular patterns of feeling and thinking. My future research will aim to determine whether and how strongly the World Climate Exercise has affected participants' actual policy engagement. This work will also reflect on my experiences as a World Climate facilitator. I will describe the facilitation process and then discuss some of my observations from the sessions. I will specify the challenges I have encountered and suggest strategies that can strengthen the learning process. World Climate is a computer-simulation-based climate change negotiations role-playing exercise developed by Climate Interactive in partnership with the System Dynamics Group at the MIT Sloan School of Management.

Climate Changes and Their Impact on Agricultural Market Systems: Examples from Nepal

Directory of Open Access Journals (Sweden)

Andrea Karin Barrueto

2017-11-01

Full Text Available Global climate models foresee changes in temperature and precipitation regimes that shift regional climate zones and influence the viability of agricultural market systems. Understanding the influence of climate change on the different sub-sectors and functions of a market system is crucial to increasing the systems’ climate resilience and to ensuring the long-term viability of the sectors. Our research applies a new approach to climate change analysis to better understand the influence of climate change on each step of an agricultural market system—on its core (processing units, storage facilities and sales and support functions (sapling supply, research, insurance and agricultural policy. We use spatial climate analyses to investigate current and projected changes in climate for different regions in Nepal. We then analyse the risks and vulnerabilities of the sub-sectors banana, charcoal, coffee, macadamia, orange, vegetables and walnut. Our results show that temperatures and precipitation levels will change differently depending on the climatic regions, and that climate change elicits different responses from the market functions both between and within each of the different sub-sectors. We conclude that climate-related interventions in market systems must account for each different market function’s specific response and exposure to climate change, in order to select adaptation measures that ensure long-term climate resilience.

Elucidating dynamic responses of North Pacific fish populations to climatic forcing: Influence of life-history strategy

Science.gov (United States)

Yatsu, A.; Aydin, K. Y.; King, J. R.; McFarlane, G. A.; Chiba, S.; Tadokoro, K.; Kaeriyama, M.; Watanabe, Y.

2008-05-01

In order to explore mechanistic linkages between low-frequency ocean/climate variability, and fish population responses, we undertook comparative studies of time-series of recruitment-related productivity and the biomass levels of fish stocks representing five life-history strategies in the northern North Pacific between the 1950s and the present. We selected seven species: Japanese sardine ( Sardinopus melanostictus) and California sardine ( Sardinopus sagax) (opportunistic strategists), walleye pollock ( Theragra chalcogramma, intermediate strategist), pink salmon ( Oncorhynchus gorbuscha, salmonic strategist), sablefish ( Anoplopoma fimbria) and Pacific halibut ( Hippoglossus stenolepis) (periodic strategists) and spiny dogfish ( Squalus acanthias, equilibrium strategist). The responses in terms of productivity of sardine, pink salmon, sablefish and halibut to climatic regime shifts were generally immediate, delayed, or no substantial responses depending on the particular regime shift year and fish stock (population). In walleye pollock, there were some periods of high productivity and low productivity, but not coincidental to climatic regime shifts, likely due to indirect climate forcing impacts on both bottom-up and top-down processes. Biomass of zooplankton and all fish stocks examined, except for spiny dogfish whose data were limited, indicated a decadal pattern with the most gradual changes in periodic strategists and most intensive and rapid changes in opportunistic strategists. Responses of sardine productivity to regime shifts were the most intense, probably due to the absence of density-dependent effects and the availability of refuges from predators when sardine biomass was extremely low. Spiny dogfish were least affected by environmental variability. Conversely, spiny dogfish are likely to withstand only modest harvest rates due to their very low intrinsic rate of increase. Thus, each life-history strategy type had a unique response to climatic

Ecological grief as a mental health response to climate change-related loss

Science.gov (United States)

Cunsolo, Ashlee; Ellis, Neville R.

2018-04-01

Climate change is increasingly understood to impact mental health through multiple pathways of risk, including intense feelings of grief as people suffer climate-related losses to valued species, ecosystems and landscapes. Despite growing research interest, ecologically driven grief, or `ecological grief', remains an underdeveloped area of inquiry. We argue that grief is a natural and legitimate response to ecological loss, and one that may become more common as climate impacts worsen. Drawing upon our own research in Northern Canada and the Australian Wheatbelt, combined with a synthesis of the literature, we offer future research directions for the study of ecological grief.

Using niche-based modelling to assess the impact of climate change on tree functional diversity in Europe

DEFF Research Database (Denmark)

Thuiller, Wilfried; Lavorel, Sandra; Sykes, Martin T.

2006-01-01

Rapid anthropogenic climate change is already affecting species distributions and ecosystem functioning worldwide. We applied niche-based models to analyse the impact of climate change on tree species and functional diversity in Europe. Present-day climate was used to predict the distributions...... of 122 tree species from different functional types (FT). We then explored projections of future distributions under one climate scenario for 2080, considering two alternative dispersal assumptions: no dispersal and unlimited dispersal. The species-rich broadleaved deciduous group appeared to play a key...... role in the future of different European regions. Temperate areas were projected to lose both species richness and functional diversity due to the loss of broadleaved deciduous trees. These were projected to migrate to boreal forests, thereby increasing their species richness and functional diversity...

Big sagebrush (Artemisia tridentata) in a shifting climate context: Assessment of seedling responses to climate

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Martha A. Brabec

2014-01-01

The loss of big sagebrush (Artemisia tridentata) throughout the Great Basin Desert has motivated efforts to restore it because of fire and other disturbance effects on sagebrush-dependent wildlife and ecosystem function. Initial establishment is the first challenge to restoration, and appropriateness of seeds, climate, and weather variability are factors that may...

Responses of tropical root crops to climate change: implications for Pacific food security

Science.gov (United States)

Gleadow, R.; Webber, B.; Macness, N.; Lisson, S.; Nauluvula, P.; Hargraves, J.; Crimp, S. J.

2013-12-01

Cassava and taro are an important source of calories in many parts of the developing world and hold much promise for meeting the need for food security in equatorial regions. Communities in the Pacific Island countries reliant on agriculture-based livelihood systems have been identified as particularly at risk from climate change, due to likely increases in crop failure, new patterns of pests and diseases, lack of appropriate seed and plant material, loss of livestock and potential loss of arable land. Recent shortfalls in agricultural production resulting from changing export markets, commodity prices, climatic variation, and population growth and urbanisation, have contributed further to regional food insecurity concerns. Cassava and taro contain herbivore defense chemicals that are detrimental to human health (cyanogenic glucosides and calcium oxalate). Unprocessed cassava can cause acute cyanide intoxication, paralysis and even death, especially during droughts. A number of activities are already underway in the Pacific region to identify ways to ameliorate existing climate risk and enhance current agricultural production. Whilst these activities are important to ensure long-term agricultural sustainability, there remains a significant degree of uncertainty as to how effective these strategies may be in the face of a changing and increasingly variable future climate. We present our current understanding of the impact of climate change on key Pacific production systems - specifically those based on the staple root crops, taro and cassava. This includes (1) Our understanding of the responses of cassava and taro crops to existing environmental drivers (climate, soil and nutrient interactions); (2) The responses of cassava and taro crops to enhanced CO2 conditions; and (3) Efforts to model productivity responses (within the APSIM framework) and results for locations in the Pacific.

Climate-related changes of soil characteristics affect bacterial community composition and function of high altitude and latitude lakes.

Science.gov (United States)

Rofner, Carina; Peter, Hannes; Catalán, Núria; Drewes, Fabian; Sommaruga, Ruben; Pérez, María Teresa

2017-06-01

Lakes at high altitude and latitude are typically unproductive ecosystems where external factors outweigh the relative importance of in-lake processes, making them ideal sentinels of climate change. Climate change is inducing upward vegetation shifts at high altitude and latitude regions that translate into changes in the pools of soil organic matter. Upon mobilization, this allochthonous organic matter may rapidly alter the composition and function of lake bacterial communities. Here, we experimentally simulate this potential climate-change effect by exposing bacterioplankton of two lakes located above the treeline, one in the Alps and one in the subarctic region, to soil organic matter from below and above the treeline. Changes in bacterial community composition, diversity and function were followed for 72 h. In the subarctic lake, soil organic matter from below the treeline reduced bulk and taxon-specific phosphorus uptake, indicating that bacterial phosphorus limitation was alleviated compared to organic matter from above the treeline. These effects were less pronounced in the alpine lake, suggesting that soil properties (phosphorus and dissolved organic carbon availability) and water temperature further shaped the magnitude of response. The rapid bacterial succession observed in both lakes indicates that certain taxa directly benefited from soil sources. Accordingly, the substrate uptake profiles of initially rare bacteria (copiotrophs) indicated that they are one of the main actors cycling soil-derived carbon and phosphorus. Our work suggests that climate-induced changes in soil characteristics affect bacterioplankton community structure and function, and in turn, the cycling of carbon and phosphorus in high altitude and latitude aquatic ecosystems. © 2016 The Authors. Global Change Biology Published by John Wiley & Sons Ltd.

Hydrological Responses to Land-Use Change Scenarios under Constant and Changed Climatic Conditions.

Science.gov (United States)

Zhang, Ling; Nan, Zhuotong; Yu, Wenjun; Ge, Yingchun

2016-02-01

This study quantified the hydrological responses to land-use change scenarios in the upper and middle Heihe River basin (HRB), northwest China, under constant and changed climatic conditions by combining a land-use/cover change model (dynamic conversion of land use and its effects, Dyna-CLUE) and a hydrological model (soil and water assessment tool, SWAT). Five land-use change scenarios, i.e., historical trend (HT), ecological protection (EP), strict ecological protection (SEP), economic development (ED), and rapid economic development (RED) scenarios, were established. Under constant climatic condition, hydrological variations are only induced by land-use changes in different scenarios. The changes in mean streamflow at the outlets of the upper and the middle HRB are not pronounced, although the different scenarios produce different outcomes. However, more pronounced changes are observed on a subbasin level. The frequency of extreme flood is projected to decrease under the SEP scenario, while under the other scenarios, no changes can be found. Two emission scenarios (A1B and B1) of three general circulation models (HadCM3, CGCM3, and CCSM3) were employed to generate future possible climatic conditions. Under changed climatic condition, hydrological variations are induced by the combination of land-use and climatic changes. The results indicate that the impacts of land-use changes become secondary when the changed climatic conditions have been considered. The frequencies of extreme flood and drought are projected to decrease and increase, respectively, under all climate scenarios. Although some agreements can be reached, pronounced difference of hydrological responses can be observed for different climate scenarios of different GCMs.

Antarctic fellfield response to climate change: a tripartite synthesis of experimental data.

Science.gov (United States)

Kennedy, Andrew D

1996-07-01

This paper explores the biological consequences of climate change by integrating the results of a tripartite investigation involving fumarole, field manipulation and laboratory incubation experiments. The geographical region for this research is the maritime Antarctic. Under contemporary climate conditions, the lithosols in this region support only a sparse cryptogamic flora of limited taxonomic diversity and low structural complexity. However, the existence in geothermal areas of temperate species (e.g. Campylopus introflexus, Marchantia polymorpha, Philonotis acicularis) growing outside their normal biogeographical range suggests that elevated temperature and humidity may alter the trajectory of community development towards Magellanic or Patagonian composition. Productivity is also likely to increase, as indicated by significantly greater vegetative biomass recorded beneath climate-ameliorating soil covers than in controls. Barren fellfield soil samples transplanted to the laboratory and incubated at temperatures of 2-25°C show rapid development of moss, algae and lichen propagules in the range 15-25°C. A variety of species develop that have not been recorded in the field. The presence of exotic taxa indicates the existence of a dormant propagule bank in maritime Antarctic soils and suggests that no significant delay is likely to occur between the onset of climate warming and community development: instead, rapid establishment of those species favoured by the new climate conditions will yield a distinct founder effect, with increasing above- and below-ground biomass stimulating biogeochemical cycling. It is argued that the combined results of this synthesis identify generic responses to climate change arising from the importance at high latitudes of low temperature and water availability as limiting factors: subject to other growth resources being non-limiting, a more consistent stimulatory response to climate change may be expected than in temperate or

Responses of Contrasting Tree Functional Types to Air Warming and Drought

Directory of Open Access Journals (Sweden)

Elisabet Martínez-Sancho

2017-11-01

Full Text Available Climate change-induced rise of air temperatures and the increase of extreme climatic events, such as droughts, will largely affect plant growth and hydraulics, leading to mortality events all over the globe. In this study, we investigated the growth and hydraulic responses of seedlings of contrasting functional types. Pinus sylvestris, Quercus spp. and Castanea sativa seedlings were grown in a common garden experiment under four treatments: control, air warming, drought and their combination during two consecutive growing periods. Height and diameter increments, stomatal conductance and stem water potentials were measured during both growing seasons. Additionally, hydraulic parameters such as xylem-specific native and maximum hydraulic conductivities, and native percentage of loss of conductivity were measured at the end of the entire experiment. Our results clearly pointed to different adaptive strategies of the studied species. Scots pine displayed a relatively isohydric behavior with a strict stomata control prohibiting native embolism whereas sweet chestnut and oak as relatively anisohydric species displayed an increased loss of native conductivity as a results of low water potentials. Seasonal timing of shoot and diameter growth also differed among functional types influencing drought impacts. Additionally, the possibility of embolism reversal seemed to be limited under the study conditions.

Climatic and land-use driven change of runoff throughout Sweden

Science.gov (United States)

Worman, A. L. E.; Riml, J.; Lindstrom, G.

