Identification of urban gas leaks and evaluation of methane emission inventories using mobile measurements

Science.gov (United States)

Zazzeri, Giulia; Lowry, Dave; Fisher, Rebecca E.; France, James L.; Butler, Dominique; Lanoisellé, Mathias; Nisbet, Euan G.

2017-04-01

Leakages from the natural gas distribution network, power plants and refineries account for the 10% of national methane emissions in the UK (http://naei.defra.gov.uk/), and are identified as a major source of methane in big conurbations (e.g. Townsend-Small et al., 2012; Phillips et al., 2013). The National Atmospheric Emission Inventories (NAEI) website provides a list of gas installations, but emissions from gas leakage, which in the inventories are estimated on the basis of the population distribution, are difficult to predict, which makes their estimation highly uncertain. Surveys with a mobile measurement system (Zazzeri et al., 2015) were carried out in the London region for detection of fugitive natural gas and in other sites in the UK (i.e. Bacton, Southampton, North Yorkshire) to identify emissions from various gas installations. The methane isotopic analysis of air samples collected during the surveys, using the methodology in Zazzeri et al. (2015), allows the calculation of the δ13C signature characterising natural gas in the UK. The isotopic value of the natural gas supply to SE London has changed a little in recent years, being close to -34 ‰ over 1998-99 period (Lowry et al., 2001) and close to -36 ‰ since at least 2002. Emissions from gas installations, such as pumping stations in NE England (-41 ± 2 ‰ ) were detected, but some of them were not listed in the inventories. Furthermore, the spatial distribution of the gas leaks identified during the surveys in the London region does not coincide with the distribution suggested by the inventories. By locating both small gas leaks and emissions from large gas installations, we can verify how these methane sources are targeted by national emission inventories. Lowry, D., Holmes, C.W., Rata, N.D., O'Brien, P., and Nisbet, E.G., 2001, London methane emissions: Use of diurnal changes in concentration and δ13C to identify urban sources and verify inventories: Journal of Geophysical Research

Exploiting coalbed methane and protecting the global environment

Energy Technology Data Exchange (ETDEWEB)

Yuheng, Gao

1996-12-31

The global climate change caused by greenhouse gases (GHGs) emission has received wide attention from all countries in the world. Global environmental protection as a common problem has confronted the human being. As a main component of coalbed methane, methane is an important factor influencing the production safety of coal mine and threatens the lives of miners. The recent research on environment science shows that methane is a very harmful GHG. Although methane gas has very little proportion in the GHGs emission and its stayed period is also very short, it has very obvious impact on the climate change. From the estimation, methane emission in the coal-mining process is only 10% of the total emission from human`s activities. As a clean energy, Methane has mature recovery technique before, during and after the process of mining. Thus, coalbed methane is the sole GHG generated in the human`s activities and being possible to be reclaimed and utilized. Compared with the global greenhouse effect of other GHGs emission abatement, coalbed methane emission abatement can be done in very low cost with many other benefits: (1) to protect global environment; (2) to improve obviously the safety of coal mine; and (3) to obtain a new kind of clean energy. Coal is the main energy in China, and coalbed contains very rich methane. According to the exploration result in recent years, about 30000{approximately}35000 billion m{sup 2} methane is contained in the coalbed below 2000 m in depth. China has formed a good development base in the field of reclamation and utilization of coalbed methane. The author hopes that wider international technical exchange and cooperation in the field will be carried out.

Global distribution of methane emissions, emission trends, and OH trends inferred from an inversion of GOSAT data for 2010-2015

Science.gov (United States)

Maasakkers, J. D.; Jacob, D.; Payer Sulprizio, M.; Hersher, M.; Scarpelli, T.; Turner, A. J.; Sheng, J.; Bloom, A. A.; Bowman, K. W.; Parker, R.

2017-12-01

We present a global inversion of methane sources and sinks using GOSAT satellite data from 2010 up to 2015. The inversion optimizes emissions and their trends at 4° × 5° resolution as well as the interannual variability of global OH concentrations. It uses an analytical approach that quantifies the information content from the GOSAT observations and provides full error characterization. We show how the analytical approach can be applied in log-space, ensuring the positivity of the posterior. The inversion starts from state-of-science a priori emission inventories including the Gridded EPA inventory for US anthropogenic emissions, detailed oil and gas emissions for Canada and Mexico, EDGAR v4.3.2 for anthropogenic emissions in other countries, the WetCHARTs product for wetlands, and our own estimates for geological seeps. Inversion results show lower emissions over Western Europe and China than predicted by EDGAR v4.3.2 but higher emissions over Japan. In contrast to previous inversions that used incorrect patterns in a priori emissions, we find that the EPA inventory does not underestimate US anthropogenic emissions. Results for trends show increasing emissions in the tropics combined with decreasing emissions in Europe, and a decline in OH concentrations contributing to the global methane trend.

Inventory of methane emissions from livestock in China from 1980 to 2013

Science.gov (United States)

Yu, Jiashuo; Peng, Shushi; Chang, Jinfeng; Ciais, Philippe; Dumas, Patrice; Lin, Xin; Piao, Shilong

2018-07-01

Livestock is the largest anthropogenic methane (CH4) source at the global scale. Previous inventories of this source for China were based on the accounting of livestock populations and constant emission factors (EFs) per head. Here, we re-evaluate how livestock CH4 emissions have changed from China over the last three decades, considering increasing population, body weight and milk production per head which cause EF to change with time, and decreasing average life span (ALS) of livestock. Our results show that annual CH4 emissions by livestock have increased from 4.5 to 11.8 Tg CH4 yr-1 over the period 1980-2013. The increasing trend in emissions (0.25 Tg CH4 yr-2) over this period is ∼12% larger than that if using constant EFs and ALS. The increasing livestock population, production per head and decreasing ALS contributed +91%, +28% and -19% to the increase in CH4 emissions from livestock, respectively. This implies that the temporal changes in EF and ALS of livestock cannot be overlooked in inventories, especially in countries like China where livestock production systems are experiencing rapid transformations.

Global health benefits of mitigating ozone pollution with methane emission controls.

Science.gov (United States)

West, J Jason; Fiore, Arlene M; Horowitz, Larry W; Mauzerall, Denise L

2006-03-14

Methane (CH(4)) contributes to the growing global background concentration of tropospheric ozone (O(3)), an air pollutant associated with premature mortality. Methane and ozone are also important greenhouse gases. Reducing methane emissions therefore decreases surface ozone everywhere while slowing climate warming, but although methane mitigation has been considered to address climate change, it has not for air quality. Here we show that global decreases in surface ozone concentrations, due to methane mitigation, result in substantial and widespread decreases in premature human mortality. Reducing global anthropogenic methane emissions by 20% beginning in 2010 would decrease the average daily maximum 8-h surface ozone by approximately 1 part per billion by volume globally. By using epidemiologic ozone-mortality relationships, this ozone reduction is estimated to prevent approximately 30,000 premature all-cause mortalities globally in 2030, and approximately 370,000 between 2010 and 2030. If only cardiovascular and respiratory mortalities are considered, approximately 17,000 global mortalities can be avoided in 2030. The marginal cost-effectiveness of this 20% methane reduction is estimated to be approximately 420,000 US dollars per avoided mortality. If avoided mortalities are valued at 1 US dollars million each, the benefit is approximately 240 US dollars per tone of CH(4) ( approximately 12 US dollars per tone of CO(2) equivalent), which exceeds the marginal cost of the methane reduction. These estimated air pollution ancillary benefits of climate-motivated methane emission reductions are comparable with those estimated previously for CO(2). Methane mitigation offers a unique opportunity to improve air quality globally and can be a cost-effective component of international ozone management, bringing multiple benefits for air quality, public health, agriculture, climate, and energy.

The indirect global warming potential and global temperature change potential due to methane oxidation

International Nuclear Information System (INIS)

Boucher, Olivier; Collins, Bill; Friedlingstein, Pierre; Shine, Keith P

2009-01-01

Methane is the second most important anthropogenic greenhouse gas in the atmosphere next to carbon dioxide. Its global warming potential (GWP) for a time horizon of 100 years is 25, which makes it an attractive target for climate mitigation policies. Although the methane GWP traditionally includes the methane indirect effects on the concentrations of ozone and stratospheric water vapour, it does not take into account the production of carbon dioxide from methane oxidation. We argue here that this CO 2 -induced effect should be included for fossil sources of methane, which results in slightly larger GWP values for all time horizons. If the global temperature change potential is used as an alternative climate metric, then the impact of the CO 2 -induced effect is proportionally much larger. We also discuss what the correction term should be for methane from anthropogenic biogenic sources.

U.S. Natural Gas System Methane Emissions: State of Knowledge from LCAs, Inventories, and Atmospheric Measurements (Presentation)

Energy Technology Data Exchange (ETDEWEB)

Heath, G.

2014-04-01

Natural gas (NG) is a potential "bridge fuel" during transition to a decarbonized energy system: It emits less carbon dioxide during combustion than other fossil fuels and can be used in many industries. However, because of the high global warming potential of methane (CH4, the major component of NG), climate benefits from NG use depend on system leakage rates. Some recent estimates of leakage have challenged the benefits of switching from coal to NG, a large near-term greenhouse gas (GHG) reduction opportunity. During this presentation, Garvin will review evidence from multiple perspectives - life cycle assessments (LCAs), inventories and measurements - about NG leakage in the US. Particular attention will be paid to a recent article in Science magazine which reviewed over 20 years of published measurements to better understand what we know about total methane emissions and those from the oil and gas sectors. Scientific and policy implications of the state of knowledge will be discussed.

Global Methane Biogeochemistry

Science.gov (United States)

Reeburgh, W. S.

2003-12-01

Methane (CH4) has been studied as an atmospheric constituent for over 200 years. A 1776 letter from Alessandro Volta to Father Campi described the first experiments on flammable "air" released by shallow sediments in Lake Maggiore (Wolfe, 1996; King, 1992). The first quantitative measurements of CH4, both involving combustion and gravimetric determination of trapped oxidation products, were reported in French by Boussingault and Boussingault, 1864 and Gautier (1901), who reported CH4 concentrations of 10 ppmv and 0.28 ppmv (seashore) and 95 ppmv (Paris), respectively. The first modern measurements of atmospheric CH4 were the infrared absorption measurements of Migeotte (1948), who estimated an atmospheric concentration of 2.0 ppmv. Development of gas chromatography and the flame ionization detector in the 1950s led to observations of vertical CH4 distributions in the troposphere and stratosphere, and to establishment of time-series sampling programs in the late 1970s. Results from these sampling programs led to suggestions that the concentration of CH4, as that of CO2, was increasing in the atmosphere. The possible role of CH4 as a greenhouse gas stimulated further research on CH4 sources and sinks. Methane has also been of interest to microbiologists, but findings from microbiology have entered the larger context of the global CH4 budget only recently.Methane is the most abundant hydrocarbon in the atmosphere. It plays important roles in atmospheric chemistry and the radiative balance of the Earth. Stratospheric oxidation of CH4 provides a means of introducing water vapor above the tropopause. Methane reacts with atomic chlorine in the stratosphere, forming HCl, a reservoir species for chlorine. Some 90% of the CH4 entering the atmosphere is oxidized through reactions initiated by the OH radical. These reactions are discussed in more detail by Wofsy (1976) and Cicerone and Oremland (1988), and are important in controlling the oxidation state of the atmosphere

Revised methane emissions factors and spatially distributed annual carbon fluxes for global livestock

Science.gov (United States)

Livestock play an important role in carbon cycling through consumption of biomass and emissions of methane. Recent research suggests that existing bottom-up inventories of livestock methane emissions in the U.S., such as those made using 2006 IPCC Tier 1 livestock emissions factors, are too low. Thi...

Methane fluxes and inventories in the accretionary prism of southwestern Taiwan

Science.gov (United States)

Lin, L. H.; Chen, N. C.; Yang, T. F.; Hong, W. L.; Chen, H. W.; Chen, H. C.; Hu, C. Y.; Huang, Y. C.; Lin, S.; Su, C. C.; Liao, W. Z.; Sun, C. H.; Wang, P. L.; Yang, T.; Jiang, S. Y.; Liu, C. S.; Wang, Y.; Chung, S. H.

2017-12-01

Sediments distributed across marine and terrestrial realms represent the largest methane reservoir on Earth. The degassing of methane facilitated through either geological structures or perturbation would contribute significantly to global climatic fluctuation and elemental cycling. The exact fluxes and processes governing methane production, consumption and transport in a geological system remain largely unknown in part due to the limited coverage and access of samples. In this study, more than 200 sediment cores were collected from offshore and onshore southwestern Taiwan and analyzed for their gas and aqueous geochemistry. These data combined with published data and existing parameters of subduction system were used to calculate methane fluxes across different geochemical transitions and to develop scenarios of mass balance to constrain deep microbial and thermogenic methane production rates within the Taiwanese accretionary prism. The results showed that high methane fluxes tend to be associated with structural features, suggesting a strong structural control on methane transport. A significant portion of ascending methane (>50%) was consumed by anaerobic oxidation of methane at most sites. Gas compositions and isotopes revealed a transition from the predominance of microbial methane in the passive margin to thermogenic methane at the upper slope of the active margin and onshore mud volcanoes. Methane production and consumption at shallow depths were nearly offset with a small fraction of residual methane discharged into seawater or the atmosphere. The flux imbalance arose primarily from the deep microbial and thermogenic production and could be likely accounted for by the sequestration of methane into hydrate forms, and clay absorption.

A method for the calculation of anaerobic oxidation of methane rates across regional scales: an example from the Belt Seas and The Sound (North Sea-Baltic Sea transition)

NARCIS (Netherlands)

Mogollón, J.M.; Dale, A.W.; Jensen, J.B.; Schlüter, M.; Regnier, P.

2013-01-01

Estimating the amount of methane in the seafloor globally as well as the flux of methane from sediments toward the ocean-atmosphere system are important considerations in both geological and climate sciences. Nevertheless, global estimates of methane inventories and rates of methane production and

Methane and nitrous oxide: Methods in national emissions inventories and options for control

Energy Technology Data Exchange (ETDEWEB)

Van Amstel, A.R. (ed.)

1993-07-01

The UN Framework Convention on Climate Change signed in Rio de Janeiro, Brazil, calls for the return of anthropogenic emissions of greenhouse gases to their 1990 levels by the year 2000 in industrialized countries. It also calls for a monitoring of the emissions of greenhouse gases. It is important that reliable and scientifically credible national inventories are available for the international negotiations. Therefore a consistent methodology and a transparent reporting format is needed. The title workshop had two main objectives: (1) to support the development a methodology and format for national emissions inventories of greenhouse gases by mid 1993, as coordinated by the Science Working Group of the IPCC and the OECD; and (2) the development of technical options for reduction of greenhouse gases and the assessment of the socio-economic feasibility of these options. The workshop consisted of key note overview presentations, and two rounds of working group sessions, each covering five parallel sessions on selected sources. In the first round of each working group session the literature, existing methods for methane and nitrous oxide inventories, and the OECD/IPCC guidelines have been addressed. Then, in the second round, options for emission reductions have been discussed, as well as their socio-economic implications. The methane sources discussed concern oil and gas, coal mining, ruminants, animal waste, landfills and sewage treatment, combustion and industry, rice production and wetlands, biomass burning. The nitrous oxide sources discussed are agricultural soils and combustion and industry. The proceedings on methane comprise 16 introductory papers and 7 papers on the results of the working groups, while in part two four introductory papers and two papers on the results of working groups on nitrous oxide are presented. In part three future emission reduction policy options are discussed. Finally, 16 poster contributions are included

ISLSCP II GlobalView: Atmospheric Methane Concentrations

Data.gov (United States)

National Aeronautics and Space Administration — ABSTRACT: The GlobalView Methane (CH4) data product contains synchronized and smoothed time series of atmospheric CH4 concentrations at selected sites that were...

ISLSCP II GlobalView: Atmospheric Methane Concentrations

Data.gov (United States)

National Aeronautics and Space Administration — The GlobalView Methane (CH4) data product contains synchronized and smoothed time series of atmospheric CH4 concentrations at selected sites that were created using...

Regional landfills methane emission inventory in Malaysia.

Science.gov (United States)

Abushammala, Mohammed F M; Noor Ezlin Ahmad Basri; Basri, Hassan; Ahmed Hussein El-Shafie; Kadhum, Abdul Amir H

2011-08-01

The decomposition of municipal solid waste (MSW) in landfills under anaerobic conditions produces landfill gas (LFG) containing approximately 50-60% methane (CH(4)) and 30-40% carbon dioxide (CO(2)) by volume. CH(4) has a global warming potential 21 times greater than CO(2); thus, it poses a serious environmental problem. As landfills are the main method for waste disposal in Malaysia, the major aim of this study was to estimate the total CH(4) emissions from landfills in all Malaysian regions and states for the year 2009 using the IPCC, 1996 first-order decay (FOD) model focusing on clean development mechanism (CDM) project applications to initiate emission reductions. Furthermore, the authors attempted to assess, in quantitative terms, the amount of CH(4) that would be emitted from landfills in the period from 1981-2024 using the IPCC 2006 FOD model. The total CH(4) emission using the IPCC 1996 model was estimated to be 318.8 Gg in 2009. The Northern region had the highest CH(4) emission inventory, with 128.8 Gg, whereas the Borneo region had the lowest, with 24.2 Gg. It was estimated that Pulau Penang state produced the highest CH(4) emission, 77.6 Gg, followed by the remaining states with emission values ranging from 38.5 to 1.5 Gg. Based on the IPCC 1996 FOD model, the total Malaysian CH( 4) emission was forecast to be 397.7 Gg by 2020. The IPCC 2006 FOD model estimated a 201 Gg CH(4) emission in 2009, and estimates ranged from 98 Gg in 1981 to 263 Gg in 2024.

Simplifiying global biogeochemistry models to evaluate methane emissions

Science.gov (United States)

Gerber, S.; Alonso-Contes, C.

2017-12-01

Process-based models are important tools to quantify wetland methane emissions, particularly also under climate change scenarios, evaluating these models is often cumbersome as they are embedded in larger land-surface models where fluctuating water table and the carbon cycle (including new readily decomposable plant material) are predicted variables. Here, we build on these large scale models but instead of modeling water table and plant productivity we provide values as boundary conditions. In contrast, aerobic and anaerobic decomposition, as well as soil column transport of oxygen and methane are predicted by the model. Because of these simplifications, the model has the potential to be more readily adaptable to the analysis of field-scale data. Here we determine the sensitivity of the model to specific setups, parameter choices, and to boundary conditions in order to determine set-up needs and inform what critical auxiliary variables need to be measured in order to better predict field-scale methane emissions from wetland soils. To that end we performed a global sensitivity analysis that also considers non-linear interactions between processes. The global sensitivity analysis revealed, not surprisingly, that water table dynamics (both mean level and amplitude of fluctuations), and the rate of the carbon cycle (i.e. net primary productivity) are critical determinants of methane emissions. The depth-scale where most of the potential decomposition occurs also affects methane emissions. Different transport mechanisms are compensating each other to some degree: If plant conduits are constrained, methane emissions by diffusive flux and ebullition compensate to some degree, however annual emissions are higher when plants help to bypass methanotrophs in temporally unsaturated upper layers. Finally, while oxygen consumption by plant roots help creating anoxic conditions it has little effect on overall methane emission. Our initial sensitivity analysis helps guiding

Global estimations of the inventory and mitigation potential of methane emissions from rice cultivation conducted using the 2006 Intergovernmental Panel on Climate Change Guidelines

Science.gov (United States)

Yan, Xiaoyuan; Akiyama, Hiroko; Yagi, Kazuyuki; Akimoto, Hajime

2009-06-01

The Intergovernmental Panel on Climate Change (IPCC) regularly publishes guidelines for national greenhouse gas inventories and methane emission (CH4) from rice paddies has been an important component of these guidelines. While there have been many estimates of global CH4 emissions from rice fields, none of them have been obtained using the IPCC guidelines. Therefore, we used the Tier 1 method described in the 2006 IPCC guidelines to estimate the global CH4 emissions from rice fields. To accomplish this, we used country-specific statistical data regarding rice harvest areas and expert estimates of relevant agricultural activities. The estimated global emission for 2000 was 25.6 Tg a-1, which is at the lower end of earlier estimates and close to the total emission summarized by individual national communications. Monte Carlo simulation revealed a 95% uncertainty range of 14.8-41.7 Tg a-1; however, the estimation uncertainty was found to depend on the reliability of the information available regarding the amount of organic amendments and the area of rice fields that were under continuous flooding. We estimated that if all of the continuously flooded rice fields were drained at least once during the growing season, the CH4 emissions would be reduced by 4.1 Tg a-1. Furthermore, we estimated that applying rice straw off season wherever and whenever possible would result in a further reduction in emissions of 4.1 Tg a-1 globally. Finally, if both of these mitigation options were adopted, the global CH4 emission from rice paddies could be reduced by 7.6 Tg a-1. Although draining continuously flooded rice fields may lead to an increase in nitrous oxide (N2O) emission, the global warming potential resulting from this increase is negligible when compared to the reduction in global warming potential that would result from the CH4 reduction associated with draining the fields.

Towards an inventory of methane emissions from manure management that is responsive to changes on Canadian farms

International Nuclear Information System (INIS)

VanderZaag, A C; Evans, L; Vergé, X P C; Desjardins, R L; MacDonald, J D

2013-01-01

Methane emissions from manure management represent an important mitigation opportunity, yet emission quantification methods remain crude and do not contain adequate detail to capture changes in agricultural practices that may influence emissions. Using the Canadian emission inventory methodology as an example, this letter explores three key aspects for improving emission quantification: (i) obtaining emission measurements to improve and validate emission model estimates, (ii) obtaining more useful activity data, and (iii) developing a methane emission model that uses the available farm management activity data. In Canada, national surveys to collect manure management data have been inconsistent and not designed to provide quantitative data. Thus, the inventory has not been able to accurately capture changes in management systems even between manure stored as solid versus liquid. To address this, we re-analyzed four farm management surveys from the past decade and quantified the significant change in manure management which can be linked to the annual agricultural survey to create a continuous time series. In the dairy industry of one province, for example, the percentage of manure stored as liquid increased by 300% between 1991 and 2006, which greatly affects the methane emission estimates. Methane emissions are greatest from liquid manure, but vary by an order of magnitude depending on how the liquid manure is managed. Even if more complete activity data are collected on manure storage systems, default Intergovernmental Panel on Climate Change (IPCC) guidance does not adequately capture the impacts of management decisions to reflect variation among farms and regions in inventory calculations. We propose a model that stays within the IPCC framework but would be more responsive to farm management by generating a matrix of methane conversion factors (MCFs) that account for key factors known to affect methane emissions: temperature, retention time and inoculum. This

Global gridded anthropogenic emissions inventory of carbonyl sulfide

Science.gov (United States)

Zumkehr, Andrew; Hilton, Tim W.; Whelan, Mary; Smith, Steve; Kuai, Le; Worden, John; Campbell, J. Elliott

2018-06-01

Atmospheric carbonyl sulfide (COS or OCS) is the most abundant sulfur containing gas in the troposphere and is an atmospheric tracer for the carbon cycle. Gridded inventories of global anthropogenic COS are used for interpreting global COS measurements. However, previous gridded anthropogenic data are a climatological estimate based on input data that is over three decades old and are not representative of current conditions. Here we develop a new gridded data set of global anthropogenic COS sources that includes more source sectors than previously available and uses the most current emissions factors and industry activity data as input. Additionally, the inventory is provided as annually varying estimates from years 1980-2012 and employs a source specific spatial scaling procedure. We estimate a global source in year 2012 of 406 Gg S y-1 (range of 223-586 Gg S y-1), which is highly concentrated in China and is twice as large as the previous gridded inventory. Our large upward revision in the bottom-up estimate of the source is consistent with a recent top-down estimate based on air-monitoring and Antarctic firn data. Furthermore, our inventory time trends, including a decline in the 1990's and growth after the year 2000, are qualitatively consistent with trends in atmospheric data. Finally, similarities between the spatial distribution in this inventory and remote sensing data suggest that the anthropogenic source could potentially play a role in explaining a missing source in the global COS budget.

Estimate of methane emissions from the U.S. natural gas industry

International Nuclear Information System (INIS)

Kirchgessner, D.A.; Lott, R.A.; Cowgill, R.M.; Harrison, M.R.; Shires, T.M.

1997-01-01

Global methane emissions from the fossil fuel industries have been poorly quantified and, in many cases, emissions are not well-known even at the country level. Historically, methane emissions from the U.S. gas industry have been based on sparse data, incorrect assumptions, or both. As a result, the estimate of the contribution these emissions make to the global methane inventory could be inaccurate. For this reason the assertion that global warming could be reduced by replacing coal and oil fuels with natural gas could not be defended. A recently completed, multi year study conducted by the U.S. Environmental Protection Agency's Office of Research and Development and the Gas Research Institute, had the objective of determining methane emissions from the U.S. gas industry with an accuracy of ± 0.5% of production. The study concluded that, in the 1992 base year, methane emissions from the industry were 314 ± 105 Bscf or 6.04 ± 2.01 Tg (all conversions to international units are made at 15.56 o C and 101.325 kPa). (author)

Methane Leakage from Oil & Gas Operations. What have we learned from recent studies in the U.S.?

Science.gov (United States)

Zavala-Araiza, Daniel; Hamburg, Steven

2016-04-01

Methane, the principal component of natural gas, is a powerful greenhouse gas. Methane losses from the natural gas supply chain erode the climate benefits of fuel switching to natural gas from other fossil fuels, reducing or eliminating them for several decades or longer. Global data on methane emissions from the oil and gas sector is uncertain and as a consequence, measuring and characterizing methane emissions is critical to the design of effective mitigation strategies. In this work, we synthesize lessons learned from dozens of U.S. studies that characterized methane emissions along each stage of the natural gas supply chain. These results are relevant to the design of methane measurement campaigns outside the U.S. A recurring theme in the research conducted in the U.S. is that public emissions inventories (e.g., The U.S. Environmental Protection Agency's National Greenhouse gas Inventory) tend to underestimate emissions for two key reasons: (1) use of non-representative emission factors and (2) inaccurate activity data (incomplete counts of facilities and equipment). Similarly, the accuracy of emission factors and the effectiveness of mitigation strategies are heavily affected by the existence of low-probability, unpredictable high emitters-which have been observed all along the supply chain- and are spatiotemporally variable. We conducted a coordinated campaign to measure methane emissions in a major gas producing region of the U.S. (Barnett Shale region of Texas) using a diversity of approaches. As part of this study we identified methods for effective quantification of regional fossil methane emissions using atmospheric data (through replicate mass balance flights and source apportionment using methane to ethane ratios) as well as how to build an accurate inventory that includes a statistical estimator that more rigorously captures the magnitude and frequency of high emitters. We found agreement between large-scale atmospheric sampling estimates and source

Forgotten carbon: indirect CO2 in greenhouse gas emission inventories

International Nuclear Information System (INIS)

Gillenwater, Michael

2008-01-01

National governments that are Parties to the United Nations Framework Convention on Climate Change (UNFCCC) are required to submit greenhouse gas (GHG) inventories accounting for the emissions and removals occurring within their geographic territories. The Intergovernmental Panel on Climate Change (IPCC) provides inventory methodology guidance to the Parties of the UNFCCC. This methodology guidance, and national inventories based on it, omits carbon dioxide (CO 2 ) from the atmospheric oxidation of methane, carbon monoxide, and non-methane volatile organic compounds emissions that result from several source categories. The inclusion of this category of 'indirect' CO 2 in GHG inventories increases global anthropogenic emissions (excluding land use and forestry) between 0.5 and 0.7%. However, the effect of inclusion on aggregate UNFCCC Annex I Party GHG emissions would be to reduce the growth of total emissions, from 1990 to 2004, by 0.2% points. The effect on the GHG emissions and emission trends of individual countries varies. The paper includes a methodology for calculating these emissions and discusses uncertainties. Indirect CO 2 is equally relevant for GHG inventories at other scales, such as global, regional, organizational, and facility. Similarly, project-based methodologies, such as those used under the Clean Development Mechanism, may need revising to account for indirect CO 2

Long-term decline of global atmospheric ethane concentrations and implications for methane.

Science.gov (United States)

Simpson, Isobel J; Sulbaek Andersen, Mads P; Meinardi, Simone; Bruhwiler, Lori; Blake, Nicola J; Helmig, Detlev; Rowland, F Sherwood; Blake, Donald R

2012-08-23

After methane, ethane is the most abundant hydrocarbon in the remote atmosphere. It is a precursor to tropospheric ozone and it influences the atmosphere's oxidative capacity through its reaction with the hydroxyl radical, ethane's primary atmospheric sink. Here we present the longest continuous record of global atmospheric ethane levels. We show that global ethane emission rates decreased from 14.3 to 11.3 teragrams per year, or by 21 per cent, from 1984 to 2010. We attribute this to decreasing fugitive emissions from ethane's fossil fuel source--most probably decreased venting and flaring of natural gas in oil fields--rather than a decline in its other major sources, biofuel use and biomass burning. Ethane's major emission sources are shared with methane, and recent studies have disagreed on whether reduced fossil fuel or microbial emissions have caused methane's atmospheric growth rate to slow. Our findings suggest that reduced fugitive fossil fuel emissions account for at least 10-21 teragrams per year (30-70 per cent) of the decrease in methane's global emissions, significantly contributing to methane's slowing atmospheric growth rate since the mid-1980s.

Atmospheric methane: Sources, sinks, and role in global change

International Nuclear Information System (INIS)

Khalil, M.A.K.

1993-01-01

Atmospheric methane is thought to be the most important trace gas involved in man-made climate change. It may be second only to carbon dioxide in causing global warming. Methane affects also the oxidizing capacity of the atmosphere by controlling tropospheric OH radicals and creating O 3 , and it affects the ozone layer in the stratosphere by contributing water vapor and removing chlorine atoms. In the long term, methane is a natural product of life on earth, reaching high concentrations during warm and biologically productive epochs. Yet the scientific understanding of atmospheric methane has evolved mostly during the past decade after it was shown that concentrations were rapidly rising. Because of the environmental importance of methane, North Atlantic Treaty Organization's Scientific and Environmental Affairs Division commissioned an Advanced Research Workshop. This book is the result of such a conference held during the week of 6 October 1991 at Timberline Lodge on Mount Hood near Portland, Oregon. (orig./KW)

Revised methane emissions factors and spatially distributed annual carbon fluxes for global livestock

Energy Technology Data Exchange (ETDEWEB)

Wolf, Julie; Asrar, Ghassem R.; West, Tristram O.

2017-09-29

Background: Livestock play an important role in carbon cycling through consumption of biomass and emissions of methane. Recent research suggests that existing bottom-up inventories of livestock methane emissions in the US, such as those made using 2006 IPCC Tier 1 livestock emissions factors, are too low. This may be due to outdated information used to develop these emissions factors. In this study, we update information for cattle and swine by region, based on reported recent changes in animal body mass, feed quality and quantity, milk productivity, and management of animals and manure. We then use this updated information to calculate new livestock methane emissions factors for enteric fermentation in cattle, and for manure management in cattle and swine.

Analysis of uncertainties in the estimates of nitrous oxide and methane emissions in the UK's greenhouse gas inventory for agriculture

Science.gov (United States)

Milne, Alice E.; Glendining, Margaret J.; Bellamy, Pat; Misselbrook, Tom; Gilhespy, Sarah; Rivas Casado, Monica; Hulin, Adele; van Oijen, Marcel; Whitmore, Andrew P.

2014-01-01

The UK's greenhouse gas inventory for agriculture uses a model based on the IPCC Tier 1 and Tier 2 methods to estimate the emissions of methane and nitrous oxide from agriculture. The inventory calculations are disaggregated at country level (England, Wales, Scotland and Northern Ireland). Before now, no detailed assessment of the uncertainties in the estimates of emissions had been done. We used Monte Carlo simulation to do such an analysis. We collated information on the uncertainties of each of the model inputs. The uncertainties propagate through the model and result in uncertainties in the estimated emissions. Using a sensitivity analysis, we found that in England and Scotland the uncertainty in the emission factor for emissions from N inputs (EF1) affected uncertainty the most, but that in Wales and Northern Ireland, the emission factor for N leaching and runoff (EF5) had greater influence. We showed that if the uncertainty in any one of these emission factors is reduced by 50%, the uncertainty in emissions of nitrous oxide reduces by 10%. The uncertainty in the estimate for the emissions of methane emission factors for enteric fermentation in cows and sheep most affected the uncertainty in methane emissions. When inventories are disaggregated (as that for the UK is) correlation between separate instances of each emission factor will affect the uncertainty in emissions. As more countries move towards inventory models with disaggregation, it is important that the IPCC give firm guidance on this topic.

Frozen heat: Global outlook on methane gas hydrates

Energy Technology Data Exchange (ETDEWEB)

Beaudoin, Yannick; Solgaard, Anne

2010-09-15

The United Nations Environment Programme via its collaborating center in Norway, UNEP/GRID-Arendal, is undertaking an assessment of the state of the knowledge of methane gas hydrates. The Global Outlook on Methane Gas Hydrates seeks to bridge the gap between the science, research and development activities related to this potential large scale unconventional source of natural gas and the needs of decision makers and the general public to understand the underlying societal and environmental drivers and impacts. The Outlook aims to provide credible and unbiased information sourced from stakeholders representing the environment, government, industry and society.

On the quality of global emission inventories. Approaches, methodologies, input data and uncertainties

International Nuclear Information System (INIS)

Olivier, J.G.J.

2002-01-01

Four key scientific questions will be investigated: (1) How does a user define the 'quality' of a global (or national) emission inventory? (Chapter 2); (2) What determines the quality of a global emission inventory? (Chapters 2 and 7); (3) How can inventory quality be achieved in practice and expressed in quantitative terms ('uncertainty')? (Chapters 3 to 6); and (4) What is the preferred approach for compiling a global emission inventory, given the practical limitations and the desired inventory quality? (Chapters 7 and 8)

Progresses in the stable isotope studies of microbial processes associated with wetland methane production

International Nuclear Information System (INIS)

Li Qing; Lin Guanghui

2013-01-01

Methane emissions from wetlands play a key role in regulating global atmospheric methane concentration, so better understanding of microbial processes for the methane emission in wetlands is critical for developing process models and reducing uncertainty in global methane emission inventory. In this review, we describe basic microbial processes for wetland methane production and then demonstrate how stable isotope fractionation and stable isotope probing can be used to investigate the mechanisms underlying different methanogenic pathways and to quantify microbial species involved in wetland methane production. When applying stable isotope technique to calculate contributions of different pathways to the total methane production in various wetlands, the technical challenge is how to determine isotopic fractionation factors for the acetate derived methane production and carbon dioxide derived methane production. Although the application of stable isotope probing techniques to study the actual functions of different microbial organisms to methane production process is significantly superior to the traditional molecular biology method, the combination of these two technologies will be crucial for direct linking of the microbial community and functional structure with the corresponding metabolic functions, and provide new ideas for future studies. (authors)

Evaluating Global Emission Inventories of Biogenic Bromocarbons

Science.gov (United States)

Hossaini, Ryan; Mantle, H.; Chipperfield, M. P.; Montzka, S. A.; Hamer, P.; Ziska, F.; Quack, B.; Kruger, K.; Tegtmeier, S.; Atlas, E.;

The IGAC activity for the development of global emissions inventories: Description and initial results

International Nuclear Information System (INIS)

Benkovitz, C.M.; Graedel, T.E.

1992-02-01

Modeling assessments of the atmospheric chemistry, air quality and climatic conditions of the past, present and future require as input inventories of emissions of the appropriate chemical species constructed on appropriate spatial and temporal scales. The task of the Global Emissions Inventories Activity (GEIA) of the International Global Atmospheric Chemistry Project (IGAC) is the production of global inventories suitable for a range of research applications. Current GEIA programs are generally based on addressing emissions by species; these include CO 2 , NH 3 /N 2 O, SO 2 /NO x , CFC, volatile organic compounds and radioisotopes. In addition a separate program to inventory emissions from biomass burning is also being structured, plus an additional program to address data management issues for all the developing inventories. Program priorities are based on current knowledge and tasks needed to produce the desired inventories. This paper will discuss the different types of global inventories to be developed by the GEIA programs, their key characteristics, and areas to be addressed in the compilation of such inventories. Results of the first GEIA task, a survey of existing inventories and auxiliary data, will be presented. The survey included status assessments for the available inventory information for nineteen different atmospheric species or groups of species on global and regional scales and over time. Of this entire body of information, the only inventory regarded as satisfactory was that for the global emissions of CFCs. An implication of the results of these assessments is that properly gridded emissions inventories are badly needed to support atmospheric modeling calculations on a variety of spatial and temporal scales. Initial studies in the development of global inventories of sulfur dioxide, currently the most advanced GEIA program, will be presented and discussed

Using global warming potential to compare methane and CO2 emissions

International Nuclear Information System (INIS)

Dufresne, J.L.

2009-01-01

Greenhouse gases affect the planetary heat budget. Any change of their concentration affects this budget and therefore the global mean surface temperature of the Earth. These gases have different radiative properties and different lifetimes in the atmosphere, which prevents any direct comparison of the consequences of their emissions on global warming. Almost twenty years ago, the Intergovernmental Panel on Climate Change (IPCC) proposed the global warming potential (GWP) as an index to compare the emissions of the various greenhouse gases. In a recent paper, it has been stated that the use of GWP leads to strongly underestimating the global warming due to constant methane emissions compared to that of constant CO 2 emissions. Here we show that it is not really the case. The GWP enables comparisons of global warming due to constant emissions for any prescribed period, 100 years being often used. But this comparison is not universal. For instance, the impact of methane is underestimated at the beginning of the chosen period while the impact of CO 2 is underestimated after this period

Global Assessment of Methane Gas Hydrates: Outreach for the public and policy makers

Science.gov (United States)

Beaudoin, Yannick

2010-05-01

The United Nations Environment Programme (UNEP), via its official collaborating center in Norway, GRID-Arendal, is in the process of implementing a Global Assessment of Methane Gas Hydrates. Global reservoirs of methane gas have long been the topic of scientific discussion both in the realm of environmental issues such as natural forces of climate change and as a potential energy resource for economic development. Of particular interest are the volumes of methane locked away in frozen molecules known as clathrates or hydrates. Our rapidly evolving scientific knowledge and technological development related to methane hydrates makes these formations increasingly prospective to economic development. In addition, global demand for energy continues, and will continue to outpace supply for the foreseeable future, resulting in pressure to expand development activities, with associated concerns about environmental and social impacts. Understanding the intricate links between methane hydrates and 1) natural and anthropogenic contributions to climate change, 2) their role in the carbon cycle (e.g. ocean chemistry) and 3) the environmental and socio-economic impacts of extraction, are key factors in making good decisions that promote sustainable development. As policy makers, environmental organizations and private sector interests seek to forward their respective agendas which tend to be weighted towards applied research, there is a clear and imminent need for a an authoritative source of accessible information on various topics related to methane gas hydrates. The 2008 United Nations Environment Programme Annual Report highlighted methane from the Arctic as an emerging challenge with respect to climate change and other environmental issues. Building upon this foundation, UNEP/GRID-Arendal, in conjunction with experts from national hydrates research groups from Canada, the US, Japan, Germany, Norway, India and Korea, aims to provide a multi-thematic overview of the key

The Fire INventory from NCAR (FINN: a high resolution global model to estimate the emissions from open burning

Directory of Open Access Journals (Sweden)

C. Wiedinmyer

2011-07-01

Full Text Available The Fire INventory from NCAR version 1.0 (FINNv1 provides daily, 1 km resolution, global estimates of the trace gas and particle emissions from open burning of biomass, which includes wildfire, agricultural fires, and prescribed burning and does not include biofuel use and trash burning. Emission factors used in the calculations have been updated with recent data, particularly for the non-methane organic compounds (NMOC. The resulting global annual NMOC emission estimates are as much as a factor of 5 greater than some prior estimates. Chemical speciation profiles, necessary to allocate the total NMOC emission estimates to lumped species for use by chemical transport models, are provided for three widely used chemical mechanisms: SAPRC99, GEOS-CHEM, and MOZART-4. Using these profiles, FINNv1 also provides global estimates of key organic compounds, including formaldehyde and methanol. Uncertainties in the emissions estimates arise from several of the method steps. The use of fire hot spots, assumed area burned, land cover maps, biomass consumption estimates, and emission factors all introduce error into the model estimates. The uncertainty in the FINNv1 emission estimates are about a factor of two; but, the global estimates agree reasonably well with other global inventories of biomass burning emissions for CO, CO₂, and other species with less variable emission factors. FINNv1 emission estimates have been developed specifically for modeling atmospheric chemistry and air quality in a consistent framework at scales from local to global. The product is unique because of the high temporal and spatial resolution, global coverage, and the number of species estimated. FINNv1 can be used for both hindcast and forecast or near-real time model applications and the results are being critically evaluated with models and observations whenever possible.

Speciation of anthropogenic emissions of non-methane volatile organic compounds: a global gridded data set for 1970–2012

Directory of Open Access Journals (Sweden)

G. Huang

2017-06-01

Full Text Available Non-methane volatile organic compounds (NMVOCs include a large number of chemical species which differ significantly in their chemical characteristics and thus in their impacts on ozone and secondary organic aerosol formation. It is important that chemical transport models (CTMs simulate the chemical transformation of the different NMVOC species in the troposphere consistently. In most emission inventories, however, only total NMVOC emissions are reported, which need to be decomposed into classes to fit the requirements of CTMs. For instance, the Emissions Database for Global Atmospheric Research (EDGAR provides spatially resolved global anthropogenic emissions of total NMVOCs. In this study the EDGAR NMVOC inventory was revised and extended in time and in sectors. Moreover the new version of NMVOC emission data in the EDGAR database were disaggregated on a detailed sector resolution to individual species or species groups, thus enhancing the usability of the NMVOC emission data by the modelling community. Region- and source-specific speciation profiles of NMVOC species or species groups are compiled and mapped to EDGAR processes (detailed resolution of sectors, with corresponding quality codes specifying the quality of the mapping. Individual NMVOC species in different profiles are aggregated to 25 species groups, in line with the common classification of the Global Emissions Initiative (GEIA. Global annual grid maps with a resolution of 0.1°  ×  0.1° for the period 1970–2012 are produced by sector and species. Furthermore, trends in NMVOC composition are analysed, taking road transport and residential sources in Germany and the United Kingdom (UK as examples.

Anthropogenic Methane Emissions in California's San Joaquin Valley: Characterizing Large Point Source Emitters

Science.gov (United States)

Hopkins, F. M.; Duren, R. M.; Miller, C. E.; Aubrey, A. D.; Falk, M.; Holland, L.; Hook, S. J.; Hulley, G. C.; Johnson, W. R.; Kuai, L.; Kuwayama, T.; Lin, J. C.; Thorpe, A. K.; Worden, J. R.; Lauvaux, T.; Jeong, S.; Fischer, M. L.

2015-12-01

Methane is an important atmospheric pollutant that contributes to global warming and tropospheric ozone production. Methane mitigation could reduce near term climate change and improve air quality, but is hindered by a lack of knowledge of anthropogenic methane sources. Recent work has shown that methane emissions are not evenly distributed in space, or across emission sources, suggesting that a large fraction of anthropogenic methane comes from a few "super-emitters." We studied the distribution of super-emitters in California's southern San Joaquin Valley, where elevated levels of atmospheric CH4 have also been observed from space. Here, we define super-emitters as methane plumes that could be reliably detected (i.e., plume observed more than once in the same location) under varying wind conditions by airborne thermal infrared remote sensing. The detection limit for this technique was determined to be 4.5 kg CH4 h-1 by a controlled release experiment, corresponding to column methane enhancement at the point of emissions greater than 20% above local background levels. We surveyed a major oil production field, and an area with a high concentration of large dairies using a variety of airborne and ground-based measurements. Repeated airborne surveys (n=4) with the Hyperspectral Thermal Emission Spectrometer revealed 28 persistent methane plumes emanating from oil field infrastructure, including tanks, wells, and processing facilities. The likelihood that a given source type was a super-emitter varied from roughly 1/3 for processing facilities to 1/3000 for oil wells. 11 persistent plumes were detected in the dairy area, and all were associated with wet manure management. The majority (11/14) of manure lagoons in the study area were super-emitters. Comparing to a California methane emissions inventory for the surveyed areas, we estimate that super-emitters comprise a minimum of 9% of inventoried dairy emissions, and 13% of inventoried oil emissions in this region.

Isotopes, Inventories and Seasonality: Unraveling Methane Source Distribution in the Complex Landscapes of the United Kingdom.

Science.gov (United States)

Lowry, D.; Fisher, R. E.; Zazzeri, G.; Lanoisellé, M.; France, J.; Allen, G.; Nisbet, E. G.

2017-12-01

Unlike the big open landscapes of many continents with large area sources dominated by one particular methane emission type that can be isotopically characterized by flight measurements and sampling, the complex patchwork of urban, fossil and agricultural methane sources across NW Europe require detailed ground surveys for characterization (Zazzeri et al., 2017). Here we outline the findings from multiple seasonal urban and rural measurement campaigns in the United Kingdom. These surveys aim to: 1) Assess source distribution and baseline in regions of planned fracking, and relate to on-site continuous baseline climatology. 2) Characterize spatial and seasonal differences in the isotopic signatures of the UNFCCC source categories, and 3) Assess the spatial validity of the 1 x 1 km UK inventory for large continuous emitters, proposed point sources, and seasonal / ephemeral emissions. The UK inventory suggests that 90% of methane emissions are from 3 source categories, ruminants, landfill and gas distribution. Bag sampling and GC-IRMS delta13C analysis shows that landfill gives a constant signature of -57 ±3 ‰ throughout the year. Fugitive gas emissions are consistent regionally depending on the North Sea supply regions feeding the network (-41 ± 2 ‰ in N England, -37 ± 2 ‰ in SE England). Ruminant, mostly cattle, emissions are far more complex as these spend winters in barns and summers in fields, but are essentially a mix of 2 end members, breath at -68 ±3 ‰ and manure at -51 ±3 ‰, resulting in broad summer field emission plumes of -64 ‰ and point winter barn emission plumes of -58 ‰. The inventory correctly locates emission hotspots from landfill, larger sewage treatment plants and gas compressor stations, giving a broad overview of emission distribution for regional model validation. Mobile surveys are adding an extra layer of detail to this which, combined with isotopic characterization, has identified spatial distribution of gas pipe leaks

Revised spatially distributed global livestock emissions

Science.gov (United States)

Asrar, G.; Wolf, J.; West, T. O.

2015-12-01

Livestock play an important role in agricultural carbon cycling through consumption of biomass and emissions of methane. Quantification and spatial distribution of methane and carbon dioxide produced by livestock is needed to develop bottom-up estimates for carbon monitoring. These estimates serve as stand-alone international emissions estimates, as input to global emissions modeling, and as comparisons or constraints to flux estimates from atmospheric inversion models. Recent results for the US suggest that the 2006 IPCC default coefficients may underestimate livestock methane emissions. In this project, revised coefficients were calculated for cattle and swine in all global regions, based on reported changes in body mass, quality and quantity of feed, milk production, and management of living animals and manure for these regions. New estimates of livestock methane and carbon dioxide emissions were calculated using the revised coefficients and global livestock population data. Spatial distribution of population data and associated fluxes was conducted using the MODIS Land Cover Type 5, version 5.1 (i.e. MCD12Q1 data product), and a previously published downscaling algorithm for reconciling inventory and satellite-based land cover data at 0.05 degree resolution. Preliminary results for 2013 indicate greater emissions than those calculated using the IPCC 2006 coefficients. Global total enteric fermentation methane increased by 6%, while manure management methane increased by 38%, with variation among species and regions resulting in improved spatial distributions of livestock emissions. These new estimates of total livestock methane are comparable to other recently reported studies for the entire US and the State of California. These new regional/global estimates will improve the ability to reconcile top-down and bottom-up estimates of methane production as well as provide updated global estimates for use in development and evaluation of Earth system models.

Impact of a global warming on biospheric sources of methane and its climatic consequences

Science.gov (United States)

Hameed, S.; Cess, R. D.

1980-01-01

Most of atmospheric methane originates by bacterial processes in anaerobic environments within the soil which are found to become more productive with increases in ambient temperature. A warming of climate, due to increasing levels of industrial gases resulting from fossil fuel burning, is thus likely to increase methane abundance within the atmosphere. This may lead to further heating of the atmosphere, since both methane and ozone (which is generated in the troposphere from reactions of methane) have greenhouse effects. This feedback mechanism has been explored with the use of a coupled climate-chemical model of the troposphere, by the calculation of the impact of the predicted global warming due to increased emissions of carbon dioxide and other industrial gases on the biospheric sources of methane.

Natural gas fugitive emissions rates constrained by global atmospheric methane and ethane.

Science.gov (United States)

Schwietzke, Stefan; Griffin, W Michael; Matthews, H Scott; Bruhwiler, Lori M P

2014-07-15

The amount of methane emissions released by the natural gas (NG) industry is a critical and uncertain value for various industry and policy decisions, such as for determining the climate implications of using NG over coal. Previous studies have estimated fugitive emissions rates (FER)--the fraction of produced NG (mainly methane and ethane) escaped to the atmosphere--between 1 and 9%. Most of these studies rely on few and outdated measurements, and some may represent only temporal/regional NG industry snapshots. This study estimates NG industry representative FER using global atmospheric methane and ethane measurements over three decades, and literature ranges of (i) tracer gas atmospheric lifetimes, (ii) non-NG source estimates, and (iii) fossil fuel fugitive gas hydrocarbon compositions. The modeling suggests an upper bound global average FER of 5% during 2006-2011, and a most likely FER of 2-4% since 2000, trending downward. These results do not account for highly uncertain natural hydrocarbon seepage, which could lower the FER. Further emissions reductions by the NG industry may be needed to ensure climate benefits over coal during the next few decades.

Global Gridded Emission Inventories of Pentabrominated Diphenyl Ether (PeBDE)

Science.gov (United States)

Li, Yi-Fan; Tian, Chongguo; Yang, Meng; Jia, Hongliang; Ma, Jianmin; Li, Dacheng

2010-05-01

Polybrominated diphenyl ethers (PBDEs) are flame retardants widely used in many everyday products such as cars, furniture, textiles, and other electronic equipment. The commercial PBDEs have three major technical mixtures: penta-(PeBDE), octa-(OBDE) and decabromodiphenyl ethers (DeBDE). PeBDE is a mixture of several BDE congeners, such as BDE-47, -99, and -100, and has been included as a new member of persistent organic pollutants (POPs) under the 2009 Stockholm Convention. In order to produce gridded emission inventories of PeBDE on a global scale, information of production, consumption, emission, and physiochemical properties of PeBDE have been searched for published papers, government reports, and internet publications. A methodology to estimate the emissions of PeBDE has been developed and global gridded emission inventories of 2 major congener in PeBDE mixture, BDE-47 and -99, on a 1 degree by 1degree latitude/longitude resolution for 2005 have been compiled. Using these emission inventories as input data, the Canadian Model for Environmental Transport of Organochlorine Pesticides (CanMETOP) model was used to simulate the transport of these chemicals and their concentrations in air were calculated for the year of 2005. The modeled air concentration of BDE-47 and -99 were compared with the monitoring air concentrations of these two congeners in the same year obtained from renowned international/national monitoring programs, such as Global Atmospheric Passive Sampling (GAPS), the Integrated Atmospheric Deposition Network (IADN), and the Chinese POPs Soil and Air Monitoring Program (SAMP), and significant correlations between the modeled results and the monitoring data were found, indicating the high quality of the produced emission inventories of BDE-47 and -99. Keywords: Pentabrominated Diphenyl Ether (PeBDE), Emission Inventories, Global, Model

Can EC and UK national methane emission inventories be verified using high precision stable isotope data?

International Nuclear Information System (INIS)

Lowry, D.; Holmes, C.W.; Nisbet, E.G.; Rata, N.D.

2002-01-01

The main anthropogenic sources of methane in industrialised countries (landfill/waste treatment, gas storage and distribution, coal) are far easier to reduce than CO 2 sources and the implementation of reduction strategies is potentially profitable. Statistical databases of methane emissions need independent external verification and carbon isotope data provide one way of estimating the expected source mix for each country if the main source types have been characterised isotopically. Using this method each country participating in the CORINAIR 94 database has been assigned an expected isotopic value for its emissions. The averaged δ 13 C of methane emitted from the CORINAIR region of Europe, based on total emissions of each country is -55.4 per mille for 1994. This European source mix can be verified using trajectory analysis for air samples collected at background stations. Methane emissions from the UK, and particularly the London region, have undergone more detailed analysis using data collected at the Royal Holloway site on the western fringe of London. If the latest emissions inventory figures are correct then the modelled isotopic change in the UK source mix is from -48.4 per mille in 1990 to -50.7 per mille in 1997. This represents a reduction in emissions of 25% over a 7-year period, important in meeting proposed UK greenhouse gas reduction targets. These changes can be tested by the isotopic analysis of air samples at carefully selected coastal background and interior sites. Regular sampling and isotopic analysis coupled with back trajectory analysis from a range of sites could provide an important tool for monitoring and verification of EC and UK methane emissions in the run-up to 2010. (author)

Mapping the spatial distribution of global anthropogenic mercury atmospheric emission inventories

Science.gov (United States)

Wilson, Simon J.; Steenhuisen, Frits; Pacyna, Jozef M.; Pacyna, Elisabeth G.

This paper describes the procedures employed to spatially distribute global inventories of anthropogenic emissions of mercury to the atmosphere, prepared by Pacyna, E.G., Pacyna, J.M., Steenhuisen, F., Wilson, S. [2006. Global anthropogenic mercury emission inventory for 2000. Atmospheric Environment, this issue, doi:10.1016/j.atmosenv.2006.03.041], and briefly discusses the results of this work. A new spatially distributed global emission inventory for the (nominal) year 2000, and a revised version of the 1995 inventory are presented. Emissions estimates for total mercury and major species groups are distributed within latitude/longitude-based grids with a resolution of 1×1 and 0.5×0.5°. A key component in the spatial distribution procedure is the use of population distribution as a surrogate parameter to distribute emissions from sources that cannot be accurately geographically located. In this connection, new gridded population datasets were prepared, based on the CEISIN GPW3 datasets (CIESIN, 2004. Gridded Population of the World (GPW), Version 3. Center for International Earth Science Information Network (CIESIN), Columbia University and Centro Internacional de Agricultura Tropical (CIAT). GPW3 data are available at http://beta.sedac.ciesin.columbia.edu/gpw/index.jsp). The spatially distributed emissions inventories and population datasets prepared in the course of this work are available on the Internet at www.amap.no/Resources/HgEmissions/

Marine methane cycle simulations for the period of early global warming

Energy Technology Data Exchange (ETDEWEB)

Elliott, S.; Maltrud, M.; Reagan, M.T.; Moridis, G.J.; Cameron-Smith, P.J.

2011-01-02

Geochemical environments, fates, and effects are modeled for methane released into seawater by the decomposition of climate-sensitive clathrates. A contemporary global background cycle is first constructed, within the framework of the Parallel Ocean Program. Input from organics in the upper thermocline is related to oxygen levels, and microbial consumption is parameterized from available rate measurements. Seepage into bottom layers is then superimposed, representing typical seabed fluid flow. The resulting CH{sub 4} distribution is validated against surface saturation ratios, vertical sections, and slope plume studies. Injections of clathrate-derived methane are explored by distributing a small number of point sources around the Arctic continental shelf, where stocks are extensive and susceptible to instability during the first few decades of global warming. Isolated bottom cells are assigned dissolved gas fluxes from porous-media simulation. Given the present bulk removal pattern, methane does not penetrate far from emission sites. Accumulated effects, however, spread to the regional scale following the modeled current system. Both hypoxification and acidification are documented. Sensitivity studies illustrate a potential for material restrictions to broaden the perturbations, since methanotrophic consumers require nutrients and trace metals. When such factors are considered, methane buildup within the Arctic basin is enhanced. However, freshened polar surface waters act as a barrier to atmospheric transfer, diverting products into the deep return flow. Uncertainties in the logic and calculations are enumerated including those inherent in high-latitude clathrate abundance, buoyant effluent rise through the column, representation of the general circulation, and bacterial growth kinetics.

Marine methane cycle simulations for the period of early global warming

Science.gov (United States)

Elliott, Scott; Maltrud, Mathew; Reagan, Matthew; Moridis, George; Cameron-Smith, Philip

2011-03-01

Geochemical environments, fates, and effects are modeled for methane released into seawater by the decomposition of climate-sensitive clathrates. A contemporary global background cycle is first constructed, within the framework of the Parallel Ocean Program. Input from organics in the upper thermocline is related to oxygen levels, and microbial consumption is parameterized from available rate measurements. Seepage into bottom layers is then superimposed, representing typical seabed fluid flow. The resulting CH4 distribution is validated against surface saturation ratios, vertical sections, and slope plume studies. Injections of clathrate-derived methane are explored by distributing a small number of point sources around the Arctic continental shelf, where stocks are extensive and susceptible to instability during the first few decades of global warming. Isolated bottom cells are assigned dissolved gas fluxes from porous-media simulation. Given the present bulk removal pattern, methane does not penetrate far from emission sites. Accumulated effects, however, spread to the regional scale following the modeled current system. Both hypoxification and acidification are documented. Sensitivity studies illustrate a potential for material restrictions to broaden the perturbations, since methanotrophic consumers require nutrients and trace metals. When such factors are considered, methane buildup within the Arctic basin is enhanced. However, freshened polar surface waters act as a barrier to atmospheric transfer, diverting products into the deep return flow. Uncertainties in the logic and calculations are enumerated including those inherent in high-latitude clathrate abundance, buoyant effluent rise through the column, representation of the general circulation, and bacterial growth kinetics.

Uncertainty of Methane Fluxes in a Northern Peatland under Global Climate Change

Science.gov (United States)

MA, S.; Jiang, J.; Huang, Y.; Luo, Y.

2016-12-01

Large uncertainty exists in predicting responses of methane fluxes to future climate change. How the uncertainty is related to methane production, oxidation, diffusion, ebullition and plant mediated transportation is still poorly understood, despite of the fact that these processes related to methane emission have been theoretically well represented. At the same time, in methane models many of the parameters are given to an empirical value according to measurements or models decades ago. It is unrealistic to testify all the parameters included in methane modules by actual in situ measurements due to the fact of high temporal and spatial variation. However it would be convincible and feasible to measure in field if models could offer better sampling strategy by telling which parameter is more important for estimation of methane emission, and project a constrained value for key parameters in each process. These feedbacks from field measurements could in turn testify the model accuracy for methane emission projection, as well as the optimization of model structures. We incorporated methane module into an existing process-based Terrestrial ECOsystem model (TECO), to simulate methane emission in a boreal peatland forest, northern Minnesota (Spruce and Peatland Responses Under Climatic and Environmental Change Experiment, SPRUCE). We performed sensitivity test and picked key parameters from the five processes for data assimilation using the Bayesian probability inversion and a Markov Chain Monte Carlo (MCMC) technique. We were able to constrain key parameters related to the five processes in the TECO-SPRUCE Methane model. The constrained model simulated daily methane emission fitted quite well with the data from field measurements. The improvement of more realistic and site-specific parameter values allow for reasonable projections of methane emission under different global changing scenarios, warming and elevated CO2, for instance, given the fact that methane emission

New global fire emission estimates and evaluation of volatile organic compounds

Science.gov (United States)

C. Wiedinmyer; L. K. Emmons; S. K. Akagi; R. J. Yokelson; J. J. Orlando; J. A. Al-Saadi; A. J. Soja

2010-01-01

A daily, high-resolution, global fire emissions model has been built to estimate emissions from open burning for air quality modeling applications: The Fire INventory from NCAR (FINN version 1). The model framework uses daily fire detections from the MODIS instruments and updated emission factors, specifically for speciated non-methane organic compounds (NMOC). Global...

Estimates and Predictions of Methane Emissions from Wastewater in China from 2000 to 2020

Science.gov (United States)

Du, Mingxi; Zhu, Qiuan; Wang, Xiaoge; Li, Peng; Yang, Bin; Chen, Huai; Wang, Meng; Zhou, Xiaolu; Peng, Changhui

2018-02-01

Methane accounts for 20% of the global warming caused by greenhouse gases, and wastewater is a major anthropogenic source of methane. Based on the Intergovernmental Panel on Climate Change greenhouse gas inventory guidelines and current research findings, we calculated the amount of methane emissions from 2000 to 2014 that originated from wastewater from different provinces in China. Methane emissions from wastewater increased from 1349.01 to 3430.03 Gg from 2000 to 2014, and the mean annual increase was 167.69 Gg. The methane emissions from industrial wastewater treated by wastewater treatment plants (EIt) accounted for the highest proportion of emissions. We also estimated the future trend of industrial wastewater methane emissions using the artificial neural network model. A comparison of the emissions for the years 2020, 2010, and 2000 showed an increasing trend in methane emissions in China and a spatial transition of industrial wastewater emissions from eastern and southern regions to central and southwestern regions and from coastal regions to inland regions. These changes were caused by changes in economics, demographics, and relevant policies.

Methane distribution and oxidation around the Lena Delta in summer 2013

Science.gov (United States)

Bussmann, Ingeborg; Hackbusch, Steffen; Schaal, Patrick; Wichels, Antje

2017-11-01

The Lena River is one of the largest Russian rivers draining into the Laptev Sea. The predicted increases in global temperatures are expected to cause the permafrost areas surrounding the Lena Delta to melt at increasing rates. This melting will result in high amounts of methane reaching the waters of the Lena and the adjacent Laptev Sea. The only biological sink that can lower methane concentrations within this system is methane oxidation by methanotrophic bacteria. However, the polar estuary of the Lena River, due to its strong fluctuations in salinity and temperature, is a challenging environment for bacteria. We determined the activity and abundance of aerobic methanotrophic bacteria by a tracer method and by the quantitative polymerase chain reaction. We described the methanotrophic population with a molecular fingerprinting method (monooxygenase intergenic spacer analysis), as well as the methane distribution (via a headspace method) and other abiotic parameters, in the Lena Delta in September 2013. The median methane concentrations were 22 nmol L-1 for riverine water (salinity (S) 20). The Lena River was not the source of methane in surface water, and the methane concentrations of the bottom water were mainly influenced by the methane concentration in surface sediments. However, the bacterial populations of the riverine and polar waters showed similar methane oxidation rates (0.419 and 0.400 nmol L-1 d-1), despite a higher relative abundance of methanotrophs and a higher estimated diversity in the riverine water than in the polar water. The methane turnover times ranged from 167 days in mixed water and 91 days in riverine water to only 36 days in polar water. The environmental parameters influencing the methane oxidation rate and the methanotrophic population also differed between the water masses. We postulate the presence of a riverine methanotrophic population that is limited by sub-optimal temperatures and substrate concentrations and a polar

Impact of transport model errors on the global and regional methane emissions estimated by inverse modelling

Directory of Open Access Journals (Sweden)

R. Locatelli

2013-10-01

Full Text Available A modelling experiment has been conceived to assess the impact of transport model errors on methane emissions estimated in an atmospheric inversion system. Synthetic methane observations, obtained from 10 different model outputs from the international TransCom-CH4 model inter-comparison exercise, are combined with a prior scenario of methane emissions and sinks, and integrated into the three-component PYVAR-LMDZ-SACS (PYthon VARiational-Laboratoire de Météorologie Dynamique model with Zooming capability-Simplified Atmospheric Chemistry System inversion system to produce 10 different methane emission estimates at the global scale for the year 2005. The same methane sinks, emissions and initial conditions have been applied to produce the 10 synthetic observation datasets. The same inversion set-up (statistical errors, prior emissions, inverse procedure is then applied to derive flux estimates by inverse modelling. Consequently, only differences in the modelling of atmospheric transport may cause differences in the estimated fluxes. In our framework, we show that transport model errors lead to a discrepancy of 27 Tg yr−1 at the global scale, representing 5% of total methane emissions. At continental and annual scales, transport model errors are proportionally larger than at the global scale, with errors ranging from 36 Tg yr−1 in North America to 7 Tg yr−1 in Boreal Eurasia (from 23 to 48%, respectively. At the model grid-scale, the spread of inverse estimates can reach 150% of the prior flux. Therefore, transport model errors contribute significantly to overall uncertainties in emission estimates by inverse modelling, especially when small spatial scales are examined. Sensitivity tests have been carried out to estimate the impact of the measurement network and the advantage of higher horizontal resolution in transport models. The large differences found between methane flux estimates inferred in these different configurations highly

Implementation of methane cycling for deep time, global warming simulations with the DCESS Earth System Model (Version 1.2)

DEFF Research Database (Denmark)

Shaffer, Gary; Villanueva, Esteban Fernández; Rondanelli, Roberto

2017-01-01

Geological records reveal a number of ancient, large and rapid negative excursions of carbon-13 isotope. Such excursions can only be explained by massive injections of depleted carbon to the Earth System over a short duration. These injections may have forced strong global warming events, sometimes....... With this improved DCESS model version and paleo-reconstructions, we are now better armed to gauge the amounts, types, time scales and locations of methane injections driving specific, observed deep time, global warming events......., or from warming-induced dissociation of methane hydrate, a solid compound of methane and water found in ocean sediments. As a consequence of the ubiquity and importance of methane in major Earth events, Earth System models should include a comprehensive treatment of methane cycling but such a treatment...

A new approach to inventorying bodies of water, from local to global scale

Directory of Open Access Journals (Sweden)

Bartout, Pascal

2015-12-01

Full Text Available Having reliable estimates of the number of water bodies on different geographical scales is of great importance to better understand biogeochemical cycles and to tackle the social issues related to the economic and cultural use of water bodies. However, limnological research suffers from a lack of reliable inventories; the available scientific references are predominately based on water bodies of natural origin, large in size and preferentially located in previously glaciated areas. Artificial, small and randomly distributed water bodies, especially ponds, are usually not inventoried. Following Wetzel’s theory (1990, some authors included them in global inventories by using remote sensing or mathematical extrapolation, but fieldwork on the ground has been done on a very limited amount of territory. These studies have resulted in an explosive increase in the estimated number of water bodies, going from 8.44 million lakes (Meybeck 1995 to 3.5 billion water bodies (Downing 2010. These numbers raise several questions, especially about the methodology used for counting small-sized water bodies and the methodological treatment of spatial variables. In this study, we use inventories of water bodies for Sweden, Finland, Estonia and France to show incoherencies generated by the “global to local” approach. We demonstrate that one universal relationship does not suffice for generating the regional or global inventories of water bodies because local conditions vary greatly from one region to another and cannot be offset adequately by each other. The current paradigm for global estimates of water bodies in limnology, which is based on one representative model applied to different territories, does not produce sufficiently exact global inventories. The step-wise progression from the local to the global scale requires the development of many regional equations based on fieldwork; a specific equation that adequately reflects the actual relationship

Implementation of methane cycling for deep-time global warming simulations with the DCESS Earth system model (version 1.2)

Science.gov (United States)

Shaffer, Gary; Fernández Villanueva, Esteban; Rondanelli, Roberto; Olaf Pepke Pedersen, Jens; Malskær Olsen, Steffen; Huber, Matthew

2017-11-01

Geological records reveal a number of ancient, large and rapid negative excursions of the carbon-13 isotope. Such excursions can only be explained by massive injections of depleted carbon to the Earth system over a short duration. These injections may have forced strong global warming events, sometimes accompanied by mass extinctions such as the Triassic-Jurassic and end-Permian extinctions 201 and 252 million years ago, respectively. In many cases, evidence points to methane as the dominant form of injected carbon, whether as thermogenic methane formed by magma intrusions through overlying carbon-rich sediment or from warming-induced dissociation of methane hydrate, a solid compound of methane and water found in ocean sediments. As a consequence of the ubiquity and importance of methane in major Earth events, Earth system models for addressing such events should include a comprehensive treatment of methane cycling but such a treatment has often been lacking. Here we implement methane cycling in the Danish Center for Earth System Science (DCESS) model, a simplified but well-tested Earth system model of intermediate complexity. We use a generic methane input function that allows variation in input type, size, timescale and ocean-atmosphere partition. To be able to treat such massive inputs more correctly, we extend the model to deal with ocean suboxic/anoxic conditions and with radiative forcing and methane lifetimes appropriate for high atmospheric methane concentrations. With this new model version, we carried out an extensive set of simulations for methane inputs of various sizes, timescales and ocean-atmosphere partitions to probe model behavior. We find that larger methane inputs over shorter timescales with more methane dissolving in the ocean lead to ever-increasing ocean anoxia with consequences for ocean life and global carbon cycling. Greater methane input directly to the atmosphere leads to more warming and, for example, greater carbon dioxide release

Implementation of methane cycling for deep-time global warming simulations with the DCESS Earth system model (version 1.2

Directory of Open Access Journals (Sweden)

G. Shaffer

2017-11-01

Full Text Available Geological records reveal a number of ancient, large and rapid negative excursions of the carbon-13 isotope. Such excursions can only be explained by massive injections of depleted carbon to the Earth system over a short duration. These injections may have forced strong global warming events, sometimes accompanied by mass extinctions such as the Triassic-Jurassic and end-Permian extinctions 201 and 252 million years ago, respectively. In many cases, evidence points to methane as the dominant form of injected carbon, whether as thermogenic methane formed by magma intrusions through overlying carbon-rich sediment or from warming-induced dissociation of methane hydrate, a solid compound of methane and water found in ocean sediments. As a consequence of the ubiquity and importance of methane in major Earth events, Earth system models for addressing such events should include a comprehensive treatment of methane cycling but such a treatment has often been lacking. Here we implement methane cycling in the Danish Center for Earth System Science (DCESS model, a simplified but well-tested Earth system model of intermediate complexity. We use a generic methane input function that allows variation in input type, size, timescale and ocean–atmosphere partition. To be able to treat such massive inputs more correctly, we extend the model to deal with ocean suboxic/anoxic conditions and with radiative forcing and methane lifetimes appropriate for high atmospheric methane concentrations. With this new model version, we carried out an extensive set of simulations for methane inputs of various sizes, timescales and ocean–atmosphere partitions to probe model behavior. We find that larger methane inputs over shorter timescales with more methane dissolving in the ocean lead to ever-increasing ocean anoxia with consequences for ocean life and global carbon cycling. Greater methane input directly to the atmosphere leads to more warming and, for example

Impact of a global warming on biospheric sources of methane and its climatic consequences

Energy Technology Data Exchange (ETDEWEB)

Hameed, S; Cess, R D

1983-01-01

Most atmospheric methane originates by bacterial processes in anaerobic environments within the soil, which become more productive with increases in ambient temperature. A warming of the climate, due to increasing levels of industrial gases resulting from fossil fuel burning, is likely to increase methane concentrations within the atmosphere, possibly leading to further heating, since both methane and ozone (which is generated in the troposphere from reactions of methane) have greenhouse effects. Investigators explored this feedback mechanism using a coupled climate-chemical model of the troposphere, by calculating the impact of the predicted global warming due to increased emissions of carbon dioxide and other industrial gases on the biospheric sources of methane. Although they found this climate feedback to be, by itself, relatively minor, it can produce measurable increases in atmospheric CH/sub 4/ concentration, a quantity that should additionally increase as a consequence of increasing anthropogenic emissions of CO and CH/sub 4/.

Methodology for methane emission inventory from Snam transmission system

International Nuclear Information System (INIS)

Premoli, M.; Riva, A.

1997-01-01

Methane, the main component of natural gas, is recognised as one of the most important contributors of the greenhouse effect, responsible for about 22% of the total. Several industries of natural gas, among which Snam, have undertaken intensive programs focused on the quantification of the total amounts of methane emitted in their operating activities. Snam elaborated a scientifically reliable methodology, for evaluating the annual methane emissions from its transmission system, based on a statistic approach using specific 'activity factors', that are the emitting equipment population and the frequency of emitting events, and emission factors. Part of the latter are based on GRI-EPA emission factors calculated for natural gas systems in the U.S. and adjusted to Snam system, and the other were measured during a field campaign on a random sample of previously identified large emission sources in Snam compressor and metering and regulating stations. The study showed that the methane release to the air from Snam natural gas transmission system was only the 0.1% of the total amount of methane in the natural gas imported and produced in Italy in 1993. (au)

Variability and quasi-decadal changes in the methane budget over the period 2000-2012

Science.gov (United States)

Saunois, Marielle; Bousquet, Philippe; Poulter, Ben; Peregon, Anna; Ciais, Philippe; Canadell, Josep G.; Dlugokencky, Edward J.; Etiope, Giuseppe; Bastviken, David; Houweling, Sander; Janssens-Maenhout, Greet; Tubiello, Francesco N.; Castaldi, Simona; Jackson, Robert B.; Alexe, Mihai; Arora, Vivek K.; Beerling, David J.; Bergamaschi, Peter; Blake, Donald R.; Brailsford, Gordon; Bruhwiler, Lori; Crevoisier, Cyril; Crill, Patrick; Covey, Kristofer; Frankenberg, Christian; Gedney, Nicola; Höglund-Isaksson, Lena; Ishizawa, Misa; Ito, Akihiko; Joos, Fortunat; Kim, Heon-Sook; Kleinen, Thomas; Krummel, Paul; Lamarque, Jean-François; Langenfelds, Ray; Locatelli, Robin; Machida, Toshinobu; Maksyutov, Shamil; Melton, Joe R.; Morino, Isamu; Naik, Vaishali; O'Doherty, Simon; Parmentier, Frans-Jan W.; Patra, Prabir K.; Peng, Changhui; Peng, Shushi; Peters, Glen P.; Pison, Isabelle; Prinn, Ronald; Ramonet, Michel; Riley, William J.; Saito, Makoto; Santini, Monia; Schroeder, Ronny; Simpson, Isobel J.; Spahni, Renato; Takizawa, Atsushi; Thornton, Brett F.; Tian, Hanqin; Tohjima, Yasunori; Viovy, Nicolas; Voulgarakis, Apostolos; Weiss, Ray; Wilton, David J.; Wiltshire, Andy; Worthy, Doug; Wunch, Debra; Xu, Xiyan; Yoshida, Yukio; Zhang, Bowen; Zhang, Zhen; Zhu, Qiuan

2017-09-01

Following the recent Global Carbon Project (GCP) synthesis of the decadal methane (CH4) budget over 2000-2012 (Saunois et al., 2016), we analyse here the same dataset with a focus on quasi-decadal and inter-annual variability in CH4 emissions. The GCP dataset integrates results from top-down studies (exploiting atmospheric observations within an atmospheric inverse-modelling framework) and bottom-up models (including process-based models for estimating land surface emissions and atmospheric chemistry), inventories of anthropogenic emissions, and data-driven approaches. The annual global methane emissions from top-down studies, which by construction match the observed methane growth rate within their uncertainties, all show an increase in total methane emissions over the period 2000-2012, but this increase is not linear over the 13 years. Despite differences between individual studies, the mean emission anomaly of the top-down ensemble shows no significant trend in total methane emissions over the period 2000-2006, during the plateau of atmospheric methane mole fractions, and also over the period 2008-2012, during the renewed atmospheric methane increase. However, the top-down ensemble mean produces an emission shift between 2006 and 2008, leading to 22 [16-32] Tg CH4 yr-1 higher methane emissions over the period 2008-2012 compared to 2002-2006. This emission increase mostly originated from the tropics, with a smaller contribution from mid-latitudes and no significant change from boreal regions. The regional contributions remain uncertain in top-down studies. Tropical South America and South and East Asia seem to contribute the most to the emission increase in the tropics. However, these two regions have only limited atmospheric measurements and remain therefore poorly constrained. The sectorial partitioning of this emission increase between the periods 2002-2006 and 2008-2012 differs from one atmospheric inversion study to another. However, all top-down studies

Global emission inventory and atmospheric transport of black carbon. Evaluation of the associated exposure

Energy Technology Data Exchange (ETDEWEB)

Wang, Rong

2015-06-01

This thesis presents research focusing on the improvement of high-resolution global black carbon (BC) emission inventory and application in assessing the population exposure to ambient BC. A particular focus of the thesis is on the construction of a high-resolution (both spatial and sectorial) fuel consumption database, which is used to develop the emission inventory of black carbon. Above all, the author updates the global emission inventory of black carbon, a resource subsequently used to study the atmospheric transport of black carbon over Asia with the help of a high-resolution nested model. The thesis demonstrates that spatial bias in fuel consumption and BC emissions can be reduced by means of the sub-national disaggregation approach. Using the inventory and nested model, ambient BC concentrations can be better validated against observations. Lastly, it provides a complete uncertainty analysis of global black carbon emissions, and this uncertainty is taken into account in the atmospheric modeling, helping to better understand the role of black carbon in regional and global air pollution.