2015-12-01

Changes in runoff can be caused by climatic variations, land-use changes and water regulation. In this paper we propose a separation of the power spectral response of runoff in watersheds in terms of the product of the power spectra of precipitation and the impulse response function for the watershed. This allows a formal separation of the spectral response in climatic factors - the precipitation - from those of land-use change and regulation - the impulse response function. The latter function characterizes the surface water-groundwater interaction, stream network topology and open channel hydraulics. Based on daily data of digitalized hydro-climatological data from 1961, we constructed synthetic, but calibrated data of runoff from 1001 watersheds in Sweden. From spectral analysis of the data we found periodic fluctuations occurring on time scales of about a decade and a bi-annual peak. These multi-annual fluctuations could be statistically linked through the coherence spectra to climatic indices like the NAO, PDO, geostrophic wind velocity and sun spot numbers on common periods of 3,6 and 7,6 years. Such long-term fluctuations in runoff are not significantly affected by the land-use or regulation other than indirectly through impact on local hydro-climate. Based on a spectral separation of precipitation and impulse response function of the watersheds, we found that the intra-annual variation in runoff was primarily affected by the land-use change in 79 unregulated catchments with up to century-long time series of measured daily discharge. There is a statistically significant increasing slope of the catchments impulse response function for 63 of the 79 catchments and this suggest a significant hydrological effect of land-use practice in agriculture, urbanisation and forestry.

Regional Energy Demand Responses To Climate Change. Methodology And Application To The Commonwealth Of Massachusetts

International Nuclear Information System (INIS)

Amato, A.D.; Ruth, M.; Kirshen, P.; Horwitz, J.

2005-01-01

Climate is a major determinant of energy demand. Changes in climate may alter energy demand as well as energy demand patterns. This study investigates the implications of climate change for energy demand under the hypothesis that impacts are scale dependent due to region-specific climatic variables, infrastructure, socioeconomic, and energy use profiles. In this analysis we explore regional energy demand responses to climate change by assessing temperature-sensitive energy demand in the Commonwealth of Massachusetts. The study employs a two-step estimation and modeling procedure. The first step evaluates the historic temperature sensitivity of residential and commercial demand for electricity and heating fuels, using a degree-day methodology. We find that when controlling for socioeconomic factors, degree-day variables have significant explanatory power in describing historic changes in residential and commercial energy demands. In the second step, we assess potential future energy demand responses to scenarios of climate change. Model results are based on alternative climate scenarios that were specifically derived for the region on the basis of local climatological data, coupled with regional information from available global climate models. We find notable changes with respect to overall energy consumption by, and energy mix of the residential and commercial sectors in the region. On the basis of our findings, we identify several methodological issues relevant to the development of climate change impact assessments of energy demand

Regional Energy Demand Responses To Climate Change. Methodology And Application To The Commonwealth Of Massachusetts

Energy Technology Data Exchange (ETDEWEB)

Amato, A.D.; Ruth, M. [Environmental Policy Program, School of Public Policy, University of Maryland, 3139 Van Munching Hall, College Park, MD (United States); Kirshen, P. [Department of Civil and Environmental Engineering, Tufts University, Anderson Hall, Medford, MA (United States); Horwitz, J. [Climatological Database Consultant, Binary Systems Software, Newton, MA (United States)

2005-07-01

Climate is a major determinant of energy demand. Changes in climate may alter energy demand as well as energy demand patterns. This study investigates the implications of climate change for energy demand under the hypothesis that impacts are scale dependent due to region-specific climatic variables, infrastructure, socioeconomic, and energy use profiles. In this analysis we explore regional energy demand responses to climate change by assessing temperature-sensitive energy demand in the Commonwealth of Massachusetts. The study employs a two-step estimation and modeling procedure. The first step evaluates the historic temperature sensitivity of residential and commercial demand for electricity and heating fuels, using a degree-day methodology. We find that when controlling for socioeconomic factors, degree-day variables have significant explanatory power in describing historic changes in residential and commercial energy demands. In the second step, we assess potential future energy demand responses to scenarios of climate change. Model results are based on alternative climate scenarios that were specifically derived for the region on the basis of local climatological data, coupled with regional information from available global climate models. We find notable changes with respect to overall energy consumption by, and energy mix of the residential and commercial sectors in the region. On the basis of our findings, we identify several methodological issues relevant to the development of climate change impact assessments of energy demand.

Improving predictions of tropical forest response to climate change through integration of field studies and ecosystem modeling

Science.gov (United States)

Feng, Xiaohui; Uriarte, María; González, Grizelle; Reed, Sasha C.; Thompson, Jill; Zimmerman, Jess K.; Murphy, Lora

2018-01-01

Tropical forests play a critical role in carbon and water cycles at a global scale. Rapid climate change is anticipated in tropical regions over the coming decades and, under a warmer and drier climate, tropical forests are likely to be net sources of carbon rather than sinks. However, our understanding of tropical forest response and feedback to climate change is very limited. Efforts to model climate change impacts on carbon fluxes in tropical forests have not reached a consensus. Here we use the Ecosystem Demography model (ED2) to predict carbon fluxes of a Puerto Rican tropical forest under realistic climate change scenarios. We parameterized ED2 with species-specific tree physiological data using the Predictive Ecosystem Analyzer workflow and projected the fate of this ecosystem under five future climate scenarios. The model successfully captured inter-annual variability in the dynamics of this tropical forest. Model predictions closely followed observed values across a wide range of metrics including above-ground biomass, tree diameter growth, tree size class distributions, and leaf area index. Under a future warming and drying climate scenario, the model predicted reductions in carbon storage and tree growth, together with large shifts in forest community composition and structure. Such rapid changes in climate led the forest to transition from a sink to a source of carbon. Growth respiration and root allocation parameters were responsible for the highest fraction of predictive uncertainty in modeled biomass, highlighting the need to target these processes in future data collection. Our study is the first effort to rely on Bayesian model calibration and synthesis to elucidate the key physiological parameters that drive uncertainty in tropical forests responses to climatic change. We propose a new path forward for model-data synthesis that can substantially reduce uncertainty in our ability to model tropical forest responses to future climate.

Climate- and successional-related changes in functional composition of European forests are strongly driven by tree mortality.

Science.gov (United States)

Ruiz-Benito, Paloma; Ratcliffe, Sophia; Zavala, Miguel A; Martínez-Vilalta, Jordi; Vilà-Cabrera, Albert; Lloret, Francisco; Madrigal-González, Jaime; Wirth, Christian; Greenwood, Sarah; Kändler, Gerald; Lehtonen, Aleksi; Kattge, Jens; Dahlgren, Jonas; Jump, Alistair S

2017-10-01

Intense droughts combined with increased temperatures are one of the major threats to forest persistence in the 21st century. Despite the direct impact of climate change on forest growth and shifts in species abundance, the effect of altered demography on changes in the composition of functional traits is not well known. We sought to (1) quantify the recent changes in functional composition of European forests; (2) identify the relative importance of climate change, mean climate and forest development for changes in functional composition; and (3) analyse the roles of tree mortality and growth underlying any functional changes in different forest types. We quantified changes in functional composition from the 1980s to the 2000s across Europe by two dimensions of functional trait variation: the first dimension was mainly related to changes in leaf mass per area and wood density (partially related to the trait differences between angiosperms and gymnosperms), and the second dimension was related to changes in maximum tree height. Our results indicate that climate change and mean climatic effects strongly interacted with forest development and it was not possible to completely disentangle their effects. Where recent climate change was not too extreme, the patterns of functional change generally followed the expected patterns under secondary succession (e.g. towards late-successional short-statured hardwoods in Mediterranean forests and taller gymnosperms in boreal forests) and latitudinal gradients (e.g. larger proportion of gymnosperm-like strategies at low water availability in forests formerly dominated by broad-leaved deciduous species). Recent climate change generally favoured the dominance of angiosperm-like related traits under increased temperature and intense droughts. Our results show functional composition changes over relatively short time scales in European forests. These changes are largely determined by tree mortality, which should be further

Riparian responses to extreme climate and land-use change scenarios.

Science.gov (United States)

Fernandes, Maria Rosário; Segurado, Pedro; Jauch, Eduardo; Ferreira, Maria Teresa

2016-11-01

Climate change will induce alterations in the hydrological and landscape patterns with effects on riparian ecotones. In this study we assess the combined effect of an extreme climate and land-use change scenario on riparian woody structure and how this will translate into a future risk of riparian functionality loss. The study was conducted in the Tâmega catchment of the Douro basin. Boosted Regression Trees (BRTs) were used to model two riparian landscape indicators related with the degree of connectivity (Mean Width) and complexity (Area Weighted Mean Patch Fractal Dimension). Riparian data were extracted by planimetric analysis of high spatial-resolution Word Imagery Layer (ESRI). Hydrological, climatic and land-use variables were obtained from available datasets and generated with process-based modeling using current climate data (2008-2014), while also considering the high-end RCP8.5 climate-change and "Icarus" socio-economic scenarios for the 2046-2065 time slice. Our results show that hydrological and land-use changes strongly influence future projections of riparian connectivity and complexity, albeit to diverse degrees and with differing effects. A harsh reduction in average flows may impair riparian zones while an increase in extreme rain events may benefit connectivity by promoting hydrologic dynamics with the surrounding floodplains. The expected increase in broad-leaved woodlands and mixed forests may enhance the riparian galleries by reducing the agricultural pressure on the area in the vicinity of the river. According to our results, 63% of river segments in the Tâmega basin exhibited a moderate risk of functionality loss, 16% a high risk, and 21% no risk. Weaknesses and strengths of the method are highlighted and results are discussed based on a resilience perspective with regard to riparian ecosystems. Copyright © 2016 Elsevier B.V. All rights reserved.

Global negative vegetation feedback to climate warming responses of leaf litter decomposition rates in cold biomes.

NARCIS (Netherlands)

Cornelissen, J.H.C.; van Bodegom, P.M.; Aerts, R.; Gallaghan, T.V.; van Logtestijn, R.S.P; Alatalo, J.; Chapin, F.S. III; Gerdol, R.; Gudmundsson, J.; Gwynn-Jones, D.; Hartley, A.E.; Hik, D.S.; Hofgaard, A.; Jonsdottir, I.S.; Karlsson, S.; Klein, J.A.; Laundre, J.; Magnusson, B.; Michelsel, A.; Molau, U.; Onipchenko, V.G.; Quested, H.M.; Sandvik, S.M.; Schmidt, I.K.; Shaver, G.R.; Solhleim, B.; Soudzilovskaia, N.A.; Stenstrom, A.; Tolvanen, A.; Totland, O.; Wada, N.; Welker, J.M.; Zhao, X.; Team, M.O.L.

2007-01-01

Whether climate change will turn cold biomes from large long-term carbon sinks into sources is hotly debated because of the great potential for ecosystem-mediated feedbacks to global climate. Critical are the direction, magnitude and generality of climate responses of plant litter decomposition.

Final technical report. Can microbial functional traits predict the response and resilience of decomposition to global change?

Energy Technology Data Exchange (ETDEWEB)

Allison, Steven D. [Univ. of California, Irvine, CA (United States)

2015-09-24

The role of specific micro-organisms in the carbon cycle, and their responses to environmental change, are unknown in most ecosystems. This knowledge gap limits scientists’ ability to predict how important ecosystem processes, like soil carbon storage and loss, will change with climate and other environmental factors. The investigators addressed this knowledge gap by transplanting microbial communities from different environments into new environments and measuring the response of community composition and carbon cycling over time. Using state-of-the-art sequencing techniques, computational tools, and nanotechnology, the investigators showed that microbial communities on decomposing plant material shift dramatically with natural and experimentally-imposed drought. Microbial communities also shifted in response to added nitrogen, but the effects were smaller. These changes had implications for carbon cycling, with lower rates of carbon loss under drought conditions, and changes in the efficiency of decomposition with nitrogen addition. Even when transplanted into the same conditions, microbial communities from different environments remained distinct in composition and functioning for up to one year. Changes in functioning were related to differences in enzyme gene content across different microbial groups. Computational approaches developed for this project allowed the conclusions to be tested more broadly in other ecosystems, and new computer models will facilitate the prediction of microbial traits and functioning across environments. The data and models resulting from this project benefit the public by improving the ability to predict how microbial communities and carbon cycling functions respond to climate change, nutrient enrichment, and other large-scale environmental changes.

The Climate Response to Explosive Volcanism in the Last Millennium Reanalysis

Science.gov (United States)

Emile-Geay, J.; Erb, M. P.; Hakim, G. J.; Anchukaitis, K. J.; Toohey, M.; Steig, E. J.

2017-12-01

Explosive volcanism substantially affects the climate system via the direct effect of radiative forcing anomalies and ensuing influences on, and feedback to, major modes of ocean-atmosphere variability. Eruptions therefore offer unparalleled natural experiments with which to study the climate response to stratospheric aerosol loading. While the instrumental record provides a few, modest examples of such eruptions, the Common Era provides a much larger sample with more dramatic instances [Sigl et al, Nature, 2015]. Here we leverage the Last Millennium Reanalysis (LMR, Hakim et al [JGR-Atm, 2016]), to probe the climate response to explosive volcanism. LMR fuses information from general circulation models and a recent multiproxy compilation [PAGES 2k Consortium, Sci Data, 2017] to depict Common Era climate: surface temperature, 500mb geopotential height, precipitation and drought indices are reconstructed at annual resolution over the past 2,000 years, with error estimates. Using forcing estimates from Toohey & Sigl [ESDD, 2017], the reconstructions shows a 0.2K cooling following the 20 largest eruptions since 750, with maximum impacts over Northern Eurasia and western North America. Comparison to the N-TREND temperature reconstruction [Anchukaitis et al, QSR 2017], which uses a completely independent methodology, shows remarkable agreement in the magnitude and spatial patterns. Surprisingly, reconstructed temperature recovers slowly (10-15y) after major eruptions, a result at odds with conventional wisdom [Robock, Rev. Geophys. 2000] but consistent with modeling results [Pausata et al, PNAS, 2015], and suggestive of an active role for ocean dynamics. Preliminary results show a marginally significant, El Niño-like sea-surface temperature response immediately after the eruption, accompanied by a significant weakening of the Walker circulation and a southward shift of the Intertropical Convergence Zone. A comparison to PMIP3 simulations shows greater magnitudes of

Grassland/atmosphere response to changing climate: Coupling regional and local scales

International Nuclear Information System (INIS)

Coughenour, M.B.; Kittel, T.G.F.; Pielke, R.A.; Eastman, J.