Attribution of changes in global wetland methane emissions from pre-industrial to present using CLM4.5-BGC

International Nuclear Information System (INIS)

Paudel, Rajendra; Mahowald, Natalie M; Hess, Peter G M; Meng, Lei; Riley, William J

2016-01-01

An understanding of potential factors controlling methane emissions from natural wetlands is important to accurately project future atmospheric methane concentrations. Here, we examine the relative contributions of climatic and environmental factors, such as precipitation, temperature, atmospheric CO 2 concentration, nitrogen deposition, wetland inundation extent, and land-use and land-cover change, on changes in wetland methane emissions from preindustrial to present day (i.e., 1850–2005). We apply a mechanistic methane biogeochemical model integrated in the Community Land Model version 4.5 (CLM4.5), the land component of the Community Earth System Model. The methane model explicitly simulates methane production, oxidation, ebullition, transport through aerenchyma of plants, and aqueous and gaseous diffusion. We conduct a suite of model simulations from 1850 to 2005, with all changes in environmental factors included, and sensitivity studies isolating each factor. Globally, we estimate that preindustrial methane emissions were higher by 10% than present-day emissions from natural wetlands, with emissions changes from preindustrial to the present of +15%, −41%, and −11% for the high latitudes, temperate regions, and tropics, respectively. The most important change is due to the estimated change in wetland extent, due to the conversion of wetland areas to drylands by humans. This effect alone leads to higher preindustrial global methane fluxes by 33% relative to the present, with the largest change in temperate regions (+80%). These increases were partially offset by lower preindustrial emissions due to lower CO 2 levels (10%), shifts in precipitation (7%), lower nitrogen deposition (3%), and changes in land-use and land-cover (2%). Cooler temperatures in the preindustrial regions resulted in our simulations in an increase in global methane emissions of 6% relative to present day. Much of the sensitivity to these perturbations is mediated in the model by

Variability and quasi-decadal changes in the methane budget over the period 2000–2012

Directory of Open Access Journals (Sweden)

M. Saunois

2017-09-01

Full Text Available Following the recent Global Carbon Project (GCP synthesis of the decadal methane (CH4 budget over 2000–2012 (Saunois et al., 2016, we analyse here the same dataset with a focus on quasi-decadal and inter-annual variability in CH4 emissions. The GCP dataset integrates results from top-down studies (exploiting atmospheric observations within an atmospheric inverse-modelling framework and bottom-up models (including process-based models for estimating land surface emissions and atmospheric chemistry, inventories of anthropogenic emissions, and data-driven approaches. The annual global methane emissions from top-down studies, which by construction match the observed methane growth rate within their uncertainties, all show an increase in total methane emissions over the period 2000–2012, but this increase is not linear over the 13 years. Despite differences between individual studies, the mean emission anomaly of the top-down ensemble shows no significant trend in total methane emissions over the period 2000–2006, during the plateau of atmospheric methane mole fractions, and also over the period 2008–2012, during the renewed atmospheric methane increase. However, the top-down ensemble mean produces an emission shift between 2006 and 2008, leading to 22 [16–32] Tg CH4 yr−1 higher methane emissions over the period 2008–2012 compared to 2002–2006. This emission increase mostly originated from the tropics, with a smaller contribution from mid-latitudes and no significant change from boreal regions. The regional contributions remain uncertain in top-down studies. Tropical South America and South and East Asia seem to contribute the most to the emission increase in the tropics. However, these two regions have only limited atmospheric measurements and remain therefore poorly constrained. The sectorial partitioning of this emission increase between the periods 2002–2006 and 2008–2012 differs from one atmospheric inversion study to

Impact of a global warming on biospheric sources of methane and its climatic consequences

Energy Technology Data Exchange (ETDEWEB)

Hameed, S; Cess, R D [State Univ. of New York at Stony Brook, Stony Brook, NY (USA). Lab. for Planetary Atmospheres Research

1983-01-01

Most of atmospheric methane originates by bacterial processes in anaerobic environments within the soil which are found to become more productive with increases in ambient temperature. A warming of climate, due to increasing levels of industrial gases resulting from fossil fuel burning, is thus likely to increase methane abundance within the atmosphere. This may lead to further heating of the atmosphere, since both methane and ozone (which is generated in the troposphere from reactions of methane) have greenhouse effects. We have explored this feedback mechanism using a coupled climate-chemical model of the troposphere, by calculating the impact of the predicted global warming due to increased emissions of carbon dioxide and other industrial gases on the biospheric sources of methane. Although we find this climate feedback to be, by itself, relatively minor, it can produce measurable increases in atmospheric CH/sub 4/ concentration, a quantity which should additionally increase as a consequence of increasing anthropogenic emissions of CO and CH/sub 4/ itself. It would thus seem useful to carefully monitor future atmospheric CH/sub 4/ concentrations.

Impact of a global warming on biospheric sources of methane and its climatic consequences

Energy Technology Data Exchange (ETDEWEB)

Hameed, S; Cess, R D

1983-02-01

Most of atmospheric methane originates by bacterial processes in anaerobic environments within the soil which are found to become more productive with increases in ambient temperature. A warming of climate, due to increasing levels of industrial gases resulting from fossil fuel burning, is thus likely to increase methane abundance within the atmosphere. This may lead to further heating of the atmosphere, since both methane and ozone (which is generated in the troposphere from reactions of methane) have greenhouse effects. We have explored this feedback mechanism using a coupled climate-chemical model of the troposphere, by calculating the impact of the predicted global warming due to increased emissions of carbon dioxide and other industrial gases on the biospheric sources of methane. Although we find this climate feedback to be, by itself, relatively minor, it can produce measurable increases in atmospheric CH/sub 4/ concentration, a quantity which should additionally increase as a consequence of increasing anthropogenic emissions of CO and CH/sub 4/ itself. It would thus seem useful to carefully monitor future atmospheric CH/sub 4/ concentrations.

The importance of sustained action against methane - note from the French delegation

International Nuclear Information System (INIS)

2009-01-01

Methane is a more powerful greenhouse gas than CO 2 . While CO 2 can persist in the atmosphere for several centuries, methane disappears in a few decades. It impact therefore varies over time: over twenty years its warming power is seventy times that of CO 2 ; over a hundred years, only twenty-four times; and over five hundred years only seven times. Methane's contribution to warming is therefore much greater in the short term. The action taken to reduce it over the next ten to twenty years will be crucial in preventing world temperatures' exceeding a dangerous threshold, such as 2 deg. C above pre-industrial temperatures. Accordingly, sustained action to reduce methane emissions will be an important factor in restricting the scope and speed of warming over the next two decades even if its effect on long-term stabilisation - dominated by CO 2 - is limited. It was agreed in the 1990's that heating power over a hundred years (twenty-four for methane) would be used for the preparation of inventories of the developed countries' emissions and targets for the purposes of the Kyoto Protocol. Certain developing countries (Brazil in particular) challenge that choice and propose using a period of five hundred years instead, which would have the effect of reducing the calculation of their emissions as methane plays a larger part in their inventories than in those of the developed countries. New Zealand is an exception among the developed countries and supports the proposal of changing to a timetable of five hundred years. Changing the weighting used in the inventories and taking a period of twenty years would give greater weight to methane, but would be unacceptable to most parties to the Convention. Nor is it a question of reducing the impact of essential short-term action on CO 2 but rather of supplementing it. A distinction must be made between medium- and long-term inventories on the one hand and immediate action to reduce actual emissions on the other. Unlike CO 2 today

The importance of addressing methane emissions as part of a comprehensive greenhouse gas management strategy

Energy Technology Data Exchange (ETDEWEB)

Bylin, Carey [U.S. Environmental Protection Agency (EPA), Washington, DC (United States); Robinson, Donald; Cacho, Mariella; Russo, Ignacio; Stricklin, Eric [ICF International, Fairfax, VA (United States); Rortveit, Geir Johan [Statoil, Stavanger (Norway); Chakraborty, A.B. [Oil and Natural Gas Corporation Ltda. (ONGC), Dehradun (India); Pontiff, Mike [Newfield, The Woodlands, TX, (United States); Smith, Reid [British Petroleum (BP), London (United Kingdom)

2012-07-01

Given the climate forcing properties of greenhouse gases (GHGs) and the current state of the global economy, it is imperative to mitigate emissions of GHGs cost-effectively. Typically, CO{sub 2} is the main focus of most companies' and governments' GHG emissions reductions strategies. However, when considering near-term goals, it becomes clear that emissions reductions of other GHGs must be pursued. One such GHG is methane, the primary component of natural gas. Reducing GHG emissions and generating profits are not necessarily a mutually exclusive endeavor as illustrated by the United States Environmental Protection Agency's (EPA) Natural Gas STAR Program. The Program is a worldwide voluntary, flexible partnership of oil and gas companies which promotes cost-effective technologies and practices to reduce methane emissions from oil and natural gas operations. In an effort to meet environmental goals without sacrificing profitability, Natural Gas STAR partner companies have identified over 60 cost-effective best practices to reduce their methane emissions, which they report to the EPA. This paper discusses: 1) the importance of reducing methane emissions and its economic impact, 2) a comparison of methane emission reduction projects relative to other greenhouse gas reduction projects in the oil and gas industry, 3) the value of source-specific methane emissions inventories, and 4) methane emission reduction opportunities from hydraulically fractured gas well completions and centrifugal compressor wet seals. From the analyses and examples in this paper, it can be concluded that methane emission reduction projects can be readily identified, profitable, and effective in mitigating global climate change. (author)

Methane monitoring from space

Science.gov (United States)

Stephan, C.; Alpers, M.; Millet, B.; Ehret, G.; Flamant, P.

2017-11-01

Methane is one of the strongest anthropogenic greenhouse gases. It contributes by its radiative forcing significantly to the global warming. For a better understanding of climate changes, it is necessary to apply precise space-based measurement techniques in order to obtain a global view on the complex processes that control the methane concentration in the atmosphere. The MERLIN mission is a joint French-German cooperation, on a micro satellite mission for space-based measurement of spatial and temporal gradients of atmospheric methane columns on a global scale. MERLIN will be the first Integrated Path Differential Absorption LIDAR for greenhouse gas monitoring from space. In contrast to passive methane missions, the LIDAR instrument allows measurements at alllatitudes, all-seasons and during night.

Methane and Nitrous Oxide Emissions from Agriculture on a Regional Scale

OpenAIRE

Agnieszka Wysocka-Czubaszek; Robert Czubaszek; Sławomir Roj-Rojewski; Piotr Banaszuk

2018-01-01

Nowadays, agriculture has to meet the growing food demand together with high requirements of environmental protection, especially regarding the climate change. The greenhouse gas emissions differ not only on a global, but also on a regional scale, and mitigation strategies are effective when they are adapted properly. Therefore, the aim of this paper is to present the results of methane (CH4) and nitrous oxide (N2O) emissions inventory on a regional level in Poland in years 1999-2015. The CH4...

Trends and inter-annual variability of methane emissions derived from 1979-1993 global CTM simulations

Directory of Open Access Journals (Sweden)

F. Dentener

2003-01-01

Full Text Available The trend and interannual variability of methane sources are derived from multi-annual simulations of tropospheric photochemistry using a 3-D global chemistry-transport model. Our semi-inverse analysis uses the fifteen years (1979--1993 re-analysis of ECMWF meteorological data and annually varying emissions including photo-chemistry, in conjunction with observed CH4 concentration distributions and trends derived from the NOAA-CMDL surface stations. Dividing the world in four zonal regions (45--90 N, 0--45 N, 0--45 S, 45--90 S we find good agreement in each region between (top-down calculated emission trends from model simulations and (bottom-up estimated anthropogenic emission trends based on the EDGAR global anthropogenic emission database, which amounts for the period 1979--1993 2.7 Tg CH4 yr-1. Also the top-down determined total global methane emission compares well with the total of the bottom-up estimates. We use the difference between the bottom-up and top-down determined emission trends to calculate residual emissions. These residual emissions represent the inter-annual variability of the methane emissions. Simulations have been performed in which the year-to-year meteorology, the emissions of ozone precursor gases, and the stratospheric ozone column distribution are either varied, or kept constant. In studies of methane trends it is most important to include the trends and variability of the oxidant fields. The analyses reveals that the variability of the emissions is of the order of 8Tg CH4 yr-1, and likely related to wetland emissions and/or biomass burning.

Modeling of methane bubbles released from large sea-floor area: Condition required for methane emission to the atmosphere

OpenAIRE

Yamamoto, A.; Yamanaka, Y.; Tajika, E.

2009-01-01

Massive methane release from sea-floor sediments due to decomposition of methane hydrate, and thermal decomposition of organic matter by volcanic outgassing, is a potential contributor to global warming. However, the degree of global warming has not been estimated due to uncertainty over the proportion of methane flux from the sea-floor to reach the atmosphere. Massive methane release from a large sea-floor area would result in methane-saturated seawater, thus some methane would reach the atm...

Update and improvement of the global krypton-85 emission inventory

International Nuclear Information System (INIS)

Ahlswede, Jochen; Hebel, Simon; Ross, J. Ole; Schoetter, Robert; Kalinowski, Martin B.

2013-01-01

Krypton-85 is mainly produced in nuclear reactors by fission of uranium and plutonium and released during chopping and dissolution of spent fuel rods in nuclear reprocessing facilities. As noble gas it is suited as a passive tracer for evaluation of atmospheric transport models. Furthermore, research is ongoing to assess its quality as an indicator for clandestine reprocessing activities. This paper continues previous efforts to compile a comprehensive historic emission inventory for krypton-85. Reprocessing facilities are the by far largest emitters of krypton-85. Information on sources and calculations used to derive the annual krypton-85 emission is provided for all known reprocessing facilities in the world. In addition, the emission characteristics of two plants, Tokai (Japan) and La Hague (France), are analysed in detail using emission data with high temporal resolution. Other types of krypton-85 sources are power reactors, naval reactors and isotope production facilities. These sources contribute only little or negligible amounts of krypton-85 compared to the large reprocessing facilities. Taking the decay of krypton-85 into account, the global atmospheric inventory is estimated to about 5500 PBq at the end of 2009. The correctness if the inventory has been proven by meteorological simulations and its error is assumed to be in the range of a few percent. - Highlights: ► Krypton-85 is mainly produced in nuclear reactors and released during reprocessing. ► Krypten-85 can be possibly used as an indicator for clandestine reprocessing. ► This work provides an up-to-date global krypton-85 emission inventory. ► The inventory includes emissions from all possible artificial sources.

Estimation of Atmospheric Methane Surface Fluxes Using a Global 3-D Chemical Transport Model

Science.gov (United States)

Chen, Y.; Prinn, R.

2003-12-01

Accurate determination of atmospheric methane surface fluxes is an important and challenging problem in global biogeochemical cycles. We use inverse modeling to estimate annual, seasonal, and interannual CH4 fluxes between 1996 and 2001. The fluxes include 7 time-varying seasonal (3 wetland, rice, and 3 biomass burning) and 3 steady aseasonal (animals/waste, coal, and gas) global processes. To simulate atmospheric methane, we use the 3-D chemical transport model MATCH driven by NCEP reanalyzed observed winds at a resolution of T42 ( ˜2.8° x 2.8° ) in the horizontal and 28 levels (1000 - 3 mb) in the vertical. By combining existing datasets of individual processes, we construct a reference emissions field that represents our prior guess of the total CH4 surface flux. For the methane sink, we use a prescribed, annually-repeating OH field scaled to fit methyl chloroform observations. MATCH is used to produce both the reference run from the reference emissions, and the time-dependent sensitivities that relate individual emission processes to observations. The observational data include CH4 time-series from ˜15 high-frequency (in-situ) and ˜50 low-frequency (flask) observing sites. Most of the high-frequency data, at a time resolution of 40-60 minutes, have not previously been used in global scale inversions. In the inversion, the high-frequency data generally have greater weight than the weekly flask data because they better define the observational monthly means. The Kalman Filter is used as the optimal inversion technique to solve for emissions between 1996-2001. At each step in the inversion, new monthly observations are utilized and new emissions estimates are produced. The optimized emissions represent deviations from the reference emissions that lead to a better fit to the observations. The seasonal processes are optimized for each month, and contain the methane seasonality and interannual variability. The aseasonal processes, which are less variable, are

Observation of Wetland Dynamics with Global Navigation Satellite Signals Reflectometry

Science.gov (United States)

Zuffada, C.; Shah, R.; Nghiem, S. V.; Cardellach, E.; Chew, C. C.

2015-12-01

Wetland dynamics is crucial to changes in both atmospheric methane and terrestrial water storage. The Intergovernmental Panel on Climate Change's Fifth Assessment Report (IPCC AR5) highlights the role of wetlands as a key driver of methane (CH4) emission, which is more than one order of magnitude stronger than carbon dioxide as a greenhouse gas in the centennial time scale. Among the multitude of methane emission sources (hydrates, livestock, rice cultivation, freshwaters, landfills and waste, fossil fuels, biomass burning, termites, geological sources, and soil oxidation), wetlands constitute the largest contributor with the widest uncertainty range of 177-284 Tg(CH4) yr-1 according to the IPCC estimate. Wetlands are highly susceptible to climate change that might lead to wetland collapse. Such wetland destruction would decrease the terrestrial water storage capacity and thus contribute to sea level rise, consequently exacerbating coastal flooding problems. For both methane change and water storage change, wetland dynamics is a crucial factor with the largest uncertainty. Nevertheless, a complete and consistent map of global wetlands still needs to be obtained as the Ramsar Convention calls for a wetlands inventory and impact assessment. We develop a new method for observations of wetland change using Global Navigation Satellite Signals Reflectometry (GNSS-R) signatures for global wetland mapping in synergy with the existing capability, not only as a static inventory but also as a temporal dataset, to advance the capability for monitoring the dynamics of wetland extent relevant to addressing the science issues of CH4 emission change and terrestrial water storage change. We will demonstrate the capability of the new GNSS-R method over a rice field in the Ebro Delta wetland in Spain.

Methane distribution and oxidation around the Lena Delta in summer 2013

Directory of Open Access Journals (Sweden)

I. Bussmann

2017-11-01

Full Text Available The Lena River is one of the largest Russian rivers draining into the Laptev Sea. The predicted increases in global temperatures are expected to cause the permafrost areas surrounding the Lena Delta to melt at increasing rates. This melting will result in high amounts of methane reaching the waters of the Lena and the adjacent Laptev Sea. The only biological sink that can lower methane concentrations within this system is methane oxidation by methanotrophic bacteria. However, the polar estuary of the Lena River, due to its strong fluctuations in salinity and temperature, is a challenging environment for bacteria. We determined the activity and abundance of aerobic methanotrophic bacteria by a tracer method and by the quantitative polymerase chain reaction. We described the methanotrophic population with a molecular fingerprinting method (monooxygenase intergenic spacer analysis, as well as the methane distribution (via a headspace method and other abiotic parameters, in the Lena Delta in September 2013. The median methane concentrations were 22 nmol L−1 for riverine water (salinity (S  < 5, 19 nmol L−1 for mixed water (5 < S < 20 and 28 nmol L−1 for polar water (S > 20. The Lena River was not the source of methane in surface water, and the methane concentrations of the bottom water were mainly influenced by the methane concentration in surface sediments. However, the bacterial populations of the riverine and polar waters showed similar methane oxidation rates (0.419 and 0.400 nmol L−1 d−1, despite a higher relative abundance of methanotrophs and a higher estimated diversity in the riverine water than in the polar water. The methane turnover times ranged from 167 days in mixed water and 91 days in riverine water to only 36 days in polar water. The environmental parameters influencing the methane oxidation rate and the methanotrophic population also differed between the water masses. We

Comparison of global inventories of CO_2 emissions from biomass burning during 2002–2011 derived from multiple satellite products

International Nuclear Information System (INIS)

Shi, Yusheng; Matsunaga, Tsuneo; Saito, Makoto; Yamaguchi, Yasushi; Chen, Xuehong

2015-01-01

This study compared five widely used globally gridded biomass burning emissions inventories for the 2002–2011 period (Global Fire Emissions Database 3 (GFED3), Global Fire Emissions Database 4 (GFED4), Global Fire Assimilation System 1.0 (GFAS1.0), Fire INventory from NCAR 1.0 (FINN1.0) and Global Inventory for Chemistry-Climate studies-GFED4 (G-G)). Average annual CO_2 emissions range from 6521.3 to 9661.5 Tg year"−"1 for five inventories, with extensive amounts in Africa, South America and Southeast Asia. Coefficient of Variation for Southern America, Northern and Southern Africa are 30%, 39% and 48%. Globally, the majority of CO_2 emissions are released from savanna burnings, followed by forest and cropland burnings. The largest differences among the five inventories are mainly attributable to the overestimation of CO_2 emissions by FINN1.0 in Southeast Asia savanna and cropland burning, and underestimation in Southern Africa savanna and Amazon forest burning. The overestimation in Africa by G-G also contributes to the differences. - Highlights: • Five widely used global biomass burning emissions inventories were compared. • Global CO_2 emissions compared well while regional differences are large. • The largest differences were found in Southeast Asia and Southern Africa. • Savanna burning emission was the largest contributor to the global emissions. • Variations in savanna burning emission led to the differences among inventories. - Differences of the five biomass burning CO_2 emissions inventories were found in Southeast Asia and Southern Africa due to the variations in savanna burning emissions estimation.

Methane and Climate Change

NARCIS (Netherlands)

Reay, D.; Smith, P.; Amstel, van A.R.

2010-01-01

Methane is a powerful greenhouse gas and is estimated to be responsible for approximately one-fifth of man-made global warming. Per kilogram, it is 25 times more powerful than carbon dioxide over a 100-year time horizon -- and global warming is likely to enhance methane release from a number of

Methane emissions from a freshwater marsh in response to experimentally simulated global warming and nitrogen enrichment

DEFF Research Database (Denmark)

Flury, Sabine; McGinnis, Daniel Frank; Gessner, Mark O.

2010-01-01

We determined methane (CH4) emissions in a field enclosure experiment in a littoral freshwater marsh under the influence of experimentally simulated warming and enhanced nitrogen deposition. Methane emissions by ebullition from the marsh composed of Phragmites australis were measured with funnel ...... to the atmosphere, even when they occupy only relatively small littoral areas. More detailed investigations are clearly needed to assess whether global warming and nitrogen deposition can have climate feedbacks by altering methane fluxes from these wetlands.  ......We determined methane (CH4) emissions in a field enclosure experiment in a littoral freshwater marsh under the influence of experimentally simulated warming and enhanced nitrogen deposition. Methane emissions by ebullition from the marsh composed of Phragmites australis were measured with funnel...... traps deployed in a series of enclosures for two 3 week periods. Diffusive fluxes were estimated on the basis of measured CH4 concentrations and application of Fick's law. Neither diffusive nor ebullitive fluxes of methane were significantly affected by warming or nitrate enrichment, possibly because...

Methane bubbling from northern lakes: present and future contributions to the global methane budget.

Science.gov (United States)

Walter, Katey M; Smith, Laurence C; Chapin, F Stuart

2007-07-15

Large uncertainties in the budget of atmospheric methane (CH4) limit the accuracy of climate change projections. Here we describe and quantify an important source of CH4 -- point-source ebullition (bubbling) from northern lakes -- that has not been incorporated in previous regional or global methane budgets. Employing a method recently introduced to measure ebullition more accurately by taking into account its spatial patchiness in lakes, we estimate point-source ebullition for 16 lakes in Alaska and Siberia that represent several common northern lake types: glacial, alluvial floodplain, peatland and thermokarst (thaw) lakes. Extrapolation of measured fluxes from these 16 sites to all lakes north of 45 degrees N using circumpolar databases of lake and permafrost distributions suggests that northern lakes are a globally significant source of atmospheric CH4, emitting approximately 24.2+/-10.5Tg CH4yr(-1). Thermokarst lakes have particularly high emissions because they release CH4 produced from organic matter previously sequestered in permafrost. A carbon mass balance calculation of CH4 release from thermokarst lakes on the Siberian yedoma ice complex suggests that these lakes alone would emit as much as approximately 49000Tg CH4 if this ice complex was to thaw completely. Using a space-for-time substitution based on the current lake distributions in permafrost-dominated and permafrost-free terrains, we estimate that lake emissions would be reduced by approximately 12% in a more probable transitional permafrost scenario and by approximately 53% in a 'permafrost-free' Northern Hemisphere. Long-term decline in CH4 ebullition from lakes due to lake area loss and permafrost thaw would occur only after the large release of CH4 associated thermokarst lake development in the zone of continuous permafrost.

The global warming potential of methane reassessed with combined stratosphere and troposphere chemistry

Science.gov (United States)

Holmes, C. D.; Archibald, A. T.; Eastham, S. D.; Søvde, O. A.

2017-12-01

Methane is a direct and indirect greenhouse gas. The direct greenhouse effect comes from the radiation absorbed and emitted by methane itself. The indirect greenhouse effect comes from radiatively active gases that are produced during methane oxidation: principally O3, H2O, and CO2. Methane also suppresses tropospheric OH, which indirectly affects numerous greenhouses gases and aerosols. Traditionally, the methane global warming potential (GWP) has included the indirect effects on tropospheric O3 and OH and stratospheric H2O, with these effects estimated independently from unrelated tropospheric and stratospheric chemistry models and observations. Using this approach the CH4 is about 28 over 100 yr (without carbon cycle feedbacks, IPCC, 2013). Here we present a comprehensive analysis of the CH4 GWP in several 3-D global atmospheric models capable of simulating both tropospheric and stratospheric chemistry (GEOS-Chem, Oslo CTM3, UKCA). This enables us to include, for the first time, the indirect effects of CH4 on stratospheric O3 and stratosphere-troposphere coupling. We diagnose the GWP from paired simulations with and without a 5% perturbation to tropospheric CH4 concentrations. Including stratospheric chemistry nearly doubles the O3 contribution to CH4 GWP because of O3 production in the lower stratosphere and because CH4 inhibits Cl-catalyzed O3 loss in the upper stratosphere. In addition, stratosphere-troposphere coupling strengthens the chemical feedback on its own lifetime. In the stratosphere, this feedback operates by a CH4 perturbation thickening the stratospheric O3 layer, which impedes UV-driven OH production in the troposphere and prolongs the CH4 lifetime. We also quantify the impact of CH4-derived H2O on the stratospheric HOx cycles but these effects are small. Combining all of the above, these models suggest that the 100-yr GWP of CH4 is over 33.5, a 20% increase over the latest IPCC assessment.

Compilation of a global inventory of emissions of nitrous oxide

NARCIS (Netherlands)

Bouwman, A.F.

1995-01-01

A global inventory with 1°x1° resolution was compiled of emissions of nitrous oxide (N ₂ O) to the atmosphere, including emissions from soils under natural vegetation, fertilized agricultural land, grasslands and animal excreta, biomass burning, forest clearing,

Inventory of methane losses from the natural gas industry

International Nuclear Information System (INIS)

Burklin, C.E.; Campbell, L.M.; Campbell, M.V.

1992-01-01

Natural gas is being considered as an important transition fuel in an integrated national strategy to reduce emissions of greenhouse gases in the United States due to its lower carbon dioxide (CO 2 ) emission per unit of energy produced. However, the contribution of atmospheric methane (CH 4 ) from the production and handling of natural gas must also be considered. Radian Corporation has been working with the Gas Research Institute and the US Environmental Protection Agency to detail the sources of methane from the natural gas industry in the United States. All aspects of natural gas production, processing, transmission, storage and distribution are being examined. Preliminary results of preliminary testing for the below-ground gas distribution industry segment are presented. The emission rate (scf/hr) is the product of the leak rate per unit length of underground pipe and the total length of US distribution system pipelines. Preliminary estimates for the below-ground distribution segment are nearly 9 billion scf/yr. This total likely underestimates below-ground methane emissions for several reasons. These preliminary analyses suggest that significant uncertainty surround current methane emission estimates from below-ground distribution systems. Emission estimates from all segments of the US Natural Gas Industry, broken down by fugitive sources and non-fugitive sources, are also presented. The specific test methods being implemented to quantify emissions from each segment are described

Methane Ebullition in Temperate Hydropower Reservoirs and Implications for US Policy on Greenhouse Gas Emissions.

Science.gov (United States)

Miller, Benjamin L; Arntzen, Evan V; Goldman, Amy E; Richmond, Marshall C

2017-10-01

The United States is home to 2198 dams actively used for hydropower production. With the December 2015 consensus adoption of the United Nations Framework Convention on Climate Change Paris Agreement, it is important to accurately quantify anthropogenic greenhouse gas emissions. Methane ebullition, or methane bubbles originating from river or lake sediments, has been shown to account for nearly all methane emissions from tropical hydropower reservoirs to the atmosphere. However, distinct ebullitive methane fluxes have been studied in comparatively few temperate hydropower reservoirs globally. This study measures ebullitive and diffusive methane fluxes from two eastern Washington reservoirs, and synthesizes existing studies of methane ebullition in temperate, boreal, and tropical hydropower reservoirs. Ebullition comprises nearly all methane emissions (>97%) from this study's two eastern Washington hydropower reservoirs to the atmosphere. Summer methane ebullition from these reservoirs was higher than ebullition in six southeastern U.S. hydropower reservoirs, however it was similar to temperate reservoirs in other parts of the world. Our literature synthesis suggests that methane ebullition from temperate hydropower reservoirs can be seasonally elevated compared to tropical climates, however annual emissions are likely to be higher within tropical climates, emphasizing the possible range of methane ebullition fluxes and the need for the further study of temperate reservoirs. Possible future changes to the Intergovernmental Panel on Climate Change and UNFCCC guidelines for national greenhouse gas inventories highlights the need for accurate assessment of reservoir emissions.

Methane Ebullition in Temperate Hydropower Reservoirs and Implications for US Policy on Greenhouse Gas Emissions

Science.gov (United States)

Miller, Benjamin L.; Arntzen, Evan V.; Goldman, Amy E.; Richmond, Marshall C.

2017-10-01

The United States is home to 2198 dams actively used for hydropower production. With the December 2015 consensus adoption of the United Nations Framework Convention on Climate Change Paris Agreement, it is important to accurately quantify anthropogenic greenhouse gas emissions. Methane ebullition, or methane bubbles originating from river or lake sediments, has been shown to account for nearly all methane emissions from tropical hydropower reservoirs to the atmosphere. However, distinct ebullitive methane fluxes have been studied in comparatively few temperate hydropower reservoirs globally. This study measures ebullitive and diffusive methane fluxes from two eastern Washington reservoirs, and synthesizes existing studies of methane ebullition in temperate, boreal, and tropical hydropower reservoirs. Ebullition comprises nearly all methane emissions (>97%) from this study's two eastern Washington hydropower reservoirs to the atmosphere. Summer methane ebullition from these reservoirs was higher than ebullition in six southeastern U.S. hydropower reservoirs, however it was similar to temperate reservoirs in other parts of the world. Our literature synthesis suggests that methane ebullition from temperate hydropower reservoirs can be seasonally elevated compared to tropical climates, however annual emissions are likely to be higher within tropical climates, emphasizing the possible range of methane ebullition fluxes and the need for the further study of temperate reservoirs. Possible future changes to the Intergovernmental Panel on Climate Change and UNFCCC guidelines for national greenhouse gas inventories highlights the need for accurate assessment of reservoir emissions.

Simulation of preindustrial atmospheric methane to constrain the global source strength of natural wetlands

NARCIS (Netherlands)

Houweling, S; Dentener, F; Lelieveld, J

2000-01-01

Previous attempts to quantify the global source strength of CH4 from natural wetlands have resulted in a range of 90-260 TE(CH4) yr(-1). This relatively uncertain estimate significantly limits our understanding of atmospheric methane. In this study we reduce this uncertainty by simulating

Ebullitive methane emissions from oxygenated wetland streams

Science.gov (United States)

Crawford, John T.; Stanley, Emily H.; Spawn, Seth A.; Finlay, Jacques C.; Striegl, Robert G.

2014-01-01

Stream and river carbon dioxide emissions are an important component of the global carbon cycle. Methane emissions from streams could also contribute to regional or global greenhouse gas cycling, but there are relatively few data regarding stream and river methane emissions. Furthermore, the available data do not typically include the ebullitive (bubble-mediated) pathway, instead focusing on emission of dissolved methane by diffusion or convection. Here, we show the importance of ebullitive methane emissions from small streams in the regional greenhouse gas balance of a lake and wetland-dominated landscape in temperate North America and identify the origin of the methane emitted from these well-oxygenated streams. Stream methane flux densities from this landscape tended to exceed those of nearby wetland diffusive fluxes as well as average global wetland ebullitive fluxes. Total stream ebullitive methane flux at the regional scale (103 Mg C yr−1; over 6400 km2) was of the same magnitude as diffusive methane flux previously documented at the same scale. Organic-rich stream sediments had the highest rates of bubble release and higher enrichment of methane in bubbles, but glacial sand sediments also exhibited high bubble emissions relative to other studied environments. Our results from a database of groundwater chemistry support the hypothesis that methane in bubbles is produced in anoxic near-stream sediment porewaters, and not in deeper, oxygenated groundwaters. Methane interacts with other key elemental cycles such as nitrogen, oxygen, and sulfur, which has implications for ecosystem changes such as drought and increased nutrient loading. Our results support the contention that streams, particularly those draining wetland landscapes of the northern hemisphere, are an important component of the global methane cycle.

Methane cycling. Nonequilibrium clumped isotope signals in microbial methane.

Science.gov (United States)

Wang, David T; Gruen, Danielle S; Lollar, Barbara Sherwood; Hinrichs, Kai-Uwe; Stewart, Lucy C; Holden, James F; Hristov, Alexander N; Pohlman, John W; Morrill, Penny L; Könneke, Martin; Delwiche, Kyle B; Reeves, Eoghan P; Sutcliffe, Chelsea N; Ritter, Daniel J; Seewald, Jeffrey S; McIntosh, Jennifer C; Hemond, Harold F; Kubo, Michael D; Cardace, Dawn; Hoehler, Tori M; Ono, Shuhei

2015-04-24

Methane is a key component in the global carbon cycle, with a wide range of anthropogenic and natural sources. Although isotopic compositions of methane have traditionally aided source identification, the abundance of its multiply substituted "clumped" isotopologues (for example, (13)CH3D) has recently emerged as a proxy for determining methane-formation temperatures. However, the effect of biological processes on methane's clumped isotopologue signature is poorly constrained. We show that methanogenesis proceeding at relatively high rates in cattle, surface environments, and laboratory cultures exerts kinetic control on (13)CH3D abundances and results in anomalously elevated formation-temperature estimates. We demonstrate quantitatively that H2 availability accounts for this effect. Clumped methane thermometry can therefore provide constraints on the generation of methane in diverse settings, including continental serpentinization sites and ancient, deep groundwaters. Copyright © 2015, American Association for the Advancement of Science.

Toward Global Mapping of Methane With TROPOMI: First Results and Intersatellite Comparison to GOSAT

Science.gov (United States)

Hu, Haili; Landgraf, Jochen; Detmers, Rob; Borsdorff, Tobias; Aan de Brugh, Joost; Aben, Ilse; Butz, André; Hasekamp, Otto

2018-04-01

The TROPOspheric Monitoring Instrument (TROPOMI), launched on 13 October 2017, aboard the Sentinel-5 Precursor satellite, measures reflected sunlight in the ultraviolet, visible, near-infrared, and shortwave infrared spectral range. It enables daily global mapping of key atmospheric species for monitoring air quality and climate. We present the first methane observations from November and December 2017, using TROPOMI radiance measurements in the shortwave infrared band around 2.3 μm. We compare our results with the methane product obtained from the Greenhouse gases Observing SATellite (GOSAT). Although different spectral ranges and retrieval methods are used, we find excellent agreement between the methane products acquired from the two satellites with a mean difference of 13.6 ppb, standard deviation of 19.6 ppb, and Pearson's correlation coefficient of 0.95. Our preliminary results capture the latitudinal gradient and show expected regional enhancements, for example, in the African Sudd wetlands, with much more detail than has been observed before.

Methane emissions from the global oil and gas supply chain: recent advances and next steps

Science.gov (United States)

Zavala Araiza, D.; Herndon, S. C.; Roscioli, J. R.; Yacovitch, T. I.; Knighton, W. B.; Johnson, M.; Tyner, D. R.; Hamburg, S.

2017-12-01

A wide body of research has characterized methane emissions from the oil and gas system in the US. In contrast, empirical data is limited for other significant oil and gas producing regions across the world. As a consequence, measuring and characterizing methane emissions across global oil and gas operations will be crucial to the design of effective mitigation strategies. Several countries have announced pledges to reduce methane emissions from this system (e.g., North America, Climate and Clean Air Coalition [CCAC] ministers). In the case of Canada, the federal government recently announced regulations supporting a 40-45% reduction of methane emissions from the oil and gas production systems. For these regulations to be effective, it is critical to understand the current methane emission patterns. We present results from a coordinated multiscale (i.e., airborne-based, ground-based) measurement campaign in Alberta, Canada. We use empirically derived emission estimates to characterize site-level emissions and derive an emissions distribution. Our work shows that many major sources of emissions are unmeasured or underreported. Consistent with previous studies in the US, a small fraction of sites disproportionately account for the majority of emissions: roughly 20% of sites accounted for 75% of emissions. An independent airborne-based regional estimate was 40% lower than the ground-based regional estimate, but not statistically different. Finally, we summarize next steps as part of the CCAC Oil and Gas Methane Study: ongoing work that is targeting oil and gas sectors/production regions with limited empirical data on methane emissions. This work builds on the approach deployed in quantifying methane emissions from the oil and gas supply chain in the US, underscoring the commitment to transparency of the collected data, external review, deployment of multiple methodologies, and publication of results in peer-reviewed journals.

Counting complete? Finalising the plant inventory of a global biodiversity hotspot.

Science.gov (United States)

Treurnicht, Martina; Colville, Jonathan F; Joppa, Lucas N; Huyser, Onno; Manning, John

2017-01-01

The Cape Floristic Region-the world's smallest and third richest botanical hotspot-has benefited from sustained levels of taxonomic effort and exploration for almost three centuries, but how close is this to resulting in a near-complete plant species inventory? We analyse a core component of this flora over a 250-year period for trends in taxonomic effort and species discovery linked to ecological and conservation attributes. We show that >40% of the current total of species was described within the first 100 years of exploration, followed by a continued steady rate of description. We propose that analysis provides important real-world insights for other hotspots in the context of global strategic plans for biodiversity in informing considerations of the likely effort required in attaining set targets of comprehensive plant inventories. In a time of unprecedented biodiversity loss, we argue for a focused research agenda across disciplines to increase the rate of species descriptions in global biodiversity hotspots.

Temperature response of methane production in liquid manures and co-digestates

DEFF Research Database (Denmark)

Elsgaard, Lars; Olsen, Anna Berg; Petersen, Søren O.

2016-01-01

Intensification of livestock production makes correct estimation of methanogenesis in liquidmanure increasingly important for inventories of CH4 emissions. Such inventories currently rely on fixed methane conversion factors as knowledge gaps remain with respect to detailed temperature responses...... gradient incubator and CH4 production was measured by gas chromatographic analysis of headspace gas after a 17-h incubation period. Methane production potentials at 5–37 °C were described by the Arrhenius equation (modelling efficiencies, 79.2–98.1%), and the four materials showed a consistent activation...

Global building inventory for earthquake loss estimation and risk management

Science.gov (United States)

Jaiswal, Kishor; Wald, David; Porter, Keith

2010-01-01

We develop a global database of building inventories using taxonomy of global building types for use in near-real-time post-earthquake loss estimation and pre-earthquake risk analysis, for the U.S. Geological Survey’s Prompt Assessment of Global Earthquakes for Response (PAGER) program. The database is available for public use, subject to peer review, scrutiny, and open enhancement. On a country-by-country level, it contains estimates of the distribution of building types categorized by material, lateral force resisting system, and occupancy type (residential or nonresidential, urban or rural). The database draws on and harmonizes numerous sources: (1) UN statistics, (2) UN Habitat’s demographic and health survey (DHS) database, (3) national housing censuses, (4) the World Housing Encyclopedia and (5) other literature.

Global radioxenon emission inventory based on nuclear power reactor reports.

Science.gov (United States)

Kalinowski, Martin B; Tuma, Matthias P

2009-01-01

Atmospheric radioactivity is monitored for the verification of the Comprehensive Nuclear-Test-Ban Treaty, with xenon isotopes 131mXe, 133Xe, 133mXe and 135Xe serving as important indicators of nuclear explosions. The treaty-relevant interpretation of atmospheric concentrations of radioxenon is enhanced by quantifying radioxenon emissions released from civilian facilities. This paper presents the first global radioxenon emission inventory for nuclear power plants, based on North American and European emission reports for the years 1995-2005. Estimations were made for all power plant sites for which emission data were unavailable. According to this inventory, a total of 1.3PBq of radioxenon isotopes are released by nuclear power plants as continuous or pulsed emissions in a generic year.

How do glacier inventory data aid global glacier assessments and projections?

Science.gov (United States)

Hock, R.

2017-12-01

Large-scale glacier modeling relies heavily on datasets that are collected by many individuals across the globe, but managed and maintained in a coordinated fashion by international data centers. The Global Terrestrial Network for Glaciers (GTN-G) provides the framework for coordinating and making available a suite of data sets such as the Randolph Glacier Inventory (RGI), the Glacier Thickness Dataset or the World Glacier Inventory (WGI). These datasets have greatly increased our ability to assess global-scale glacier mass changes. These data have also been vital for projecting the glacier mass changes of all mountain glaciers in the world outside the Greenland and Antarctic ice sheet, a total >200,000 glaciers covering an area of more than 700,000 km2. Using forcing from 8 to 15 GCMs and 4 different emission scenarios, global-scale glacier evolution models project multi-model mean net mass losses of all glaciers between 7 cm and 24 cm sea-level equivalent by the end of the 21st century. Projected mass losses vary greatly depending on the choice of the forcing climate and emission scenario. Insufficiently constrained model parameters likely are an important reason for large differences found among these studies even when forced by the same emission scenario, especially on regional scales.

Validation of the Swiss methane emission inventory by atmospheric observations and inverse modelling

Directory of Open Access Journals (Sweden)

S. Henne

2016-03-01

Full Text Available Atmospheric inverse modelling has the potential to provide observation-based estimates of greenhouse gas emissions at the country scale, thereby allowing for an independent validation of national emission inventories. Here, we present a regional-scale inverse modelling study to quantify the emissions of methane (CH4 from Switzerland, making use of the newly established CarboCount-CH measurement network and a high-resolution Lagrangian transport model. In our reference inversion, prior emissions were taken from the "bottom-up" Swiss Greenhouse Gas Inventory (SGHGI as published by the Swiss Federal Office for the Environment in 2014 for the year 2012. Overall we estimate national CH4 emissions to be 196 ± 18 Gg yr−1 for the year 2013 (1σ uncertainty. This result is in close agreement with the recently revised SGHGI estimate of 206 ± 33 Gg yr−1 as reported in 2015 for the year 2012. Results from sensitivity inversions using alternative prior emissions, uncertainty covariance settings, large-scale background mole fractions, two different inverse algorithms (Bayesian and extended Kalman filter, and two different transport models confirm the robustness and independent character of our estimate. According to the latest SGHGI estimate the main CH4 source categories in Switzerland are agriculture (78 %, waste handling (15 % and natural gas distribution and combustion (6 %. The spatial distribution and seasonal variability of our posterior emissions suggest an overestimation of agricultural CH4 emissions by 10 to 20 % in the most recent SGHGI, which is likely due to an overestimation of emissions from manure handling. Urban areas do not appear as emission hotspots in our posterior results, suggesting that leakages from natural gas distribution are only a minor source of CH4 in Switzerland. This is consistent with rather low emissions of 8.4 Gg yr−1 reported by the SGHGI but inconsistent with the much higher value of 32 Gg yr−1 implied by the

COMPILATION OF REGIONAL TO GLOBAL INVENTORIES OF ANTHROPOGENIC EMISSIONS

International Nuclear Information System (INIS)

BENKOVITZ, C.M.

2002-01-01

The mathematical modeling of the transport and transformation of trace species in the atmosphere is one of the scientific tools currently used to assess atmospheric chemistry, air quality, and climatic conditions. From the scientific but also from the management perspectives accurate inventories of emissions of the trace species at the appropriate spatial, temporal, and species resolution are required. There are two general methodologies used to estimate regional to global emissions: bottom-up and top-down (also known as inverse modeling). Bottom-up methodologies to estimate industrial emissions are based on activity data, emission factors (amount of emissions per unit activity), and for some inventories additional parameters (such as sulfur content of fuels). Generally these emissions estimates must be given finer sectoral, spatial (usually gridded), temporal, and for some inventories species resolution. Temporal and spatial resolution are obtained via the use of surrogate information, such as population, land use, traffic counts, etc. which already exists in or can directly be converted to gridded form. Speciation factors have been and are being developed to speciate inventories of NO(sub x), particulate matter, and hydrocarbons. Top-down (inverse modeling) methodologies directly invert air quality measurements in terms of poorly known but critical parameters to constrain the emissions needed to explain these measurements; values of these parameters are usually computed using atmospheric transport models. Currently there are several strong limitations of inverse modeling, but the continued evolution of top-down estimates will be facilitated by the development of denser monitoring networks and by the massive amounts of data from satellite observations

Temporal comparison of global inventories of CO2 emissions from biomass burning during 2002-2011 derived from remotely sensed data.

Science.gov (United States)

Shi, Yusheng; Matsunaga, Tsuneo

2017-07-01

Biomass burning is a large important source of greenhouse gases and atmospheric aerosols, and can contribute greatly to the temporal variations of CO 2 emissions at regional and global scales. In this study, we compared four globally gridded CO 2 emission inventories from biomass burning during the period of 2002-2011, highlighting the similarities and differences in seasonality and interannual variability of the CO 2 emissions both at regional and global scales. The four datasets included Global Fire Emissions Database 4s with small fires (GFED4s), Global Fire Assimilation System 1.0 (GFAS1.0), Fire INventory from NCAR 1.0 (FINN1.0), and Global Inventory for Chemistry-Climate studies-GFED4s (G-G). The results showed that in general, the four inventories presented consistent temporal trend but with large differences as well. Globally, CO 2 emissions of GFED4s, GFAS1.0, and G-G all peaked in August with the exception in FINN1.0, which recorded another peak in annual March. The interannual trend of all datasets displayed an overall decrease in CO 2 emissions during 2002-2011, except for the inconsistent FINN1.0, which showed a tendency to increase during the considered period. Meanwhile, GFED4s and GFAS1.0 noted consistent agreement from 2002 to 2011 at both global (R 2  > 0.8) and continental levels (R 2  > 0.7). FINN1.0 was found to have the poorest temporal correlations with the other three inventories globally (R 2  80%) but showed small variations through the years (<40%).

THE DEVELOPMENT OF A 1990 GLOBAL INVENTORY FOR SO(X) AND NO(X) ON A 1(DEGREE) X 1(DEGREE) LATITUDE-LONGITUDE GRID

International Nuclear Information System (INIS)

VAN HEYST, B.J.

1999-01-01

Sulfur and nitrogen oxides emitted to the atmosphere have been linked to the acidification of water bodies and soils and perturbations in the earth's radiation balance. In order to model the global transport and transformation of SO(sub x) and NO(sub x), detailed spatial and temporal emission inventories are required. Benkovitz et al. (1996) published the development of an inventory of 1985 global emissions of SO(sub x) and NO(sub x) from anthropogenic sources. The inventory was gridded to a 1(degree) x 1(degree) latitude-longitude grid and has served as input to several global modeling studies. There is now a need to provide modelers with an update of this inventory to a more recent year, with a split of the emissions into elevated and low level sources. This paper describes the development of a 1990 update of the SO(sub x) and NO(sub x) global inventories that also includes a breakdown of sources into 17 sector groups. The inventory development starts with a gridded global default EDGAR inventory (Olivier et al, 1996). In countries where more detailed national inventories are available, these are used to replace the emissions for those countries in the global default. The gridded emissions are distributed into two height levels (0-100m and and gt;100m) based on the final plume heights that are estimated to be typical for the various sectors considered. The sources of data as well as some of the methodologies employed to compile and develop the 1990 global inventory for SO(sub x) and NO(sub x) are discussed. The results reported should be considered to be interim since the work is still in progress and additional data sets are expected to become available

Identifying sources of methane sampled in the Arctic using δ13C in CH4 and Lagrangian particle dispersion modelling.

Science.gov (United States)

Cain, Michelle; France, James; Pyle, John; Warwick, Nicola; Fisher, Rebecca; Lowry, Dave; Allen, Grant; O'Shea, Sebastian; Illingworth, Samuel; Jones, Ben; Gallagher, Martin; Welpott, Axel; Muller, Jennifer; Bauguitte, Stephane; George, Charles; Hayman, Garry; Manning, Alistair; Myhre, Catherine Lund; Lanoisellé, Mathias; Nisbet, Euan

2016-04-01

An airmass of enhanced methane was sampled during a research flight at ~600 m to ~2000 m altitude between the North coast of Norway and Svalbard on 21 July 2012. The largest source of methane in the summertime Arctic is wetland emissions. Did this enhancement in methane come from wetland emissions? The airmass was identified through continuous methane measurements using a Los Gatos fast greenhouse gas analyser on board the UK's BAe-146 Atmospheric Research Aircraft (ARA) as part of the MAMM (Methane in the Arctic: Measurements and Modelling) campaign. A Lagrangian particle dispersion model (the UK Met Office's NAME model) was run backwards to identify potential methane source regions. This was combined with a methane emission inventory to create "pseudo observations" to compare with the aircraft observations. This modelling was used to constrain the δ13C CH4 wetland source signature (where δ13C CH4 is the ratio of 13C to 12C in methane), resulting in a most likely signature of -73‰ (±4‰7‰). The NAME back trajectories suggest a methane source region of north-western Russian wetlands, and -73‰ is consistent with in situ measurements of wetland methane at similar latitudes in Scandinavia. This analysis has allowed us to study emissions from remote regions for which we do not have in situ observations, giving us an extra tool in the determination of the isotopic source variation of global methane emissions.

Carbon (14C,13C) and hydrogen (D) isotope measurements on atmospheric methane and its sources (sinks)

International Nuclear Information System (INIS)

Levin, I.; Doerr, H.

1991-07-01

Concentrations and isotope ratios ( 13 C/ 12 C and D/H) of atmospheric methane and methane from other sources were determined by gas chromatography and mass spectroscopy in specially prepared samples. The results were used for assessing the atmospheric methane inventory. (BBR) [de

Enteric methane emissions from German dairy cows

DEFF Research Database (Denmark)

Dammgen, U; Rosemann, C; Haenel, H D

2012-01-01

Up to now, the German agricultural emission inventory used a model for the assessment of methane emissions from enteric fermentation that combined an estimate of the energy and feed requirements as a function of performance parameters and diet composition, with the constant methane conversion rate......, as stated by IPCC. A methane emission model was selected here that is based on German feed data. It was combined with the hitherto applied model describing energy requirements. The emission rates thus calculated deviate from those previously obtained. In the new model, the methane conversion rate is back......-calculated from emission rates and gross energy intake rates. For German conditions of animal performance and diet composition, the national means of methane conversion rates range between 71 kJ MJ(-1) and 61 kJ MJ(-1) for low and high performances (4700 kg animal(-1) a(-1) in 1990 to 7200 kg animal(-1) a(-1...

Methane emissions from U.S. natural gas operations

International Nuclear Information System (INIS)

Lott, R.A.

1992-01-01

The Gas Research Institute and the U.S. Environmental Protection Agency are cofunding and comanaging a program to evaluate methane emissions from U.S. natural gas operations. The purpose of the program is to provide an emissions inventory accurate enough for global climate modeling and for addressing the policy question of ''whether encouraging the increased use of natural gas is a viable strategy for reducing the U.S. contribution to global warming''. The program is comprised of three phases: Scoping, Methods Development, and Implementation. The purpose of Phase I was to define the problem. Phase II of the program concentrated on developing techniques for measuring steady state or fugitive emissions and for calculating the highly variable unsteady emissions from the variety of sources that comprise the gas industry. Because of the large number of sources within each source type, techniques were also developed for extrapolating emissions data to similar sources within the industry. Phase III of the program was started in early 1992 and should be completed in early 1994. The purpose of the current phase of the program is to collect sufficient data to achieve the accuracy goal of determining emissions to within ± 0.5 percent of production. Based on the limited amount of data collected to date, methane emissions from the U.S. gas industry appear to be in the range of 1 percent of production. (au) (19 refs.)

Greenhouse gas inventories for England, Scotland, Wales and Northern Ireland: 1990 and 1995. A scoping study

Energy Technology Data Exchange (ETDEWEB)

Salway, A.G.; Dore, C.; Watterson, J.; Murrells, T.

1999-11-01

This report presents the results of a scoping study to develop a methodology to produce desegregated greenhouse gas emission inventories for the devoved administrations of the UK. Separate greenhouse gas emission inventories were estimated for England, Scotland, Wales and Northern Ireland for the years 1990 and 1995. The gases reported are carbon dioxide, methane, nitrous oxide, hydrofluorocarbons, perfluorocarbons, and SF{sub 6}. The estimates are consistent with the 1997 UK Greenhouse Gas Inventory and hence the UNFCCC reporting guidelines. Some emissions mainly mobile and offshore sources could not be allocated to any region, so an extra unallocated category was used to report these. Where possible the same methodology was used to calculate the regional emissions as for the UK Inventory. The study showed that the distribution of regional greenhouse gas emissions expressed as global warming potentials in 1995 were: England 75.5%, Scotland, 11.4%; Wales 6.4%; Northern Ireland 3.1%: unallocated, 4%. Following this scoping study, it is intended to publish annually disaggregated inventories for each year from 1990 for England, Scotland, Wales and Northern Ireland, in addition to the UK Greenhouse Gas Inventory. 50 refs., 6 figs., 16 tabs., 2 apps.

Cryptic Methane Emissions from Upland Forest Ecosystems

Energy Technology Data Exchange (ETDEWEB)

Megonigal, Patrick [Smithsonian Institution, Washington, DC (United States); Pitz, Scott [Johns Hopkins Univ., Baltimore, MD (United States); Smithsonian Institution, Washington, DC (United States)

2016-04-19

This exploratory research on Cryptic Methane Emissions from Upland Forest Ecosystems was motivated by evidence that upland ecosystems emit 36% as much methane to the atmosphere as global wetlands, yet we knew almost nothing about this source. The long-term objective was to refine Earth system models by quantifying methane emissions from upland forests, and elucidate the biogeochemical processes that govern upland methane emissions. The immediate objectives of the grant were to: (i) test the emerging paradigm that upland trees unexpectedly transpire methane, (ii) test the basic biogeochemical assumptions of an existing global model of upland methane emissions, and (iii) develop the suite of biogeochemical approaches that will be needed to advance research on upland methane emissions. We instrumented a temperate forest system in order to explore the processes that govern upland methane emissions. We demonstrated that methane is emitted from the stems of dominant tree species in temperate upland forests. Tree emissions occurred throughout the growing season, while soils adjacent to the trees consumed methane simultaneously, challenging the concept that forests are uniform sinks of methane. High frequency measurements revealed diurnal cycling in the rate of methane emissions, pointing to soils as the methane source and transpiration as the most likely pathway for methane transport. We propose the forests are smaller methane sinks than previously estimated due to stem emissions. Stem emissions may be particularly important in upland tropical forests characterized by high rainfall and transpiration, resolving differences between models and measurements. The methods we used can be effectively implemented in order to determine if the phenomenon is widespread.

Termites facilitate methane oxidation and shape the methanotrophic community

NARCIS (Netherlands)

Ho, A.; Erens, H.; Mujinya, B.B.; Boeckx, P.; Baert, G.; Schneider, B.; Frenzel, P.; Boon, N.; Van Ranst, E.

2013-01-01

Termite-derived methane contributes 3-4% to the total methane budget globally. Termites are not known to harbor methane-oxidizing microorganisms (methanotrophs). However, a considerable fraction of methane produced can be consumed by methanotrophs that inhabit the mound material. Yet, methanotroph

Normalization in EDIP97 and EDIP2003: updated European inventory for 2004 and guidance towards a consistent use in practice

DEFF Research Database (Denmark)

Laurent, Alexis; Olsen, Stig Irving; Hauschild, Michael Zwicky

2011-01-01

Purpose: When performing a life cycle assessment (LCA), the LCA practitioner faces the need to express the characterized results in a form suitable for the final interpretation. This can be done using normalization against some common reference impact—the normalization references—which require...... regular updates. The study presents updated sets of normalization inventories, normalization references for the EDIP97/EDIP2003 methodology and guidance on their consistent use in practice. Materials and methods: The base year of the inventory is 2004; the geographical scope for the non-global impacts...... is limited to Europe. The emission inventory was collected from different publicly available databases and monitoring bodies. Where necessary, gaps were filled using extrapolations. A new approach for inventorizing specific groups of substances—non-methane volatile organic compounds and pesticides—was also...

Improved methane removal in exhaust gas from biogas upgrading process using immobilized methane-oxidizing bacteria.

Science.gov (United States)

Sun, Meng-Ting; Yang, Zhi-Man; Fu, Shan-Fei; Fan, Xiao-Lei; Guo, Rong-Bo

2018-05-01

Methane in exhaust gas from biogas upgrading process, which is a greenhouse gas, could cause global warming. The biofilter with immobilized methane-oxidizing bacteria (MOB) is a promising approach for methane removal, and the selections of inoculated MOB culture and support material are vital for the biofilter. In this work, five MOB consortia were enriched at different methane concentrations. The MOB-20 consortium enriched at the methane concentration of 20.0% (v/v) was then immobilized on sponge and two particle sizes of volcanic rock in biofilters to remove methane in exhaust gas from biogas upgrading process. Results showed that the immobilized MOB performed more admirable methane removal capacity than suspended cells. The immobilized MOB on sponge reached the highest methane removal efficiency (RE) of 35%. The rough surface, preferable hydroscopicity, appropriate pore size and particle size of support material might favor the MOB immobilization and accordingly methane removal. Copyright © 2018 Elsevier Ltd. All rights reserved.

Airborne Quantification of Methane Emissions in the San Francisco Bay Area of California

Science.gov (United States)

Guha, A.; Newman, S.; Martien, P. T.; Young, A.; Hilken, H.; Faloona, I. C.; Conley, S.

2017-12-01

The Bay Area Air Quality Management District, the San Francisco Bay Area's air quality regulatory agency, has set a goal to reduce the region's greenhouse gas (GHG) emissions 80% below 1990 levels by 2050, consistent with the State of California's climate protection goal. The Air District maintains a regional GHG emissions inventory that includes emissions estimates and projections which influence the agency's programs and regulatory activities. The Air District is currently working to better characterize methane emissions in the GHG inventory through source-specific measurements, to resolve differences between top-down regional estimates (Fairley and Fischer, 2015; Jeong et al., 2016) and the bottom-up inventory. The Air District funded and participated in a study in Fall 2016 to quantify methane emissions from a variety of sources from an instrumented Mooney aircraft. This study included 40 hours of cylindrical vertical profile flights that combined methane and wind measurements to derive mass emission rates. Simultaneous measurements of ethane provided source-apportionment between fossil-based and biological methane sources. The facilities sampled included all five refineries in the region, five landfills, two dairy farms and three wastewater treatment plants. The calculated mass emission rates were compared to bottom-up rates generated by the Air District and to those from facility reports to the US EPA as part of the mandatory GHG reporting program. Carbon dioxide emission rates from refineries are found to be similar to bottom-up estimates for all sources, supporting the efficacy of the airborne measurement methodology. However, methane emission estimates from the airborne method showed significant differences for some source categories. For example, methane emission estimates based on airborne measurements were up to an order of magnitude higher for refineries, and up to five times higher for landfills compared to bottom-up methods, suggesting significant

Estimating Global Seafloor Total Organic Carbon Using a Machine Learning Technique and Its Relevance to Methane Hydrates

Science.gov (United States)

Lee, T. R.; Wood, W. T.; Dale, J.

2017-12-01

Empirical and theoretical models of sub-seafloor organic matter transformation, degradation and methanogenesis require estimates of initial seafloor total organic carbon (TOC). This subsurface methane, under the appropriate geophysical and geochemical conditions may manifest as methane hydrate deposits. Despite the importance of seafloor TOC, actual observations of TOC in the world's oceans are sparse and large regions of the seafloor yet remain unmeasured. To provide an estimate in areas where observations are limited or non-existent, we have implemented interpolation techniques that rely on existing data sets. Recent geospatial analyses have provided accurate accounts of global geophysical and geochemical properties (e.g. crustal heat flow, seafloor biomass, porosity) through machine learning interpolation techniques. These techniques find correlations between the desired quantity (in this case TOC) and other quantities (predictors, e.g. bathymetry, distance from coast, etc.) that are more widely known. Predictions (with uncertainties) of seafloor TOC in regions lacking direct observations are made based on the correlations. Global distribution of seafloor TOC at 1 x 1 arc-degree resolution was estimated from a dataset of seafloor TOC compiled by Seiter et al. [2004] and a non-parametric (i.e. data-driven) machine learning algorithm, specifically k-nearest neighbors (KNN). Built-in predictor selection and a ten-fold validation technique generated statistically optimal estimates of seafloor TOC and uncertainties. In addition, inexperience was estimated. Inexperience is effectively the distance in parameter space to the single nearest neighbor, and it indicates geographic locations where future data collection would most benefit prediction accuracy. These improved geospatial estimates of TOC in data deficient areas will provide new constraints on methane production and subsequent methane hydrate accumulation.

A global building inventory for earthquake loss estimation and risk management

Science.gov (United States)

Jaiswal, K.; Wald, D.; Porter, K.

2010-01-01

We develop a global database of building inventories using taxonomy of global building types for use in near-real-time post-earthquake loss estimation and pre-earthquake risk analysis, for the U.S. Geological Survey's Prompt Assessment of Global Earthquakes for Response (PAGER) program. The database is available for public use, subject to peer review, scrutiny, and open enhancement. On a country-by-country level, it contains estimates of the distribution of building types categorized by material, lateral force resisting system, and occupancy type (residential or nonresidential, urban or rural). The database draws on and harmonizes numerous sources: (1) UN statistics, (2) UN Habitat's demographic and health survey (DHS) database, (3) national housing censuses, (4) the World Housing Encyclopedia and (5) other literature. ?? 2010, Earthquake Engineering Research Institute.

Centennial evolution of the atmospheric methane budget: what do the carbon isotopes tell us?

Directory of Open Access Journals (Sweden)

K. R. Lassey

2007-01-01

Full Text Available Little is known about how the methane source inventory and sinks have evolved over recent centuries. New and detailed records of methane mixing ratio and isotopic composition (12CH4, 13CH4 and 14CH4 from analyses of air trapped in polar ice and firn can enhance this knowledge. We use existing bottom-up constructions of the source history, including "EDGAR"-based constructions, as inputs to a model of the evolving global budget for methane and for its carbon isotope composition through the 20th century. By matching such budgets to atmospheric data, we examine the constraints imposed by isotope information on those budget evolutions. Reconciling both 12CH4 and 13CH4 budgets with EDGAR-based source histories requires a combination of: a greater proportion of emissions from biomass burning and/or of fossil methane than EDGAR constructions suggest; a greater contribution from natural such emissions than is commonly supposed; and/or a significant role for active chlorine or other highly-fractionating tropospheric sink as has been independently proposed. Examining a companion budget evolution for 14CH4 exposes uncertainties in inferring the fossil-methane source from atmospheric 14CH4 data. Specifically, methane evolution during the nuclear era is sensitive to the cycling dynamics of "bomb 14C" (originating from atmospheric weapons tests through the biosphere. In addition, since ca. 1970, direct production and release of 14CH4 from nuclear-power facilities is influential but poorly quantified. Atmospheric 14CH4 determinations in the nuclear era have the potential to better characterize both biospheric carbon cycling, from photosynthesis to methane synthesis, and the nuclear-power source.

Methane emissions from natural wetlands

Energy Technology Data Exchange (ETDEWEB)

Meyer, J.L. [Georgia Univ., Athens, GA (United States); Burke, R.A. Jr. [Environmental Protection Agency, Athens, GA (United States). Environmental Research Lab.

1993-09-01

Analyses of air trapped in polar ice cores in conjunction with recent atmospheric measurements, indicate that the atmospheric methane concentration increased by about 250% during the past two or three hundred years (Rasmussen and Khalil, 1984). Because methane is a potent ``greenhouse`` gas, the increasing concentrations are expected to contribute to global warning (Dickinson and Cicerone, 1986). The timing of the methane increase suggests that it is related to the rapid growth of the human population and associated industrialization and agricultural development. The specific causes of the atmospheric methane concentration increase are not well known, but may relate to either increases in methane sources, decreases in the strengths of the sinks, or both.

Constraining global methane emissions and uptake by ecosystems

International Nuclear Information System (INIS)

Spahni, R.; Wania, R.; Neef, L.; Van Weele, M.; Van Velthoven, P.; Pison, I.; Bousquet, P.

2011-01-01

Natural methane (CH 4 ) emissions from wet ecosystems are an important part of today's global CH 4 budget. Climate affects the exchange of CH 4 between ecosystems and the atmosphere by influencing CH 4 production, oxidation, and transport in the soil. The net CH 4 exchange depends on ecosystem hydrology, soil and vegetation characteristics. Here, the LPJ-WHyMe global dynamical vegetation model is used to simulate global net CH 4 emissions for different ecosystems: northern peat-lands (45 degrees-90 degrees N), naturally inundated wetlands (60 degrees S-45 degrees N), rice agriculture and wet mineral soils. Mineral soils are a potential CH 4 sink, but can also be a source with the direction of the net exchange depending on soil moisture content. The geographical and seasonal distributions are evaluated against multi-dimensional atmospheric inversions for 2003-2005, using two independent four-dimensional variational assimilation systems. The atmospheric inversions are constrained by the atmospheric CH 4 observations of the SCIAMACHY satellite instrument and global surface networks. Compared to LPJ-WHyMe the inversions result in a significant reduction in the emissions from northern peat-lands and suggest that LPJ-WHyMe maximum annual emissions peak about one month late. The inversions do not put strong constraints on the division of sources between inundated wetlands and wet mineral soils in the tropics. Based on the inversion results we diagnose model parameters in LPJ-WHyMe and simulate the surface exchange of CH 4 over the period 1990-2008. Over the whole period we infer an increase of global ecosystem CH 4 emissions of +1.11 TgCH 4 yr -1 , not considering potential additional changes in wetland extent. The increase in simulated CH 4 emissions is attributed to enhanced soil respiration resulting from the observed rise in land temperature and in atmospheric carbon dioxide that were used as input. The long term decline of the atmospheric CH 4 growth rate from 1990

Natural and Anthropogenic Methane Sources, New England, USA, 1990-1994

Data.gov (United States)

National Aeronautics and Space Administration — This data set contains an inventory of natural and anthropogenic methane emissions for all counties in the six New England states of Connecticut, Rhode Island,...

An Aerial ``Sniffer Dog'' for Methane

Science.gov (United States)

Nathan, Brian; Schaefer, Dave; Zondlo, Mark; Khan, Amir; Lary, David

2012-10-01

The Earth's surface and its atmosphere maintain a ``Radiation Balance.'' Any factor which influences this balance is labeled as a mechanism of ``Radiative Forcing'' (RF). Greenhouse Gas (GHG) concentrations are among the most important forcing mechanisms. Methane, the second-most-abundant noncondensing greenhouse gas, is over 25 times more effective per molecule at radiating heat than the most abundant, Carbon Dioxide. Methane is also the principal component of Natural Gas, and gas leaks can cause explosions. Additionally, massive quantities of methane reside (in the form of natural gas) in underground shale basins. Recent technological advancements--specifically the combination of horizontal drilling and hydraulic fracturing--have allowed drillers access to portions of these ``plays'' which were previously unreachable, leading to an exponential growth in the shale gas industry. Presently, very little is known about the amount of methane which escapes into the global atmosphere from the extraction process. By using remote-controlled robotic helicopters equipped with specially developed trace gas laser sensors, we can get a 3-D profile of where and how methane is being released into the global atmosphere.

Methane emission from wetland rice fields

NARCIS (Netherlands)

Denier van der Gon, H.A.C.

1996-01-01

Methane (CH ₄ ) is an important greenhouse gas and plays a key role in tropospheric and stratospheric chemistry. Wetland rice fields are an important source of methane, accounting for approximately 20% of the global anthropogenic

Sources of atmospheric methane from coastal marine wetlands

International Nuclear Information System (INIS)

Harriss, R.C.; Sebacher, D.I.; Bartlett, K.B.; Bartlett, D.S.

1982-01-01

Biological methanogenesis in wetlands is believed to be one of the major sources of global tropospheric methane. The present paper reports measurements of methane distribution in the soils, sediments, water and vegetation of coastal marine wetlands. Measurements, carried out in the salt marshes Bay Tree Creek in Virginia and Panacea in northwest Florida, reveal methane concentrations in soils and sediments to vary with depth below the surface and with soil temperature. The fluxes of methane from marsh soils to the atmosphere at the soil-air interface are estimated to range from -0.00067 g CH 4 /sq m per day (methane sink) to 0.024 g CH 4 /sq m per day, with an average value of 0.0066 g CH 4 /sq m per day. Data also demonstrate the important role of tidal waters percolating through marsh soils in removing methane from the soils and releasing it to the atmosphere. The information obtained, together with previous studies, provides a framework for the design of a program based on in situ and remote sensing measurements to study the global methane cycle

The California Baseline Methane Survey

Science.gov (United States)

Duren, R. M.; Thorpe, A. K.; Hopkins, F. M.; Rafiq, T.; Bue, B. D.; Prasad, K.; Mccubbin, I.; Miller, C. E.

2017-12-01

The California Baseline Methane Survey is the first systematic, statewide assessment of methane point source emissions. The objectives are to reduce uncertainty in the state's methane budget and to identify emission mitigation priorities for state and local agencies, utilities and facility owners. The project combines remote sensing of large areas with airborne imaging spectroscopy and spatially resolved bottom-up data sets to detect, quantify and attribute emissions from diverse sectors including agriculture, waste management, oil and gas production and the natural gas supply chain. Phase 1 of the project surveyed nearly 180,000 individual facilities and infrastructure components across California in 2016 - achieving completeness rates ranging from 20% to 100% per emission sector at < 5 meters spatial resolution. Additionally, intensive studies of key areas and sectors were performed to assess source persistence and variability at times scales ranging from minutes to months. Phase 2 of the project continues with additional data collection in Spring and Fall 2017. We describe the survey design and measurement, modeling and analysis methods. We present initial findings regarding the spatial, temporal and sectoral distribution of methane point source emissions in California and their estimated contribution to the state's total methane budget. We provide case-studies and lessons learned about key sectors including examples where super-emitters were identified and mitigated. We summarize challenges and recommendations for future methane research, inventories and mitigation guidance within and beyond California.

Methane emissions from coal mining

International Nuclear Information System (INIS)

Boyer, C.M.; Kelafant, J.R.; Kuuskraa, V.A.; Manger, K.C.; Kruger, D.

1990-09-01

The report estimates global methane emissions from coal mining on a country specific basis, evaluates the technologies available to degasify coal seams and assesses the economics of recovering methane liberated during mining. 33 to 64 million tonnes were liberated in 1987 from coal mining, 75 per cent of which came from China, the USSR, Poland and the USA. Methane emissions from coal mining are likely to increase. Emission levels vary between surface and underground mines. The methane currently removed from underground mines for safety reasons could be used in a number of ways, which may be economically attractive. 55 refs., 19 figs., 24 tabs

International IPCC workshop on methane and nitrous oxide: methods in national emissions inventories and options for control

Energy Technology Data Exchange (ETDEWEB)

Amstel, A.R. van (ed.)

1993-07-01

This workshop had two main objectives: to support the development of an internationally agreed methodology and reporting format for national emission inventories of greenhouse gases by mid 1993, as coordinated by the Science Working Group of the Intergovernmental Panel on Climate Change (IPCC) and the Organization for Economic Cooperation and Development (OECD); and the development of technical options for reduction of these greenhouse gases and the assessment of the socio-economic feasibility of these options. These proceedings contain the overview papers presented at the workshop, the background papers prepared for the working group sessions and the conclusions and recommendations of the working groups put forward during these sessions. 16 poster summaries are also included. During the workshop, 8 different sources of methane were discussed - oil and gas, coal mining, ruminants, animal waste, landfills and sewage treatments, combustion and industry, rice production and wetlands, and biomass burning - and 2 sources of nitrous oxide - agricultural soils and combustion and industry. All papers have been abstracted separately.

National inventory of Global Change relevant research in Norway; Nasjonal kartlegging av global change-relevant forskning

Energy Technology Data Exchange (ETDEWEB)

NONE

2001-05-01

The Norwegian Global Change Committee has made an inventory of global change research (GCR) projects funded by the Research Council of Norway (RCN) in 2001. In lack of a rigid definition, GCR was defined as research that can be considered relevant to the science agenda of the four major international global change programmes DIVERSITAS, IGBP, IHDP and WCRP. Relevance was judged based on the objectives stated for each of the international programmes and their core projects. It was not attempted to check whether the projects had any kind of link to the programmes they were considered relevant for. The grants provided by the RCN in 2001 to GCR as defined above amounts to about 77 mill. NOK. Based on a recent survey on climate change research it is reasonable to estimate that the RCN finances between 30 and 40 % of all GCR in Norway. Accordingly, the total value of Norwegian research relevant to the four international global change programmes in 2001 can be estimated to 192 - 254 mill. NOK.

From Inventory to Insight: Making Sense of the Global Landscape of Higher Education Research, Training, and Publication

Science.gov (United States)

Rumbley, Laura E.; Stanfield, David A.; de Gayardon, Ariane

2014-01-01

Through a yearlong study, the Boston College Center for International Higher Education developed a (third edition) global inventory of higher education research centers/institutes, academic programs, and journals/publications. As higher education expands globally, these resources are essential for training effective leaders and producing research…

Update and improvement of the global krypton-85 emission inventory.

Science.gov (United States)

Ahlswede, Jochen; Hebel, Simon; Ross, J Ole; Schoetter, Robert; Kalinowski, Martin B

2013-01-01

Krypton-85 is mainly produced in nuclear reactors by fission of uranium and plutonium and released during chopping and dissolution of spent fuel rods in nuclear reprocessing facilities. As noble gas it is suited as a passive tracer for evaluation of atmospheric transport models. Furthermore, research is ongoing to assess its quality as an indicator for clandestine reprocessing activities. This paper continues previous efforts to compile a comprehensive historic emission inventory for krypton-85. Reprocessing facilities are the by far largest emitters of krypton-85. Information on sources and calculations used to derive the annual krypton-85 emission is provided for all known reprocessing facilities in the world. In addition, the emission characteristics of two plants, Tokai (Japan) and La Hague (France), are analysed in detail using emission data with high temporal resolution. Other types of krypton-85 sources are power reactors, naval reactors and isotope production facilities. These sources contribute only little or negligible amounts of krypton-85 compared to the large reprocessing facilities. Taking the decay of krypton-85 into account, the global atmospheric inventory is estimated to about 5500 PBq at the end of 2009. The correctness if the inventory has been proven by meteorological simulations and its error is assumed to be in the range of a few percent. Copyright © 2012 Elsevier Ltd. All rights reserved.

Global Inverse Modeling of CH4 and δ13C-CH4 Measurements to Understand Recent Trends in Methane Emissions

Science.gov (United States)

Karmakar, S.; Butenhoff, C. L.; Rice, A. L.; Khalil, A. K.

2017-12-01

Methane (CH4) is the second most important greenhouse gas with a radiative forcing of 0.97 W/m2 including both direct and indirect effects and a global warming potential of 28 over a 100-year time horizon. After a decades-long period of decline beginning in the 1980s, the methane growth rate rebounded in 2007 for reasons that are of current debate. During this same growth period atmospheric methane became less enriched in the 13CH4 isotope suggesting the recent CH4 growth was caused by an increase in 13CH4-depleted biogenic emissions. Recent papers have attributed this growth to increasing emissions from wetlands, rice agriculture, and ruminants. In this work we provide additional insight into the recent behavior of atmospheric methane and global wetland emissions by performing a three-dimensional Bayesian inversion of surface CH4 and 13CH4/12CH4 ratios using NOAA Global Monitoring Division (GMD) "event-level" CH4 measurements and the GEOS-Chem chemical-transport model (CTM) at a horizontal grid resolution of 2ox2.5o. The spatial pattern of wetland emissions was prescribed using soil moisture and temperature from GEOS-5 meteorology fields and soil carbon pools from the Lund-Potsdam-Jena global vegetation model. In order to reduce the aggregation error caused by a potentially flawed distribution and to account for isotopic measurements that indicate northern high latitude wetlands are isotopically depleted in 13CH4 relative to tropical wetlands we separated our pattern into three latitudinal bands (90-30°N, 30°N-0, 0-90°S). Our preliminary results support previous claims that the recent increase in atmospheric methane is driven by increases in biogenic CH4 emissions. We find that while wetland emissions from northern high latitudes (90-30°N) remained relatively constant during this time, southern hemisphere wetland emissions rebounded from a decade-long decline and began to rise again in 2007 and have remained elevated to the present. Emissions from rice

The Global Search for Abiogenic GHGs, via Methane Isotopes and Ethane

Science.gov (United States)

Malina, Edward; Muller, Jan-Peter; Walton, David; Potts, Dale

2015-04-01

The importance of Methane as an anthropogenic Green House Gas (GHG) is well recognized in the scientific community, and is second only to Carbon Dioxide in terms of influence on the Earth's radiation budget (Parker, et al, 2011) suggesting that the ability to apportion the source of the methane (whether it is biogenic, abiogenic or thermogenic) has never been more important. It has been proposed (Etiope, 2009) that it may be possible to distinguish between a biogenic methane source (e.g. bacteria fermentation) and an abiogenic source (e.g. gas seepage or fugitive emissions) via the retrieval of the abundances of methane isotopes (12CH4 and 13CH4) and through the ratio of ethane (C2H6) to methane (CH4) concentrations. Using ultra fine spectroscopy (simulations, we show that it is possible to distinguish between methane isotopes using the FTS based instruments on ACE and GOSAT, and retrieve the abundances in the Short Wave Infra-red (SWIR) at 1.65μm, 2.3μm, 3.3μm and Thermal IR, 7.8μm wavebands for methane, and the 3.3μm and 7μm wavebands for ethane. Initially we use the spectral line database HITRAN to determine the most appropriate spectral waveband to retrieve methane isotopes (and ethane) with minimal water vapour, CO2 and NO2 impact. Following this, we have evaluated the detectability of these trace gases using the more sophisticated Radiative Transfer Models (RTMs) SCIATRAN, the Oxford RFM and MODTRAN 5 in the SWIR, in order to determine the barriers to retrieving methane isotopes in both ACE (limb profile) and GOSAT (nadir measurements) instruments, including a preliminary investigation into the effects of clouds, aerosols, surface reflectance on the retrieval of methane isotopes. The aim of these RTM simulations is to further narrow down the spectral regions (originally identified in the HITRAN assessment) where methane isotopes can/may be retrieved from orbit. The key outputs from the RTM study are absorption and radiance data, which allow us to

Estimation of global inventories of radioactive waste and other radioactive materials

International Nuclear Information System (INIS)

2008-06-01

A variety of nuclear activities have been carried out in the second part of the twentieth century for different purposes. Initially the emphasis was on military applications, but with the passage of time the main focus of nuclear activities has shifted to peaceful uses of nuclear energy and to the use of radioactive material in industry, medicine and research. Regardless of the objectives, the nuclear activities generate radioactive waste. It was considered worthwhile to produce a set of worldwide data that could be assessed to evaluate the legacy of the nuclear activities performed up to the transition between the twentieth and the twenty first century. The assessment tries to cover the inventory of all the human produced radioactive material that can be considered to result from both military and civilian applications. This has caused remarkable difficulties since much of the data, particularly relating to military programmes, are not readily available. Consequently the data on the inventory of radioactive material should be considered as order-of-magnitude approximations. This report as a whole should be considered as a first iteration in a continuing process of updating and upgrading. The accumulations of radioactive materials can be considered a burden for human society, both at present and in the future, since they require continuing monitoring and control. Knowing the amounts and types of such radioactive inventories can help in the assessment of the relative burdens. Knowledge of the national or regional radioactive waste inventory is necessary for planning management operations, including the sizing and design of conditioning, storage and disposal facilities. A global inventory, either of radioactive waste or of other environmental accumulations of radioactive material, could be used to provide a perspective on the requirements and burdens associated with their management, by means of comparisons with the burdens caused by other types of waste or other

Global height-resolved methane retrievals from the Infrared Atmospheric Sounding Interferometer (IASI on MetOp

Directory of Open Access Journals (Sweden)

R. Siddans

2017-11-01

Full Text Available This paper describes the global height-resolved methane (CH4 retrieval scheme for the Infrared Atmospheric Sounding Interferometer (IASI on MetOp, developed at the Rutherford Appleton Laboratory (RAL. The scheme precisely fits measured spectra in the 7.9 micron region to allow information to be retrieved on two independent layers centred in the upper and lower troposphere. It also uses nitrous oxide (N2O spectral features in the same spectral interval to directly retrieve effective cloud parameters to mitigate errors in retrieved methane due to residual cloud and other geophysical variables. The scheme has been applied to analyse IASI measurements between 2007 and 2015. Results are compared to model fields from the MACC greenhouse gas inversion and independent measurements from satellite (GOSAT, airborne (HIPPO and ground (TCCON sensors. The estimated error on methane mixing ratio in the lower- and upper-tropospheric layers ranges from 20 to 100 and from 30 to 40 ppbv, respectively, and error on the derived column-average ranges from 20 to 40 ppbv. Vertical sensitivity extends through the lower troposphere, though it decreases near to the surface. Systematic differences with the other datasets are typically  < 10 ppbv regionally and  < 5 ppbv globally. In the Southern Hemisphere, a bias of around 20 ppbv is found with respect to MACC, which is not explained by vertical sensitivity or found in comparison of IASI to TCCON. Comparisons to HIPPO and MACC support the assertion that two layers can be independently retrieved and provide confirmation that the estimated random errors on the column- and layer-averaged amounts are realistic. The data have been made publically available via the Centre for Environmental Data Analysis (CEDA data archive (Siddans, 2016.