1993-10-01

The objectives of the study were: to evaluate the response of grassland ecosystems to atmospheric change at regional and site scales, and to develop multiscaled modeling systems to relate ecological and atmospheric models with different spatial and temporal resolutions. A menu-driven shell was developed to facilitate use of models at different temporal scales and to facilitate exchange information between models at different temporal scales. A detailed ecosystem model predicted that C 3 temperate grasslands wig respond more strongly to elevated CO 2 than temperate C 4 grasslands in the short-term while a large positive N-PP response was predicted for a C 4 Kenyan grassland. Long-term climate change scenarios produced either decreases or increases in Colorado plant productivity (NPP) depending on rainfall, but uniform increases in N-PP were predicted in Kenya. Elevated CO 2 is likely to have little effect on ecosystem carbon storage in Colorado while it will increase carbon storage in Kenya. A synoptic climate classification processor (SCP) was developed to evaluate results of GCM climate sensitivity experiments. Roughly 80% agreement was achieved with manual classifications. Comparison of lx and 2xCO 2 GCM Simulations revealed relatively small differences

Inter- and intra-specific responses to elevated ozone and chamber climate in northern birches.

Science.gov (United States)

Manninen, S; Huttunen, S; Vanhatalo, M; Pakonen, T; Hämäläinen, A

2009-05-01

We studied the responses of micropropagated, northern provenances of downy, mountain and silver birches to elevated ozone (O(3)) and changing climate using open-top chambers (OTCs). Contrary to our hypothesis, northern birches were sensitive to O(3), i.e. O(3) levels of 31-36 ppb reduced the leaf and root biomasses by -10%, whereas wood biomass was affected to a lesser extent. The warmer and drier OTC climate enhanced growth in general, though there were differences among the species and clones, e.g. in bud burst and biomass production. Inter- and intra-specific responses to O(3) and changing climate relate to traits such as allocation patterns between the above- and belowground parts (i.e. root/shoot ratio), which further relate to nutrient and water economy. Our experiments may have mimicked future conditions quite well, but only long-term field studies can yield the information needed to forecast responses at both tree and ecosystem levels.

Taking the pulse of mountains: Ecosystem responses to climatic variability

Science.gov (United States)

Fagre, Daniel B.; Peterson, David L.; Hessl, Amy E.

2003-01-01

An integrated program of ecosystem modeling and field studies in the mountains of the Pacific Northwest (U.S.A.) has quantified many of the ecological processes affected by climatic variability. Paleoecological and contemporary ecological data in forest ecosystems provided model parameterization and validation at broad spatial and temporal scales for tree growth, tree regeneration and treeline movement. For subalpine tree species, winter precipitation has a strong negative correlation with growth; this relationship is stronger at higher elevations and west-side sites (which have more precipitation). Temperature affects tree growth at some locations with respect to length of growing season (spring) and severity of drought at drier sites (summer). Furthermore, variable but predictable climate-growth relationships across elevation gradients suggest that tree species respond differently to climate at different locations, making a uniform response of these species to future climatic change unlikely. Multi-decadal variability in climate also affects ecosystem processes. Mountain hemlock growth at high-elevation sites is negatively correlated with winter snow depth and positively correlated with the winter Pacific Decadal Oscillation (PDO) index. At low elevations, the reverse is true. Glacier mass balance and fire severity are also linked to PDO. Rapid establishment of trees in subalpine ecosystems during this century is increasing forest cover and reducing meadow cover at many subalpine locations in the western U.S.A. and precipitation (snow depth) is a critical variable regulating conifer expansion. Lastly, modeling potential future ecosystem conditions suggests that increased climatic variability will result in increasing forest fire size and frequency, and reduced net primary productivity in drier, east-side forest ecosystems. As additional empirical data and modeling output become available, we will improve our ability to predict the effects of climatic change

Predicting tree biomass growth in the temperate-boreal ecotone: is tree size, age, competition or climate response most important?

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Foster, Jane R.; Finley, Andrew O.; D'Amato, Anthony W.; Bradford, John B.; Banerjee, Sudipto

2016-01-01

As global temperatures rise, variation in annual climate is also changing, with unknown consequences for forest biomes. Growing forests have the ability to capture atmospheric CO2and thereby slow rising CO2 concentrations. Forests’ ongoing ability to sequester C depends on how tree communities respond to changes in climate variation. Much of what we know about tree and forest response to climate variation comes from tree-ring records. Yet typical tree-ring datasets and models do not capture the diversity of climate responses that exist within and among trees and species. We address this issue using a model that estimates individual tree response to climate variables while accounting for variation in individuals’ size, age, competitive status, and spatially structured latent covariates. Our model allows for inference about variance within and among species. We quantify how variables influence aboveground biomass growth of individual trees from a representative sample of 15 northern or southern tree species growing in a transition zone between boreal and temperate biomes. Individual trees varied in their growth response to fluctuating mean annual temperature and summer moisture stress. The variation among individuals within a species was wider than mean differences among species. The effects of mean temperature and summer moisture stress interacted, such that warm years produced positive responses to summer moisture availability and cool years produced negative responses. As climate models project significant increases in annual temperatures, growth of species likeAcer saccharum, Quercus rubra, and Picea glauca will vary more in response to summer moisture stress than in the past. The magnitude of biomass growth variation in response to annual climate was 92–95% smaller than responses to tree size and age. This means that measuring or predicting the physical structure of current and future forests could tell us more about future C dynamics than growth

Predicting tree biomass growth in the temperate-boreal ecotone: Is tree size, age, competition, or climate response most important?

Science.gov (United States)

Foster, Jane R; Finley, Andrew O; D'Amato, Anthony W; Bradford, John B; Banerjee, Sudipto

2016-06-01

As global temperatures rise, variation in annual climate is also changing, with unknown consequences for forest biomes. Growing forests have the ability to capture atmospheric CO2 and thereby slow rising CO2 concentrations. Forests' ongoing ability to sequester C depends on how tree communities respond to changes in climate variation. Much of what we know about tree and forest response to climate variation comes from tree-ring records. Yet typical tree-ring datasets and models do not capture the diversity of climate responses that exist within and among trees and species. We address this issue using a model that estimates individual tree response to climate variables while accounting for variation in individuals' size, age, competitive status, and spatially structured latent covariates. Our model allows for inference about variance within and among species. We quantify how variables influence aboveground biomass growth of individual trees from a representative sample of 15 northern or southern tree species growing in a transition zone between boreal and temperate biomes. Individual trees varied in their growth response to fluctuating mean annual temperature and summer moisture stress. The variation among individuals within a species was wider than mean differences among species. The effects of mean temperature and summer moisture stress interacted, such that warm years produced positive responses to summer moisture availability and cool years produced negative responses. As climate models project significant increases in annual temperatures, growth of species like Acer saccharum, Quercus rubra, and Picea glauca will vary more in response to summer moisture stress than in the past. The magnitude of biomass growth variation in response to annual climate was 92-95% smaller than responses to tree size and age. This means that measuring or predicting the physical structure of current and future forests could tell us more about future C dynamics than growth responses

Investigations of the Climate System Response to Climate Engineering in a Hierarchy of Models

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McCusker, Kelly E.

Global warming due to anthropogenic emissions of greenhouse gases is causing negative impacts on diverse ecological and human systems around the globe, and these impacts are projected to worsen as climate continues to warm. In the absence of meaningful greenhouse gas emissions reductions, new strategies have been proposed to engineer the climate, with the aim of preventing further warming and avoiding associated climate impacts. We investigate one such strategy here, falling under the umbrella of `solar radiation management', in which sulfate aerosols are injected into the stratosphere. We use a global climate model with a coupled mixed-layer depth ocean and with a fully-coupled ocean general circulation model to simulate the stabilization of climate by balancing increasing carbon dioxide with increasing stratospheric sulfate concentrations. We evaluate whether or not severe climate impacts, such as melting Arctic sea ice, tropical crop failure, or destabilization of the West Antarctic ice sheet, could be avoided. We find that while tropical climate emergencies might be avoided by use of stratospheric aerosol injections, avoiding polar emergencies cannot be guaranteed due to large residual climate changes in those regions, which are in part due to residual atmospheric circulation anomalies. We also find that the inclusion of a fully-coupled ocean is important for determining the regional climate response because of its dynamical feedbacks. The efficacy of stratospheric sulfate aerosol injections, and solar radiation management more generally, depends on its ability to be maintained indefinitely, without interruption from a variety of possible sources, such as technological failure, a breakdown in global cooperation, lack of funding, or negative unintended consequences. We next consider the scenario in which stratospheric sulfate injections are abruptly terminated after a multi- decadal period of implementation while greenhouse gas emissions have continued unabated

Effects of climate change on timber supply and possible management responses

International Nuclear Information System (INIS)

Comeau, P.G.

1991-01-01

Potential effects of climate change on Pacific Northwest forests include increases in net primary production of some high-elevation or high-latitude forests due to temperature increases; reduced net primary production or tree mortality due to increased water stress or failure to meet chilling requirements; and increased risk of damage from insects and fires. The net effects of climate change will vary depending on the species involved, current environmental conditions, and the nature, magnitude, and rate of climate change. Risks are likely to differ substantially for regeneration, young established forests, and mature established forests. Decisions about responses have to be made in the face of considerable uncertainty about future climate, resources, and market conditions. A proactive option involves developing flexible, adaptive approaches to forest management that serve to reduce future risk. Strategic decisions could include decisions about land purchases or sales based on assessments of risk of impact from climate change. Selection of species least vulnerable to potential climate change, increased investment in fire control and pest management in vulnerable areas, and other operational decisions can be made. Timing of actions will be important, and a substantial body of information is required as a basis for making informed decisions, some of which is already available. 8 refs

Business responses to global climate change

Energy Technology Data Exchange (ETDEWEB)

Pinkse, J.M.

2006-04-27

This research project studies the evolution and determinants of corporate climate strategies of multinationals. Since most companies are affected by global climate change in a direct or indirect way, a range of strategies are emerging to mitigate climate change. These strategies are not only of a political nature (e.g. influencing government institutions), but also of a competitive nature. The aim is to introduce a typology of corporate climate strategies, paying specific attention to the market components related to climate change. More and more, multinationals' actions in reducing greenhouse gas emissions are aimed at achieving a sustained competitive advantage in addition to compliance with government regulation. What factors determine these market strategies for climate change will be explored in a theoretical framework based on institutional theory and the resource-based view of the firm.

Araucaria growth response to solar and climate variability in South Brazil

Science.gov (United States)

Prestes, Alan; Klausner, Virginia; Rojahn da Silva, Iuri; Ojeda-González, Arian; Lorensi, Caren

2018-05-01

In this work, the Sun-Earth-climate relationship is studied using tree growth rings of Araucaria angustifolia (Bertol.) O. Kuntze collected in the city of Passo Fundo, located in the state of Rio Grande do Sul (RS), Brazil. These samples were previously studied by Rigozo et al. (2008); however, their main interest was to search for the solar periodicities in the tree-ring width mean time series without interpreting the rest of the periodicities found. The question arises as to what are the drivers related to those periodicities. For this reason, the classical method of spectral analysis by iterative regression and wavelet methods are applied to find periodicities and trends present in each tree-ring growth, in Southern Oscillation Index (SOI), and in annual mean temperature anomaly between the 24 and 44° S. In order to address the aforementioned question, this paper discusses the correlation between the growth rate of the tree rings with temperature and SOI. In each tree-ring growth series, periods between 2 and 7 years were found, possibly related to the El Niño/La Niña phenomena, and a ˜ 23-year period was found, which may be related to temperature variation. These novel results might represent the tree-ring growth response to local climate conditions during its lifetime, and to nonlinear coupling between the Sun and the local climate variability responsible to the regional climate variations.

Tree growth response to climate change at the deciduous-boreal forest ecotone, Ontario, Canada

Energy Technology Data Exchange (ETDEWEB)

Goldblum, D. [Wisconsin-Whitewater Univ., Whitewater, WI (United States). Dept. of Geography and Geology; Rigg, L.S. [Northern Illinois Univ., DeKalb, IL (United States). Dept. of Geography

2005-11-01

Recent interest in the impact that future climate change may have on forest communities can be attributed to the fact that migration of tree species has been slow with respect to past climate changes and also because of the high degree of habitat fragmentation that has occurred in the recent past. For that reason, this study examined the implications of climate change on the future of sugar maple, white spruce and balsam fir. These trees represent the 3 dominant forest species at the deciduous-boreal forest ecotone in Ontario, Canada. The analysis was based on the responses of individual species to past monthly temperature and precipitation conditions as well as simulated monthly temperature and precipitation conditions in the study area for the 2080s. The sensitivity of the tree species to past climate with predicted conditions for the 2080 period was also considered. In particular, tree-ring analysis was used to compare local species-specific growth responses with instrumental climate records since 1900 to determine which climate variables control growth rates of these 3 species. Present temperature and precipitation averages were compared with general circulation model (GCM) predictions of monthly temperature and monthly precipitation to evaluate the potential benefit or harm to the dominant tree species over the next 80 years. It was concluded that sugar maple may persist in the medium term up to several centuries, as existing trees pass through their natural life-span without reproductive replacement. However, with extreme climate change, over many centuries, even the sugar maple at this northern range limit might be in jeopardy. White spruce is likely to benefit less, and the dominant balsam fir is likely to experience a decrease in growth potential. These projected changes would enhance the future status of sugar maple at its northern limit and facilitate range expansion northward in response to global warming. Although the study concerns only a small area

Playing fair: the contribution of high-functioning recess to overall school climate in low-income elementary schools.

Science.gov (United States)

London, Rebecca A; Westrich, Lisa; Stokes-Guinan, Katie; McLaughlin, Milbrey

2015-01-01

Recess is a part of the elementary school day with strong implications for school climate. Positive school climate has been linked to a host of favorable student outcomes, from attendance to achievement. We examine 6 low-income elementary schools' experiences implementing a recess-based program designed to provide safe, healthy, and inclusive play to study how improving recess functioning can affect school climate. Data from teacher, principal, and recess coach interviews; student focus groups; recess observations; and a teacher survey are triangulated to understand the ways that recess changed during implementation. Comparing schools that achieved higher- and lower-functioning recesses, we link recess functioning with school climate. Recess improved in all schools, but 4 of the 6 achieved a higher-functioning recess. In these schools, teachers and principals agreed that by the end of the year, recess offered opportunities for student engagement, conflict resolution, pro-social skill development, and emotional and physical safety. Respondents in these four schools linked these changes to improved overall school climate. Recess is an important part of the school day for contributing to school climate. Creating a positive recess climate helps students to be engaged in meaningful play and return to class ready to learn. © 2014, American School Health Association.