The Potential for Methane Isotopologue Channels in GOSAT-2

Science.gov (United States)

Malina, Edward; Yoshida, Yukio; Matsunaga, Tsuneo; Muller, Jan-Peter

2017-04-01

Of the major Greenhouse Gases (GHGs) currently considered as having a major impact on atmospheric chemistry, Methane is amongst the most important (IPCC, 2014). Methane concentration in the atmosphere has been documented to be rising steadily over the past century, aside from an unexplained short period in the middle of the last decade (Heimann., 2011), leading to renewed efforts to understand global atmospheric Methane. Atmospheric Methane is primarily composed of two key isotopologues, 12CH4 and 13CH4, which have a natural abundance of about 98% and 1.1% respectively. It is a well-established fact that different sources of Methane (i.e. biogenic sources such as methanogens, or non-biogenic such as industrial hydrocarbon burning) vary in the abundance of these isotopologues (Etiope, 2009). The global identification of the ratios of these isotopologues could vastly increase knowledge of global Methane sources, and shed some light on global Methane growth. GOSAT-2 due to be launched in 2018 is a follow on from the original GOSAT mission launched in 2009. GOSAT-2 aims to continue the legacy of GOSAT by providing global measurements of Methane and Carbon Dioxide on a global basis in order to monitor GHG emissions. GOSAT-2 in the context of this study has a significant advantage over GOSAT, which is the extension of the sensitivity of band 3 to 2330nm from 2080nm where significant numbers of Methane spectral lines are located. In this study we apply the well-established Information Content (IC) analysis techniques originally proposed by Rodgers (2000) to determine the potential benefit of retrieving total column Methane isotopologue concentrations assuming bands 2 and 3 of the GOSAT-2/TANSO-FTS-2 instrument. The value of such studies has been proven on multiple occasions and can provide guidance on appropriate potential retrieval setups. Due to the fact that there has been limited research in this area, no 'a priori' state vectors or Variance Covariance Matrices (VCMs

High-resolution atmospheric emission inventory of the argentine energy sector. Comparison with edgar global emission database

Directory of Open Access Journals (Sweden)

S. Enrique Puliafito

2017-12-01

Full Text Available This study presents a 2014 high-resolution spatially disaggregated emission inventory (0.025° × 0.025° horizontal resolution, of the main activities in the energy sector in Argentina. The sub-sectors considered are public generation of electricity, oil refineries, cement production, transport (maritime, air, rail and road, residential and commercial. The following pollutants were included: greenhouse gases (CO2, CH4, N2O, ozone precursors (CO, NOx, VOC and other specific air quality indicators such as SO2, PM10, and PM2.5. This work could contribute to a better geographical allocation of the pollutant sources through census based population maps. Considering the sources of greenhouse gas emissions, the total amount is 144 Tg CO2eq, from which the transportation sector emits 57.8 Tg (40%; followed by electricity generation, with 40.9 Tg (28%; residential + commercial, with 31.24 Tg (22%; and cement and refinery production, with 14.3 Tg (10%. This inventory shows that 49% of the total emissions occur in rural areas: 31% in rural areas of medium population density, 13% in intermediate urban areas and 7% in densely populated urban areas. However, if emissions are analyzed by extension (per square km, the largest impact is observed in medium and densely populated urban areas, reaching more than 20.3 Gg per square km of greenhouse gases, 297 Mg/km2 of ozone precursors gases and 11.5 Mg/km2 of other air quality emissions. A comparison with the EDGAR global emission database shows that, although the total country emissions are similar for several sub sectors and pollutants, its spatial distribution is not applicable to Argentina. The road and residential transport emissions represented by EDGAR result in an overestimation of emissions in rural areas and an underestimation in urban areas, especially in more densely populated areas. EDGAR underestimates 60 Gg of methane emissions from road transport sector and fugitive emissions from refining

Influence of updating global emission inventory of black carbon on evaluation of the climate and health impact

Science.gov (United States)

Wang, Rong; Tao, Shu; Balkanski, Yves; Ciais, Philippe

2013-04-01

Black carbon (BC) is an air component of particular concern in terms of air quality and climate change. Black carbon emissions are often estimated based on the fuel data and emission factors. However, large variations in emission factors reported in the literature have led to a high uncertainty in previous inventories. Here, we develop a new global 0.1°×0.1° BC emission inventory for 2007 with full uncertainty analysis based on updated source and emission factor databases. Two versions of LMDz-OR-INCA models, named as INCA and INCA-zA, are run to evaluate the new emission inventory. INCA is built up based on a regular grid system with a resolution of 1.27° in latitude and 2.50° in longitude, while INCA-zA is specially zoomed to 0.51°×0.66° (latitude×longitude) in Asia. By checking against field observations, we compare our inventory with ACCMIP, which is used by IPCC in the 5th assessment report, and also evaluate the influence of model resolutions. With the newly calculated BC air concentrations and the nested model, we estimate the direct radiative forcing of BC and the premature death and mortality rate induced by BC exposure with Asia emphasized. Global BC direct radiative forcing at TOA is estimated to be 0.41 W/m2 (0.2 - 0.8 as inter-quartile range), which is 17% higher than that derived from the inventory adopted by IPCC-AR5 (0.34 W/m2). The estimated premature deaths induced by inhalation exposure to anthropogenic BC (0.36 million in 2007) and the percentage of high risk population are higher than those previously estimated. Ninety percents of the global total anthropogenic PD occur in Asia with 0.18 and 0.08 million deaths in China and India, respectively.

Factors Controlling Methane in Arctic Lakes of Southwest Greenland.

Science.gov (United States)

Northington, Robert M; Saros, Jasmine E

2016-01-01

We surveyed 15 lakes during the growing season of 2014 in Arctic lakes of southwest Greenland to determine which factors influence methane concentrations in these systems. Methane averaged 2.5 μmol L-1 in lakes, but varied a great deal across the landscape with lakes on older landscapes farther from the ice sheet margin having some of the highest values of methane reported in lakes in the northern hemisphere (125 μmol L-1). The most important factors influencing methane in Greenland lakes included ionic composition (SO4, Na, Cl) and chlorophyll a in the water column. DOC concentrations were also related to methane, but the short length of the study likely underestimated the influence and timing of DOC on methane concentrations in the region. Atmospheric methane concentrations are increasing globally, with freshwater ecosystems in northern latitudes continuing to serve as potentially large sources in the future. Much less is known about how freshwater lakes in Greenland fit in the global methane budget compared to other, more well-studied areas of the Arctic, hence our work provides essential data for a more complete view of this rapidly changing region.

A 1990 global emission inventory of anthropogenic sources of carbon monoxide on 1o x 1o developed in the framework of EDGAR/GEIA

International Nuclear Information System (INIS)

Olivier, J.G.J.; Bouwman, A.F.; Bloos, J.P.J.; Berdowski, J.J.M.; Visschedijk, A.J.H.

1999-01-01

A global emission inventory of carbon monoxide (CO) emissions with 1 o x 1 o latitude-longitude resolution was compiled for 1990 on a sectoral basis. The sectoral sources considered include large-scale biomass burning (29%, of which savanna burning, 18%, and deforestation, 11%), fossil fuel combustion (27%, predominantly in road transport), biofuel combustion (19%, predominantly fuelwood combustion), agricultural waste burning (21%) and industrial process sources (4%). The inventory was compiled using mostly national statistics as activity data, emission factors at global or country level, and specific grid maps to convert, by sector, country total emissions to the 1 o x 1 o grid. A special effort was made to compile a global inventory of biofuel use, since this was considered to be a significant source on a global level, and a major source in some regions such as India and China. The global anthropogenic source of CO in 1990 is estimated at about 974 Tg CO yr -1 . The inventory is available on a sectoral basis on a 1 o x 1 o grid for input to global atmospheric models and on a regional/country basis for policy analysis. (author)

Reconciling Top-Down and Bottom-Up Estimates of Oil and Gas Methane Emissions in the Barnett Shale

Science.gov (United States)

Hamburg, S.

2015-12-01

Top-down approaches that use aircraft, tower, or satellite-based measurements of well-mixed air to quantify regional methane emissions have typically estimated higher emissions from the natural gas supply chain when compared to bottom-up inventories. A coordinated research campaign in October 2013 used simultaneous top-down and bottom-up approaches to quantify total and fossil methane emissions in the Barnett Shale region of Texas. Research teams have published individual results including aircraft mass-balance estimates of regional emissions and a bottom-up, 25-county region spatially-resolved inventory. This work synthesizes data from the campaign to directly compare top-down and bottom-up estimates. A new analytical approach uses statistical estimators to integrate facility emission rate distributions from unbiased and targeted high emission site datasets, which more rigorously incorporates the fat-tail of skewed distributions to estimate regional emissions of well pads, compressor stations, and processing plants. The updated spatially-resolved inventory was used to estimate total and fossil methane emissions from spatial domains that match seven individual aircraft mass balance flights. Source apportionment of top-down emissions between fossil and biogenic methane was corroborated with two independent analyses of methane and ethane ratios. Reconciling top-down and bottom-up estimates of fossil methane emissions leads to more accurate assessment of natural gas supply chain emission rates and the relative contribution of high emission sites. These results increase our confidence in our understanding of the climate impacts of natural gas relative to more carbon-intensive fossil fuels and the potential effectiveness of mitigation strategies.

Methanation of Carbon Dioxide

OpenAIRE

Goodman, Daniel Jacob

2013-01-01

The emission of greenhouse gases into the atmosphere has been linked to global warming. Carbon dioxide's (CO2) one of the most abundant greenhouse gases. Natural gas, mainly methane, is the cleanest fossil fuel for electricity production helping meet the United States ever growing energy needs. The methanation of CO2 has the potential to address both of these problems if a catalyst can be developed that meets the activity, economic and environmental requirements to industrialize the process. ...

Feasibility of atmospheric methane removal using methanotrophic biotrickling filters.

Science.gov (United States)

Yoon, Sukhwan; Carey, Jeffrey N; Semrau, Jeremy D

2009-07-01

Methane is a potent greenhouse gas with a global warming potential ~23 times that of carbon dioxide. Here, we describe the modeling of a biotrickling filtration system composed of methane-consuming bacteria, i.e., methanotrophs, to assess the utility of these systems in removing methane from the atmosphere. Model results indicate that assuming the global average atmospheric concentration of methane, 1.7 ppmv, methane removal is ineffective using these methanotrophic biofilters as the methane concentration is too low to enable cell survival. If the concentration is increased to 500-6,000 ppmv, however, similar to that found above landfills and in concentrated animal feeding operations (factory farms), 4.98-35.7 tons of methane can be removed per biofilter per year assuming biotrickling filters of typical size (3.66 m in diameter and 11.5 m in height). Using reported ranges of capital, operational, and maintenance costs, the cost of the equivalent ton of CO(2) removal using these systems is $90-$910 ($2,070-$20,900 per ton of methane), depending on the influent concentration of methane and if heating is required. The use of methanotrophic biofilters for controlling methane emissions is technically feasible and, provided that either the costs of biofilter construction and operation are reduced or the value of CO(2) credits is increased, can also be economically attractive.

Methane flux from boreal peatlands

International Nuclear Information System (INIS)

Crill, P.; Bartlett, K.; Roulet, N.

1992-01-01

The peatlands in the boreal zone (roughly 45 deg - 60 degN) store a significant reservoir of carbon, much of which is potentially available for exchange with the atmosphere. The anaerobic conditions that cause these soils to accumulate carbon also makes wet, boreal peatlands significant sources of methane to the global troposphere. It is estimated that boreal wetlands contribute approximately 19.5 Tg methane per year. The data available on the magnitude of boreal methane emissions have rapidly accumulated in the past twenty years. This paper offers a short review of the flux measured (with range roughly 1 - 2000 mg methane/m2d), considers environmental controls of the flux and briefly discusses how climate change might affect future fluxes

Modelling global methane emissions from livestock: Biological and nutritional controls

Science.gov (United States)

Johnson, Donald E.

1992-01-01

The available observations of methane production from the literature have been compiled into a ruminant methane data base. This data base includes 400 treatment mean observations of methane losses from cattle and sheep, and minor numbers of measurements from other species. Methane loss varied from 2.0 to 11.6 percent of dietary gross energy. Measurements included describe the many different weights and physiological states of the animals fed and diets ranging from all forage to all concentrate diets or mixtures. An auxiliary spreadsheet lists approximately 1000 individual animal observations. Many important concepts have emerged from our query and analysis of this data set. The majority of the world's cattle, sheep, and goats under normal husbandry circumstances likely produce methane very close to 6 percent of their daily diets gross energy (2 percent of the diet by weight). Although individual animals or losses from specific dietary research circumstances can vary considerably, the average for the vast majority of groups of ruminant livestock are likely to fall between 5.5 to 6.5 percent. We must caution, however, that little experimental data is available for two-thirds of the world's ruminants in developing countries. Available evidence suggests similar percentage of emissions, but this supposition needs confirmation. More importantly, data is skimpy or unavailable to describe diet consumption, animal weight, and class distribution.

Impact of ADTT concepts on the management of global plutonium inventories

International Nuclear Information System (INIS)

Davidson, J.W.; Krakowski, R.A.; Arthur, E.D.

1996-01-01

The impact of a number of current and future nuclear systems on global plutonium inventories is assessed under realistic forecasts of nuclear power growth. Advanced systems, such as those employing Accelerator Driven Transmutation Technologies (ADTT) and liquid metal reactors, show significant promise for meeting future plutonium management needs. These analyses also indicate requirements for a higher level of detail in the nuclear fuel cycle model and for development of a metric to more quantitatively assess the proliferation risk of plutonium arising from the civilian fuel cycle

Methane emissions from coal mining

International Nuclear Information System (INIS)

Williams, A.; Mitchell, C.

1993-01-01

This paper outlines some of the problems associated with the prediction of levels of methane emission from underground and surface coal mines. Current knowledge of coal mining emissions sources is outlined. On the basis of this information the methodology proposed by the IPCC/OECD Programme on National Inventories is critically examined and alternatives considered. Finally, the technical options for emissions control are examined together with their feasibility. 8 refs., 6 figs., 2 tabs

Nitrogen as a regulatory factor of methane oxidation in soils and sediments

NARCIS (Netherlands)

Bodelier, P.L.E.; Laanbroek, H.J.

2004-01-01

The oxidation of methane by methane-oxidising microorganisms is an important link in the global methane budget. Oxic soils are a net sink while wetland soils are a net source of atmospheric methane. It has generally been accepted that the consumption of methane in upland as well as lowland systems

Global data bases on distribution, characteristics and methane emission of natural wetlands: Documentation of archived data tape

Science.gov (United States)

Matthews, Elaine

1989-01-01

Global digital data bases on the distribution and environmental characteristics of natural wetlands, compiled by Matthews and Fung (1987), were archived for public use. These data bases were developed to evaluate the role of wetlands in the annual emission of methane from terrestrial sources. Five global 1 deg latitude by 1 deg longitude arrays are included on the archived tape. The arrays are: (1) wetland data source, (2) wetland type, (3) fractional inundation, (4) vegetation type, and (5) soil type. The first three data bases on wetland locations were published by Matthews and Fung (1987). The last two arrays contain ancillary information about these wetland locations: vegetation type is from the data of Matthews (1983) and soil type from the data of Zobler (1986). Users should consult original publications for complete discussion of the data bases. This short paper is designed only to document the tape, and briefly explain the data sets and their initial application to estimating the annual emission of methane from natural wetlands. Included is information about array characteristics such as dimensions, read formats, record lengths, blocksizes and value ranges, and descriptions and translation tables for the individual data bases.

Counting complete? Finalising the plant inventory of a global biodiversity hotspot

Directory of Open Access Journals (Sweden)

Martina Treurnicht

2017-02-01

Full Text Available The Cape Floristic Region—the world’s smallest and third richest botanical hotspot—has benefited from sustained levels of taxonomic effort and exploration for almost three centuries, but how close is this to resulting in a near-complete plant species inventory? We analyse a core component of this flora over a 250-year period for trends in taxonomic effort and species discovery linked to ecological and conservation attributes. We show that >40% of the current total of species was described within the first 100 years of exploration, followed by a continued steady rate of description. We propose that <1% of the flora is still to be described. We document a relatively constant cohort of taxonomists, working over 250 years at what we interpret to be their ‘taxonomic maximum.’ Rates of description of new species were independent of plant growth-form but narrow-range taxa have constituted a significantly greater proportion of species discoveries since 1950. This suggests that the fraction of undiscovered species predominantly comprises localised endemics that are thus of high conservation concern. Our analysis provides important real-world insights for other hotspots in the context of global strategic plans for biodiversity in informing considerations of the likely effort required in attaining set targets of comprehensive plant inventories. In a time of unprecedented biodiversity loss, we argue for a focused research agenda across disciplines to increase the rate of species descriptions in global biodiversity hotspots.

Landfill Methane

Science.gov (United States)

Landfill methane (CH4) accounts for approximately 1.3% (0.6 Gt) of global anthropogenic greenhouse gas emissions relative to total emissions from all sectors of about 49 Gt CO2-eq yr-1. For countries with a history of controlled landfilling, landfills can be one of the larger national sources of ant...

Atmospheric Methane characterisation over the South African interior

CSIR Research Space (South Africa)

Feig, Gregor T

2016-10-01

Full Text Available The concentrations of atmospheric methane have an important impact on the global climate system and are important in the production of tropospheric ozone as it acts as an ozone precursor. The ambient concentrations of methane have increased more...

Interactions between nitrogenous fertilizers and methane cycling in wetland and upland soils

NARCIS (Netherlands)

Bodelier, P.L.E.

2011-01-01

Recent dynamics and uncertainties in global methane budgets necessitate research of controls of sources and sinks of atmospheric methane. Production of methane by methanogenic archaea in wetlands is a major source while consumption by methane oxidizing bacteria in upland soils is a major sink.

Source Attribution of Methane Emissions in Northeastern Colorado Using Ammonia to Methane Emission Ratios

Science.gov (United States)

Eilerman, S. J.; Neuman, J. A.; Peischl, J.; Aikin, K. C.; Ryerson, T. B.; Perring, A. E.; Robinson, E. S.; Holloway, M.; Trainer, M.

2015-12-01

Due to recent advances in extraction technology, oil and natural gas extraction and processing in the Denver-Julesburg basin has increased substantially in the past decade. Northeastern Colorado is also home to over 250 concentrated animal feeding operations (CAFOs), capable of hosting over 2 million head of ruminant livestock (cattle and sheep). Because of methane's high Global Warming Potential, quantification and attribution of methane emissions from oil and gas development and agricultural activity are important for guiding greenhouse gas emission policy. However, due to the co-location of these different sources, top-down measurements of methane are often unable to attribute emissions to a specific source or sector. In this work, we evaluate the ammonia:methane emission ratio directly downwind of CAFOs using a mobile laboratory. Several CAFOs were chosen for periodic study over a 12-month period to identify diurnal and seasonal variation in the emission ratio as well as differences due to livestock type. Using this knowledge of the agricultural ammonia:methane emission ratio, aircraft measurements of ammonia and methane over oil and gas basins in the western US during the Shale Oil and Natural Gas Nexus (SONGNEX) field campaign in March and April 2015 can be used for source attribution of methane emissions.

Estimate of the emissions of methane in a dairy farm and a proposal of mitigation

International Nuclear Information System (INIS)

Schmidt, R; Alvarez, E; Gely, M; Pagano, A; Crozza, D

2005-01-01

The methane represents one of the most potent greenhouse gas and recent inventories express that the systems of handling of the manure of the livestock have influence in the global emissions of methane (Martinez et. al, 2003).This residue, during the periods of storage to open sky, suffers a natural anaerobic decomposition and gases like ammonium, hydrogen, sulfhydric, methane and dioxide of carbon; are generated and emitted to the atmosphere (EPA, 1999, Misselbrook et. al, 2001; Martinez et. al, 2003).In a report presented by the EPA (EPA, 1999) it was estimated that the methane emission originated in United States (1997) for the handling of the manure of the livestock ascended to 3.0 T g., what represents 10% of the total content of the methane emissions in that country.It is also expected that these emissions caused by the cattle residual grow above 25% from the 2000 to the 2020.In Argentina, and in particular in the region that includes the territorial space of the present study, in the Party of Olavarria located in the center of the Buenos Aires Province, it is considered that there are 8265 heads of bovine livestock, distributed under different forms of exploitation, dairy farms, cattle-breeding ranch and feedlots.These figures show the clearly incipient advance of the bovine livestock in this area, showing that the values of generated methane can influence thoroughly in the contribution of the greenhouse gas.The objective of the present study resides in carrying out an estimate of the equivalent quantity of CO 2 that is emitted to the atmosphere and how much it could decrease if the methodology of anaerobic digestion is applied, for the conversion of the bovine manure in biogas

A Global Inventory of Burned Areas at 1 Km Resolution for the Year 2000 Derived from Spot Vegetation Data

International Nuclear Information System (INIS)

Tansey, K.; Gregoire, J.M.; Boschetti, L.; Maggi, M.; Binaghi, E.; Brivio, P.A.; Stroppiana, D.; Ershov, D.; Flasse, S.; Fraser, R.; Graetz, D.; Peduzzi, P.; Pereira, J.; Silva, J.; Sousa, A.

2004-01-01

Biomass burning constitutes a major contribution to global emissions of carbon dioxide, carbon monoxide, methane, greenhouse gases and aerosols. Furthermore, biomass burning has an impact on health, transport, the environment and land use. Vegetation fires are certainly not recent phenomena and the impacts are not always negative. However, evidence suggests that fires are becoming more frequent and there is a large increase in the number of fires being set by humans for a variety of reasons. Knowledge of the interactions and feedbacks between biomass burning, climate and carbon cycling is needed to help the prediction of climate change scenarios. To obtain this knowledge, the scientific community requires, in the first instance, information on the spatial and temporal distribution of biomass burning at the global scale. This paper presents an inventory of burned areas at monthly time periods for the year 2000 at a resolution of 1 kilometer (km) and is available to the scientific community at no cost. The burned area products have been derived from a single source of satellite-derived images, the SPOT VEGETATION S1 1 km product, using algorithms developed and calibrated at regional scales by a network of partners. In this paper, estimates of burned area, number of burn scars and average size of the burn scar are described for each month of the year 2000. The information is reported at the country level. This paper makes a significant contribution to understanding the effect of biomass burning on atmospheric chemistry and the storage and cycling of carbon by constraining one of the main parameters used in the calculation of gas emissions

A Global Inventory of Burned Areas at 1 Km Resolution for the Year 2000 Derived from Spot Vegetation Data

Energy Technology Data Exchange (ETDEWEB)

Tansey, K. [Department of Geography, University of Leicester, University Road, Leicester, LE1 7RH (United Kingdom); Gregoire, J.M.; Boschetti, L.; Maggi, M. [European Commission Joint Research Centre (JRC), Ispra, I-21020 (Italy); Binaghi, E. [Universita dell' Insubria, Via Ravasi 2, I-21100 Varese (Italy); Brivio, P.A.; Stroppiana, D. [Institute for Electromagnetic Sensing of the Environment CNR-IREA, Via Bassini 15, I-20133 Milan (Italy); Ershov, D. [International Forest Institute IFI, Novocheriomushkinskaya str. 69a, Moscow, 117418 (Russian Federation); Flasse, S. [Flasse Consulting, 3 Sycamore Crescent, Maidstone, ME16 0AG (United Kingdom); Fraser, R. [Natural Resources Canada, Canada Centre for Remote Sensing (CCRS), 588 Booth St., Ottawa, ON, K1A 0Y7 (Canada); Graetz, D. [CSIRO Earth Observation Centre GPO 3023, Canberra, ACT, 2601 (Australia); Peduzzi, P. [United Nations Environment Programme UNEP, Early Warning Unit UNEP/DEWA/GRID, International Environment House, 1219 Geneva (Switzerland); Pereira, J. [Tropical Research Institute, Travessa Conde da Ribeira 9, 1300-142 Lisbon (Portugal); Silva, J. [Department of Forestry, Technical University of Lisbon, Tapada da Ajuda, 1349-017 Lisbon (Portugal); Sousa, A. [Department of Rural Engineering, University of Evora, Apartado 94, 7002-554 Evora (Portugal)

2004-12-01

Biomass burning constitutes a major contribution to global emissions of carbon dioxide, carbon monoxide, methane, greenhouse gases and aerosols. Furthermore, biomass burning has an impact on health, transport, the environment and land use. Vegetation fires are certainly not recent phenomena and the impacts are not always negative. However, evidence suggests that fires are becoming more frequent and there is a large increase in the number of fires being set by humans for a variety of reasons. Knowledge of the interactions and feedbacks between biomass burning, climate and carbon cycling is needed to help the prediction of climate change scenarios. To obtain this knowledge, the scientific community requires, in the first instance, information on the spatial and temporal distribution of biomass burning at the global scale. This paper presents an inventory of burned areas at monthly time periods for the year 2000 at a resolution of 1 kilometer (km) and is available to the scientific community at no cost. The burned area products have been derived from a single source of satellite-derived images, the SPOT VEGETATION S1 1 km product, using algorithms developed and calibrated at regional scales by a network of partners. In this paper, estimates of burned area, number of burn scars and average size of the burn scar are described for each month of the year 2000. The information is reported at the country level. This paper makes a significant contribution to understanding the effect of biomass burning on atmospheric chemistry and the storage and cycling of carbon by constraining one of the main parameters used in the calculation of gas emissions.

Implementation of methane cycling for deep time, global warming simulations with the DCESS Earth System Model (Version 1.2)

DEFF Research Database (Denmark)

Shaffer, Gary; Villanueva, Esteban Fernández; Rondanelli, Roberto

2017-01-01

Geological records reveal a number of ancient, large and rapid negative excursions of carbon-13 isotope. Such excursions can only be explained by massive injections of depleted carbon to the Earth System over a short duration. These injections may have forced strong global warming events, sometimes....... With this improved DCESS model version and paleo-reconstructions, we are now better armed to gauge the amounts, types, time scales and locations of methane injections driving specific, observed deep time, global warming events....

Factors Affecting Mitigation of Methane Emission from Ruminants: Management Strategies

Directory of Open Access Journals (Sweden)

Afshar Mirzaei-Aghsaghali

2015-06-01

Full Text Available Nowadays, greenhouse gas emission which results in elevating global temperature is an important subject of worldwide ecological and environmental concern. Among greenhouse gases, methane is considered a potent greenhouse gas with 21 times more global warming potential than carbon dioxide. Worldwide, ruminant livestock produce about 80 million metric tons of methane each year, accounting for about 28% of global emissions from human related activities. Therefore it is impelling animal scientists to finding solutions to mitigate methane emission from ruminants. It seems that solutions can be discussed in four topics including: nutrition (feeding, biotechnology, microbiology and management strategies. We have already published the first review article on feeding strategies. In the current review, management strategies such as emphasizing on animals - type and individual variability, reducing livestock numbers, improving animal productivity and longevity as well as pasture management; that can be leads to decreasing methane production from ruminant animal production are discussed.

Validation of farm-scale methane emissions using nocturnal boundary layer budgets

Directory of Open Access Journals (Sweden)

J. Stieger

2015-12-01

Full Text Available This study provides the first experimental validation of Swiss agricultural methane emission estimates at the farm scale. We measured CH4 concentrations at a Swiss farmstead during two intensive field campaigns in August 2011 and July 2012 to (1 quantify the source strength of livestock methane emissions using a tethered balloon system and (2 to validate inventory emission estimates via nocturnal boundary layer (NBL budgets. Field measurements were performed at a distance of 150 m from the nearest farm buildings with a tethered balloon system in combination with gradient measurements at eight heights on a 10 m tower to better resolve the near-surface concentrations. Vertical profiles of air temperature, relative humidity, CH4 concentration, wind speed, and wind direction showed that the NBL was strongly influenced by local transport processes and by the valley wind system. Methane concentrations showed a pronounced time course, with highest concentrations in the second half of the night. NBL budget flux estimates were obtained via a time–space kriging approach. Main uncertainties of NBL budget flux estimates were associated with nonstationary atmospheric conditions and the estimate of the inversion height zi (top of volume integration. The mean NBL budget fluxes of 1.60 ± 0.31 μg CH4 m-2 s-1 (1.40 ± 0.50 and 1.66 ± 0.20 μg CH4 m-2 s-1 in 2011 and 2012 respectively were in good agreement with local inventory estimates based on current livestock number and default emission factors, with 1.29 ± 0.47 and 1.74 ± 0.63 μg CH4 m-2 s-1 for 2011 and 2012 respectively. This indicates that emission factors used for the national inventory reports are adequate, and we conclude that the NBL budget approach is a useful tool to validate emission inventory estimates.

Validation of farm-scale methane emissions using nocturnal boundary layer budgets

Science.gov (United States)

Stieger, J.; Bamberger, I.; Buchmann, N.; Eugster, W.

2015-12-01

This study provides the first experimental validation of Swiss agricultural methane emission estimates at the farm scale. We measured CH4 concentrations at a Swiss farmstead during two intensive field campaigns in August 2011 and July 2012 to (1) quantify the source strength of livestock methane emissions using a tethered balloon system and (2) to validate inventory emission estimates via nocturnal boundary layer (NBL) budgets. Field measurements were performed at a distance of 150 m from the nearest farm buildings with a tethered balloon system in combination with gradient measurements at eight heights on a 10 m tower to better resolve the near-surface concentrations. Vertical profiles of air temperature, relative humidity, CH4 concentration, wind speed, and wind direction showed that the NBL was strongly influenced by local transport processes and by the valley wind system. Methane concentrations showed a pronounced time course, with highest concentrations in the second half of the night. NBL budget flux estimates were obtained via a time-space kriging approach. Main uncertainties of NBL budget flux estimates were associated with nonstationary atmospheric conditions and the estimate of the inversion height zi (top of volume integration). The mean NBL budget fluxes of 1.60 ± 0.31 μg CH4 m-2 s-1 (1.40 ± 0.50 and 1.66 ± 0.20 μg CH4 m-2 s-1 in 2011 and 2012 respectively) were in good agreement with local inventory estimates based on current livestock number and default emission factors, with 1.29 ± 0.47 and 1.74 ± 0.63 μg CH4 m-2 s-1 for 2011 and 2012 respectively. This indicates that emission factors used for the national inventory reports are adequate, and we conclude that the NBL budget approach is a useful tool to validate emission inventory estimates.

National inventory report. Greenhouse gas emissions 1990-2009

Energy Technology Data Exchange (ETDEWEB)

2011-05-15

Emissions of the following greenhouse gases are covered in this report: carbon dioxide (CO{sub 2}), methane (CH{sub 4}), nitrous oxide (N{sub 2}O), perfluoro carbons (PFCs), hydro fluorocarbons (HFCs) and sulphur hexafluoride (SF{sub 6}). In addition, the inventory includes calculations of emissions of the precursors NO{sub x}, NMVOC, and CO, as well as for SO{sub 2}. Indirect CO{sub 2} emissions originating from the fossil part of CH{sub 4} and NMVOC are calculated according to the reporting guidelines to the UNFCCC, and accounted for in the inventory. (AG)

National inventory report. Greenhouse gas emissions 1990-2010

Energy Technology Data Exchange (ETDEWEB)

Kolshus, Hans H.; Gjerald, Eilev; Hoem, Britta; Ramberg, Simen Helgesen; Haugland, Hege; Valved, Hilde; Nelson, George Nicholas; Asphjell, Torgrim; Christophersen, Oeyvind; Gaustad, Alice; Rubaek, Birgitte; Hvalryg, Marte Monsen

2012-07-01

Emissions of the following greenhouse gases are covered in this report: carbon dioxide (CO{sub 2}), methane (CH{sub 4}), nitrous oxide (N{sub 2}O), perfluoro carbons (PFCs), hydro fluorocarbons (HFCs) and sulphur hexafluoride (SF{sub 6}). In addition, the inventory includes calculations of emissions of the precursors NO{sub x}, NMVOC, and CO, as well as for SO{sub 2}. Indirect CO{sub 2} emissions originating from the fossil part of CH{sub 4} and NMVOC are calculated according to the reporting guidelines to the UNFCCC, and accounted for in the inventory.(eb)

Carbon and hydrogen isotope composition and C-14 concentration in methane from sources and from the atmosphere: Implications for a global methane budget

Science.gov (United States)

Wahlen, Martin

1994-01-01

The topics covered include the following: biogenic methane studies; forest soil methane uptake; rice field methane sources; atmospheric measurements; stratospheric samples; Antarctica; California; and Germany.

Inventory of Dutch National Research on Global Climate Change: Inside and outside the National Research Programme

International Nuclear Information System (INIS)

Smythe, K.D.; Bernabo, C.; Kingma, J.; Vrakking, W.

1993-04-01

This summary of Dutch research on global climate change was compiled from a survey of the major research organisations in the Netherlands. The scope and structure of the survey and this report were based on a request for information from the World Meteorological Organisation for an intergovernmental meeting on the World Climate Programme (WCP) held (from 14 to 16 April 1993). The WMO request emphasized activities related to the WCP and its associated programmes. To extend the usefulness of the exercise, an attempt has been made to broaden the focus to give additional attention to the Intergovernmental Geosphere-Biosphere Programme (IGBP) and the Human Dimensions Programme (HDP). This was the first attempt to inventory the research projects on global climate change underway in the Netherlands - both inside and outside the National Research Programme. Other surveys on Dutch climate-related research have been conducted. The most extensive effort was a cataloging of publications from climate research in the Netherlands from 1981 to 1991, which was conducted by the Netherlands Royal Academy of Sciences (KNAW). That inventory is being updated to include publications through 1992. The database resulting from this exercise will be a useful tool for organisations sponsoring and conducting global climate change research in their efforts to stimulate cooperation and promote coordination among research groups in the Netherlands and abroad. There are plans to update the inventory in the future and to provide the information to participating Dutch organisations as well as research organisations in other countries. An overview of the current research is provided in Volume 1 with a list of projects

Methane emissions from enteric fermentation in dairy cows, 1990-2008

NARCIS (Netherlands)

Bannink, A.

2011-01-01

The Dutch protocol for the national inventory estimates the methane emission of the average Dutch dairy cow based on a Tier 3 approach. A dynamic, mechanistic model is used to represent the enteric fermentation processes, using annual national statistics on feed intake and feed composition as model

Fugitive Methane Emission Identification and Source Attribution: Ethane-to-Methane Analysis Using a Portable Cavity Ring-Down Spectroscopy Analyzer

Science.gov (United States)

Kim-Hak, D.; Fleck, D.

2017-12-01

Natural gas analysis and methane specifically have become increasingly important by virtue of methane's 28-36x greenhouse warming potential compared to CO2 and accounting for 10% of total greenhouse gas emissions in the US alone. Additionally, large uncontrolled leaks, such as the recent one from Aliso Canyon in Southern California, originating from uncapped wells, storage facilities and coal mines have increased the total global contribution of methane missions even further. Determining the specific fingerprint of methane sources by quantifying the ethane to methane (C2:C1) ratios provides us with means to understand processes yielding methane and allows for sources of methane to be mapped and classified through these processes; i.e. biogenic or thermogenic, oil vs. gas vs. coal gas-related. Here we present data obtained using a portable cavity ring-down spectrometry analyzer weighing less than 25 lbs and consuming less than 35W that simultaneously measures methane and ethane in real-time with a raw 1-σ precision of plane gas propagation.

Large methane releases lead to strong aerosol forcing and reduced cloudiness

DEFF Research Database (Denmark)

Kurten, T.; Zhou, L.; Makkonen, R.

2011-01-01

The release of vast quantities of methane into the atmosphere as a result of clathrate destabilization is a potential mechanism for rapid amplification of global warming. Previous studies have calculated the enhanced warming based mainly on the radiative effect of the methane itself, with smaller...... is predicted to significantly decrease hydroxyl radical (OH) concentrations, while moderately increasing ozone (O-3). These changes lead to a 70% increase in the atmospheric lifetime of methane, and an 18% decrease in global mean cloud droplet number concentrations (CDNC). The CDNC change causes a radiative...... forcing that is comparable in magnitude to the long-wave radiative forcing ("enhanced greenhouse effect") of the added methane. Together, the indirect CH4-O-3 and CH4-OHaerosol forcings could more than double the warming effect of large methane increases. Our findings may help explain the anomalously...

Permafrost slowly exhales methane

Science.gov (United States)

Herndon, Elizabeth M.

2018-04-01

Permafrost soils store vast quantities of organic matter that are vulnerable to decomposition under a warming climate. Recent research finds that methane release from thawing permafrost may outpace carbon dioxide as a major contributor to global warming over the next century.

Methane emissions from the natural gas industry

International Nuclear Information System (INIS)

Harrison, M.R.; Cowgill, R.M.; Campbell, L.M.; Lott, R.A.

1993-01-01

The U.S. EPA and the United Nation's Intergovernmental Panel on Climate Change (IPCC) have suggested that global warming could be reduced if more energy was generated using natural gas rather than fuels such as coal. An increased use of natural gas instead of coal would decrease global warming since methane emits less carbon dioxide (CO 2 ) than any fossil fuel. However, methane is a more potent as a greenhouse gas than CO 2 , and leakage from the gas system could reduce or eliminate the inherent advantage of natural gas. For this reason, methane emissions must be quantified before a national policy on preferred fuels is developed. Therefore, GRI and EPA have developed this confunded program to quantify methane emissions from the U.S. gas industry. This paper presents, for general industry review, the approach and methodology that the project is using to determine the emissions. The study will measure or calculate all gas industry methane emissions - from production at the wellhead, through the system, to the customer's meter. When these data are combined with data from other studies, a definitive comparison of the relative environmental impact of using methane versus other fuels will be possible. The study will also provide data that can be used by the industry to identify cost-effective mitigation techniques to reduce losses. The methane emissions project is being conducted in three phases: the first two phases have identified and ranked all known potential methane-emitting sources and established methods for measuring, calculating, and extrapolating emissions from those sources. The third phase, which is currently in progress, will gather sufficient data to achieve the accuracy goal. This paper briefly summarizes the methodology being used for the completion of the third phase

Reducing methane emissions from ruminant animals

Energy Technology Data Exchange (ETDEWEB)

Mathison, G.W.; Okine, E.K.; McAllister, T.A.; Dong, Y.; Galbraith, J.; Dmytruk, O.I.N. [University of Alberta, Edmonton, AB (Canada). Dept. of Agriculture, Food and Nutrition Science

1998-09-01

In 1992 it was estimated that 30 x 10{sup 12}g more methane was emitted into the atmosphere than was removed, with animals being considered the largest single anthropogenic source. Ruminants produce 97% of the methane generated in enteric fermentation by animals. Estimates for methane emissions from animal wastes vary between 6 and 31% of that produced directly by the animal, with the most likely value being between 5 and 10% globally. Methane inhibitors can reduce methane emissions to zero in the short term but due to microbial adaptation the effects of these compounds are quickly neutralized and feed intake is often depressed. Methane emissions per unit of feed consumed from sheep and cattle fed hay diets appear to be quite similar but differences between other ruminants have been measured. The most practical way of influencing methane emissions per unit product is to increase productivity level since the proportion of feed energy required to just maintain the animal will be reduced, methane production falls with increased intake level, and the animal may go to market sooner. The most promising avenues for future research for reducing methanogenesis are the development of new products for reducing protozoal numbers in the rumen and the use of bacterocins or other compounds which specifically target methanogenic bacteria.

Mapping Global Forest Aboveground Biomass with Spaceborne LiDAR, Optical Imagery, and Forest Inventory Data

Directory of Open Access Journals (Sweden)

Tianyu Hu

2016-07-01

Full Text Available As a large carbon pool, global forest ecosystems are a critical component of the global carbon cycle. Accurate estimations of global forest aboveground biomass (AGB can improve the understanding of global carbon dynamics and help to quantify anthropogenic carbon emissions. Light detection and ranging (LiDAR techniques have been proven that can accurately capture both horizontal and vertical forest structures and increase the accuracy of forest AGB estimation. In this study, we mapped the global forest AGB density at a 1-km resolution through the integration of ground inventory data, optical imagery, Geoscience Laser Altimeter System/Ice, Cloud, and Land Elevation Satellite data, climate surfaces, and topographic data. Over 4000 ground inventory records were collected from published literatures to train the forest AGB estimation model and validate the resulting global forest AGB product. Our wall-to-wall global forest AGB map showed that the global forest AGB density was 210.09 Mg/ha on average, with a standard deviation of 109.31 Mg/ha. At the continental level, Africa (333.34 ± 63.80 Mg/ha and South America (301.68 ± 67.43 Mg/ha had higher AGB density. The AGB density in Asia, North America and Europe were 172.28 ± 94.75, 166.48 ± 84.97, and 132.97 ± 50.70 Mg/ha, respectively. The wall-to-wall forest AGB map was evaluated at plot level using independent plot measurements. The adjusted coefficient of determination (R2 and root-mean-square error (RMSE between our predicted results and the validation plots were 0.56 and 87.53 Mg/ha, respectively. At the ecological zone level, the R2 and RMSE between our map and Intergovernmental Panel on Climate Change suggested values were 0.56 and 101.21 Mg/ha, respectively. Moreover, a comprehensive comparison was also conducted between our forest AGB map and other published regional AGB products. Overall, our forest AGB map showed good agreements with these regional AGB products, but some of the regional

Methane hydrates in quaternary climate change

International Nuclear Information System (INIS)

Kennett, J. P.; Hill, T. M.; Behl, R. J.

2005-01-01

The hydrate reservoir in marine sediments is known to contain a large volume of exchangeable carbon stored as solid methane hydrate and associated free gas. This reservoir has been shown to be potentially unstable in response to changing intermediate water temperature and sea level (pressure). Evidence continues to grow for past episodes of major methane release at times of climatic warming. Yet few studies of late Quaternary climate change include methane hydrates as an integral part of the global climate system, in spite of the largest known oscillations at this time in sea level and upper ocean temperature changes for the Cenozoic or earlier, conditions that favor instability of the methane hydrate reservoir. Abrupt increases in atmospheric methane recorded in polar ice cores are widely believed to have resulted, not from ocean-floor methane degassing, but instead from continental wetland activation, a hypothesis thus far unsupported by geological data. Furthermore, as part of this Wetland Methane Hypothesis, the abrupt methane increases have been seen as a response to climatic warming rather than contributing significantly to the change. An alternative view (formulated as the Clathrate Gun Hypothesis) is that the speed, magnitude and timing of abrupt climate change in the recent geologic past are consistent with the process of major degassing of methane hydrates. We summarize aspects of this hypothesis here and needs to test this hypothesis. (Author)

Tapping methane hydrates for unconventional natural gas

Science.gov (United States)

Ruppel, Carolyn

2007-01-01

Methane hydrate is an icelike form of concentrated methane and water found in the sediments of permafrost regions and marine continental margins at depths far shallower than conventional oil and gas. Despite their relative accessibility and widespread occurrence, methane hydrates have never been tapped to meet increasing global energy demands. With rising natural gas prices, production from these unconventional gas deposits is becoming economically viable, particularly in permafrost areas already being exploited for conventional oil and gas. This article provides an overview of gas hydrate occurrence, resource assessment, exploration, production technologies, renewability, and future challenges.

An Improved Approach to Estimate Methane Emissions from Coal Mining in China.

Science.gov (United States)

Zhu, Tao; Bian, Wenjing; Zhang, Shuqing; Di, Pingkuan; Nie, Baisheng

2017-11-07

China, the largest coal producer in the world, is responsible for over 50% of the total global methane (CH 4 ) emissions from coal mining. However, the current emission inventory of CH4 from coal mining has large uncertainties because of the lack of localized emission factors (EFs). In this study, province-level CH4 EFs from coal mining in China were developed based on the data analysis of coal production and corresponding discharged CH4 emissions from 787 coal mines distributed in 25 provinces with different geological and operation conditions. Results show that the spatial distribution of CH 4 EFs is highly variable with values as high as 36 m3/t and as low as 0.74 m3/t. Based on newly developed CH 4 EFs and activity data, an inventory of the province-level CH4 emissions was built for 2005-2010. Results reveal that the total CH 4 emissions in China increased from 11.5 Tg in 2005 to 16.0 Tg in 2010. By constructing a gray forecasting model for CH 4 EFs and a regression model for activity, the province-level CH 4 emissions from coal mining in China are forecasted for the years of 2011-2020. The estimates are compared with other published inventories. Our results have a reasonable agreement with USEPA's inventory and are lower by a factor of 1-2 than those estimated using the IPCC default EFs. This study could help guide CH 4 mitigation policies and practices in China.

Emissions inventories and options for control. Summary report

Energy Technology Data Exchange (ETDEWEB)

Swart, R.J.; Van Amstel, A.R.; Van den Born, G.J.; Kroeze, C.

1995-10-01

This report is the final summary report of the project `Social causes of the greenhouse effect, emissions inventories and options for control`. The objectives of the project, that started in 1990, were to support the development of a comprehensive Dutch climate policy and to identify gaps in the knowledge about sources of greenhouse gases. The four phases of the project are summarized. In the first phase, a first national inventory of greenhouse gas emissions was made, capturing carbon dioxide (CO{sub 2}), chlorofluorocarbons (CFCs), methane (CH{sub 4}), nitrous oxide (N{sub 2}O) and the ozone precursors carbon monoxide (CO), nitrogen oxides (NO{sub x} ) and volatile organic compounds (VOC). In the second phase, the acquired expertise was used to support the development of Guidelines for National Emissions Inventories by the joint OECD/IPCC programme through workshop organization and participation in the international planning group. In the third phase, a detailed analysis was performed of the sources of methane, its current and future emissions and the options for control. Finally, a similar analysis was performed for nitrous oxide. In these studies, it was found that policies not specifically aiming at mitigating climate change, would help to control the emissions of the non-CO{sub 2} greenhouse gases. While for methane, national emissions would even decrease because of measures in the livestock management and waste disposal sectors, for nitrous oxide the reductions in agricultural emissions would be outweighed by increases, especially in the transportation sector. The project shows that the application of more detailed information leads to differences with the Guidelines, both because of the limited number of source categories in the Guidelines and because of different, locally specific emissions factors. 4 figs., 2 tabs., 14 refs.

Methane emissions from MBT landfills

Energy Technology Data Exchange (ETDEWEB)

Heyer, K.-U., E-mail: heyer@ifas-hamburg.de; Hupe, K.; Stegmann, R.

2013-09-15

) model of the IPCC Guidelines for National Greenhouse Gas Inventories, 2006, was used to estimate the methane emissions from MBT landfills. Due to the calculation made by the authors emissions in the range of 60,000–135,000 t CO{sub 2-eq.}/a for all German MBT landfills can be expected. This wide range shows the uncertainties when the here used procedure and the limited available data are applied. It is therefore necessary to generate more data in the future in order to calculate more precise methane emission rates from MBT landfills. This is important for the overall calculation of the climate gas production in Germany which is required once a year by the German Government.

Breeding Ruminants that Emit Less Methane – The Role of International Collaboration

NARCIS (Netherlands)

Oddy, V.H.; Haas, de Y.; Basarab, J.; Cammack, K.; Hayes, B.J.; Hegarty, R.; Lassen, J.; McEwan, J.; Miller, S.; Pinares-Patino, C.

2014-01-01

Ruminants contribute to global greenhouse gas (GHG) emissions, principally as enteric methane (CH4) emissions. Direct selection for reduced CH4 emissions through combined selection for both low residual feed intake and methane yield could potentially provide a long term reduction in enteric methane

Nonequilibrium clumped isotope signals in microbial methane

Science.gov (United States)

Wang, David T.; Gruen, Danielle S.; Lollar, Barbara Sherwood; Hinrichs, Kai-Uwe; Stewart, Lucy C.; Holden, James F.; Hristov, Alexander N.; Pohlman, John W.; Morrill, Penny L.; Könneke, Martin; Delwiche, Kyle B.; Reeves, Eoghan P.; Sutcliffe, Chelsea N.; Ritter, Daniel J.; Seewald, Jeffrey S.; McIntosh, Jennifer C.; Hemond, Harold F.; Kubo, Michael D.; Cardace, Dawn; Hoehler, Tori M.; Ono, Shuhei

2015-01-01

Methane is a key component in the global carbon cycle with a wide range of anthropogenic and natural sources. Although isotopic compositions of methane have traditionally aided source identification, the abundance of its multiply-substituted “clumped” isotopologues, e.g., 13CH3D, has recently emerged as a proxy for determining methane-formation temperatures; however, the impact of biological processes on methane’s clumped isotopologue signature is poorly constrained. We show that methanogenesis proceeding at relatively high rates in cattle, surface environments, and laboratory cultures exerts kinetic control on 13CH3D abundances and results in anomalously elevated formation temperature estimates. We demonstrate quantitatively that H2 availability accounts for this effect. Clumped methane thermometry can therefore provide constraints on the generation of methane in diverse settings, including continental serpentinization sites and ancient, deep groundwaters.

The Boston Methane Project: Mapping Surface Emissions to Inform Atmospheric Estimation of Urban Methane Flux

Science.gov (United States)

Phillips, N.; Crosson, E.; Down, A.; Hutyra, L.; Jackson, R. B.; McKain, K.; Rella, C.; Raciti, S. M.; Wofsy, S. C.

2012-12-01

Lost and unaccounted natural gas can amount to over 6% of Massachusetts' total annual greenhouse gas inventory (expressed as equivalent CO2 tonnage). An unknown portion of this loss is due to natural gas leaks in pipeline distribution systems. The objective of the Boston Methane Project is to estimate the overall leak rate from natural gas systems in metropolitan Boston, and to compare this flux with fluxes from the other primary methane emissions sources. Companion talks at this meeting describe the atmospheric measurement and modeling framework, and chemical and isotopic tracers that can partition total atmospheric methane flux into natural gas and non-natural gas components. This talk focuses on estimation of surface emissions that inform the atmospheric modeling and partitioning. These surface emissions include over 3,300 pipeline natural gas leaks in Boston. For the state of Massachusetts as a whole, the amount of natural gas reported as lost and unaccounted for by utility companies was greater than estimated landfill emissions by an order of magnitude. Moreover, these landfill emissions were overwhelmingly located outside of metro Boston, while gas leaks are concentrated in exactly the opposite pattern, increasing from suburban Boston toward the urban core. Work is in progress to estimate spatial distribution of methane emissions from wetlands and sewer systems. We conclude with a description of how these spatial data sets will be combined and represented for application in atmospheric modeling.

Stimulation by ammonium-based fertilizers of methane oxidation in soil around rice roots

NARCIS (Netherlands)

Bodelier, P.L.E.; Roslev, P.; Henckel, T.; Frenzel, P.

2000-01-01

Methane is involved in a number of chemical and physical processes in the Earths atmosphere, including global warming(1), Atmospheric methane originates mainly from biogenic sources, such as rice paddies and natural wetlands; the former account for at least 30% of the global annual emission of

Compilation of a global N{sub 2}O emission inventory for tropical rainforest soils using a detailed biogeochemical model

Energy Technology Data Exchange (ETDEWEB)

Werner, C.

2007-09-15

Nitrous oxide (N{sub 2}O) is a potent trace gas contributing to approximately 6% to the observed anthropogenic global warming. Soils have been identified to be the major source of atmospheric N{sub 2}O and tropical rainforest soils are thought to account for the largest part. Furthermore, various studies have shown that the magnitude of N{sub 2}O emissions from tropical rainforest soil is highly variable on spatial and temporal scales. Detailed, process-based models coupled to Geographic Information Systems (GIS) are considered promising tools for the calculation of N{sub 2}O emission inventories. This methodology explicitly accounts for the governing microbial processes as well as the environmental controls. Moreover, mechanistic biogeochemical models operating in daily time-steps (e.g. ForestDNDC-tropica) have been shown to capture the observed intra- and inter-annual variations of N{sub 2}O emissions. However, detailed N{sub 2}O emission datasets are required for model calibration and testing, but are currently few in numbers. In this study an automated measurement system was used to derive detailed datasets of N{sub 2}O, methane (CH{sub 4}) and carbon dioxide (CO{sub 2}) soil-atmosphere exchange and important environmental parameters from tropical rainforest soils in Kenya and Southwest China. Distinct differences were identified in the magnitude of the C and N soil-atmosphere exchange at the investigated sites and forest types. However, common features such as N{sub 2}O pulse emissions after dry season or the pronounced soil moisture dependency of N{sub 2}O emissions were observed at both sites. The derived datasets are unique for these tropical regions as so far no information about the source strength of these regions was available and, for the first time, the N{sub 2}O, CH{sub 4} and CO{sub 2} soil-atmosphere exchange was recorded in sub-daily resolution. The datasets were utilized in conjunction with available high-resolution datasets from Australian

Comparison of real-time BTEX flux measurements to reported emission inventories in the Upper Green River Basin, Wyoming.

Science.gov (United States)

Edie, R.; Robertson, A.; Murphy, S. M.; Soltis, J.; Field, R. A.; Zimmerle, D.; Bell, C.

2017-12-01

Other Test Method 33a (OTM-33a) is an EPA-developed near-source measurement technique that utilizes a Gaussian plume inversion to calculate the flux of a point source 20 to 200 meters away. In 2014, the University of Wyoming mobile laboratory—equipped with a Picarro methane analyzer and an Ionicon Proton Transfer Reaction Time of Flight Mass Spectrometer—measured methane and BTEX fluxes from oil and gas operations in the Upper Green River Basin (UGRB), Wyoming. In this study, OTM-33a BTEX flux measurements are compared to BTEX emissions reported by operators in the Wyoming Department of Environmental Quality (WY-DEQ) emission inventory. On average, OTM-33a measured BTEX fluxes are almost twice as high as those reported in the emission inventory. To further constrain errors in the OTM-33a method, methane test releases were performed at the Colorado State University Methane Emissions Test and Evaluation Center (METEC) in June of 2017. The METEC facility contains decommissioned oil and gas equipment arranged in realistic well pad layouts. Each piece of equipment has a multitude of possible emission points. A Gaussian fit of measurement error from these 29 test releases indicate the median OTM-33a measurement quantified 55% of the metered flowrate. BTEX results from the UGRB campaign and inventory analysis will be presented, along with a discussion of errors associated with the OTM-33a measurement technique. Real-time BTEX and methane mixing ratios at the measurement locations (which show a lack of correlation between VOC and methane sources in 20% of sites sampled) will also be discussed.

Genes, isotopes, and ecosystem biogeochemistry. Dissecting methane flux at the leading edge of global change

Energy Technology Data Exchange (ETDEWEB)

Saleska, Scott [Univ. of Arizona, Tucson, AZ (United States); Rich, Virginia [The Ohio State Univ., Columbus, OH (United States); Tyson, Gene [Univ. of Queensland, St. Lucia (Australia); Chanton, Jeff [Florida State Univ., Tallahassee, FL (United States); Crill, Patrick [Stockholm Univ. (Sweden); Li, Changshen [Univ. of New Hampshire, Durham, NH (United States)

2016-02-22

This project integrates across three fields (microbiology, biogeochemistry, and modeling) to understand the mechanisms of methane cycling in thawing permafrost. We have made substantial progress in each area, and in cross-cutting interdisciplinary synthesis. Large releases of CH₄ from thawing permafrost to the atmosphere, a strong positive feedback to global warming, are plausible but little is known about the controls on such release. Our project (“IsoGenie”) addresses the key question: What is the interplay of microbial communities and soil organic matter composition in the decomposition of organic C to CH₄ across a permafrost thaw gradient?

Methane emissions from a high arctic valley: findings and challenges

DEFF Research Database (Denmark)

Mastepanov, Mikhail; Sigsgaard, Charlotte; Ström, Lena

2008-01-01

Wet tundra ecosystems are well-known to be a significant source of atmospheric methane. With the predicted stronger effect of global climate change on arctic terrestrial ecosystems compared to lower-latitudes, there is a special obligation to study the natural diversity and the range of possible...... feedback effects on global climate that could arise from Arctic tundra ecosystems. One of the prime candidates for such a feedback mechanism is a potential change in the emissions of methane. Long-term datasets on methane emissions from high arctic sites are almost non-existing but badly needed...... for analyses of controls on interannual and seasonal variations in emissions. To help fill this gap we initiated a measurement program in a productive high arctic fen in the Zackenberg valley, NE Greenland. Methane flux measurements have been carried out at the same location since 1997. Compared...

Large methane releases lead to strong aerosol forcing and reduced cloudiness

Directory of Open Access Journals (Sweden)

T. Kurtén

2011-07-01

Full Text Available The release of vast quantities of methane into the atmosphere as a result of clathrate destabilization is a potential mechanism for rapid amplification of global warming. Previous studies have calculated the enhanced warming based mainly on the radiative effect of the methane itself, with smaller contributions from the associated carbon dioxide or ozone increases. Here, we study the effect of strongly elevated methane (CH₄ levels on oxidant and aerosol particle concentrations using a combination of chemistry-transport and general circulation models. A 10-fold increase in methane concentrations is predicted to significantly decrease hydroxyl radical (OH concentrations, while moderately increasing ozone (O₃. These changes lead to a 70 % increase in the atmospheric lifetime of methane, and an 18 % decrease in global mean cloud droplet number concentrations (CDNC. The CDNC change causes a radiative forcing that is comparable in magnitude to the longwave radiative forcing ("enhanced greenhouse effect" of the added methane. Together, the indirect CH₄-O₃ and CH₄-OH-aerosol forcings could more than double the warming effect of large methane increases. Our findings may help explain the anomalously large temperature changes associated with historic methane releases.

Photocatalytic conversion of methane to methanol

Energy Technology Data Exchange (ETDEWEB)

Taylor, C.E.; Noceti, R.P.; D`Este, J.R. [Pittsburgh Energy Technology Center, PA (United States)

1995-12-31

A long-term goal of our research group is the exploration of novel pathways for the direct oxidation of methane to liquid fuels, chemicals, and intermediates. The use of three relatively abundant and inexpensive reactants, light, water, and methane, to produce methanol is attractive. The products of reaction, methanol and hydrogen, are both commercially desirable, methanol being used as is or converted to a variety of other chemicals, and the hydrogen could be utilized in petroleum and/or chemical manufacturing. Methane is produced as a by-product of coal gasification. Depending upon reactor design and operating conditions, up to 18% of total gasifier product may be methane. In addition, there are vast proven reserves of geologic methane in the world. Unfortunately, a large fraction of these reserves are in regions where there is little local demand for methane and it is not economically feasible to transport it to a market. There is a global research effort under way in academia, industry, and government to find methods to convert methane to useful, more readily transportable and storable materials. Methanol, the initial product of methane oxidation, is a desirable product of conversion because it retains much of the original energy of the methane while satisfying transportation and storage requirements. Investigation of direct conversion of methane to transportation fuels has been an ongoing effort at PETC for over 10 years. One of the current areas of research is the conversion of methane to methanol, under mild conditions, using light, water, and a semiconductor photocatalyst. The use of three relatively abundant and inexpensive reactants, light, water, and methane, to produce methanol, is attractive. Research in the laboratory is directed toward applying the techniques developed for the photocatalytic splitting of the water and the photochemical conversion of methane.

Use of the HadGEM2 climate-chemistry model to investigate interannual variability in methane sources

Science.gov (United States)

Hayman, Garry; O'Connor, Fiona; Clark, Douglas; Huntingford, Chris; Gedney, Nicola

2013-04-01

The global mean atmospheric concentration of methane (CH4) has more than doubled during the industrial era [1] and now constitutes ? 20% of the anthropogenic climate forcing by greenhouse gases [2]. The globally-averaged CH4 growth rate, derived from surface measurements, has fallen significantly from a high of 16 ppb yr-1 in the late 1970s/early 1980s and was close to zero between 1999 and 2006 [1]. This overall period of declining or low growth was however interspersed with years of positive growth-rate anomalies (e.g., in 1991-1992, 1998-1999 and 2002-2003). Since 2007, renewed growth has been evident [1, 3], with the largest increases observed over polar northern latitudes and the Southern Hemisphere in 2007 and in the tropics in 2008. The observed inter-annual variability in atmospheric methane concentrations and the associated changes in growth rates have variously been attributed to changes in different methane sources and sinks [1, 4]. In this paper, we report results from runs of the HadGEM2 climate-chemistry model [5] using year- and month-specific emission datasets. The HadGEM2 model includes the comprehensive atmospheric chemistry and aerosol package, the UK Chemistry Aerosol community model (UKCA, http://www.ukca.ac.uk/wiki/index.php). The Standard Tropospheric Chemistry scheme was selected for this work. This chemistry scheme simulates the Ox, HOx and NOx chemical cycles and the oxidation of CO, methane, ethane and propane. Year- and month-specific emission datasets were generated for the period from 1997 to 2009 for the emitted species in the chemistry scheme (CH4, CO, NOx, HCHO, C2H6, C3H8, CH3CHO, CH3CHOCH3). The approach adopted varied depending on the source sector: Anthropogenic: The emissions from anthropogenic sources were based on decadal-averaged emission inventories compiled by [6] for the Coupled Carbon Cycle Climate Model Intercomparison Project (C4MIP). These were then used to derive year-specific emission datasets by scaling the

A 21st-century shift from fossil-fuel to biogenic methane emissions indicated by ¹³CH₄.

Science.gov (United States)

Schaefer, Hinrich; Mikaloff Fletcher, Sara E; Veidt, Cordelia; Lassey, Keith R; Brailsford, Gordon W; Bromley, Tony M; Dlugokencky, Edward J; Michel, Sylvia E; Miller, John B; Levin, Ingeborg; Lowe, Dave C; Martin, Ross J; Vaughn, Bruce H; White, James W C

2016-04-01

Between 1999 and 2006, a plateau interrupted the otherwise continuous increase of atmospheric methane concentration [CH4] since preindustrial times. Causes could be sink variability or a temporary reduction in industrial or climate-sensitive sources. We reconstructed the global history of [CH4] and its stable carbon isotopes from ice cores, archived air, and a global network of monitoring stations. A box-model analysis suggests that diminishing thermogenic emissions, probably from the fossil-fuel industry, and/or variations in the hydroxyl CH4 sink caused the [CH4] plateau. Thermogenic emissions did not resume to cause the renewed [CH4] rise after 2006, which contradicts emission inventories. Post-2006 source increases are predominantly biogenic, outside the Arctic, and arguably more consistent with agriculture than wetlands. If so, mitigating CH4 emissions must be balanced with the need for food production. Copyright © 2016, American Association for the Advancement of Science.

Modeling of Oceanic Gas Hydrate Instability and Methane Release in Response to Climate Change

Energy Technology Data Exchange (ETDEWEB)

Reagan, Matthew; Reagan, Matthew T.; Moridis, George J.

2008-04-15

Paleooceanographic evidence has been used to postulate that methane from oceanic hydrates may have had a significant role in regulating global climate, implicating global oceanic deposits of methane gas hydrate as the main culprit in instances of rapid climate change that have occurred in the past. However, the behavior of contemporary oceanic methane hydrate deposits subjected to rapid temperature changes, like those predicted under future climate change scenarios, is poorly understood. To determine the fate of the carbon stored in these hydrates, we performed simulations of oceanic gas hydrate accumulations subjected to temperature changes at the seafloor and assessed the potential for methane release into the ocean. Our modeling analysis considered the properties of benthic sediments, the saturation and distribution of the hydrates, the ocean depth, the initial seafloor temperature, and for the first time, estimated the effect of benthic biogeochemical activity. The results show that shallow deposits--such as those found in arctic regions or in the Gulf of Mexico--can undergo rapid dissociation and produce significant methane fluxes of 2 to 13 mol/yr/m{sup 2} over a period of decades, and release up to 1,100 mol of methane per m{sup 2} of seafloor in a century. These fluxes may exceed the ability of the seafloor environment (via anaerobic oxidation of methane) to consume the released methane or sequester the carbon. These results will provide a source term to regional or global climate models in order to assess the coupling of gas hydrate deposits to changes in the global climate.

Methane rising from the Deep: Hydrates, Bubbles, Oil Spills, and Global Warming

Science.gov (United States)

Leifer, I.; Rehder, G. J.; Solomon, E. A.; Kastner, M.; Asper, V. L.; Joye, S. B.

2011-12-01

Elevated methane concentrations in near-surface waters and the atmosphere have been reported for seepage from depths of nearly 1 km at the Gulf of Mexico hydrate observatory (MC118), suggesting that for some methane sources, deepsea methane is not trapped and can contribute to atmospheric greenhouse gas budgets. Ebullition is key with important sensitivity to the formation of hydrate skins and oil coatings, high-pressure solubility, bubble size and bubble plume processes. Bubble ROV tracking studies showed survival to near thermocline depths. Studies with a numerical bubble propagation model demonstrated that consideration of structure I hydrate skins transported most methane only to mid-water column depths. Instead, consideration of structure II hydrates, which are stable to far shallower depths and appropriate for natural gas mixtures, allows bubbles to survive to far shallower depths. Moreover, model predictions of vertical methane and alkane profiles and bubble size evolution were in better agreement with observations after consideration of structure II hydrate properties as well as an improved implementation of plume properties, such as currents. These results demonstrate the importance of correctly incorporating bubble hydrate processes in efforts to predict the impact of deepsea seepage as well as to understand the fate of bubble-transported oil and methane from deepsea pipeline leaks and well blowouts. Application to the DWH spill demonstrated the importance of deepsea processes to the fate of spilled subsurface oil. Because several of these parameters vary temporally (bubble flux, currents, temperature), sensitivity studies indicate the importance of real-time monitoring data.

Efficient 1.6 Micron Laser Source for Methane DIAL

Science.gov (United States)

Shuman, Timothy; Burnham, Ralph; Nehrir, Amin R.; Ismail, Syed; Hair, Johnathan W.

2013-01-01

Methane is a potent greenhouse gas and on a per molecule basis has a warming influence 72 times that of carbon dioxide over a 20 year horizon. Therefore, it is important to look at near term radiative effects due to methane to develop mitigation strategies to counteract global warming trends via ground and airborne based measurements systems. These systems require the development of a time-resolved DIAL capability using a narrow-line laser source allowing observation of atmospheric methane on local, regional and global scales. In this work, a demonstrated and efficient nonlinear conversion scheme meeting the performance requirements of a deployable methane DIAL system is presented. By combining a single frequency 1064 nm pump source and a seeded KTP OPO more than 5 mJ of 1.6 µm pulse energy is generated with conversion efficiencies in excess of 20%. Even without active cavity control instrument limited linewidths (50 pm) were achieved with an estimated spectral purity of 95%. Tunable operation over 400 pm (limited by the tuning range of the seed laser) was also demonstrated. This source demonstrated the critical needs for a methane DIAL system motivating additional development of the technology.

Template-Assisted Wet-Combustion Synthesis of Fibrous Nickel-Based Catalyst for Carbon Dioxide Methanation and Methane Steam Reforming.

Science.gov (United States)

Aghayan, M; Potemkin, D I; Rubio-Marcos, F; Uskov, S I; Snytnikov, P V; Hussainova, I

2017-12-20

Efficient capture and recycling of CO 2 enable not only prevention of global warming but also the supply of useful low-carbon fuels. The catalytic conversion of CO 2 into an organic compound is a promising recycling approach which opens new concepts and opportunities for catalytic and industrial development. Here we report about template-assisted wet-combustion synthesis of a one-dimensional nickel-based catalyst for carbon dioxide methanation and methane steam reforming. Because of a high temperature achieved in a short time during reaction and a large amount of evolved gases, the wet-combustion synthesis yields homogeneously precipitated nanoparticles of NiO with average particle size of 4 nm on alumina nanofibers covered with a NiAl 2 O 4 nanolayer. The as-synthesized core-shell structured fibers exhibit outstanding activity in steam reforming of methane and sufficient activity in carbon dioxide methanation with 100% selectivity toward methane formation. The as-synthesized catalyst shows stable operation under the reaction conditions for at least 50 h.

Reduction of ruminant methane emissions - a win-win-win opportunity for business, development, and the environment

Energy Technology Data Exchange (ETDEWEB)

Livingston, R. [Appropriate Technology International, Washington, DC (United States)

1997-12-31

This paper describes research efforts of The Global Livestock Producers Program (GLPP) in establishing self-sustaining enterprises for cost-effective technologies (i.e., animal nutrition and genetic improvement) and global methane emissions reductions in developing world nations. The US Environmental Protection Agency has funded several studies to examine the possibilities of reducing ruminant methane emissions in India, Tanzania, Bangladesh, and Brazil. The results of the studies showed that: (1) many developing countries` production systems are inefficient, and (2) great potential exists for decreasing global methane emissions through increasing animal productivity. From this effort, the GLPP established livestock development projects in India, Zimbabwe, and Tanzania, and is developing projects for Bangladesh, Nepal, and Brazil. The GLPP has developed a proven methodology for assessing ruminant methane and incorporating methane emissions monitoring into viable projects.

High-global warming potential F-gas emissions in California: comparison of ambient-based versus inventory-based emission estimates, and implications of refined estimates.

Science.gov (United States)

Gallagher, Glenn; Zhan, Tao; Hsu, Ying-Kuang; Gupta, Pamela; Pederson, James; Croes, Bart; Blake, Donald R; Barletta, Barbara; Meinardi, Simone; Ashford, Paul; Vetter, Arnie; Saba, Sabine; Slim, Rayan; Palandre, Lionel; Clodic, Denis; Mathis, Pamela; Wagner, Mark; Forgie, Julia; Dwyer, Harry; Wolf, Katy

2014-01-21

To provide information for greenhouse gas reduction policies, the California Air Resources Board (CARB) inventories annual emissions of high-global-warming potential (GWP) fluorinated gases, the fastest growing sector of greenhouse gas (GHG) emissions globally. Baseline 2008 F-gas emissions estimates for selected chlorofluorocarbons (CFC-12), hydrochlorofluorocarbons (HCFC-22), and hydrofluorocarbons (HFC-134a) made with an inventory-based methodology were compared to emissions estimates made by ambient-based measurements. Significant discrepancies were found, with the inventory-based emissions methodology resulting in a systematic 42% under-estimation of CFC-12 emissions from older refrigeration equipment and older vehicles, and a systematic 114% overestimation of emissions for HFC-134a, a refrigerant substitute for phased-out CFCs. Initial, inventory-based estimates for all F-gas emissions had assumed that equipment is no longer in service once it reaches its average lifetime of use. Revised emission estimates using improved models for equipment age at end-of-life, inventories, and leak rates specific to California resulted in F-gas emissions estimates in closer agreement to ambient-based measurements. The discrepancies between inventory-based estimates and ambient-based measurements were reduced from -42% to -6% for CFC-12, and from +114% to +9% for HFC-134a.

Prediction of the methane conversion factor (Ym) for dairy cows on the basis of national farm data

DEFF Research Database (Denmark)

Hellwing, Anne Louise Frydendahl; Weisbjerg, Martin Riis; Brask, Maike

2016-01-01

Methane constitutes a significant loss of feed gross energy in ruminants, and there is an ongoing struggle for identifying feed and animal characteristics feasible for documentation of National Greenhouse Gas Inventories. The aim of the current study was to develop a model that predicts the methane...... and feed composition as variables, and one using yield of energy corrected milk and feed composition as variables. The methane conversion factor was significantly reduced with increased content of starch and fat in the ration, whereas neutral detergent fibre content surprisingly did not have a significant...

Methane oxidation associated to submerged brown-mosses buffers methane emissions from Siberian polygonal peatlands

Science.gov (United States)

Liebner, Susanne; Zeyer, Josef; Knoblauch, Christian

2010-05-01

Circumpolar peatlands store roughly 18 % of the globally stored carbon in soils [based on 1, 2]. Also, northern wetlands and tundra are a net source of methane (CH4), an effective greenhouse gas (GHG), with an estimated annual CH4 release of 7.2% [3] or 8.1% [4] of the global total CH4 emission. Although it is definite that Arctic tundra significantly contributes to the global methane emissions in general, regional variations in GHG fluxes are enormous. CH4 fluxes of polygonal tundra within the Siberian Lena Delta, for example, were reported to be low [5, 6], particularly at open water polygonal ponds and small lakes [7] which make up around 10 % of the delta's surface. Low methane emissions from polygonal ponds oppose that Arctic permafrost thaw ponds are generally known to emit large amounts of CH4 [8]. Combining tools of biogeochemistry and molecular microbiology, we identified sinks of CH4 in polygonal ponds from the Lena Delta that were not considered so far in GHG studies from Arctic wetlands. Pore water CH4 profiling in polygonal ponds on Samoylov, a small island in the central part of the Lena Delta, revealed a pronounced zone of CH4 oxidation near the vegetation surface in submerged layers of brown-mosses. Here, potential CH4 oxidation was an order of magnitude higher than in non-submerged mosses and in adjacent bulk soil. We could additionally show that this moss associated methane oxidation (MAMO) is hampered when exposure of light is prevented. Shading of plots with submerged Scorpidium scorpioides inhibited MAMO leading to higher CH4 concentrations and an increase in CH4 fluxes by a factor of ~13. Compared to non-submerged mosses, the submerged mosses also showed significantly lower δ13C values indicating that they use carbon dioxide derived from methane oxidation for photosynthesis. Applying stable isotope probing of DNA, type II methanotrophs were identified to be responsible for the oxidation of CH4 in the submerged Scorpidium scorpioides. Our

Methane emissions from different coastal wetlands in New England, US

Science.gov (United States)

Wang, F.; Tang, J.; Kroeger, K. D.; Gonneea, M. E.

2017-12-01

According to the IPCC, methane have 25 times warming effect than CO2, and natural wetlands contribute 20-39 % to the global emission of methane. Although most of these methane was from inland wetlands, there was still large uncertain in the methane emissions in coastal wetlands. In the past three years, we have investigated methane emissions in coastal wetlands in MA, USA. Contrary to previous assumptions, we have observed relative larger methane flux in some salt marshes than freshwater wetlands. We further detect the methane source, and found that plant activities played an important role in methane flux, for example, the growth of S. aterniflora, the dominate plants in salt marsh, could enhance methane emission, while in an fresh water wetland that was dominated by cattail, plant activity oxided methane and reduced total flux. Phragmite, an invasive plant at brackish marsh, have the highest methane flux among all coastal wetland investigated. This study indicated that coastal wetland could still emit relatively high amount of methane even under high water salinity condiations, and plant activity played an important role in methane flux, and this role was highly species-specific.

Understanding the physiological and molecular mechanisms of rice-microbial interactions that produce methane

Science.gov (United States)

The second most abundant greenhouse gas, methane, is ~25 times more potent in global warming potential than carbon dioxide, and 7-17% of atmospheric methane comes from flooded rice fields. Methane emissions can be greatly reduced by using alternate wetting and drying irrigation management and/or cul...

A marine microbial consortium apparently mediating anaerobic oxidation of methane

DEFF Research Database (Denmark)

Boetius, A.; Ravenschlag, K.; Schubert, CJ

2000-01-01

microorganisms mediating this reaction have not yet been isolated, and the pathway of anaerobic oxidation of methane is insufficiently understood. Recent data suggest that certain archaea reverse the process of methanogenesis by interaction with sulphate-reducing bacteria(5-7). Here we provide microscopic...... cells and are surrounded by sulphate-reducing bacteria. These aggregates were abundant in gas-hydrate-rich sediments with extremely high rates of methane-based sulphate reduction, and apparently mediate anaerobic oxidation of methane.......A large fraction of globally produced methane is converted to CO2 by anaerobic oxidation in marine sediments(1). Strong geochemical evidence for net methane consumption in anoxic sediments is based on methane profiles(2), radiotracer experiments(3) and stable carbon isotope data(4). But the elusive...