Climatic origins predict variation in photoprotective leaf pigments in response to drought and low temperatures in live oaks (Quercus series Virentes).

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Ramírez-Valiente, Jose A; Koehler, Kari; Cavender-Bares, Jeannine

2015-05-01

Climate is a major selective force in nature. Exploring patterns of inter- and intraspecific genetic variation in functional traits may explain how species have evolved and may continue evolving under future climate change. Photoprotective pigments play an important role in short-term responses to climate stress in plants but knowledge of their long-term role in adaptive processes is lacking. In this study, our goal was to determine how photoprotective mechanisms, morphological traits and their plasticity have evolved in live oaks (Quercus series Virentes) in response to different climatic conditions. For this purpose, seedlings originating from 11 populations from four live oak species (Quercus virginiana, Q. geminata, Q. fusiformis and Q. oleoides) were grown under contrasting common environmental conditions of temperature (tropical vs temperate) and water availability (droughted vs well-watered). Xanthophyll cycle pigments, anthocyanin accumulation, chlorophyll fluorescence parameters and leaf anatomical traits were measured. Seedlings originating from more mesic source populations of Q. oleoides and Q. fusiformis increased the xanthophyll de-epoxidation state under water-limiting conditions and showed higher phenotypic plasticity for this trait, suggesting adaptation to local climate. Likewise, seedlings originating from warmer climates had higher anthocyanin concentration in leaves under cold winter conditions but not higher de-epoxidation state. Overall, our findings suggest that (i) climate has been a key factor in shaping species and population differences in stress tolerance for live oaks, (ii) anthocyanins are used under cold stress in species with limited freezing tolerance and (iii) xanthophyll cycle pigments are used when photoprotection under drought conditions is needed. © The Author 2015. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Farmer’s perception of climate change and responsive strategies in three selected provinces of South Africa

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Zelda A. Elum

2017-01-01

Full Text Available The world has responded to climate change phenomenon through two broad response mechanisms (mitigation and adaptation strategies with the aim of moderating the adverse effects of climate change and/or to exploit any arising beneficial opportunities. The paper aims to examine the trend in climate parameters, farmers’ perception of climate change, constraints faced in production and to identify the strategies (if any that farmers have adopted to cope with the effects of changing climate. A one-way analysis of variance, percentage analysis and Garrett ranking technique were applied to a set of primary data collected from 150 randomly sampled farmers with the aid of questionnaires in three purposively selected provinces through the months of June to August 2015. The analytical results of obtained recent weather data revealed that the climate parameters have significantly changed over time and these were substantiated by farmers’ experiences. The farmers are engaging in various climate-response strategies, among which, the planting of drought-tolerant varieties is most common. Therefore, it is important to enhance farmers’ access to improved drought-tolerant seeds and efficient irrigation systems. Also observed, is that the lack of awareness of insurance products and inability to afford insurance premiums were the principal reasons majority of the farmers did not have insurance. These present a need to strengthen insurance adoption among farmers through various supporting programmes that may include premium subsidies and media outreach. The paper under one platform provides evidence of changing climate, farmers’ responses towards mitigating perceived adverse effects of the changed climate, and South Africa’s national policy on adaptation and mitigation.

'Tales of Symphonia': extinction dynamics in response to past climate change in Madagascan rainforests.

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Virah-Sawmy, Malika; Bonsall, Michael B; Willis, Katherine J

2009-12-23

Madagascar's rainforests are among the most biodiverse in the world. Understanding the population dynamics of important species within these forests in response to past climatic variability provides valuable insight into current and future species composition. Here, we use a population-level approach to analyse palaeoecological records over the last 5300 years to understand how populations of Symphonia cf. verrucosa became locally extinct in some rainforest fragments along the southeast coast of Madagascar in response to rapid climate change, yet persisted in others. Our results indicate that regional (climate) variability contributed to synchronous decline of S. cf. verrucosa populations in these forests. Superimposed on regional fluctuations were local processes that could have contributed or mitigated extinction. Specifically, in the forest with low soil nutrients, population model predictions indicated that there was coexistence between S. cf. verrucosa and Erica spp., but in the nutrient-rich forest, interspecific effects between Symphonia and Erica spp. may have pushed Symphonia to extinction at the peak of climatic change. We also demonstrate that Symphonia is a good indicator of a threshold event, exhibiting erratic fluctuations prior to and long after the critical climatic point has passed.

A cross-sectoral analysis of climate change risk drivers based on companies' responses to the CDP's climate change information request

OpenAIRE

Groth, Markus; Brunsmeier, Annette

2016-01-01

Companies are increasingly concerned with current and future climate change risks that have the potential to generate a substantial change in their business operations, revenue and/or expenditure. Therefore, the paper focusses on the companies' perspective and aims to create a higher awareness of companies' risk drivers when it comes to specific challenges of different sectors as well as each company within its sector. Based on companies' responses to the CDP's climate change information requ...

Variations of Climate-Growth Response of Major Conifers at Upper Distributional Limits in Shika Snow Mountain, Northwestern Yunnan Plateau, China

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Yun Zhang

2017-10-01

Full Text Available Improved understanding of climate-growth relationships of multiple species is fundamental to understanding and predicting the response of forest growth to future climate change. Forests are mainly composed of conifers in Northwestern Yunnan Plateau, but variations of growth response to climate conditions among the species are not well understood. To detect the growth response of multiple species to climate change, we developed residual chronologies of four major conifers, i.e., George’s fir (Abies georgei Orr, Likiang spruce (Picea likiangensis (Franch. E.Pritz., Gaoshan pine (Pinus densata Mast. and Chinese larch (Larix potaninii Batalin at the upper distributional limits in Shika Snow Mountain. Using the dendroclimatology method, we analyzed correlations between the residual chronologies and climate variables. The results showed that conifer radial growth was influenced by both temperature and precipitation in Shika Snow Mountain. Previous November temperature, previous July temperature, and current May precipitation were the common climatic factors that had consistent influences on radial growth of the four species. Temperature in the previous post-growing season (September–October and moisture conditions in the current growing season (June–August were the common climatic factors that had divergent impacts on the radial growth of the four species. Based on the predictions of climate models and our understanding of the growth response of four species to climate variables, we may understand the growth response to climate change at the species level. It is difficult to predict future forest growth in the study area, since future climate change might cause both increases and decreases for the four species and indirect effects of climate change on forests should be considered.

A case study of teaching social responsibility to doctoral students in the climate sciences.

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Børsen, Tom; Antia, Avan N; Glessmer, Mirjam Sophia

2013-12-01

The need to make young scientists aware of their social responsibilities is widely acknowledged, although the question of how to actually do it has so far gained limited attention. A 2-day workshop entitled "Prepared for social responsibility?" attended by doctoral students from multiple disciplines in climate science, was targeted at the perceived needs of the participants and employed a format that took them through three stages of ethics education: sensitization, information and empowerment. The workshop aimed at preparing doctoral students to manage ethical dilemmas that emerge when climate science meets the public sphere (e.g., to identify and balance legitimate perspectives on particular types of geo-engineering), and is an example of how to include social responsibility in doctoral education. The paper describes the workshop from the three different perspectives of the authors: the course teacher, the head of the graduate school, and a graduate student. The elements that contributed to the success of the workshop, and thus make it an example to follow, are (1) the involvement of participating students, (2) the introduction of external expertise and role models in climate science, and (3) a workshop design that focused on ethical analyses of examples from the climate sciences.

Multiple phenological responses to climate change among 42 plant species in Xi'an, China.

Science.gov (United States)

Dai, Junhu; Wang, Huanjiong; Ge, Quansheng

2013-09-01

Phenological data of 42 woody plants in a temperate deciduous forest from the Chinese Phenological Observation Network (CPON) and the corresponding meteorological data from 1963 to 2011 in Xi'an, Shaanxi Province, China were collected and analyzed. The first leaf date (FLD), leaf coloring date (LCD) and first flower date (FFD) are revealed as strong biological signals of climatic change. The FLD, LCD and FFD of most species are sensitive to average temperature during a certain period before phenophase onset. Regional precipitation also has a significant impact on phenophases of about half of the species investigated. Affected by climate change, the FLD and FFD of these species have advanced by 5.54 days and 10.20 days on average during 2003-2011 compared with the period 1963-1996, respectively. Meanwhile, the LCD has delayed by 10.59 days, and growing season length has extended 16.13 days. Diverse responses of phenology commonly exist among different species and functional groups during the study period. Especially for FFD, the deviations between the above two periods ranged from -20.68 to -2.79 days; biotic pollination species showed a significantly greater advance than abiotic pollination species. These results were conducive to the understanding of possible changes in both the structure of plant communities and interspecific relationships in the context of climate change.

Nile Basin Vegetation Response and Vulnerability to Climate Change: A Multi-Sensor Remote Sensing Approach

Science.gov (United States)

Yitayew, M.; Didan, K.; Barreto-munoz, A.

2013-12-01

The Nile Basin is one of the world's water resources hotspot that is home to over 437 million people in ten riparian countries with 54% or 238 millions live directly within the basin. The basin like all other basins of the world is facing water resources challenges exacerbated by climate change and increased demand. Nowadays any water resource management action in the basin has to assess the impacts of climate change to be able to predict future water supply and also to help in the negotiation process. Presently, there is a lack of basin wide weather networks to understand sensitivity of the vegetation cover to the impacts of climate change. Vegetation plays major economic and ecological functions in the basin and provides key services ranging from pastoralism, agricultural production, firewood, habitat and food sources for the rich wildlife, as well as a major role in the carbon cycle and climate regulation of the region. Under the threat of climate change and the incessant anthropogenic pressure the distribution and services of the region's ecosystems are projected to change The goal of this work is to assess and characterize how the basin vegetation productivity, distribution, and phenology have changed over the last 30+ years and what are the key climatic drivers of this change. This work makes use of a newly generated multi-sensor long-term land surface data set about vegetation and phenology. Vegetation indices derived from remotely sensed surface reflectance data are commonly used to characterize phenology or vegetation dynamics accurately and with enough spatial and temporal resolution to support change detection. We used more than 30 years of vegetation index and growing season data from AVHRR and MODIS sensors compiled by the Vegetation Index and Phenology laboratory (VIP LAB) at the University of Arizona. Available climate data about precipitation and temperature for the corresponding 30 years period is also used for this analysis. We looked at the

Forest Owners' Response to Climate Change: University Education Trumps Value Profile.

Science.gov (United States)

Blennow, Kristina; Persson, Johannes; Persson, Erik; Hanewinkel, Marc

2016-01-01

Do forest owners' levels of education or value profiles explain their responses to climate change? The cultural cognition thesis (CCT) has cast serious doubt on the familiar and often criticized "knowledge deficit" model, which says that laypeople are less concerned about climate change because they lack scientific knowledge. Advocates of CCT maintain that citizens with the highest degrees of scientific literacy and numeracy are not the most concerned about climate change. Rather, this is the group in which cultural polarization is greatest, and thus individuals with more limited scientific literacy and numeracy are more concerned about climate change under certain circumstances than those with higher scientific literacy and numeracy. The CCT predicts that cultural and other values will trump the positive effects of education on some forest owners' attitudes to climate change. Here, using survey data collected in 2010 from 766 private forest owners in Sweden and Germany, we provide the first evidence that perceptions of climate change risk are uncorrelated with, or sometimes positively correlated with, education level and can be explained without reference to cultural or other values. We conclude that the recent claim that advanced scientific literacy and numeracy polarizes perceptions of climate change risk is unsupported by the forest owner data. In neither of the two countries was university education found to reduce the perception of risk from climate change. Indeed in most cases university education increased the perception of risk. Even more importantly, the effect of university education was not dependent on the individuals' value profile.

Forest Owners' Response to Climate Change: University Education Trumps Value Profile.

Directory of Open Access Journals (Sweden)

Kristina Blennow

Full Text Available Do forest owners' levels of education or value profiles explain their responses to climate change? The cultural cognition thesis (CCT has cast serious doubt on the familiar and often criticized "knowledge deficit" model, which says that laypeople are less concerned about climate change because they lack scientific knowledge. Advocates of CCT maintain that citizens with the highest degrees of scientific literacy and numeracy are not the most concerned about climate change. Rather, this is the group in which cultural polarization is greatest, and thus individuals with more limited scientific literacy and numeracy are more concerned about climate change under certain circumstances than those with higher scientific literacy and numeracy. The CCT predicts that cultural and other values will trump the positive effects of education on some forest owners' attitudes to climate change. Here, using survey data collected in 2010 from 766 private forest owners in Sweden and Germany, we provide the first evidence that perceptions of climate change risk are uncorrelated with, or sometimes positively correlated with, education level and can be explained without reference to cultural or other values. We conclude that the recent claim that advanced scientific literacy and numeracy polarizes perceptions of climate change risk is unsupported by the forest owner data. In neither of the two countries was university education found to reduce the perception of risk from climate change. Indeed in most cases university education increased the perception of risk. Even more importantly, the effect of university education was not dependent on the individuals' value profile.

US forest response to projected climate-related stress: a tolerance perspective.

Science.gov (United States)

Liénard, Jean; Harrison, John; Strigul, Nikolay

2016-08-01

Although it is widely recognized that climate change will require a major spatial reorganization of forests, our ability to predict exactly how and where forest characteristics and distributions will change has been rather limited. Current efforts to predict future distribution of forested ecosystems as a function of climate include species distribution models (for fine-scale predictions) and potential vegetation climate envelope models (for coarse-grained, large-scale predictions). Here, we develop and apply an intermediate approach wherein we use stand-level tolerances of environmental stressors to understand forest distributions and vulnerabilities to anticipated climate change. In contrast to other existing models, this approach can be applied at a continental scale while maintaining a direct link to ecologically relevant, climate-related stressors. We first demonstrate that shade, drought, and waterlogging tolerances of forest stands are strongly correlated with climate and edaphic conditions in the conterminous United States. This discovery allows the development of a tolerance distribution model (TDM), a novel quantitative tool to assess landscape level impacts of climate change. We then focus on evaluating the implications of the drought TDM. Using an ensemble of 17 climate change models to drive this TDM, we estimate that 18% of US ecosystems are vulnerable to drought-related stress over the coming century. Vulnerable areas include mostly the Midwest United States and Northeast United States, as well as high-elevation areas of the Rocky Mountains. We also infer stress incurred by shifting climate should create an opening for the establishment of forest types not currently seen in the conterminous United States. © 2016 John Wiley & Sons Ltd.