Glacial-interglacial water cycle, global monsoon and atmospheric methane changes

Energy Technology Data Exchange (ETDEWEB)

Guo, Zhengtang; Wu, Haibin [Chinese Academy of Sciences, Key Laboratory of Cenozoic Geology and Environment, Institute of Geology and Geophysics, Beijing (China); Zhou, Xin [Chinese Academy of Sciences, Key Laboratory of Cenozoic Geology and Environment, Institute of Geology and Geophysics, Beijing (China); University of Science and Technology of China, School of Earth and Space Sciences and Institute of Polar Environment, Hefei (China)

2012-09-15

The causes of atmospheric methane (CH{sub 4}) changes are still a major contention, in particular with regards to the relative contributions of glacial-interglacial cycles, monsoons in both hemispheres and the late Holocene human intervention. Here, we explore the CH{sub 4} signals in the Antarctic EPICA Dome C and Vostok ice records using the methods of timeseries analyses and correlate them with insolation and geological records to address these issues. The results parse out three distinct groups of CH{sub 4} signals attributable to different drivers. The first group ({proportional_to}80% variance), well tracking the marine {delta}{sup 18}O record, is attributable to glacial-interglacial modulation on the global water cycle with the effects shared by wetlands at all latitudes, from monsoonal and non-monsoonal regions in both hemispheres. The second group ({proportional_to}15% variance), centered at the {proportional_to}10-kyr semi-precession frequency, is linkable with insolation-driven tropical monsoon changes in both hemispheres. The third group ({proportional_to}5% variance), marked by millennial frequencies, is seemingly related with the combined effect of ice-volume and bi-hemispheric insolation changes at the precession bands. These results indicate that bi-hemispheric monsoon changes have been a constant driver of atmospheric CH{sub 4}. This mechanism also partially explains the Holocene CH{sub 4} reversal since {proportional_to}5 kyr BP besides the human intervention. In the light of these results, we propose that global monsoon can be regarded as a system consisting of two main integrated components, one primarily driven by the oscillations of Inter-Tropical Convergence Zone (ITCZ) in response to the low-latitude summer insolation changes, anti-phase between the two hemispheres (i.e. the ITCZ monsoon component); and another modulated by the glacial-interglacial cycles, mostly synchronous at the global scale (i.e. the glacial-interglacial monsoon

In situ observations of the isotopic composition of methane at the Cabauw tall tower site

Directory of Open Access Journals (Sweden)

T. Röckmann

2016-08-01

Full Text Available High-precision analyses of the isotopic composition of methane in ambient air can potentially be used to discriminate between different source categories. Due to the complexity of isotope ratio measurements, such analyses have generally been performed in the laboratory on air samples collected in the field. This poses a limitation on the temporal resolution at which the isotopic composition can be monitored with reasonable logistical effort. Here we present the performance of a dual isotope ratio mass spectrometric system (IRMS and a quantum cascade laser absorption spectroscopy (QCLAS-based technique for in situ analysis of the isotopic composition of methane under field conditions. Both systems were deployed at the Cabauw Experimental Site for Atmospheric Research (CESAR in the Netherlands and performed in situ, high-frequency (approx. hourly measurements for a period of more than 5 months. The IRMS and QCLAS instruments were in excellent agreement with a slight systematic offset of (+0.25 ± 0.04 ‰ for δ13C and (−4.3 ± 0.4 ‰ for δD. This was corrected for, yielding a combined dataset with more than 2500 measurements of both δ13C and δD. The high-precision and high-temporal-resolution dataset not only reveals the overwhelming contribution of isotopically depleted agricultural CH4 emissions from ruminants at the Cabauw site but also allows the identification of specific events with elevated contributions from more enriched sources such as natural gas and landfills. The final dataset was compared to model calculations using the global model TM5 and the mesoscale model FLEXPART-COSMO. The results of both models agree better with the measurements when the TNO-MACC emission inventory is used in the models than when the EDGAR inventory is used. This suggests that high-resolution isotope measurements have the potential to further constrain the methane budget when they are performed at multiple sites that are representative for

Greenhouse effect contributions of US landfill methane

International Nuclear Information System (INIS)

Augenstein, D.

1991-01-01

The greenhouse effect has recently been receiving a great deal of scientific and popular attention. The term refers to a cause-and-effect relationship in which ''heat blanketing'' of the earth, due to trace gas increases in the atmosphere, is expected to result in global warming. The trace gases are increasing as the result of human activities. Carbon dioxide (CO 2 ) is the trace gas contributing most importantly to the ''heat blanketing'' and currently receives the most attention. Less widely recognized has been the high importance of methane (CH 4 ). Methane's contribution to the increased heat blanketing occurring since 1980 is estimated to be over a third as much as that of carbon dioxide. Gas from landfills has in turn been recognized to be a source of methane to the atmospheric buildup. However the magnitude of the landfill methane contribution, and the overall significance of landfill methane to the greenhouse phenomenon has been uncertain and the subject of some debate. (Author)

Decarbonisation of fossil energy via methane pyrolysis

Energy Technology Data Exchange (ETDEWEB)

Kreysa, G.; Agar, D.W.; Schultz, I. [Technische Univ. Dortmund (Germany)

2010-12-30

Despite the rising consumption of energy over the last few decades, the proven reserves of fossil fuels have steadily increased. Additionally, there are potentially tremendous reserves of methane hydrates available, which remain to be exploited. The use of fossil energy sources is thus increasingly being dictated less by supply than by the environmental concerns raised by climate change. In the context of the decarbonisation of the global energy system that this has stimulated, new means must be explored for using methane as energy source. Noncatalytic thermal pyrolysis of methane is proposed here as a promising concept for utilising methane with low to zero carbon dioxide emissions. Following cracking, only the energy content of the hydrogen is used, while the carbon can be stored safely and retrievably in disused coal mines. The thermodynamics and different process engineering concepts for the technical realisation of such a carbon moratorium technology are discussed. The possible contribution of methane pyrolysis to carbon negative geoengineering is also addressed. (orig.)

Recent patterns of methane and nitrous oxide fluxes in the terrestrial biosphere: The bottom-up approach (Invited)

Science.gov (United States)

Tian, H.

2013-12-01

Accurately estimating methane and nitrous oxide emissions from terrestrial ecosystems is critical for resolving global budgets of these greenhouse gases (GHGs) and continuing to mitigate climate warming. In this study, we use a bottom-up approach to estimate annual budgets of both methane and nitrous oxide in global terrestrial ecosystem during 1981-2010 and analyze the underlying mechanisms responsible for spatial and temporal variations in these GHGs. Both methane and nitrous oxide emissions significantly increased from 1981 to 2010, primarily owing to increased air temperature, nitrogen fertilizer use, and land use change. Methane and nitrous oxide emissions increased the fastest in Asia due to the more prominent environmental changes compared to other continents. The cooling effects by carbon dioxide sink in the terrestrial biosphere might be completely offset by increasing methane and nitrous oxide emissions, resulting in a positive global warming potential. Asia and South America were the largest contributors to increasing global warming potential. This study suggested that current management practices might not be effective enough to reduce future global warming.

A calculation code for estimating the global inventory of tritium from the ICSI Pilot Installation

International Nuclear Information System (INIS)

Pavelescu, Alexandru Octavian; Prisecaru, Ilie; Stefanescu, Ioan

2007-01-01

The paper describes the TRITINV program which performs a global updating of the total tritium inventory within the whole ICSI heavy water detritiation installation. The calculation does not take into account the distribution or the type of the tritium inventory on the installation modules. The program stores all the values submitted by user or computed, into a database which is permanently upgraded. It can also create charts based on its data and print or export this data in other formats. The application has been successfully tested and responded well to the initial requirements. It can be modified or improved anytime using the Microsoft Access 2003 Program. An important advancement would consist in upgrading the TRITINV into a stand-alone application by editing and compiling it in Microsoft Visual Studio 2005. (authors)

Root biomass as a major means of affecting methane emissions

Science.gov (United States)

Human activities are contributing to greenhouse gas emissions. Methane, the second most abundant greenhouse gas, is ~25 times more potent in global warming potential than carbon dioxide, and 7-17% of atmospheric methane comes from paddy rice fields. The purpose of the study was to investigate gene...

FY1995 molecular control technology for mining of methane-gas-hydrate; 1995 nendo methane hydrate no bunshi seigyo mining

Energy Technology Data Exchange (ETDEWEB)

NONE

1997-03-01

The objectives of the investigation are as follows: 1) developing a method to control formation/dissociation of methane-gas-hydrate, 2) developing a technology to displace methane gas by CO{sub 2} in methane-gas-hydrate deposit, 3) developing a technology to produce methane gas from the deposit efficiently. The final purpose of the project is to create new mining industry that solves both the problems of energy and global environment. 1) Clustering of water molecules is found to play the key role in the methane gas hydrate formation. 2) Equilibrium properties and kinetics of gas hydrates formation and dissociation in bulk-scale gas-hydrate are clarified in the practical environmental conditions. 3) Particle size of hydrate deposit influences the formation and dissociation of bulk-scale gas-hydrate crystal. 4) Mass transfer between gas and liquid phase in turbulent bubbly flow is a function of bubble diameter. The mass transfer depends on interfacial dynamics. (NEDO)

TITAN'S TRANSPORT-DRIVEN METHANE CYCLE

International Nuclear Information System (INIS)

Mitchell, Jonathan L.

2012-01-01

The mechanisms behind the occurrence of large cloud outbursts and precipitation on Titan have been disputed. A global- and annual-mean estimate of surface fluxes indicated only 1% of the insolation, or ∼0.04 W m –2 , is exchanged as sensible and/or latent fluxes. Since these fluxes are responsible for driving atmospheric convection, it has been argued that moist convection should be quite rare and precipitation even rarer, even if evaporation globally dominates the surface-atmosphere energy exchange. In contrast, climate simulations indicate substantial cloud formation and/or precipitation. We argue that the top-of-atmosphere (TOA) radiative imbalance is diagnostic of horizontal heat transport by Titan's atmosphere, and thus constrains the strength of the methane cycle. Simple calculations show the TOA radiative imbalance is ∼0.5-1 W m –2 in Titan's equatorial region, which implies 2-3 MW of latitudinal heat transport by the atmosphere. Our simulation of Titan's climate suggests this transport may occur primarily as latent heat, with net evaporation at the equator and net accumulation at higher latitudes. Thus, the methane cycle could be 10-20 times previous estimates. Opposing seasonal transport at solstices, compensation by sensible heat transport, and focusing of precipitation by large-scale dynamics could further enhance the local, instantaneous strength of Titan's methane cycle by a factor of several. A limited supply of surface liquids in regions of large surface radiative imbalance may throttle the methane cycle, and if so, we predict more frequent large storms over the lakes district during Titan's northern summer.

Improved provincial emission inventory and speciation profiles of anthropogenic non-methane volatile organic compounds: a case study for Jiangsu, China

Directory of Open Access Journals (Sweden)

Y. Zhao

2017-06-01

Full Text Available Non-methane volatile organic compounds (NMVOCs are the key precursors of ozone (O3 and secondary organic aerosol (SOA formation. Accurate estimation of their emissions plays a crucial role in air quality simulation and policy making. We developed a high-resolution anthropogenic NMVOC emission inventory for Jiangsu in eastern China from 2005 to 2014, based on detailed information of individual local sources and field measurements of source profiles of the chemical industry. A total of 56 NMVOCs samples were collected in nine chemical plants and were then analyzed with a gas chromatography – mass spectrometry system (GC-MS. Source profiles of stack emissions from synthetic rubber, acetate fiber, polyether, vinyl acetate and ethylene production, and those of fugitive emissions from ethylene, butanol and octanol, propylene epoxide, polyethylene and glycol production were obtained. Various manufacturing technologies and raw materials led to discrepancies in source profiles between our domestic field tests and foreign results for synthetic rubber and ethylene production. The provincial NMVOC emissions were calculated to increase from 1774 Gg in 2005 to 2507 Gg in 2014, and relatively large emission densities were found in cities along the Yangtze River with developed economies and industries. The estimates were larger than those from most other available inventories, due mainly to the complete inclusion of emission sources and to the elevated activity levels from plant-by-plant investigation in this work. Industrial processes and solvent use were the largest contributing sectors, and their emissions were estimated to increase, respectively, from 461 to 958 and from 38 to 966 Gg. Alkanes, aromatics and oxygenated VOCs (OVOCs were the most important species, accounting for 25.9–29.9, 20.8–23.2 and 18.2–21.0 % to annual total emissions, respectively. Quantified with a Monte Carlo simulation, the uncertainties of annual NMVOC emissions

Improved provincial emission inventory and speciation profiles of anthropogenic non-methane volatile organic compounds: a case study for Jiangsu, China

Science.gov (United States)

Zhao, Yu; Mao, Pan; Zhou, Yaduan; Yang, Yang; Zhang, Jie; Wang, Shekou; Dong, Yanping; Xie, Fangjian; Yu, Yiyong; Li, Wenqing

2017-06-01

Non-methane volatile organic compounds (NMVOCs) are the key precursors of ozone (O3) and secondary organic aerosol (SOA) formation. Accurate estimation of their emissions plays a crucial role in air quality simulation and policy making. We developed a high-resolution anthropogenic NMVOC emission inventory for Jiangsu in eastern China from 2005 to 2014, based on detailed information of individual local sources and field measurements of source profiles of the chemical industry. A total of 56 NMVOCs samples were collected in nine chemical plants and were then analyzed with a gas chromatography - mass spectrometry system (GC-MS). Source profiles of stack emissions from synthetic rubber, acetate fiber, polyether, vinyl acetate and ethylene production, and those of fugitive emissions from ethylene, butanol and octanol, propylene epoxide, polyethylene and glycol production were obtained. Various manufacturing technologies and raw materials led to discrepancies in source profiles between our domestic field tests and foreign results for synthetic rubber and ethylene production. The provincial NMVOC emissions were calculated to increase from 1774 Gg in 2005 to 2507 Gg in 2014, and relatively large emission densities were found in cities along the Yangtze River with developed economies and industries. The estimates were larger than those from most other available inventories, due mainly to the complete inclusion of emission sources and to the elevated activity levels from plant-by-plant investigation in this work. Industrial processes and solvent use were the largest contributing sectors, and their emissions were estimated to increase, respectively, from 461 to 958 and from 38 to 966 Gg. Alkanes, aromatics and oxygenated VOCs (OVOCs) were the most important species, accounting for 25.9-29.9, 20.8-23.2 and 18.2-21.0 % to annual total emissions, respectively. Quantified with a Monte Carlo simulation, the uncertainties of annual NMVOC emissions vary slightly through the years

Large emissions from floodplain trees close the Amazon methane budget

Science.gov (United States)

Pangala, Sunitha R.; Enrich-Prast, Alex; Basso, Luana S.; Peixoto, Roberta Bittencourt; Bastviken, David; Hornibrook, Edward R. C.; Gatti, Luciana V.; Marotta, Humberto; Calazans, Luana Silva Braucks; Sakuragui, Cassia Mônica; Bastos, Wanderley Rodrigues; Malm, Olaf; Gloor, Emanuel; Miller, John Bharat; Gauci, Vincent

2017-12-01

Wetlands are the largest global source of atmospheric methane (CH4), a potent greenhouse gas. However, methane emission inventories from the Amazon floodplain, the largest natural geographic source of CH4 in the tropics, consistently underestimate the atmospheric burden of CH4 determined via remote sensing and inversion modelling, pointing to a major gap in our understanding of the contribution of these ecosystems to CH4 emissions. Here we report CH4 fluxes from the stems of 2,357 individual Amazonian floodplain trees from 13 locations across the central Amazon basin. We find that escape of soil gas through wetland trees is the dominant source of regional CH4 emissions. Methane fluxes from Amazon tree stems were up to 200 times larger than emissions reported for temperate wet forests and tropical peat swamp forests, representing the largest non-ebullitive wetland fluxes observed. Emissions from trees had an average stable carbon isotope value (δ13C) of -66.2 ± 6.4 per mil, consistent with a soil biogenic origin. We estimate that floodplain trees emit 15.1 ± 1.8 to 21.2 ± 2.5 teragrams of CH4 a year, in addition to the 20.5 ± 5.3 teragrams a year emitted regionally from other sources. Furthermore, we provide a ‘top-down’ regional estimate of CH4 emissions of 42.7 ± 5.6 teragrams of CH4 a year for the Amazon basin, based on regular vertical lower-troposphere CH4 profiles covering the period 2010-2013. We find close agreement between our ‘top-down’ and combined ‘bottom-up’ estimates, indicating that large CH4 emissions from trees adapted to permanent or seasonal inundation can account for the emission source that is required to close the Amazon CH4 budget. Our findings demonstrate the importance of tree stem surfaces in mediating approximately half of all wetland CH4 emissions in the Amazon floodplain, a region that represents up to one-third of the global wetland CH4 source when trees are combined with other emission sources.

Large emissions from floodplain trees close the Amazon methane budget.

Science.gov (United States)

Pangala, Sunitha R; Enrich-Prast, Alex; Basso, Luana S; Peixoto, Roberta Bittencourt; Bastviken, David; Hornibrook, Edward R C; Gatti, Luciana V; Marotta, Humberto; Calazans, Luana Silva Braucks; Sakuragui, Cassia Mônica; Bastos, Wanderley Rodrigues; Malm, Olaf; Gloor, Emanuel; Miller, John Bharat; Gauci, Vincent

2017-12-14

Wetlands are the largest global source of atmospheric methane (CH 4 ), a potent greenhouse gas. However, methane emission inventories from the Amazon floodplain, the largest natural geographic source of CH 4 in the tropics, consistently underestimate the atmospheric burden of CH 4 determined via remote sensing and inversion modelling, pointing to a major gap in our understanding of the contribution of these ecosystems to CH 4 emissions. Here we report CH 4 fluxes from the stems of 2,357 individual Amazonian floodplain trees from 13 locations across the central Amazon basin. We find that escape of soil gas through wetland trees is the dominant source of regional CH 4 emissions. Methane fluxes from Amazon tree stems were up to 200 times larger than emissions reported for temperate wet forests and tropical peat swamp forests, representing the largest non-ebullitive wetland fluxes observed. Emissions from trees had an average stable carbon isotope value (δ 13 C) of -66.2 ± 6.4 per mil, consistent with a soil biogenic origin. We estimate that floodplain trees emit 15.1 ± 1.8 to 21.2 ± 2.5 teragrams of CH 4 a year, in addition to the 20.5 ± 5.3 teragrams a year emitted regionally from other sources. Furthermore, we provide a 'top-down' regional estimate of CH 4 emissions of 42.7 ± 5.6 teragrams of CH 4 a year for the Amazon basin, based on regular vertical lower-troposphere CH 4 profiles covering the period 2010-2013. We find close agreement between our 'top-down' and combined 'bottom-up' estimates, indicating that large CH 4 emissions from trees adapted to permanent or seasonal inundation can account for the emission source that is required to close the Amazon CH 4 budget. Our findings demonstrate the importance of tree stem surfaces in mediating approximately half of all wetland CH 4 emissions in the Amazon floodplain, a region that represents up to one-third of the global wetland CH 4 source when trees are combined with other emission sources.

Robust IR Remote Sensing Technique of the Total Column of Trace Gases Including Carbon Dioxide and Methane

Science.gov (United States)

Georgieva, E. M.; Heaps, W. S.

2011-01-01

Progress on the development of a differential radiometer based upon the Fabry-Perot interferometer (FPI) for methane (CH4) and carbon dioxide (C02) detection in the atmosphere is presented. Methane measurements are becoming increasingly important as a component of NASA's programs to understand the global carbon cycle and quantifY the threat of global warming. Methane is the third most important greenhouse gas in the Earth's radiation budget (after water vapor and carbon dioxide) and the second most important anthropogenic contributor to global warming. The importance of global warming and air quality to society caused the National Research Council to recommend that NASA develop the following missions [1]: ASCENDS (Active Sensing of C02 Emissions over Nights, Days, and Seasons), GEOCAPE (Geostationary Coastal and Air Pollution Events), and GACM (Global Atmosphere Composition Mission). Though methane measurements are not specifically called out in these missions, ongoing environmental changes have raised the importance of understanding the methane budget. In the decadal survey is stated that "to close the carbon budget, we would also address methane, but the required technology is not obvious at this time. If appropriate and cost-effective methane technology becomes available, we strongly recommend adding a methane capability". In its 2007 report the International Panel on Climate Change identified methane as a key uncertainty in our understanding saying that the causes of recent changes in the growth rate of atmospheric CH4 are not well understood. What we do know is that methane arises from a number of natural sources including wet lands and the oceans plus man made sources from agriculture, as well as coal and petroleum production and distribution. It has recently been pointed out that large amount of methane are frozen in the permafrost of Canada and Siberia. There is a fear that melting of this permafrost driven by global warming may release large amounts of

Minimal geological methane emissions during the Younger Dryas-Preboreal abrupt warming event.

Science.gov (United States)

Petrenko, Vasilii V; Smith, Andrew M; Schaefer, Hinrich; Riedel, Katja; Brook, Edward; Baggenstos, Daniel; Harth, Christina; Hua, Quan; Buizert, Christo; Schilt, Adrian; Fain, Xavier; Mitchell, Logan; Bauska, Thomas; Orsi, Anais; Weiss, Ray F; Severinghaus, Jeffrey P

2017-08-23

Methane (CH 4 ) is a powerful greenhouse gas and plays a key part in global atmospheric chemistry. Natural geological emissions (fossil methane vented naturally from marine and terrestrial seeps and mud volcanoes) are thought to contribute around 52 teragrams of methane per year to the global methane source, about 10 per cent of the total, but both bottom-up methods (measuring emissions) and top-down approaches (measuring atmospheric mole fractions and isotopes) for constraining these geological emissions have been associated with large uncertainties. Here we use ice core measurements to quantify the absolute amount of radiocarbon-containing methane ( 14 CH 4 ) in the past atmosphere and show that geological methane emissions were no higher than 15.4 teragrams per year (95 per cent confidence), averaged over the abrupt warming event that occurred between the Younger Dryas and Preboreal intervals, approximately 11,600 years ago. Assuming that past geological methane emissions were no lower than today, our results indicate that current estimates of today's natural geological methane emissions (about 52 teragrams per year) are too high and, by extension, that current estimates of anthropogenic fossil methane emissions are too low. Our results also improve on and confirm earlier findings that the rapid increase of about 50 per cent in mole fraction of atmospheric methane at the Younger Dryas-Preboreal event was driven by contemporaneous methane from sources such as wetlands; our findings constrain the contribution from old carbon reservoirs (marine methane hydrates, permafrost and methane trapped under ice) to 19 per cent or less (95 per cent confidence). To the extent that the characteristics of the most recent deglaciation and the Younger Dryas-Preboreal warming are comparable to those of the current anthropogenic warming, our measurements suggest that large future atmospheric releases of methane from old carbon sources are unlikely to occur.

Minimal geological methane emissions during the Younger Dryas-Preboreal abrupt warming event

Science.gov (United States)

Petrenko, Vasilii V.; Smith, Andrew M.; Schaefer, Hinrich; Riedel, Katja; Brook, Edward; Baggenstos, Daniel; Harth, Christina; Hua, Quan; Buizert, Christo; Schilt, Adrian; Fain, Xavier; Mitchell, Logan; Bauska, Thomas; Orsi, Anais; Weiss, Ray F.; Severinghaus, Jeffrey P.

2017-08-01

Methane (CH4) is a powerful greenhouse gas and plays a key part in global atmospheric chemistry. Natural geological emissions (fossil methane vented naturally from marine and terrestrial seeps and mud volcanoes) are thought to contribute around 52 teragrams of methane per year to the global methane source, about 10 per cent of the total, but both bottom-up methods (measuring emissions) and top-down approaches (measuring atmospheric mole fractions and isotopes) for constraining these geological emissions have been associated with large uncertainties. Here we use ice core measurements to quantify the absolute amount of radiocarbon-containing methane (14CH4) in the past atmosphere and show that geological methane emissions were no higher than 15.4 teragrams per year (95 per cent confidence), averaged over the abrupt warming event that occurred between the Younger Dryas and Preboreal intervals, approximately 11,600 years ago. Assuming that past geological methane emissions were no lower than today, our results indicate that current estimates of today’s natural geological methane emissions (about 52 teragrams per year) are too high and, by extension, that current estimates of anthropogenic fossil methane emissions are too low. Our results also improve on and confirm earlier findings that the rapid increase of about 50 per cent in mole fraction of atmospheric methane at the Younger Dryas-Preboreal event was driven by contemporaneous methane from sources such as wetlands; our findings constrain the contribution from old carbon reservoirs (marine methane hydrates, permafrost and methane trapped under ice) to 19 per cent or less (95 per cent confidence). To the extent that the characteristics of the most recent deglaciation and the Younger Dryas-Preboreal warming are comparable to those of the current anthropogenic warming, our measurements suggest that large future atmospheric releases of methane from old carbon sources are unlikely to occur.

Methane Emissions from Natural Gas in the Urban Region of Boston, Massachusetts

Science.gov (United States)

McKain, K.; Down, A.; Raciti, S. M.; Budney, J.; Hutyra, L.; Floerchinger, C. R.; Herndon, S. C.; Zahniser, M. S.; Nehrkorn, T.; Jackson, R. B.; Phillips, N. G.; Wofsy, S. C.

2014-12-01

Methane emissions from the natural gas supply chain must be quantified to assess environmental impacts of natural gas and to develop emission reduction strategies. We report natural gas emission rates for one year in the urban region of Boston, MA, using an atmospheric measurement and modeling framework. Continuous methane observations from four stations are combined with a high-resolution transport model to quantify the regional average emission rate, 20.6 ± 1.7 (95 % CI) g CH4 m-2 yr-1. Simultaneous observations of atmospheric ethane, compared with the ethane to methane ratio in pipeline gas, demonstrate that natural gas accounted for 58 - 100 % of methane emissions, depending on season. Using government statistics and geospatial data on energy consumption, we estimate the fractional loss rate to the atmosphere from all downstream components of the natural gas system, including transmission, distribution, and end-use, was 2.9 ± 0.3 % in the Boston urban region, compared to 1.1 % inferred by the Massachusetts greenhouse gas inventory.

Methanogenesis in oxygenated soils is a substantial fraction of wetland methane emissions

Energy Technology Data Exchange (ETDEWEB)

Angle, Jordan C.; Morin, Timothy H.; Solden, Lindsey M.; Narrowe, Adrienne B.; Smith, Garrett J.; Borton, Mikayla A.; Rey-Sanchez, Camilo; Daly, Rebecca A.; Mirfenderesgi, Golnazalsdat; Hoyt, David W.; Riley, William J.; Miller, Christopher S.; Bohrer, Gil; Wrighton, Kelly C.

2017-11-16

The current paradigm, widely incorporated in soil biogeochemical models, is that microbial methanogenesis can only occur in anoxic habitats1-4. In contrast, here porewater and greenhouse-gas flux measurements show clear evidence for methane production in well-oxygenated soils from a freshwater wetland. A comparison of oxic to anoxic soils revealed up to ten times greater methane production and nine times more methanogenesis activity in oxygenated soils. Metagenomic and metatranscriptomic sequencing recovered the first near complete genomes for a novel methanogen species, and showed acetoclastic production from this organism was the dominant methanogenesis pathway in oxygenated soils. This organism, Candidatus Methanosaeta oxydurans, is prevalent across methane emitting ecosystems, suggesting a global significance. Moreover, in this wetland, we estimated that a dominant fraction of methane fluxes could be attributed to methanogenesis in oxygenated soils. Together our findings challenge a widely-held assumption about methanogenesis, with significant ramifications for global methane estimates and Earth system modeling.

Methane recovery from landfill in China

Energy Technology Data Exchange (ETDEWEB)

Gaolai, L.

1996-12-31

GEF has approved a special project for a demonstration project for Methane Recovery from the Urban Refuse Land Fill. This paper will introduce the possibility of GHG reduction from the landfill in China, describe the activities of the GEF project, and the priorities for international cooperation in this field. The Global Environment Facility (GEF) approved the project, China Promoting Methane Recovery and Unlization from Mixed Municipal Refuse, at its Council meeting in last April. This project is the first one supported by international organization in this field.

Methane as a climate gas

Energy Technology Data Exchange (ETDEWEB)

Karlsdottir, S.

1996-03-01

This paper was read at the workshop ``The Norwegian Climate and Ozone Research Programme`` held on 11-12 March 1996. Methane is a key component in the atmosphere where its concentration has increased rapidly since pre-industrial time. About 2/3 of it is caused by human activities. Changes in methane will affect the concentrations of other gases, and a model is a very important tool to study sensitivity due to changes in concentration of gases. The author used a three-dimensional global chemistry transport model to study the effect of changes in methane concentration on other trace gases. The model includes natural and anthropogenic emissions of NOx, CO, CH{sub 4} and non-methane hydrocarbons. Wet and dry deposition are also included. The chemical scheme in the model includes 49 compounds, 101 reactions, and 16 photolytic reactions. The trace gas concentrations are calculated every 30 min, using a quasi steady state approximation. Model calculations of three cases are reported and compared. Enhanced methane concentration will have strongest effect in remote regions. In polluted areas local chemistry will have remarked effect. The feedback was always positive. Average atmospheric lifetime calculated in the model was 7.6 years, which agrees with recent estimates based on observations. 8 refs.

Contribution of Anthropogenic and Natural Emissions to Global CH4 Balances by Utilizing δ13C-CH4 Observations in CarbonTracker Data Assimilation System (CTDAS)

Science.gov (United States)

Kangasaho, V. E.; Tsuruta, A.; Aalto, T.; Backman, L. B.; Houweling, S.; Krol, M. C.; Peters, W.; van der Laan-Luijkx, I. T.; Lienert, S.; Joos, F.; Dlugokencky, E. J.; Michael, S.; White, J. W. C.

2017-12-01

The atmospheric burden of CH4 has more than doubled since preindustrial time. Evaluating the contribution from anthropogenic and natural emissions to the global methane budget is of great importance to better understand the significance of different sources at the global scale, and their contribution to changes in growth rate of atmospheric CH4 before and after 2006. In addition, observations of δ13C-CH4 suggest an increase in natural sources after 2006, which matches the observed increase and variation of CH4 abudance. Methane emission sources can be identified using δ13C-CH4, because different sources produce methane with process-specific isotopic signatures. This study focuses on inversion model based estimates of global anthropogenic and natural methane emission rates to evaluate the existing methane emission estimates with a new δ13C-CH4 inversion system. In situ measurements of atmospheric methane and δ13C-CH4 isotopic signature, provided by the NOAA Global Monitoring Division and the Institute of Arctic and Alpine Research, will be assimilated into the CTDAS-13C-CH4. The system uses the TM5 atmospheric transport model as an observation operator, constrained by ECMWF ERA Interim meteorological fields, and off-line TM5 chemistry fields to account for the atmospheric methane sink. LPX-Bern DYPTOP ecosystem model is used for prior natural methane emissions from wetlands, peatlands and mineral soils, GFED v4 for prior fire emissions and EDGAR v4.2 FT2010 inventory for prior anthropogenic emissions. The EDGAR antropogenic emissions are re-divided into enteric fermentation and manure management, landfills and waste water, rice, coal, oil and gas, and residential emissions, and the trend of total emissions is scaled to match optimized anthropogenic emissions from CTE-CH4. In addition to these categories, emissions from termites and oceans are included. Process specific δ13C-CH4 isotopic signatures are assigned to each emission source to estimate 13CH4 fraction

Isotopic source signatures: Impact of regional variability on the δ13CH4 trend and spatial distribution

Science.gov (United States)

Feinberg, Aryeh I.; Coulon, Ancelin; Stenke, Andrea; Schwietzke, Stefan; Peter, Thomas

2018-02-01

The atmospheric methane growth rate has fluctuated over the past three decades, signifying variations in methane sources and sinks. Methane isotopic ratios (δ13CH4) differ between emission categories, and can therefore be used to distinguish which methane sources have changed. However, isotopic modelling studies have mainly focused on uncertainties in methane emissions rather than uncertainties in isotopic source signatures. We simulated atmospheric δ13CH4 for the period 1990-2010 using the global chemistry-climate model SOCOL. Empirically-derived regional variability in the isotopic signatures was introduced in a suite of sensitivity simulations. These simulations were compared to a baseline simulation with commonly used global mean isotopic signatures. We investigated coal, natural gas/oil, wetland, livestock, and biomass burning source signatures to determine whether regional variations impact the observed isotopic trend and spatial distribution. Based on recently published source signature datasets, our calculated global mean isotopic signatures are in general lighter than the commonly used values. Trends in several isotopic signatures were also apparent during the period 1990-2010. Tropical livestock emissions grew during the 2000s, introducing isotopically heavier livestock emissions since tropical livestock consume more C4 vegetation than midlatitude livestock. Chinese coal emissions, which are isotopically heavy compared to other coals, increase during the 2000s leading to higher global values of δ13CH4 for coal emissions. EDGAR v4.2 emissions disagree with the observed atmospheric isotopic trend for almost all simulations, confirming past doubts about this emissions inventory. The agreement between the modelled and observed δ13CH4 interhemispheric differences improves when regional source signatures are used. Even though the simulated results are highly dependent on the choice of methane emission inventories, they emphasize that the commonly used

Vista-LA: Mapping methane-emitting infrastructure in the Los Angeles megacity

Science.gov (United States)

Carranza, Valerie; Rafiq, Talha; Frausto-Vicencio, Isis; Hopkins, Francesca M.; Verhulst, Kristal R.; Rao, Preeti; Duren, Riley M.; Miller, Charles E.

2018-03-01

Methane (CH4) is a potent greenhouse gas (GHG) and a critical target of climate mitigation efforts. However, actionable emission reduction efforts are complicated by large uncertainties in the methane budget on relevant scales. Here, we present Vista, a Geographic Information System (GIS)-based approach to map potential methane emissions sources in the South Coast Air Basin (SoCAB) that encompasses Los Angeles, an area with a dense, complex mixture of methane sources. The goal of this work is to provide a database that, together with atmospheric observations, improves methane emissions estimates in urban areas with complex infrastructure. We aggregated methane source location information into three sectors (energy, agriculture, and waste) following the frameworks used by the State of California GHG Inventory and the Intergovernmental Panel on Climate Change (IPCC) Guidelines for GHG Reporting. Geospatial modeling was applied to publicly available datasets to precisely geolocate facilities and infrastructure comprising major anthropogenic methane source sectors. The final database, Vista-Los Angeles (Vista-LA), is presented as maps of infrastructure known or expected to emit CH4. Vista-LA contains over 33 000 features concentrated on Vista-LA is used as a planning and analysis tool for atmospheric measurement surveys of methane sources, particularly for airborne remote sensing, and methane hotspot detection using regional observations. This study represents a first step towards developing an accurate, spatially resolved methane flux estimate for point sources in SoCAB, with the potential to address discrepancies between bottom-up and top-down methane emissions accounting in this region. The Vista-LA datasets and associated metadata are available from the Oak Ridge National Laboratory Distributed Active Archive Center for Biogeochemical Dynamics (ORNL DAAC; https://doi.org/10.3334/ORNLDAAC/1525).

Mitigation options for methane emissions from rice fields in the Philippines

Energy Technology Data Exchange (ETDEWEB)

Lantin, R.S.; Buendia, L.V.; Wassmann, R. [International Rice Research Institute, Laguna (Philippines)] [and others

1996-12-31

The contribution of Philippine rice production to global methane emission and breakthroughs in methane emission studies conducted in the country are presented in this paper. A significant impact in the reduction of GHG emissions from agriculture can be achieved if methane emissions from ricefields can be abated. This study presents the contribution of Philippine rice cultivation to global methane emission and breakthroughs in methane emission studies in the country which address the issue of mitigation. Using the derived emission factors from local measurements, rice cultivation contributes 566.6 Gg of methane emission in the Philippines. This value is 62% of the total methane emitted from the agriculture sector. The emission factors employed which are 78% of the IPCC value for irrigated rice and 95% for rainfed rice were derived from measurements with an automatic system taken during the growth duration in the respective ecosystems. Plots drained for 2 weeks at midtillering and before harvest gave a significant reduction in methane emission as opposed to continuously flooded plots and plots drained before harvest. The cultivar Magat reduced methane emission by 50% as compared to the check variety IR72. The application of ammonium sulfate instead of urea reduced methane emission by 10% to 34%. Addition of 6 t ha{sup {minus}1} phosphogypsum in combination with urea reduced emission by 74% as opposed to plots applied with urea alone. It is also from the results of such measurements that abatement strategies are based as regards to modifying treatments such as water management, fertilization, and choice of rice variety. It is not easy to identify and recommend mitigation strategies that will fit a particular cropping system. However, the identified mitigation options provide focus for the abatement of methane emission from ricefields.

Ruminal Methane Production on Simple Phenolic Acids Addition in in Vitro Gas Production Method

Directory of Open Access Journals (Sweden)

A. Jayanegara

2009-04-01

Full Text Available Methane production from ruminants contributes to total global methane production, which is an important contributor to global warming. In this experiment, six sources of simple phenolic acids (benzoic, cinnamic, phenylacetic, caffeic, p-coumaric and ferulic acids at two different levels (2 and 5 mM added to hay diet were evaluated for their potential to reduce enteric methane production using in vitro Hohenheim gas production method. The measured variables were gas production, methane, organic matter digestibility (OMD, and short chain fatty acids (SCFA. The results showed that addition of cinnamic, caffeic, p-coumaric and ferulic acids at 5 mM significantly (P p-coumaric > ferulic > cinnamic. The addition of simple phenols did not significantly decrease OMD. Addition of simple phenols tends to decrease total SCFA production. It was concluded that methane decrease by addition of phenolic acids was relatively small, and the effect of phenolic acids on methane decrease depended on the source and concentration applied.

Direct measurements of methane emissions from abandoned oil and gas wells in Pennsylvania.

Science.gov (United States)

Kang, Mary; Kanno, Cynthia M; Reid, Matthew C; Zhang, Xin; Mauzerall, Denise L; Celia, Michael A; Chen, Yuheng; Onstott, Tullis C

2014-12-23

Abandoned oil and gas wells provide a potential pathway for subsurface migration and emissions of methane and other fluids to the atmosphere. Little is known about methane fluxes from the millions of abandoned wells that exist in the United States. Here, we report direct measurements of methane fluxes from abandoned oil and gas wells in Pennsylvania, using static flux chambers. A total of 42 and 52 direct measurements were made at wells and at locations near the wells ("controls") in forested, wetland, grassland, and river areas in July, August, October 2013 and January 2014, respectively. The mean methane flow rates at these well locations were 0.27 kg/d/well, and the mean methane flow rate at the control locations was 4.5 × 10(-6) kg/d/location. Three out of the 19 measured wells were high emitters that had methane flow rates that were three orders of magnitude larger than the median flow rate of 1.3 × 10(-3) kg/d/well. Assuming the mean flow rate found here is representative of all abandoned wells in Pennsylvania, we scaled the methane emissions to be 4-7% of estimated total anthropogenic methane emissions in Pennsylvania. The presence of ethane, propane, and n-butane, along with the methane isotopic composition, indicate that the emitted methane is predominantly of thermogenic origin. These measurements show that methane emissions from abandoned oil and gas wells can be significant. The research required to quantify these emissions nationally should be undertaken so they can be accurately described and included in greenhouse gas emissions inventories.

Terrestrial plant methane production and emission

DEFF Research Database (Denmark)

Bruhn, Dan; Møller, Ian M.; Mikkelsen, Teis Nørgaard

2012-01-01

In this minireview, we evaluate all experimental work published on the phenomenon of aerobic methane (CH4) generation in terrestrial plants and plant. Clearly, despite much uncertainty and skepticism, we conclude that the phenomenon is true. Four stimulating factors have been observed to induce...... aerobic CH4 into a global budget is inadequate. Thus it is too early to draw the line under the aerobic methane emission in plants. Future work is needed for establishing the relative contribution of several proven potential CH4 precursors in plant material....