Global response to solar radiation absorbed by phytoplankton in a coupled climate model

Energy Technology Data Exchange (ETDEWEB)

Patara, Lavinia [Centro Euro-Mediterraneo per i Cambiamenti Climatici (CMCC), Bologna (Italy); Helmholtz Centre for Ocean Research Kiel (GEOMAR), Kiel (Germany); Vichi, Marcello; Masina, Simona [Centro Euro-Mediterraneo per i Cambiamenti Climatici (CMCC), Bologna (Italy); Istituto Nazionale di Geofisica e Vulcanologia (INGV), Centro Euro-Mediterraneo per i Cambiamenti Climatici (CMCC), Bologna (Italy); Fogli, Pier Giuseppe [Centro Euro-Mediterraneo per i Cambiamenti Climatici (CMCC), Bologna (Italy); Manzini, Elisa [Centro Euro-Mediterraneo per i Cambiamenti Climatici (CMCC), Bologna (Italy); Max-Planck-Institut fuer Meteorologie, Hamburg (Germany)

2012-10-15

The global climate response to solar radiation absorbed by phytoplankton is investigated by performing multi-century simulations with a coupled ocean-atmosphere-biogeochemistry model. The absorption of solar radiation by phytoplankton increases radiative heating in the near-surface ocean and raises sea surface temperature (SST) by overall {approx}0.5 C. The resulting increase in evaporation enhances specific atmospheric humidity by 2-5%, thereby increasing the Earth's greenhouse effect and the atmospheric temperatures. The Hadley Cell exhibits a weakening and poleward expansion, therefore reducing cloudiness at subtropical-middle latitudes and increasing it at tropical latitudes except near the Equator. Higher SST at polar latitudes reduces sea ice cover and albedo, thereby increasing the high-latitude ocean absorption of solar radiation. Changes in the atmospheric baroclinicity cause a poleward intensification of mid-latitude westerly winds in both hemispheres. As a result, the North Atlantic Ocean meridional overturning circulation extends more northward, and the equatorward Ekman transport is enhanced in the Southern Ocean. The combination of local and dynamical processes decreases upper-ocean heat content in the Tropics and in the subpolar Southern Ocean, and increases it at middle latitudes. This study highlights the relevance of coupled ocean-atmosphere processes in the global climate response to phytoplankton solar absorption. Given that simulated impacts of phytoplankton on physical climate are within the range of natural climate variability, this study suggests the importance of phytoplankton as an internal constituent of the Earth's climate and its potential role in participating in its long-term climate adjustments. (orig.)

Global response to solar radiation absorbed by phytoplankton in a coupled climate model

International Nuclear Information System (INIS)

Patara, Lavinia; Vichi, Marcello; Masina, Simona; Fogli, Pier Giuseppe; Manzini, Elisa

2012-01-01

The global climate response to solar radiation absorbed by phytoplankton is investigated by performing multi-century simulations with a coupled ocean-atmosphere-biogeochemistry model. The absorption of solar radiation by phytoplankton increases radiative heating in the near-surface ocean and raises sea surface temperature (SST) by overall ∼0.5 C. The resulting increase in evaporation enhances specific atmospheric humidity by 2-5%, thereby increasing the Earth's greenhouse effect and the atmospheric temperatures. The Hadley Cell exhibits a weakening and poleward expansion, therefore reducing cloudiness at subtropical-middle latitudes and increasing it at tropical latitudes except near the Equator. Higher SST at polar latitudes reduces sea ice cover and albedo, thereby increasing the high-latitude ocean absorption of solar radiation. Changes in the atmospheric baroclinicity cause a poleward intensification of mid-latitude westerly winds in both hemispheres. As a result, the North Atlantic Ocean meridional overturning circulation extends more northward, and the equatorward Ekman transport is enhanced in the Southern Ocean. The combination of local and dynamical processes decreases upper-ocean heat content in the Tropics and in the subpolar Southern Ocean, and increases it at middle latitudes. This study highlights the relevance of coupled ocean-atmosphere processes in the global climate response to phytoplankton solar absorption. Given that simulated impacts of phytoplankton on physical climate are within the range of natural climate variability, this study suggests the importance of phytoplankton as an internal constituent of the Earth's climate and its potential role in participating in its long-term climate adjustments. (orig.)

The Response of Tree-Ring Growth to Climate at Upper Timberline of Southern Aspect of Mt. Taibai

Directory of Open Access Journals (Sweden)

Qin Jin

2016-01-01

Full Text Available In recent years, the impact of climate change on vegetation in Qinling mountainous area has already been authenticated by numerous investigations, nevertheless, as the major ridge of Qinling Mountains as well as national natural conservation reserve, the ecology response of Mt. Taibai sub-alpine vegetation to climate change has not yet gained enough public attention.In this study, in accordance with the method of dendrochronology, response analysis was carried out to contrast characteristic parameters of tree-ring width chronologies for Larix chinensis from different elevations as well as their response pattern to climate change. The result showed that, Mean sensitivity, standard deviation and variance in first eigenvector are increasing with the rise of elevation, but the correlation coefficients (R1, R2, R3 were decreasing which indicated that the strength of the tree’s common or relative response to environment was decreasing with altitude. Precipitation had stronger correlation with the tree-ring radial growth than air temperature in both of the sites, during the growing season, trees in lower altitude had better correlation with temperature than in higher altitude, thus showing the different response to climate between the two different sites.

Trends in global vegetation activity and climatic drivers indicate a decoupled response to climate change

DEFF Research Database (Denmark)

Schut, Antonius G T; Ivits, Eva; Conijn, Jacob G.

2015-01-01

Detailed understanding of a possible decoupling between climatic drivers of plant productivity and the response of ecosystems vegetation is required. We compared trends in six NDVI metrics (1982-2010) derived from the GIMMS3g dataset with modelled biomass productivity and assessed uncertainty...... in trend estimates. Annual total biomass weight (TBW) was calculated with the LINPAC model. Trends were determined using a simple linear regression, a Thiel-Sen medium slope and a piecewise regression (PWR) with two segments. Values of NDVI metrics were related to Net Primary Production (MODIS......-NPP) and TBWper biome and land-use type. The simple linear and Thiel-Sen trends did not differ much whereas PWR increased the fraction of explained variation, depending on the NDVI metric considered. A positive trend in TBW indicating more favorable climatic conditions was found for 24% of pixels on land...

A meta-analysis of soil exoenzyme responses to simulated climate change

Science.gov (United States)

Gebhardt, M.; Espinosa, N. J.; Blankinship, J. C.; Gallery, R. E.

2017-12-01

Microorganisms produce extracellular enzymes to decompose plant matter and drive biogeochemical transformations in soils. Climate change factors, such as warming and altered precipitation patterns, can impact enzyme activity through both direct and indirect mechanisms. Although many individual studies have examined how soil exoenzyme activities respond to climate change manipulations, there is disagreement surrounding the direction of these responses. We performed a synthesis of published studies to examine the influence of warming and altered precipitation on microbial exoenzyme activity. We found that warming increased enzyme activity with a more pronounced effect for oxidative relative to hydrolytic enzymes. Reduced precipitation consistently decreased exoenzyme activity. These responses, however, varied by season, biome, and enzyme type. The majority of studies fitting our criteria (e.g., experiments lasting a minimum of one growing season, paired treatments and controls) were located in North America and Europe. Inferences from this analysis therefore exclude many important ecosystems such as hyper-arid, wetlands, and artic systems. Carbon degrading enzyme activities were less sensitive to climate change manipulations when compared to phosphorus and nitrogen degrading enzyme activities. Linking enzyme activity to biogeochemical processes requires concomitant measurements of organic and inorganic carbon pools, mineralogy, nutrients, microbial biomass and community structure, and heterotrophic respiration within individual studies. Furthermore, linking these parameters to climate and environmental factors will require a comprehensive and consistent inclusion of biotic and abiotic variables among researchers and experiments. Globally, soils contain the largest carbon pools. Understanding the impacts of large-scale perturbations on soil enzyme activity will help to constrain predictions on the fate of biogeochemical transformations and improve model projections.

Phenological response of an Arizona dryland forest to short-term climatic extremes

Science.gov (United States)

Walker, Jessica; de Beurs, Kirsten; Wynne, Randolph

2015-01-01

Baseline information about dryland forest phenology is necessary to accurately anticipate future ecosystem shifts. The overarching goal of our study was to investigate the variability of vegetation phenology across a dryland forest landscape in response to climate alterations. We analyzed the influence of site characteristics and climatic conditions on the phenological patterns of an Arizona, USA, ponderosa pine (Pinus ponderosa) forest during a five-year period (2005 to 2009) that encompassed extreme wet and dry precipitation regimes. We assembled 80 synthetic Landsat images by applying the spatial and temporal adaptive reflectance fusion method (STARFM) to 500 m MODIS and 30 m Landsat-5 Thematic Mapper (TM) data. We tested relationships between site characteristics and the timing of peak Normalized Difference Vegetation Index (NDVI) to assess the effect of climatic stress on the green-up of individual pixels during or after the summer monsoon. Our results show that drought-induced stress led to a fragmented phenological response that was highly dependent on microsite parameters, as both the spatial autocorrelation of peak timing and the number of significant site variables increased during the drought year. Pixels at lower elevations and with higher proportions of herbaceous vegetation were more likely to exhibit dynamic responses to changes in precipitation conditions. Our study demonstrates the complexity of responses within dryland forest ecosystems and highlights the need for standardized monitoring of phenology trends in these areas. The spatial and temporal variability of phenological signals may provide a quantitative solution to the problem of how to evaluate dryland land surface trends across time.

Phenological Response of an Arizona Dryland Forest to Short-Term Climatic Extremes

Directory of Open Access Journals (Sweden)

Jessica Walker

2015-08-01

Full Text Available Baseline information about dryland forest phenology is necessary to accurately anticipate future ecosystem shifts. The overarching goal of our study was to investigate the variability of vegetation phenology across a dryland forest landscape in response to climate alterations. We analyzed the influence of site characteristics and climatic conditions on the phenological patterns of an Arizona, USA, ponderosa pine (Pinus ponderosa forest during a five-year period (2005 to 2009 that encompassed extreme wet and dry precipitation regimes. We assembled 80 synthetic Landsat images by applying the spatial and temporal adaptive reflectance fusion method (STARFM to 500 m MODIS and 30 m Landsat-5 Thematic Mapper (TM data. We tested relationships between site characteristics and the timing of peak Normalized Difference Vegetation Index (NDVI to assess the effect of climatic stress on the green-up of individual pixels during or after the summer monsoon. Our results show that drought-induced stress led to a fragmented phenological response that was highly dependent on microsite parameters, as both the spatial autocorrelation of peak timing and the number of significant site variables increased during the drought year. Pixels at lower elevations and with higher proportions of herbaceous vegetation were more likely to exhibit dynamic responses to changes in precipitation conditions. Our study demonstrates the complexity of responses within dryland forest ecosystems and highlights the need for standardized monitoring of phenology trends in these areas. The spatial and temporal variability of phenological signals may provide a quantitative solution to the problem of how to evaluate dryland land surface trends across time.

Shorebird Migration Patterns in Response to Climate Change: A Modeling Approach

Science.gov (United States)

Smith, James A.

2010-01-01

The availability of satellite remote sensing observations at multiple spatial and temporal scales, coupled with advances in climate modeling and information technologies offer new opportunities for the application of mechanistic models to predict how continental scale bird migration patterns may change in response to environmental change. In earlier studies, we explored the phenotypic plasticity of a migratory population of Pectoral sandpipers by simulating the movement patterns of an ensemble of 10,000 individual birds in response to changes in stopover locations as an indicator of the impacts of wetland loss and inter-annual variability on the fitness of migratory shorebirds. We used an individual based, biophysical migration model, driven by remotely sensed land surface data, climate data, and biological field data. Mean stop-over durations and stop-over frequency with latitude predicted from our model for nominal cases were consistent with results reported in the literature and available field data. In this study, we take advantage of new computing capabilities enabled by recent GP-GPU computing paradigms and commodity hardware (general purchase computing on graphics processing units). Several aspects of our individual based (agent modeling) approach lend themselves well to GP-GPU computing. We have been able to allocate compute-intensive tasks to the graphics processing units, and now simulate ensembles of 400,000 birds at varying spatial resolutions along the central North American flyway. We are incorporating additional, species specific, mechanistic processes to better reflect the processes underlying bird phenotypic plasticity responses to different climate change scenarios in the central U.S.

Engaging Storm Spotters and Community College Students in Regional Responses to Climate Change

Science.gov (United States)

Mooney, M. E.; Ackerman, S. A.; Buhr, S. M.

2012-12-01

Resiliency to natural hazards includes climate literacy. With a record number of billion dollar weather disasters in 2011, each one enhanced by a warmer atmosphere, our nation needs new strategies to respond, mitigate, communicate and adapt to the impacts of climate change. We know that actions we take today matter, but finding ways to mobilize our citizenry remains largely elusive. One way to galvanize a meaningful response to climate change could involve National Weather Service (NWS) storm spotters and Community College students. Dedicated storm spotters represent decades of NOAA NWS efforts to engage and enlist public participation in community safety. Why not leverage this wealth of human capital to cultivate a similar mitigation and stewardship response? The Cooperative Institute for Meteorological Satellite Studies (CIMSS) at the University of Wisconsin-Madison conducted a pilot project with NWS storm spotters in the spring of 2011 via a web seminar on climate change, climate mitigation and emerging applications to access weather and climate data with mobile devices. Nineteen storm spotters participated and eleven provided feedback via a follow-up survey. A third of the respondents indicated that they had taken actions to minimize their carbon footprint; a majority (90%) indicated their likelihood to take action in the near future and more than two-thirds said they wanted to learn more about climate mitigation and sustainability. One attendee commented "Thank-you for putting together this web seminar. As a weather spotter, I found the information helpful, even humbling, to know climate change is already happening." CIMSS is also collaborating with the Cooperative Institute for Research in Environmental Sciences (CIRES) and Madison Area Technical College (MATC) on a climate education project where community college students take an on-line climate change course followed by the opportunity to apply for a summer internship. Through this program, two students

The amenity value of the climate. The household production function approach

International Nuclear Information System (INIS)

Maddison, David

2003-01-01

A basic assumption of the hedonic technique is that there are no barriers to mobility that prevent prices changing to reflect the net benefits of a given location. But climate variables are undeviating over relatively large distances and the absence of a common language coupled with the existence of political boundaries may prevent the net advantages associated with a particular region from being eliminated. Apart from in a handful of countries, methods alternative to the hedonic approach may therefore be required to estimate the amenity value of climate. Adopting the household production function approach this paper undertakes a systematic examination of the role played by climate in determining consumption patters using data from 88 different countries. Given certain assumptions the paper then proceeds to calculate the constant utility change in the cost of living for a 2.5C increase in globally averaged mean temperature. It is determined that high latitude countries benefit from limited climate change whereas low latitude countries suffer significant losses

Responses of alpine grassland on Qinghai–Tibetan plateau to climate warming and permafrost degradation: a modeling perspective

International Nuclear Information System (INIS)

Yi, Shuhua; Wang, Xiaoyun; Qin, Yu; Ding, Yongjian; Xiang, Bo

2014-01-01

Permafrost plays a critical role in soil hydrology. Thus, the degradation of permafrost under warming climate conditions may affect the alpine grassland ecosystem on the Qinghai–Tibetan Plateau. Previous space-for-time studies using plot and basin scales have reached contradictory conclusions. In this study, we applied a process-based ecosystem model (DOS-TEM) with a state-of-the-art permafrost hydrology scheme to examine this issue. Our results showed that 1) the DOS-TEM model could properly simulate the responses of soil thermal and hydrological dynamics and of ecosystem dynamics to climate warming and spatial differences in precipitation; 2) the simulated results were consistent with plot-scale studies showing that warming caused an increase in maximum unfrozen thickness, a reduction in vegetation and soil carbon pools as a whole, and decreases in soil water content, net primary production, and heterotrophic respiration; and 3) the simulated results were also consistent with basin-scale studies showing that the ecosystem responses to warming were different in regions with different combinations of water and energy constraints. Permafrost prevents water from draining into water reservoirs. However, the degradation of permafrost in response to warming is a long-term process that also enhances evapotranspiration. Thus, the degradation of the alpine grassland ecosystem on the Qinghai–Tibetan Plateau (releasing carbon) cannot be mainly attributed to the disappearing waterproofing function of permafrost. (letter)

Water yield responses to climate change and variability across the North–South Transect of Eastern China (NSTEC)

Science.gov (United States)

Nan Lu; Ge Sun; Xiaoming Feng; Bojie Fu

2013-01-01

China is facing a growing water crisis due to climate and land use change, and rise in human water demand across this rapidly developing country. Understanding the spatial and temporal ecohydrologic responses to climate change is critical to sustainable water resource management. We investigated water yield (WY) responses to historical (1981–2000) and projected...

Predicting ecological responses in a changing ocean: the effects of future climate uncertainty.

Science.gov (United States)

Freer, Jennifer J; Partridge, Julian C; Tarling, Geraint A; Collins, Martin A; Genner, Martin J

2018-01-01

Predicting how species will respond to climate change is a growing field in marine ecology, yet knowledge of how to incorporate the uncertainty from future climate data into these predictions remains a significant challenge. To help overcome it, this review separates climate uncertainty into its three components (scenario uncertainty, model uncertainty, and internal model variability) and identifies four criteria that constitute a thorough interpretation of an ecological response to climate change in relation to these parts (awareness, access, incorporation, communication). Through a literature review, the extent to which the marine ecology community has addressed these criteria in their predictions was assessed. Despite a high awareness of climate uncertainty, articles favoured the most severe emission scenario, and only a subset of climate models were used as input into ecological analyses. In the case of sea surface temperature, these models can have projections unrepresentative against a larger ensemble mean. Moreover, 91% of studies failed to incorporate the internal variability of a climate model into results. We explored the influence that the choice of emission scenario, climate model, and model realisation can have when predicting the future distribution of the pelagic fish, Electrona antarctica . Future distributions were highly influenced by the choice of climate model, and in some cases, internal variability was important in determining the direction and severity of the distribution change. Increased clarity and availability of processed climate data would facilitate more comprehensive explorations of climate uncertainty, and increase in the quality and standard of marine prediction studies.

An Analysis of the Relationship Between Organizational Climate and the Performance of Counselor Functions.

Science.gov (United States)

Cottingham, Harold F.; And Others

The study was designed to determine if a significant relationship existed between the organizational climate of the high school and the functions counselors performed in nine selected high schools in Pinellas County, Florida. Two instruments were used: (1) The Organizational Climate Description Questionnaire (OCDQ) dealing with eight…

Global mortality consequences of climate change accounting for adaptation costs and benefits

Science.gov (United States)

Rising, J. A.; Jina, A.; Carleton, T.; Hsiang, S. M.; Greenstone, M.

2017-12-01

Empirically-based and plausibly causal estimates of the damages of climate change are greatly needed to inform rapidly developing global and local climate policies. To accurately reflect the costs of climate change, it is essential to estimate how much populations will adapt to a changing climate, yet adaptation remains one of the least understood aspects of social responses to climate. In this paper, we develop and implement a novel methodology to estimate climate impacts on mortality rates. We assemble comprehensive sub-national panel data in 41 countries that account for 56% of the world's population, and combine them with high resolution daily climate data to flexibly estimate the causal effect of temperature on mortality. We find the impacts of temperature on mortality have a U-shaped response; both hot days and cold days cause excess mortality. However, this average response obscures substantial heterogeneity, as populations are differentially adapted to extreme temperatures. Our empirical model allows us to extrapolate response functions across the entire globe, as well as across time, using a range of economic, population, and climate change scenarios. We also develop a methodology to capture not only the benefits of adaptation, but also its costs. We combine these innovations to produce the first causal, micro-founded, global, empirically-derived climate damage function for human health. We project that by 2100, business-as-usual climate change is likely to incur mortality-only costs that amount to approximately 5% of global GDP for 5°C degrees of warming above pre-industrial levels. On average across model runs, we estimate that the upper bound on adaptation costs amounts to 55% of the total damages.

Consistency and discrepancy in the atmospheric response to Arctic sea-ice loss across climate models

Science.gov (United States)

Screen, James A.; Deser, Clara; Smith, Doug M.; Zhang, Xiangdong; Blackport, Russell; Kushner, Paul J.; Oudar, Thomas; McCusker, Kelly E.; Sun, Lantao

2018-03-01

The decline of Arctic sea ice is an integral part of anthropogenic climate change. Sea-ice loss is already having a significant impact on Arctic communities and ecosystems. Its role as a cause of climate changes outside of the Arctic has also attracted much scientific interest. Evidence is mounting that Arctic sea-ice loss can affect weather and climate throughout the Northern Hemisphere. The remote impacts of Arctic sea-ice loss can only be properly represented using models that simulate interactions among the ocean, sea ice, land and atmosphere. A synthesis of six such experiments with different models shows consistent hemispheric-wide atmospheric warming, strongest in the mid-to-high-latitude lower troposphere; an intensification of the wintertime Aleutian Low and, in most cases, the Siberian High; a weakening of the Icelandic Low; and a reduction in strength and southward shift of the mid-latitude westerly winds in winter. The atmospheric circulation response seems to be sensitive to the magnitude and geographic pattern of sea-ice loss and, in some cases, to the background climate state. However, it is unclear whether current-generation climate models respond too weakly to sea-ice change. We advocate for coordinated experiments that use different models and observational constraints to quantify the climate response to Arctic sea-ice loss.

Mapping long-term wetland response to climate

Science.gov (United States)

Zhou, Q.; Gallant, A.; Rover, J.

2016-12-01

Wetlands provide unique feeding and breeding habitat for numerous waterfowl species. The distribution of wetlands has been considerably changed due to agricultural land conversion and hydrologic modification. Climate change may further impact wetlands through altered moisture regimes. This study characterized long-term variation in wetland conditions by using dense time series from all available Landsat data from 1985 to 2014. We extracted harmonic frequencies from 30 years to two years to delineate the long-term variation in all seven Landsat bands. A cluster analysis and unsupervised classification then enabled us to map different classes of wetland response. We demonstrated the method in the Prairie Pothole Region in North Dakota.

Invasive species unchecked by climate - response

DEFF Research Database (Denmark)

Burrows, Michael T.; Schoeman, David S.; Duarte, Carlos M.

2012-01-01

environments. This may be particularly true in the world's boreal oceans as melting sea ice facilitates new migratory passages between the Atlantic and Pacific Oceans. Moreover, as the ebb and flow of biodiversity intensifies under anthropogenic climate change, novel climates and communities of species......Hulme points out that observed rates of range expansion by invasive alien species are higher than the median speed of isotherm movement over the past 50 years, which in turn has outpaced the rates of climate-associated range changes of marine and terrestrial species. This is not surprising, given...... of climate-change-induced range shifts between native and alien species are meaningful only after the initial invasive spread has reached a stable range boundary. A focus on regions with high velocities of climate change, and on regions such as the tropics where novel thermal niches are being created, should...

Semiarid watershed response in central New Mexico and its sensitivity to climate variability and change

Directory of Open Access Journals (Sweden)

E. R. Vivoni

2009-06-01

Full Text Available Hydrologic processes in the semiarid regions of the Southwest United States are considered to be highly susceptible to variations in temperature and precipitation characteristics due to the effects of climate change. Relatively little is known about the potential impacts of climate change on the basin hydrologic response, namely streamflow, evapotranspiration and recharge, in the region. In this study, we present the development and application of a continuous, semi-distributed watershed model for climate change studies in semiarid basins of the Southwest US. Our objective is to capture hydrologic processes in large watersheds, while accounting for the spatial and temporal variations of climate forcing and basin properties in a simple fashion. We apply the model to the Río Salado basin in central New Mexico since it exhibits both a winter and summer precipitation regime and has a historical streamflow record for model testing purposes. Subsequently, we use a sequence of climate change scenarios that capture observed trends for winter and summer precipitation, as well as their interaction with higher temperatures, to perform long-term ensemble simulations of the basin response. Results of the modeling exercise indicate that precipitation uncertainty is amplified in the hydrologic response, in particular for processes that depend on a soil saturation threshold. We obtained substantially different hydrologic sensitivities for winter and summer precipitation ensembles, indicating a greater sensitivity to more intense summer storms as compared to more frequent winter events. In addition, the impact of changes in precipitation characteristics overwhelmed the effects of increased temperature in the study basin. Nevertheless, combined trends in precipitation and temperature yield a more sensitive hydrologic response throughout the year.

Educational climate seems unrelated to leadership skills of clinical consultants responsible of postgraduate medical education in clinical departments

DEFF Research Database (Denmark)

Malling, Bente Vigh; Mortensen, Lene S.; Scherpbier, Albert J J

2010-01-01

The educational climate is crucial in postgraduate medical education. Although leaders are in the position to influence the educational climate, the relationship between leadership skills and educational climate is unknown. This study investigates the relationship between the educational climate...... in clinical departments and the leadership skills of clinical consultants responsible for education....

Health-sector responses to address the impacts of climate change in Nepal.

Science.gov (United States)

Dhimal, Meghnath; Dhimal, Mandira Lamichhane; Pote-Shrestha, Raja Ram; Groneberg, David A; Kuch, Ulrich

2017-09-01

Nepal is highly vulnerable to global climate change, despite its negligible emission of global greenhouse gases. The vulnerable climate-sensitive sectors identified in Nepal's National Adaptation Programme of Action (NAPA) to Climate Change 2010 include agriculture, forestry, water, energy, public health, urbanization and infrastructure, and climate-induced disasters. In addition, analyses carried out as part of the NAPA process have indicated that the impacts of climate change in Nepal are not gender neutral. Vector-borne diseases, diarrhoeal diseases including cholera, malnutrition, cardiorespiratory diseases, psychological stress, and health effects and injuries related to extreme weather are major climate-sensitive health risks in the country. In recent years, research has been done in Nepal in order to understand the changing epidemiology of diseases and generate evidence for decision-making. Based on this evidence, the experience of programme managers, and regular surveillance data, the Government of Nepal has mainstreamed issues related to climate change in development plans, policies and programmes. In particular, the Government of Nepal has addressed climate-sensitive health risks. In addition to the NAPA report, several policy documents have been launched, including the Climate Change Policy 2011; the Nepal Health Sector Programme - Implementation Plan II (NHSP-IP 2) 2010-2015; the National Health Policy 2014; the National Health Sector Strategy 2015-2020 and its implementation plan (2016-2021); and the Health National Adaptation Plan (H-NAP): climate change and health strategy and action plan (2016-2020). However, the translation of these policies and plans of action into tangible action on the ground is still in its infancy in Nepal. Despite this, the health sector's response to addressing the impact of climate change in Nepal may be taken as a good example for other low- and middle-income countries.

Uncertainty Quantification given Discontinuous Climate Model Response and a Limited Number of Model Runs

Science.gov (United States)

Sargsyan, K.; Safta, C.; Debusschere, B.; Najm, H.

2010-12-01

Uncertainty quantification in complex climate models is challenged by the sparsity of available climate model predictions due to the high computational cost of model runs. Another feature that prevents classical uncertainty analysis from being readily applicable is bifurcative behavior in climate model response with respect to certain input parameters. A typical example is the Atlantic Meridional Overturning Circulation. The predicted maximum overturning stream function exhibits discontinuity across a curve in the space of two uncertain parameters, namely climate sensitivity and CO2 forcing. We outline a methodology for uncertainty quantification given discontinuous model response and a limited number of model runs. Our approach is two-fold. First we detect the discontinuity with Bayesian inference, thus obtaining a probabilistic representation of the discontinuity curve shape and location for arbitrarily distributed input parameter values. Then, we construct spectral representations of uncertainty, using Polynomial Chaos (PC) expansions on either side of the discontinuity curve, leading to an averaged-PC representation of the forward model that allows efficient uncertainty quantification. The approach is enabled by a Rosenblatt transformation that maps each side of the discontinuity to regular domains where desirable orthogonality properties for the spectral bases hold. We obtain PC modes by either orthogonal projection or Bayesian inference, and argue for a hybrid approach that targets a balance between the accuracy provided by the orthogonal projection and the flexibility provided by the Bayesian inference - where the latter allows obtaining reasonable expansions without extra forward model runs. The model output, and its associated uncertainty at specific design points, are then computed by taking an ensemble average over PC expansions corresponding to possible realizations of the discontinuity curve. The methodology is tested on synthetic examples of

Estimation of the Source Apportionment of Phosphorus and Its Responses to Future Climate Changes Using Multi-Model Applications

Directory of Open Access Journals (Sweden)

Jian Sha

2018-04-01

Full Text Available The eutrophication issue in the Yangtze Basin was considered, and the phosphorus loads from its tributary, the Modaoxi River, were estimated. The phosphorus flux and source apportionment of the Modaoxi River watershed were modeled and quantified, and their changes with respect to future projected climate scenarios were simulated with multiple model applications. The Regional Nutrient Management (ReNuMa model based on Generalized Watershed Loading Functions (GWLF was employed as a tool to model the hydrochemical processes of the watershed and thereby estimate the monthly streamflow and the phosphorus flux as well as its source apportionment. The Long Ashton Research Station Weather Generator (LARS-WG was used to predict future daily weather data through the statistical downscaling of the general circulation model (GCM outputs based on projected climate scenarios. The synthetic time series of daily precipitation and temperatures generated by LARS-WG were further used as input data for ReNuMa to estimate the responses of the watershed hydrochemical processes to future changed climate conditions. The results showed that both models could be successfully applied and that the future wetter and warmer climate trends would have generally positive impacts on the watershed phosphorus yields, with greater contributions coming from runoff. These results could provide valuable support for local water environmental management.

Animal responses to natural disturbance and climate extremes: a review

Science.gov (United States)

Sergio, Fabrizio; Blas, Julio; Hiraldo, Fernando

2018-02-01

Natural disturbances, such as droughts, fires or hurricanes, are key drivers of ecological heterogeneity and ecosystem function. The frequency and severity of these episodes is unequivocally expected to increase in the coming decades, through the concerted action of climate change and anthropogenic pressures. This will impose severe challenges for many biota through exposure to rapidly changing conditions never experienced in the preceding millennia. Thus, it is urgently needed to gain a thorough understanding of animal responses and adaptations to disturbances in order to better estimate potential future impacts. Here, we review such adjustments and find that animals may respond to disturbances through changes in: (1) behaviour, such as altered mobility, emigration, resource-switching, refuge use, suspended animation, or biotic interactions; (2) life history traits, such as survival, aging, longevity, recruitment, reproductive restraint, breeding output, phenology and bet-hedging tactics; (3) morphology, such as rapid evolution through size-dependent mortality or facultative metamorphosis; (4) physiology, such as altered body condition, pathogen prevalence and transmission, or adrenocortical modulation of stress responses to emergency conditions; (5) genetic structure, such as changes in frequency of polymorphic variants or diversity-modulation through mortality bottlenecks. Individual-level responses scale up to population and community responses, such as altered density, population dynamics, distribution, local extinction and colonization, or assemblage structure and diversity. Overall, disturbances have pervasive effects on individuals, populations and communities of vertebrates and invertebrates of all realms, biomes, continents and ecosystems. Their rapidly increasing incidence and severity will bring unique study opportunities for researchers and novel, unpredictable challenges for managers, while demanding tougher choices and more proactive crisis

Empirically Derived and Simulated Sensitivity of Vegetation to Climate Across Global Gradients of Temperature and Precipitation

Science.gov (United States)

Quetin, G. R.; Swann, A. L. S.

2017-12-01

Successfully predicting the state of vegetation in a novel environment is dependent on our process level understanding of the ecosystem and its interactions with the environment. We derive a global empirical map of the sensitivity of vegetation to climate using the response of satellite-observed greenness and leaf area to interannual variations in temperature and precipitation. Our analysis provides observations of ecosystem functioning; the vegetation interactions with the physical environment, across a wide range of climates and provide a functional constraint for hypotheses engendered in process-based models. We infer mechanisms constraining ecosystem functioning by contrasting how the observed and simulated sensitivity of vegetation to climate varies across climate space. Our analysis yields empirical evidence for multiple physical and biological mediators of the sensitivity of vegetation to climate as a systematic change across climate space. Our comparison of remote sensing-based vegetation sensitivity with modeled estimates provides evidence for which physiological mechanisms - photosynthetic efficiency, respiration, water supply, atmospheric water demand, and sunlight availability - dominate the ecosystem functioning in places with different climates. Earth system models are generally successful in reproducing the broad sign and shape of ecosystem functioning across climate space. However, this general agreement breaks down in hot wet climates where models simulate less leaf area during a warmer year, while observations show a mixed response but overall more leaf area during warmer years. In addition, simulated ecosystem interaction with temperature is generally larger and changes more rapidly across a gradient of temperature than is observed. We hypothesize that the amplified interaction and change are both due to a lack of adaptation and acclimation in simulations. This discrepancy with observations suggests that simulated responses of vegetation to

Difference in tree growth responses to climate at the upper treeline: Qilian Juniper in the Anyemaqen Mountains.

Science.gov (United States)

Peng, Jianfeng; Gou, Xiaohua; Chen, Fahu; Li, Jinbao; Liu, Puxing; Zhang, Yong; Fang, Keyan

2008-08-01

Three ring-width chronologies were developed from Qilian Juniper (Sabina przewalskii Kom.) at the upper treeline along a west-east gradient in the Anyemaqen Mountains. Most chronological statistics, except for mean sensitivity (MS), decreased from west to east. The first principal component (PC1) loadings indicated that stands in a similar climate condition were most important to the variability of radial growth. PC2 loadings decreased from west to east, suggesting the difference of tree-growth between eastern and western Anyemaqen Mountains. Correlations between standard chronologies and climatic factors revealed different climatic influences on radial growth along a west-east gradient in the study area. Temperature of warm season (July-August) was important to the radial growth at the upper treeline in the whole study area. Precipitation of current May was an important limiting factor of tree growth only in the western (drier) upper treeline, whereas precipitation of current September limited tree growth in the eastern (wetter) upper treeline. Response function analysis results showed that there were regional differences between tree growth and climatic factors in various sampling sites of the whole study area. Temperature and precipitation were the important factors influencing tree growth in western (drier) upper treeline. However, tree growth was greatly limited by temperature at the upper treeline in the middle area, and was more limited by precipitation than temperature in the eastern (wetter) upper treeline.

Climate change and biological invasions: evidence, expectations, and response options.

Science.gov (United States)

Hulme, Philip E

2017-08-01

integrates bioclimatic suitability and population-level demographic rates but also simulation of landscape-level processes (e.g. dispersal, land-use change, host/habitat distribution, non-climatic edaphic constraints). In terms of invasive alien species that have known economic or biodiversity impacts, the taxa that are likely to be the most responsive are plant pathogens and insect pests of agricultural crops. However, the extent to which climate adaptation strategies lead to new crops, altered rotations, and different farming practices (e.g. irrigation, fertilization) will all shape the potential agricultural impacts of alien species. The greatest uncertainty in the effects of climate change on biological invasions exists with identifying the future character of new species introductions and predicting ecosystem impacts. Two complementary strategies may work under these conditions of high uncertainty: (i) prioritise ecosystems in terms of their perceived vulnerability to climate change and prevent ingress or expansion of alien species therein that may exacerbate problems; (ii) target those ecosystem already threatened by alien species and implement management to prevent the situation deteriorating under climate change. © 2016 Cambridge Philosophical Society.

Extension Agrometeorology as the Answer to Stakeholder Realities: Response Farming and the Consequences of Climate Change

Directory of Open Access Journals (Sweden)

Durton Nanja

2013-08-01

Full Text Available Extension agrometeorology is applied in agrometeorological extension work to advice and serve farmers. In agrometeorology, response farming has been developed decades ago. Climate change complicates response farming, but does not alter it. This paper reports on new operationalization of that response farming in new educational commitments in agroclimatology. It is explained how “Science Field Shops” are an example in Indonesia. This was based on a thorough analysis of what climate change means for farmers in Asia. For Africa, we report on eying the training of agrometeorological extension trainers (“product intermediaries” in West Africa, based on a thorough analysis of what climate change means for farmers in Africa. We also compare experience with reaching farmers in South Africa and farmer communities in Zambia, as new forms of supporting response farming, all under conditions of a changing climate. The paper, for the first time, connects results from four different programs the senior author is taking part in. There is first and foremost the need for training material to make it possible for the product intermediaries to participate in training extension intermediaries. This should, particularly, bring new knowledge to farmers. With what is presently available and with new approaches, climate extension should be developed and tested with farmers in ways that improve farmer preparedness and decision making.

The response of surface ozone to climate change over the Eastern United States

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P. N. Racherla

2008-02-01

Full Text Available We investigate the response of surface ozone (O₃ to future climate change in the eastern United States by performing simulations corresponding to present (1990s and future (2050s climates using an integrated model of global climate, tropospheric gas-phase chemistry, and aerosols. A future climate has been imposed using ocean boundary conditions corresponding to the IPCC SRES A2 scenario for the 2050s decade. Present-day anthropogenic emissions and CO₂/CH₄ mixing ratios have been used in both simulations while climate-sensitive emissions were allowed to vary with the simulated climate. The severity and frequency of O₃ episodes in the eastern U.S. increased due to future climate change, primarily as a result of increased O₃ chemical production. The 95th percentile O₃ mixing ratio increased by 5 ppbv and the largest frequency increase occured in the 80–90 ppbv range; the US EPA's current 8-h ozone primary standard is 80 ppbv. The increased O₃ chemical production is due to increases in: 1 natural isoprene emissions; 2 hydroperoxy radical concentrations resulting from increased water vapor concentrations; and, 3 NO_x concentrations resulting from reduced PAN. The most substantial and statistically significant (p<0.05 increases in episode frequency occurred over the southeast and midatlantic U.S., largely as a result of 20% higher annual-average natural isoprene emissions. These results suggest a lengthening of the O₃ season over the eastern U.S. in a future climate to include late spring and early fall months. Increased chemical production and shorter average lifetime are two consistent features of the seasonal response of surface O₃, with increased dry deposition loss rates contributing most to the reduced lifetime in all seasons except summer. Significant interannual variability is observed in the frequency of O₃

Methods for Assessing Uncertainties in Climate Change, Impacts and Responses (Invited)

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Manning, M. R.; Swart, R.

2009-12-01

Assessing the scientific uncertainties or confidence levels for the many different aspects of climate change is particularly important because of the seriousness of potential impacts and the magnitude of economic and political responses that are needed to mitigate climate change effectively. This has made the treatment of uncertainty and confidence a key feature in the assessments carried out by the Intergovernmental Panel on Climate Change (IPCC). Because climate change is very much a cross-disciplinary area of science, adequately dealing with uncertainties requires recognition of their wide range and different perspectives on assessing and communicating those uncertainties. The structural differences that exist across disciplines are often embedded deeply in the corresponding literature that is used as the basis for an IPCC assessment. The assessment of climate change science by the IPCC has from its outset tried to report the levels of confidence and uncertainty in the degree of understanding in both the underlying multi-disciplinary science and in projections for future climate. The growing recognition of the seriousness of this led to the formation of a detailed approach for consistent treatment of uncertainties in the IPCC’s Third Assessment Report (TAR) [Moss and Schneider, 2000]. However, in completing the TAR there remained some systematic differences between the disciplines raising concerns about the level of consistency. So further consideration of a systematic approach to uncertainties was undertaken for the Fourth Assessment Report (AR4). The basis for the approach used in the AR4 was developed at an expert meeting of scientists representing many different disciplines. This led to the introduction of a broader way of addressing uncertainties in the AR4 [Manning et al., 2004] which was further refined by lengthy discussions among many IPCC Lead Authors, for over a year, resulting in a short summary of a standard approach to be followed for that

Climate change and climate policy

International Nuclear Information System (INIS)

Alfsen, Knut H.; Kolshus, Hans H.; Torvanger, Asbjoern

2000-08-01

The climate issue is a great political and scientific challenge for several reasons: (1) There are many uncertain aspects of the climate problem, such as future emission of climate gases, the response of the climate system upon these gases, and the effects of climate changes. (2) It is probable, however, that anthropogenic emission of climate gases, deforestation etc. will cause noticeable climate changes in the future. This might be observed as increased frequency of extreme weather situations. This appears to be a greater threat than a gradual increase of temperature and precipitation. (3) Since the climate system is large and react only relatively slowly on changes in for instance the emission of climate gases, the climate problem can only be solved by means of long-term measures. (4) The climate changes may be irreversible. A rational short-term strategy is to ensure maximum flexibility, which can be done by ''slowing down'' (curtailing emissions) and by avoiding irreversible actions as much as possible. The long-term challenge is to develop an economically responsible alternative to the present fossil-based energy system that permits carbon-efficient technologies to compete on price with coal and unconventional oil and gas. Norway is in a special position by being a large exporter of fossil fuel and at the same time wanting to appear responsible in environmental matters. This combination may incur considerable expenses upon Norway and it is therefore important that environmental commitments like the Kyoto agreement can be honoured to the lowest possible cost. The costs can be minimized by: (1) minimizing the measure costs in Norway, (2) working to make the international quota price as low as possible, and (3) reducing the loss of petroleum income as much as possible. This report describes the earth's climate history, the forces behind climatic changes and what the prospects for the future look like. It also reviews what is being done to curtail the emission of

The response of land-falling tropical cyclone characteristics to projected climate change in northeast Australia

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Parker, Chelsea L.; Bruyère, Cindy L.; Mooney, Priscilla A.; Lynch, Amanda H.

2018-01-01

Land-falling tropical cyclones along the Queensland coastline can result in serious and widespread damage. However, the effects of climate change on cyclone characteristics such as intensity, trajectory, rainfall, and especially translation speed and size are not well-understood. This study explores the relative change in the characteristics of three case studies by comparing the simulated tropical cyclones under current climate conditions with simulations of the same systems under future climate conditions. Simulations are performed with the Weather Research and Forecasting Model and environmental conditions for the future climate are obtained from the Community Earth System Model using a pseudo global warming technique. Results demonstrate a consistent response of increasing intensity through reduced central pressure (by up to 11 hPa), increased wind speeds (by 5-10% on average), and increased rainfall (by up to 27% for average hourly rainfall rates). The responses of other characteristics were variable and governed by either the location and trajectory of the current climate cyclone or the change in the steering flow. The cyclone that traveled furthest poleward encountered a larger climate perturbation, resulting in a larger proportional increase in size, rainfall rate, and wind speeds. The projected monthly average change in the 500 mb winds with climate change governed the alteration in the both the trajectory and translation speed for each case. The simulated changes have serious implications for damage to coastal settlements, infrastructure, and ecosystems through increased wind speeds, storm surge, rainfall, and potentially increased size of some systems.

Why we shouldn't underestimate the impact of plant functional diversity

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Groner, V.; Raddatz, T.; Reick, C. H.; Claussen, M.

2017-12-01

We present a series of coupled land-atmosphere simulations with different combinations of plant functional types (PFTs) from mid-Holocene to preindustrial to show how plant functional diversity affects simulated climate-vegetation interaction under changing environmental conditions in subtropical Africa. Scientists nowadays agree that the establishment of the ``green'' Sahara was triggered by external changes in the Earth's orbit and amplified by internal feedback mechanisms. The timing and abruptness of the transition to the ``desert'' state are in turn still under debate. While some previous studies indicated an abrupt collapse of vegetation implying a strong climate-vegetation feedback, others suggested a gradual vegetation decline thereby questioning the existence of a strong climate-vegetation feedback. However, none of these studies explicitly accounted for the role of plant diversity. We show that the introduction or removal of a single PFT can bring about significant impacts on the simulated climate-vegetation system response to changing orbital forcing. While simulations with the standard set of PFTs show a gradual decrease of precipitation and vegetation cover over time, the reduction of plant functional diversity can cause either an abrupt decline of both variables or an even slower response to the external forcing. PFT composition seems to be the decisive factor for the system response to external forcing, and an increase in plant functional diversity does not necessarily increase the stability of the climate-vegetation system. From this we conclude that accounting for plant functional diversity in future studies - not only on palaeo climates - could significantly improve the understanding of climate-vegetation interaction in semi-arid regions, the predictability of the vegetation response to changing climate, and respectively, of the resulting feedback on precipitation.

Climate Change and Infectious Disease Risk in Western Europe: A Survey of Dutch Expert Opinion on Adaptation Responses and Actors.

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Akin, Su-Mia; Martens, Pim; Huynen, Maud M T E

2015-08-18

There is growing evidence of climate change affecting infectious disease risk in Western Europe. The call for effective adaptation to this challenge becomes increasingly stronger. This paper presents the results of a survey exploring Dutch expert perspectives on adaptation responses to climate change impacts on infectious disease risk in Western Europe. Additionally, the survey explores the expert sample's prioritization of mitigation and adaptation, and expert views on the willingness and capacity of relevant actors to respond to climate change. An integrated view on the causation of infectious disease risk is employed, including multiple (climatic and non-climatic) factors. The results show that the experts consider some adaptation responses as relatively more cost-effective, like fostering interagency and community partnerships, or beneficial to health, such as outbreak investigation and response. Expert opinions converge and diverge for different adaptation responses. Regarding the prioritization of mitigation and adaptation responses expert perspectives converge towards a 50/50 budgetary allocation. The experts consider the national government/health authority as the most capable actor to respond to climate change-induced infectious disease risk. Divergence and consensus among expert opinions can influence adaptation policy processes. Further research is necessary to uncover prevailing expert perspectives and their roots, and compare these.

Climate change and species interactions: ways forward.

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Angert, Amy L; LaDeau, Shannon L; Ostfeld, Richard S

2013-09-01

With ongoing and rapid climate change, ecologists are being challenged to predict how individual species will change in abundance and distribution, how biotic communities will change in structure and function, and the consequences of these climate-induced changes for ecosystem functioning. It is now well documented that indirect effects of climate change on species abundances and distributions, via climatic effects on interspecific interactions, can outweigh and even reverse the direct effects of climate. However, a clear framework for incorporating species interactions into projections of biological change remains elusive. To move forward, we suggest three priorities for the research community: (1) utilize tractable study systems as case studies to illustrate possible outcomes, test processes highlighted by theory, and feed back into modeling efforts; (2) develop a robust analytical framework that allows for better cross-scale linkages; and (3) determine over what time scales and for which systems prediction of biological responses to climate change is a useful and feasible goal. We end with a list of research questions that can guide future research to help understand, and hopefully mitigate, the negative effects of climate change on biota and the ecosystem services they provide. © 2013 New York Academy of Sciences.

Integrated watershed-scale response to climate change for selected basins across the United States

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Markstrom, Steven L.; Hay, Lauren E.; Ward-Garrison, D. Christian; Risley, John C.; Battaglin, William A.; Bjerklie, David M.; Chase, Katherine J.; Christiansen, Daniel E.; Dudley, Robert W.; Hunt, Randall J.; Koczot, Kathryn M.; Mastin, Mark C.; Regan, R. Steven; Viger, Roland J.; Vining, Kevin C.; Walker, John F.

2012-01-01

A study by the U.S. Geological Survey (USGS) evaluated the hydrologic response to different projected carbon emission scenarios of the 21st century using a hydrologic simulation model. This study involved five major steps: (1) setup, calibrate and evaluated the Precipitation Runoff Modeling System (PRMS) model in 14 basins across the United States by local USGS personnel; (2) acquire selected simulated carbon emission scenarios from the World Climate Research Programme's Coupled Model Intercomparison Project; (3) statistical downscaling of these scenarios to create PRMS input files which reflect the future climatic conditions of these scenarios; (4) generate PRMS projections for the carbon emission scenarios for the 14 basins; and (5) analyze the modeled hydrologic response. This report presents an overview of this study, details of the methodology, results from the 14 basin simulations, and interpretation of these results. A key finding is that the hydrological response of the different geographical regions of the United States to potential climate change may be different, depending on the dominant physical processes of that particular region. Also considered is the tremendous amount of uncertainty present in the carbon emission scenarios and how this uncertainty propagates through the hydrologic simulations.

Climate-smart technologies. Integrating renewable energy and energy efficiency in mitigation and adaptation responses

Energy Technology Data Exchange (ETDEWEB)

Leal Filho, Walter; Mannke, Franziska; Schulte, Veronika [Hamburg Univ. of Applied Sciences (Germany). Faculty of Life Sciences; Mohee, Romeela; Surroop, Dinesh (eds.) [Mauritius Univ., Reduit (Mauritius). Chemical and Environmental Engineering Dept.

2013-11-01

Explores the links between climate change and technologies. Relates to the links between renewable energy and climate change. Documents and promotes a collection of experiences from island nations. Has a strong international focus and value to developing countries. The book addresses the perceived need for a publication with looks at both, climate smart technologies and the integration of renewable energy and energy efficiency in mitigation and adaptation responses. Based on a set of papers submitted as part of the fifth on-line climate conference (CLIMATE 2012) and a major conference on renewable energy on island States held in Mauritius in 2012, the book provides a wealth of information on climate change strategies and the role of smart technologies. The book has been produced in the context of the project ''Small Developing Island Renewable Energy Knowledge and Technology Transfer Network'' (DIREKT), funded by the ACP Science and Technology Programme, an EU programme for cooperation between the European Union and the ACP region.

The climate response to five trillion tonnes of carbon

Science.gov (United States)

Tokarska, Katarzyna B.; Gillett, Nathan P.; Weaver, Andrew J.; Arora, Vivek K.; Eby, Michael

2016-09-01

Concrete actions to curtail greenhouse gas emissions have so far been limited on a global scale, and therefore the ultimate magnitude of climate change in the absence of further mitigation is an important consideration for climate policy. Estimates of fossil fuel reserves and resources are highly uncertain, and the amount used under a business-as-usual scenario would depend on prevailing economic and technological conditions. In the absence of global mitigation actions, five trillion tonnes of carbon (5 EgC), corresponding to the lower end of the range of estimates of the total fossil fuel resource, is often cited as an estimate of total cumulative emissions. An approximately linear relationship between global warming and cumulative CO2 emissions is known to hold up to 2 EgC emissions on decadal to centennial timescales; however, in some simple climate models the predicted warming at higher cumulative emissions is less than that predicted by such a linear relationship. Here, using simulations from four comprehensive Earth system models, we demonstrate that CO2-attributable warming continues to increase approximately linearly up to 5 EgC emissions. These models simulate, in response to 5 EgC of CO2 emissions, global mean warming of 6.4-9.5 °C, mean Arctic warming of 14.7-19.5 °C, and mean regional precipitation increases by more than a factor of four. These results indicate that the unregulated exploitation of the fossil fuel resource could ultimately result in considerably more profound climate changes than previously suggested.

Hydrologic response and watershed sensitivity to climate warming in California's Sierra Nevada.

Directory of Open Access Journals (Sweden)

Sarah E Null

Full Text Available 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.

Plant functional types define magnitude of drought response in peatland CO2 exchange.

Science.gov (United States)

Kuiper, Jan J; Mooij, Wolf M; Bragazza, Luca; Robroek, Bjorn J M

2014-01-01

Peatlands are important sinks for atmospheric carbon (C), yet the role of plant functional types (PFTs) for C sequestration under climatic perturbations is still unclear. A plant-removal experiment was used to study the importance of vascular PFTs for the net ecosystem CO2 exchange (NEE) during (i.e., resistance) and after (i.e., recovery) an experimental drought. The removal of PFTs caused a decrease of NEE, but the rate differed between microhabitats (i.e., hummocks and lawns) and the type of PFTs. Ericoid removal had a large effect on NEE in hummocks, while the graminoids played a major role in the lawns. The removal of PFTs did not affect the resistance or the recovery after the experimental drought. We argue that the response of Sphagnum mosses (the only PFT present in all treatments) to drought is dominant over that of coexisting PFTs. However, we observed that the moment in time when the system switched from C sink to C source during the drought was controlled by the vascular PFTs. In the light of climate change, the shifts in species composition or even the loss of certain PFTs are expected to strongly affect the future C dynamics in response to environmental stress.

Multiple stressors, nonlinear effects and the implications of climate change impacts on marine coastal ecosystems.

Science.gov (United States)

Hewitt, Judi E; Ellis, Joanne I; Thrush, Simon F

2016-08-01

Global climate change will undoubtedly be a pressure on coastal marine ecosystems, affecting not only species distributions and physiology but also ecosystem functioning. In the coastal zone, the environmental variables that may drive ecological responses to climate change include temperature, wave energy, upwelling events and freshwater inputs, and all act and interact at a variety of spatial and temporal scales. To date, we have a poor understanding of how climate-related environmental changes may affect coastal marine ecosystems or which environmental variables are likely to produce priority effects. Here we use time series data (17 years) of coastal benthic macrofauna to investigate responses to a range of climate-influenced variables including sea-surface temperature, southern oscillation indices (SOI, Z4), wind-wave exposure, freshwater inputs and rainfall. We investigate responses from the abundances of individual species to abundances of functional traits and test whether species that are near the edge of their tolerance to another stressor (in this case sedimentation) may exhibit stronger responses. The responses we observed were all nonlinear and some exhibited thresholds. While temperature was most frequently an important predictor, wave exposure and ENSO-related variables were also frequently important and most ecological variables responded to interactions between environmental variables. There were also indications that species sensitive to another stressor responded more strongly to weaker climate-related environmental change at the stressed site than the unstressed site. The observed interactions between climate variables, effects on key species or functional traits, and synergistic effects of additional anthropogenic stressors have important implications for understanding and predicting the ecological consequences of climate change to coastal ecosystems. © 2015 John Wiley & Sons Ltd.

The climate response of the Indo-Pacific warm pool to glacial sea level

Science.gov (United States)

Di Nezio, Pedro N.; Timmermann, Axel; Tierney, Jessica E.; Jin, Fei-Fei; Otto-Bliesner, Bette; Rosenbloom, Nan; Mapes, Brian; Neale, Rich; Ivanovic, Ruza F.; Montenegro, Alvaro

2016-06-01

Growing climate proxy evidence suggests that changes in sea level are important drivers of tropical climate change on glacial-interglacial timescales. These paleodata suggest that rainfall patterns over the Indo-Pacific warm pool (IPWP) are highly sensitive to the landmass configuration of the Maritime Continent and that lowered sea level contributed to large-scale drying during the Last Glacial Maximum (LGM, approximately 21,000 years B.P.). Using the Community Earth System Model Version 1.2 (CESM1), we investigate the mechanisms by which lowered sea level influenced the climate of the IPWP during the LGM. The CESM1 simulations show that, in agreement with previous hypotheses, changes in atmospheric circulation are initiated by the exposure of the Sunda and Sahul shelves. Ocean dynamical processes amplify the changes in atmospheric circulation by increasing the east-west sea surface temperature (SST) gradient along the equatorial Indian Ocean. The coupled mechanism driving this response is akin to the Bjerknes feedback and results in a large-scale climatic reorganization over the Indian Ocean with impacts extending from east Africa to the western tropical Pacific. Unlike exposure of the Sunda shelf, exposure of Sahul shelf and the associated changes in surface albedo play a key role because of the positive feedback. This mechanism could explain the pattern of dry (wet) eastern (western) Indian Ocean identified in climate proxies and LGM simulations. However, this response also requires a strengthened SST gradient along the equatorial Indian Ocean, a pattern that is not evident in marine paleoreconstructions. Strategies to resolve this issue are discussed.