Comparison of global inventories of CO emissions from biomass burning derived from remotely sensed data

Directory of Open Access Journals (Sweden)

D. Stroppiana

2010-12-01

Full Text Available We compare five global inventories of monthly CO emissions named VGT, ATSR, MODIS, GFED3 and MOPITT based on remotely sensed active fires and/or burned area products for the year 2003. The objective is to highlight similarities and differences by focusing on the geographical and temporal distribution and on the emissions for three broad land cover classes (forest, savanna/grassland and agriculture. Globally, CO emissions for the year 2003 range between 365 Tg CO (GFED3 and 1422 Tg CO (VGT. Despite the large uncertainty in the total amounts, some common spatial patterns typical of biomass burning can be identified in the boreal forests of Siberia, in agricultural areas of Eastern Europe and Russia and in savanna ecosystems of South America, Africa and Australia. Regionally, the largest difference in terms of total amounts (CV > 100% and seasonality is observed at the northernmost latitudes, especially in North America and Siberia where VGT appears to overestimate the area affected by fires. On the contrary, Africa shows the best agreement both in terms of total annual amounts (CV = 31% and of seasonality despite some overestimation of emissions from forest and agriculture observed in the MODIS inventory. In Africa VGT provides the most reliable seasonality. Looking at the broad land cover types, the range of contribution to the global emissions of CO is 64–74%, 23–32% and 3–4% for forest, savanna/grassland and agriculture, respectively. These results suggest that there is still large uncertainty in global estimates of emissions and it increases if the comparison is carried by out taking into account the temporal (month and spatial (0.5° × 0.5° cell dimensions. Besides the area affected by fires, also vegetation characteristics and conditions at the time of burning should also be accurately parameterized since they can greatly influence the global estimates of CO emissions.

Methane emissions from termites - landscape level estimates and methods of measurement

Science.gov (United States)

Jamali, Hizbullah; Livesley, Stephen J.; Hutley, Lindsay B.; Arndt, Stefan K.

2013-04-01

Termites contribute between mound-building termite species diurnally and seasonally in tropical savannas in the Northern Territory, Australia. Our results showed that there were significant diel and seasonal variations of methane emissions from termite mounds and we observed large species-specific differences. On a diurnal basis, methane fluxes were least at the coolest time of the day and greatest at the warmest for all species for both wet and dry seasons. We observed a strong and significant positive correlation between methane flux and mound temperature for all species. Fluxes in the wet season were 5-26-fold greater than those in the dry season and this was related to population dynamics of the termites. We observed significant relationships between mound methane flux and mound carbon dioxide flux, enabling the prediction of methane flux from measured carbon dioxide flux. However, these relationships were clearly termite species specific. We also determined significant relationships between mound flux and gas concentration inside mound, for both gases, and for all termite species, thereby enabling the prediction of flux from measured mound internal gas concentration. However, these relationships were also termite species specific. Consequently, there was no generic relationship that would enable an easier prediction of methane flux from termite mounds. On a landscape scale we estimated that termites were a methane source of +0.24 kg methane-C ha-1 year-1 whilst savanna soils were a methane sink of 1.14 kg methane-C ha-1 year-1. Termites therefore only offset 21% of methane consumed by savanna soil resulting in net sink strength of -0.90 kg methane-C ha-1 year-1 for these savannas. Assuming a similar contribution of termites in the savannas and tropical rain forests worldwide, termites would globally produce around 27 Tg CO2-e year-1, which is 0.2% of the global methane source budget or an order of magnitude smaller than many of the previous estimates.

National- to port-level inventories of shipping emissions in China

Science.gov (United States)

Fu, Mingliang; Liu, Huan; Jin, Xinxin; He, Kebin

2017-11-01

Shipping in China plays a global role, and has led worldwide maritime transportation for the last decade. However, without taking national or local port boundaries into account, it is impossible to determine the responsibility that each local authority has on emission controls, nor compare them with land-based emissions to determine the priority for controlling these emissions. In this study, we provide national- to port-level inventories for China. The results show that in 2013, the total emissions of CO, non-methane volatile organic compounds (NMVOCs), nitrogen oxides (NO x ), particulate matter (PM), SO2 and CO2 were 0.0741 ± 0.0004 Tg•yr-1, 0.0691 ± 0.0004 Tg•yr-1, 1.91 ± 0.01 Tg•yr-1, 0.164 ± 0.001 Tg•yr-1, 1.30 ± 0.01 Tg•yr-1 and 86.3 ± 0.3 Tg•yr-1 in China, respectively. By providing high-resolution spatial distribution maps of these emissions, we identify three hotspots, centered on the Bohai Rim Area, the Yangtze River Delta and Pearl River Delta. These three hotspots account for 8% of the ocean area evaluated in this study, but contribute around 37% of total shipping emissions. Compared with on-road mobile source emissions, NO x and PM emissions from ships are equivalent to about 34% and 29% of the total mobile vehicle emissions in China. Moreover, this study provides detailed emission inventories for 24 ports in the country, which also greatly contributes to our understanding of global shipping emissions, given that eight of these ports rank within the top twenty of the port league table. Several ports in China suffer emissions 12-147 times higher than those at Los Angeles port. The ports of Ningbo-Zhou Shan, Shanghai, Hong Kong and Dalian dominate the port-level inventories, with individual emissions accounting for 28%-31%, 10%-14%, 10%-12% and 8%-14% of total emissions, respectively.

Development and governance of renewable methane use in transport

Energy Technology Data Exchange (ETDEWEB)

Lampinen, Ari

2013-10-15

Renewable methane is promoted in many countries as a sustainable alternative to fossil fuels in all types of transport applications. This article examines development, governance and motives for the use of biogas, synthetic biogas, wind methane and other types of renewable methane in transport. Fossil methane fuels, such as natural gas, shale gas and synthetic natural gas, are included as a comparison. Compressed town gas played an important role in the adoption of methane for traffic use, so its history is also examined. Three waves of development in the use of traffic biogas are identified: the Second World War, the 1970s oil crises, and the present day quest for sustainability. While biogas has been used in transport since the 1930s, the other renewable methane fuels are now emerging in the commercial market with only a few years of history. The article looks at the use of renewable methane in a global perspective, although most of the examples are from Europe, as the majority of the technological and political advances have been European.

Integrating Natural Gas Hydrates in the Global Carbon Cycle

Energy Technology Data Exchange (ETDEWEB)

David Archer; Bruce Buffett

2011-12-31

We produced a two-dimensional geological time- and basin-scale model of the sedimentary margin in passive and active settings, for the simulation of the deep sedimentary methane cycle including hydrate formation. Simulation of geochemical data required development of parameterizations for bubble transport in the sediment column, and for the impact of the heterogeneity in the sediment pore fluid flow field, which represent new directions in modeling methane hydrates. The model is somewhat less sensitive to changes in ocean temperature than our previous 1-D model, due to the different methane transport mechanisms in the two codes (pore fluid flow vs. bubble migration). The model is very sensitive to reasonable changes in organic carbon deposition through geologic time, and to details of how the bubbles migrate, in particular how efficiently they are trapped as they rise through undersaturated or oxidizing chemical conditions and the hydrate stability zone. The active margin configuration reproduces the elevated hydrate saturations observed in accretionary wedges such as the Cascadia Margin, but predicts a decrease in the methane inventory per meter of coastline relative to a comparable passive margin case, and a decrease in the hydrate inventory with an increase in the plate subduction rate.

Comparison of the HadGEM2 climate-chemistry model against in situ and SCIAMACHY atmospheric methane data

Directory of Open Access Journals (Sweden)

G. D. Hayman

2014-12-01

Full Text Available Wetlands are a major emission source of methane (CH4 globally. In this study, we evaluate wetland emission estimates derived using the UK community land surface model (JULES, the Joint UK Land Earth Simulator against atmospheric observations of methane, including, for the first time, total methane columns derived from the SCIAMACHY instrument on board the ENVISAT satellite. Two JULES wetland emission estimates are investigated: (a from an offline run driven with Climatic Research Unit–National Centers for Environmental Prediction (CRU-NCEP meteorological data and (b from the same offline run in which the modelled wetland fractions are replaced with those derived from the Global Inundation Extent from Multi-Satellites (GIEMS remote sensing product. The mean annual emission assumed for each inventory (181 Tg CH4 per annum over the period 1999–2007 is in line with other recently published estimates. There are regional differences as the unconstrained JULES inventory gives significantly higher emissions in the Amazon (by ~36 Tg CH4 yr−1 and lower emissions in other regions (by up to 10 Tg CH4 yr−1 compared to the JULES estimates constrained with the GIEMS product. Using the UK Hadley Centre's Earth System model with atmospheric chemistry (HadGEM2, we evaluate these JULES wetland emissions against atmospheric observations of methane. We obtain improved agreement with the surface concentration measurements, especially at high northern latitudes, compared to previous HadGEM2 runs using the wetland emission data set of Fung et al. (1991. Although the modelled monthly atmospheric methane columns reproduce the large-scale patterns in the SCIAMACHY observations, they are biased low by 50 part per billion by volume (ppb. Replacing the HadGEM2 modelled concentrations above 300 hPa with HALOE–ACE assimilated TOMCAT output results in a significantly better agreement with the SCIAMACHY observations. The use of the GIEMS product to constrain the JULES

Methane, where does it come from and what is its impact on climate?

International Nuclear Information System (INIS)

Andre, Jean-Claude; Boucher, Olivier; Bousquet, Philippe; Chanin, Marie-Lise; Chappellaz, Jerome; Tardieu, Bernard; Denegre, Jean; Beauvais, Muriel; Lefaudeux, Francois; Appert, Olivier; Desmarest, Patrice; Feillet, Pierre; Jarry, Bruno; Minster, Jean-Francois; Masson-Delmotte, Valerie; Dessus, Benjamin; Le Treut, Herve

2013-01-01

This report proposes a detailed presentation of knowledge on methane and on its role in the atmosphere. The first part addresses methane and the greenhouse effect: general considerations on methane in the atmosphere, radiative properties and importance with respect to the greenhouse effect, methane and future climate change. The second part proposes a presentation of methane sources and sinks. The third part addresses the study of methane fluxes: possible approaches to assess methane fluxes, measurement of atmospheric methane, the issue of atmospheric inversion (an approach to convert atmospheric observations into methane fluxes, lessons learned from atmospheric inversions, perspectives to improve knowledge on methane fluxes). The next chapters discuss the past, present and future evolution of methane in the atmosphere, discuss the carbon equivalence of methane (Kyoto protocol, policies of climate change, global warming power, role of methane, metrics, emission reduction), and comment the current perceivable evolutions, propose some methodological recommendations and actions to be implemented on the short term with no regret

Inversion Estimate of California Methane Emissions Using a Bayesian Inverse Model with Multi-Tower Greenhouse Gas Monitoring Network and Aircraft Measurements

Science.gov (United States)

Cui, Y.; Falk, M.; Chen, Y.; Herner, J.; Croes, B. E.; Vijayan, A.

2017-12-01

Methane (CH4) is an important short-lived climate pollutant (SLCP), and the second most important greenhouse gas (GHG) in California which accounts for 9% of the statewide GHG emissions inventory. Over the years, California has enacted several ambitious climate change mitigation goals, including the California Global Warming Solutions Act of 2006 which requires ARB to reduce statewide GHG emissions to 1990 emission level by 2020, as well as Assembly Bill 1383 which requires implementation of a climate mitigation program to reduce statewide methane emissions by 40% below the 2013 levels. In order to meet these requirements, ARB has proposed a comprehensive SLCP Strategy with goals to reduce oil and gas related emissions and capture methane emissions from dairy operations and organic waste. Achieving these goals will require accurate understanding of the sources of CH4 emissions. Since direct monitoring of CH4 emission sources in large spatial and temporal scales is challenging and resource intensive, we developed a complex inverse technique combined with atmospheric three-dimensional (3D) transport model and atmospheric observations of CH4 concentrations from a regional tower network and aircraft measurements, to gain insights into emission sources in California. In this study, develop a comprehensive inversion estimate using available aircraft measurements from CalNex airborne campaigns (May-June 2010) and three years of hourly continuous measurements from the ARB Statewide GHG Monitoring Network (2014-2016). The inversion analysis is conducted using two independent 3D Lagrangian models (WRF-STILT and WRF-FLEXPART), with a variety of bottom-up prior inputs from national and regional inventories, as well as two different probability density functions (Gaussian and Lognormal). Altogether, our analysis provides a detailed picture of the spatially resolved CH4 emission sources and their temporal variation over a multi-year period.

Short communication: Genetic study of methane production predicted from milk fat composition in dairy cows

NARCIS (Netherlands)

Engelen, van S.; Bovenhuis, H.; Dijkstra, J.; Arendonk, van J.A.M.; Visker, M.H.P.W.

2015-01-01

Dairy cows produce enteric methane, a greenhouse gas with 25 times the global warming potential of CO2. Breeding could make a permanent, cumulative, and long-term contribution to methane reduction. Due to a lack of accurate, repeatable, individual methane measurements needed for breeding, indicators

Verification of Agricultural Methane Emission Inventories

Science.gov (United States)

Desjardins, R. L.; Pattey, E.; Worth, D. E.; VanderZaag, A.; Mauder, M.; Srinivasan, R.; Worthy, D.; Sweeney, C.; Metzger, S.

2017-12-01

It is estimated that agriculture contributes more than 40% of anthropogenic methane (CH4) emissions in North America. However, these estimates, which are either based on the Intergovernmental Panel on Climate Change (IPCC) methodology or inverse modeling techniques, are poorly validated due to the challenges of separating interspersed CH4 sources within agroecosystems. A flux aircraft, instrumented with a fast-response Picarro CH4 analyzer for the eddy covariance (EC) technique and a sampling system for the relaxed eddy accumulation technique (REA), was flown at an altitude of about 150 m along several 20-km transects over an agricultural region in Eastern Canada. For all flight days, the top-down CH4 flux density measurements were compared to the footprint adjusted bottom-up estimates based on an IPCC Tier II methodology. Information on the animal population, land use type and atmospheric and surface variables were available for each transect. Top-down and bottom-up estimates of CH4 emissions were found to be poorly correlated, and wetlands were the most frequent confounding source of CH4; however, there were other sources such as waste treatment plants and biodigesters. Spatially resolved wavelet covariance estimates of CH4 emissions helped identify the contribution of wetlands to the overall CH4 flux, and the dependence of these emissions on temperature. When wetland contribution in the flux footprint was minimized, top-down and bottom-up estimates agreed to within measurement error. This research demonstrates that although existing aircraft-based technology can be used to verify regional ( 100 km2) agricultural CH4 emissions, it remains challenging due to diverse sources of CH4 present in many regions. The use of wavelet covariance to generate spatially-resolved flux estimates was found to be the best way to separate interspersed sources of CH4.

Veracruz State Preliminary Greenhouse Gases Emissions Inventory

Science.gov (United States)

Welsh Rodriguez, C.; Rodriquez Viqueira, L.; Guzman Rojas, S.

2007-05-01

At recent years, the international organisms such as United Nations, has discussed that the temperature has increased slightly and the pattern of precipitations has changed in different parts of the world, which cause either extreme droughts or floods and that the extreme events have increased. These are some of the risks of global climate change because of the increase of gas concentration in the atmosphere such as carbon dioxides, nitrogen oxides and methane - which increase the greenhouse effect. Facing the consequences that could emerge because of the global temperature grown, there is a genuine necessity in different sectors of reduction the greenhouse gases and reduced the adverse impacts of climate change. To solve that, many worldwide conventions have been realized (Rio de Janeiro, Kyoto, Montreal) where different countries have established political compromises to stabilize their emissions of greenhouse gases. The mitigation and adaptation policies merge as a response to the effects that the global climate change could have, on the humans as well as the environment. That is the reason to provide the analysis of the areas and geographic zones of the country that present major vulnerability to the climate change. The development of an inventory of emissions that identifies and quantifies the principal sources of greenhouse gases of a country, and also of a region is basic to any study about climate change, also to develop specific political programs that allow to preserve and even improve a quality of the atmospheric environment, and maybe to incorporate to international mechanisms such as the emissions market. To estimate emissions in a systematic and consistent way on a regional, national and international level is a requirement to evaluate the feasibility and the cost-benefit of instrumented possible mitigation strategies and to adopt politics and technologies to reduce emissions. Mexico has two national inventories of emissions, 1990 and 1995, now it is

A New Appraisal of Northern Peatlands and Global Atmospheric Methane Over the Holocene

Science.gov (United States)

MacDonald, G. M.; Holmquist, J. R.; Kremenetski, K.; Loisel, J.

2015-12-01

Use of large databases of peat cores to examine linkages between northern peatlands and atmospheric CH4 over the Holocene has been prone to uncertainties regarding 1. comparability of radiocarbon techniques and material dated, 2. appropriate summed probability distributions, 3. spatial representativeness of the sites, particularly in capturing sites south of the subarctic, 4. potential impacts of local lateral peatland expansion versus continental-scale peatland initiation, particularly in the late Holocene, and 5. impacts of changes in the proportion of high methane-producing fens vs Sphagnum bogs. We present a comparison of radiocarbon measurements from conventional counts, atomic mass spectrometry and differing peat materials to demonstrate a general compatibility of the various types of dates. We compare and apply several summed probability distribution methods to minimize any statistical bias in our analysis. We then present our analysis of a new data set of 7571 peatland cores from 4420 sites that extend into the temperate zone. Of these, 3732 cores inform on lateral expansion and 329 dates constrain the timing of fen-bog transition. Based on these data in original and gridded form we show that widespread peat initiation commenced at 16 kcal yr BP and reached a maximum rate at 11-8 kcal yr BP. Most sites began as fens, and peak transition to bogs occurred between 5 and 3 kcal yr BP, with a 1000 year lag between Eurasia and North America. There is no global late Holocene increase in lateral expansion. Based on modeled northern peatland area and ratio of fen/bog sites, CH4 production from northern peatlands increased rapidly from 11 to 9 cal yr BP, followed by slower increase until reaching a maximum at 5 kcal yr BP at 25 Tg per yr. From 4 kcal yr BP to Present, bogs become a dominant feature in the northern peatland landscape and CH4 production decreased to reach modern-day levels at about 20 Tg per yr. Northern peatlands have been a key infleunce on global

THE EARNINGS PER SHARE AND INVENTORY TURNOVER RATIOS IN THE GLOBAL FINANCIAL CRISIS: A COMPARATIVE STUDY FOR FOOD AND TEXTILE SECTORS IN ISTANBUL STOCK EXCHANGE

Directory of Open Access Journals (Sweden)

Sudi APAK

2009-01-01

Full Text Available The ongoing financial crisis in the global markets, which originated in the US subprime mortgage segment (real estate and quickly spread into other market segments and countries, is already seen today as one of the biggest financial crises in history. Underlying the subprime crisis had essentially two interrelated factors; the boom in US real estate markets, and the high liquidity demand in the global financial markets. The later period was, in turn, fuelled by the significant easing of US monetary policy over an extended period of time and by the additional boost to global liquidity as many emerging markets had tied their exchange rates to the US dollar and therefore had to match the expansive US monetary policy. The occurrence of market crash or financial crisis is possible key factor of earning per share (EPS and inventory turnover ratios (ITR inefficiency. This paper empirically investigates that the effects of the current financial crisis on the efficiency -earning per share (EPS and inventory turnover ratios- listed food and textile companies in Istanbul Stock Exchange (ISE. The EPS and inventory turnover ratios, applying the multivariate test statistics for the two sub-periods of pre-crisis and the crisis time. The article proceeds in the following manner. Firstly, the study will explain main reasons of global financial crises. Secondly the study will analyze all EPS and inventory turnover ratios changing are of related companies. Finally, that will be argued for adjustment of related ratios of sectors.

Interactions between methane and the nitrogen cycle in light of climate change

NARCIS (Netherlands)

Bodelier, P.L.E.; Steenbergh, A.K.

2014-01-01

Next to carbon dioxide, methane is the most important greenhouse gas which predominantly is released from natural wetlands and rice paddies. Climate change predictions indicate enhanced methane emission from global ecosystems under elevated CO2 and temperature. However, the extent of this positive

Sustainability: Bypassing the methane cycle : News & Views

NARCIS (Netherlands)

Bodelier, Paul L. E.

2015-01-01

A genetically modified rice with more starch in its grains also provides fewer nutrients for methane-producing soil microbes. This dual benefit might help to meet the urgent need for globally sustainable food production.

Methane airborne measurements and comparison to global models during BARCA

Science.gov (United States)

Beck, Veronika; Chen, Huilin; Gerbig, Christoph; Bergamaschi, Peter; Bruhwiler, Lori; Houweling, Sander; Röckmann, Thomas; Kolle, Olaf; Steinbach, Julia; Koch, Thomas; Sapart, Célia J.; van der Veen, Carina; Frankenberg, Christian; Andreae, Meinrat O.; Artaxo, Paulo; Longo, Karla M.; Wofsy, Steven C.

2012-08-01

Tropical regions, especially the Amazon region, account for large emissions of methane (CH4). Here, we present CH4 observations from two airborne campaigns conducted within the BARCA (Balanço Atmosférico Regional de Carbono na Amazônia) project in the Amazon basin in November 2008 (end of the dry season) and May 2009 (end of the wet season). We performed continuous measurements of CH4 onboard an aircraft for the first time in the Amazon region, covering the whole Amazon basin with over 150 vertical profiles between altitudes of 500 m and 4000 m. The observations support the finding of previous ground-based, airborne, and satellite measurements that the Amazon basin is a large source of atmospheric CH4. Isotope analysis verified that the majority of emissions can be attributed to CH4 emissions from wetlands, while urban CH4 emissions could be also traced back to biogenic origin. A comparison of five TM5 based global CH4 inversions with the observations clearly indicates that the inversions using SCIAMACHY observations represent the BARCA observations best. The calculated CH4 flux estimate obtained from the mismatch between observations and TM5-modeled CH4 fields ranges from 36 to 43 mg m-2 d-1 for the Amazon lowland region.

The Change in Oceanic O2 Inventory Associated with Recent Global Warming

Science.gov (United States)

Keeling, Ralph; Garcia, Hernan

2002-01-01

Oceans general circulation models predict that global warming may cause a decrease in the oceanic O2 inventory and an associated O2 outgassing. An independent argument is presented here in support of this prediction based on observational evidence of the ocean's biogeochemical response to natural warming. On time scales from seasonal to centennial, natural O2 flux/heat flux ratios are shown to occur in a range of 2 to 10 nmol O2 per Joule of warming, with larger ratios typically occurring at higher latitudes and over longer time scales. The ratios are several times larger than would be expected solely from the effect of heating on the O2 solubility, indicating that most of the O2 exchange is biologically mediated through links between heating and stratification. The change in oceanic O2 inventory through the 1990's is estimated to be 0.3 - 0.4 x 10(exp 14) mol O2 per year based on scaling the observed anomalous long-term ocean warming by natural O2 flux/heating ratios and allowing for uncertainty due to decadal variability. Implications are discussed for carbon budgets based on observed changes in atmospheric O2/N2 ratio and based on observed changes in ocean dissolved inorganic carbon.

Global Air Quality and Health Co-benefits of Mitigating Near-term Climate Change Through Methane and Black Carbon Emission Controls

Science.gov (United States)

Anenberg, Susan C.; Schwartz, Joel; Shindell, Drew Todd; Amann, Markus; Faluvegi, Gregory S.; Klimont, Zbigniew; Janssens-Maenhout, Greet; Pozzoli, Luca; Dingenen, Rita Van; Vignati, Elisabetta;

LANDFILL OPERATION FOR CARBON SEQUESTRATION AND MAXIMUM METHANE EMISSION CONTROL

Energy Technology Data Exchange (ETDEWEB)

Don Augenstein

1999-01-11

''Conventional'' waste landfills emit methane, a potent greenhouse gas, in quantities such that landfill methane is a major factor in global climate change. Controlled landfilling is a novel approach to manage landfills for rapid completion of total gas generation, maximizing gas capture and minimizing emissions of methane to the atmosphere. With controlled landfilling, methane generation is accelerated and brought to much earlier completion by improving conditions for biological processes (principally moisture levels) in the landfill. Gas recovery efficiency approaches 100% through use of surface membrane cover over porous gas recovery layers operated at slight vacuum. A field demonstration project's results at the Yolo County Central Landfill near Davis, California are, to date, highly encouraging. Two major controlled landfilling benefits would be the reduction of landfill methane emissions to minuscule levels, and the recovery of greater amounts of landfill methane energy in much shorter times than with conventional landfill practice. With the large amount of US landfill methane generated, and greenhouse potency of methane, better landfill methane control can play a substantial role in reduction of US greenhouse gas emissions.

Subterranean karst environments as a global sink for atmospheric methane

Science.gov (United States)

Webster, Kevin D.; Drobniak, Agnieszka; Etiope, Giuseppe; Mastalerz, Maria; Sauer, Peter E.; Schimmelmann, Arndt

2018-03-01

The air in subterranean karst cavities is often depleted in methane (CH4) relative to the atmosphere. Karst is considered a potential sink for the atmospheric greenhouse gas CH4 because its subsurface drainage networks and solution-enlarged fractures facilitate atmospheric exchange. Karst landscapes cover about 14% of earth's continental surface, but observations of CH4 concentrations in cave air are limited to localized studies in Gibraltar, Spain, Indiana (USA), Vietnam, Australia, and by incomplete isotopic data. To test if karst is acting as a global CH4 sink, we measured the CH4 concentrations, δ13CCH4, and δ2HCH4 values of cave air from 33 caves in the USA and three caves in New Zealand. We also measured CO2 concentrations, δ13CCO2, and radon (Rn) concentrations to support CH4 data interpretation by assessing cave air residence times and mixing processes. Among these caves, 35 exhibited subatmospheric CH4 concentrations in at least one location compared to their local atmospheric backgrounds. CH4 concentrations, δ13CCH4, and δ2HCH4 values suggest that microbial methanotrophy within caves is the primary CH4 consumption mechanism. Only 5 locations from 3 caves showed elevated CH4 concentrations compared to the atmospheric background and could be ascribed to local CH4 sources from sewage and outgassing swamp water. Several associated δ13CCH4 and δ2HCH4 values point to carbonate reduction and acetate fermentation as biochemical pathways of limited methanogenesis in karst environments and suggest that these pathways occur in the environment over large spatial scales. Our data show that karst environments function as a global CH4 sink.

A two-dimensional model of the passive coastal margin deep sedimentary carbon and methane cycles

Directory of Open Access Journals (Sweden)

D. E. Archer

2012-08-01

Full Text Available We present a new geologic-time and basin-spatial scale model of the continental margin methane cycle. The model, SpongeBOB, is used to simulate evolution of the carbon cycle in a passive sedimentary continental margin in response to changing oceanographic and geologic forcing over a time scale of 200 million years. The geochemistry of the sediment column is altered by the addition of vertical high-permeability channels intended to mimic the effects of heterogeneity in the real sediment column due to faults, and produces results consistent with measured pore-water tracers SO₄²⁻ and ¹²⁹I. Pore water dissolved inorganic carbon (DIC concentrations are consistent with chemical weathering (CaCO₃ formation from igneous rocks at depth within the sediment column. The carbon isotopic composition of the DIC is consistent with a methane production efficiency from particulate organic carbon (POC of 50%, which is somewhat lower than redox balance with the H / C of organic matter in the model. The hydrate inventory in the model is somewhat less sensitive to temperature than our previous results with a one-dimensional model, quite sensitive to reasonable changes in POC, and extremely sensitive to the ability of methane bubbles to rise within the sediment column, and how far gas-phase methane can get through the sediment column before it redissolves when it reaches undersaturated conditions. Hydrate formation is also sensitive to deep respiration of migrating petroleum. Other phenomena which we simulated had only a small impact on the hydrate inventory, including thermogenic methane production and production/decomposition of dissolved organic carbon.

Evaluation of the FEERv1.0 Global Top-Down Biomass Burning Emissions Inventory over Africa

Science.gov (United States)

Ellison, L.; Ichoku, C. M.

2014-12-01

With the advent of the Fire Energetics and Emissions Research (FEER) global top-down biomass burning emissions product from NASA Goddard Space Flight Center, a subsequent effort is going on to analyze and evaluate some of the main (particulate and gaseous) constituents of this emissions inventory against other inventories of biomass burning emissions over the African continent. There is consistent and continual burning during the dry season in NSSA of many small slash-and-burn fires that, though may be relatively small fires individually, collectively contribute 20-25% of the global total carbon emissions from biomass burning. As a top-down method of estimating biomass-burning emissions, FEERv1.0 is able to yield higher and more realistic emissions than previously obtainable using bottom-up methods. Results of such comparisons performed in detail over Africa will be discussed in this presentation. This effort is carried out in conjunction with a NASA-funded interdisciplinary research project investigating the effects of biomass burning on the regional climate system in Northern Sub-Saharan Africa (NSSA). Essentially, that project aims to determine how fires may have affected the severe droughts that plagued the NSSA region in recent history. Therefore, it is imperative that the biomass burning emissions input data over Africa be as accurate as possible in order to obtain a confident understanding of their interactions and feedbacks with the hydrological cycle in NSSA.

Modelling of oceanic gas hydrate instability and methane release in response to climate change

International Nuclear Information System (INIS)

Reagan, M.T.; Moridis, G.J.

2008-01-01

Methane releases from oceanic hydrates are thought to have played a significant role in climatic changes that have occurred in the past. In this study, gas hydrate accumulations subjected to temperature changes were modelled in order to assess their potential for future methane releases into the ocean. Recent ocean and atmospheric chemistry studies were used to model 2 climate scenarios. Two types of hydrate accumulations were used to represent dispersed, low-saturation deposits. The 1-D multiphase thermodynamic-hydrological model considered the properties of benthic sediments; ocean depth; sea floor temperature; the saturation and distribution of the hydrates; and the effect of benthic biogeochemical activity. Results of the simulations showed that shallow deposits undergo rapid dissociation and are capable of producing methane fluxes of 2 to 13 mol m 3 per year over a period of decades. The fluxes exceed the ability of the anaerobic sea floor environment to sequester or consume the methane. A large proportion of the methane released in the scenarios emerged in the gas phase. Arctic hydrates may pose a threat to regional and global ecological systems. It was concluded that results of the study will be coupled with global climate models in order to assess the impact of the methane releases in relation to global climatic change. 39 refs., 5 figs

Sediment trapping by dams creates methane emission hot spots

DEFF Research Database (Denmark)

Maeck, A.; Delsontro, T.; McGinnis, Daniel F.

2013-01-01

Inland waters transport and transform substantial amounts of carbon and account for similar to 18% of global methane emissions. Large reservoirs with higher areal methane release rates than natural waters contribute significantly to freshwater emissions. However, there are millions of small dams...... worldwide that receive and trap high loads of organic carbon and can therefore potentially emit significant amounts of methane to the atmosphere. We evaluated the effect of damming on methane emissions in a central European impounded river. Direct comparison of riverine and reservoir reaches, where...... sedimentation in the latter is increased due to trapping by dams, revealed that the reservoir reaches are the major source of methane emissions (similar to 0.23 mmol CH4 m(-2) d(-1) vs similar to 19.7 mmol CH4 m(-2) d(-1), respectively) and that areal emission rates far exceed previous estimates for temperate...

Working group report: methane emissions from coal mining

International Nuclear Information System (INIS)

Kruger, D.

1993-01-01

The process of coalification inherently generates methane and other byproducts. The amount of methane released during coal mining is a function of coal rank and depth, gas content, and mining methods, as well as other factors such as moisture. In most underground mines, methane is removed by drawing large quantities of air through the mine releasing the air into the atmosphere. In surface mines, exposed coal faces and surfaces, as well as areas of coal rubble created by blasting operations are believed to be the major sources of methane. A portion of the methane emitted from coal mining comes from post-mining activities such as coal processing, transportation, and utilisation. Some methane is also released from coal waste piles and abandoned mines. This paper highlights difficulties with previous methane emission studies namely: absence of data on which to base estimates; use of national data to develop global estimates; failure to include all possible emission sources; overreliance on statistical estimation methodologies. It recommends a 'tiered' approach for the estimation of emissions from underground mines, surface mines and post-mining activities. For each source, two or more approaches (or 'tiers') are presented, with the first tier requiring basic and readily available data and higher tiers requiring additional data. 29 refs., 3 tabs

Advancing national greenhouse gas inventories for agriculture in developing countries: improving activity data, emission factors and software technology

International Nuclear Information System (INIS)

Ogle, Stephen M; Hartman, Melannie; Spencer, Shannon; Buendia, Leandro; Butterbach-Bahl, Klaus; Breidt, F Jay; Yagi, Kazuyuki; Nayamuth, Rasack; Wirth, Tom; Smith, Pete

2013-01-01

Developing countries face many challenges when constructing national inventories of greenhouse gas (GHG) emissions, such as lack of activity data, insufficient measurements for deriving country-specific emission factors, and a limited basis for assessing GHG mitigation options. Emissions from agricultural production are often significant sources in developing countries, particularly soil nitrous oxide, and livestock enteric and manure methane, in addition to wetland rice methane. Consequently, estimating GHG emissions from agriculture is an important part of constructing developing country inventories. While the challenges may seem insurmountable, there are ways forward such as: (a) efficiently using resources to compile activity data by combining censuses and surveys; (b) using a tiered approach to measure emissions at appropriately selected sites, coupled with modeling to derive country-specific emission factors; and (c) using advanced software systems to guide compilers through the inventory process. With a concerted effort by compilers and assistance through capacity-building efforts, developing country compilers could produce transparent, accurate, complete, consistent and comparable inventories, as recommended by the IPCC (Intergovernmental Panel on Climate Change). In turn, the resulting inventories would provide the foundation for robust GHG mitigation analyses and allow for the development of nationally appropriate mitigation actions and low emission development strategies. (letter)

Ground based mobile isotopic methane measurements in the Front Range, Colorado

Science.gov (United States)

Vaughn, B. H.; Rella, C.; Petron, G.; Sherwood, O.; Mielke-Maday, I.; Schwietzke, S.

2014-12-01

Increased development of unconventional oil and gas resources in North America has given rise to attempts to monitor and quantify fugitive emissions of methane from the industry. Emission estimates of methane from oil and gas basins can vary significantly from one study to another as well as from EPA or State estimates. New efforts are aimed at reconciling bottom-up, or inventory-based, emission estimates of methane with top-down estimates based on atmospheric measurements from aircraft, towers, mobile ground-based vehicles, and atmospheric models. Attributing airborne measurements of regional methane fluxes to specific sources is informed by ground-based measurements of methane. Stable isotopic measurements (δ13C) of methane help distinguish between emissions from the O&G industry, Confined Animal Feed Operations (CAFO), and landfills, but analytical challenges typically limit meaningful isotopic measurements to individual point sampling. We are developing a toolbox to use δ13CH4 measurements to assess the partitioning of methane emissions for regions with multiple methane sources. The method was applied to the Denver-Julesberg Basin. Here we present data from continuous isotopic measurements obtained over a wide geographic area by using MegaCore, a 1500 ft. tube that is constantly filled with sample air while driving, then subsequently analyzed at slower rates using cavity ring down spectroscopy (CRDS). Pressure, flow and calibration are tightly controlled allowing precise attribution of methane enhancements to their point of collection. Comparisons with point measurements are needed to confirm regional values and further constrain flux estimates and models. This effort was made in conjunction with several major field campaigns in the Colorado Front Range in July-August 2014, including FRAPPÉ (Front Range Air Pollution and Photochemistry Experiment), DISCOVER-AQ, and the Air Water Gas NSF Sustainability Research Network at the University of Colorado.

Technical Note: Methionine, a precursor of methane in living plants

Science.gov (United States)

Lenhart, K.; Althoff, F.; Greule, M.; Keppler, F.

2015-03-01

When terrestrial plants were identified as producers of the greenhouse gas methane, much discussion and debate ensued not only about their contribution to the global methane budget but also with regard to the validity of the observation itself. Although the phenomenon has now become more accepted for both living and dead plants, the mechanism of methane formation in living plants remains to be elucidated and its precursor compounds to be identified. We made use of stable isotope techniques to verify the in vivo formation of methane, and, in order to identify the carbon precursor, 13C positionally labeled organic compounds were employed. Here we show that the amino acid L-methionine acts as a methane precursor in living plants. Employing 13C-labeled methionine clearly identified the sulfur-bound methyl group of methionine as a carbon precursor of methane released from lavender (Lavandula angustifolia). Furthermore, when lavender plants were stressed physically, methane release rates and the stable carbon isotope values of the emitted methane greatly increased. Our results provide additional support that plants possess a mechanism for methane production and suggest that methionine might play an important role in the formation of methane in living plants, particularly under stress conditions.

Impact of peat mining, and restoration on methane turnover potentials and methane-cycling microorganisms in a northern bog

NARCIS (Netherlands)

Reumer, Max; Harnisz, M.; Lee, H.J.; Reim, A.; Grunert, O.; Putkinen, A.; Fritze, H.; Bodelier, P.L.E.; Ho, A.

2018-01-01

Ombrotrophic peatlands are a recognized global carbon reservoir. Without restoration and peat regrowth, harvested peatlands are dramatically altered, impairing its carbon sink function, with consequences for methane turnover. Previous studies determined the impact of commercial mining on the peat

Formation of methane and nitrous oxide in plants

Science.gov (United States)

Keppler, Frank; Lenhart, Katharina

2017-04-01

Methane, the second important anthropogenic greenhouse gas after carbon dioxide, is the most abundant reduced organic compound in the atmosphere and plays a central role in atmospheric chemistry. The global atmospheric methane budget is determined by many natural and anthropogenic terrestrial and aquatic surface sources, balanced primarily by one major sink (hydroxyl radicals) in the atmosphere. Natural sources of atmospheric methane in the biosphere have until recently been attributed to originate solely from strictly anaerobic microbial processes in wetland soils and rice paddies, the intestines of termites and ruminants, human and agricultural waste, and from biomass burning, fossil fuel mining and geological sources including mud volcanoes and seeps. However, recent studies suggested that terrestrial vegetation, fungi and mammals may also produce methane without the help of methanogens and under aerobic conditions (e.g. Keppler et al. 2009, Wang et al. 2013). These novel sources have been termed "aerobic methane production" to distinguish them from the well-known anaerobic methane production pathway. Nitrous oxide is another important greenhouse gas and major source of ozone-depleting nitric oxide. About two thirds of nitrous oxide emissions are considered to originate from anthropogenic and natural terrestrial sources, and are almost exclusively related to microbial processes in soils and sediments. However, the global nitrous oxide budget still has major uncertainties since it is unclear if all major sources have been identified but also the emission estimates of the know sources and stratospheric sink are afflicted with high uncertainties. Plants contribute, although not yet quantified, to nitrous oxide emissions either indirectly as conduits of soil derived nitrous oxide (Pihlatie et al. 2005), or directly via generation of nitrous oxide in leaves (Dean & Harper 1986) or on the leaf surface induced by UV irradiation (Bruhn et al. 2014). Moreover, lichens

Creating a Global Building Inventory for Earthquake Loss Assessment and Risk Management

Science.gov (United States)

Jaiswal, Kishor; Wald, David J.

2008-01-01

Earthquakes have claimed approximately 8 million lives over the last 2,000 years (Dunbar, Lockridge and others, 1992) and fatality rates are likely to continue to rise with increased population and urbanizations of global settlements especially in developing countries. More than 75% of earthquake-related human casualties are caused by the collapse of buildings or structures (Coburn and Spence, 2002). It is disheartening to note that large fractions of the world's population still reside in informal, poorly-constructed & non-engineered dwellings which have high susceptibility to collapse during earthquakes. Moreover, with increasing urbanization half of world's population now lives in urban areas (United Nations, 2001), and half of these urban centers are located in earthquake-prone regions (Bilham, 2004). The poor performance of most building stocks during earthquakes remains a primary societal concern. However, despite this dark history and bleaker future trends, there are no comprehensive global building inventories of sufficient quality and coverage to adequately address and characterize future earthquake losses. Such an inventory is vital both for earthquake loss mitigation and for earthquake disaster response purposes. While the latter purpose is the motivation of this work, we hope that the global building inventory database described herein will find widespread use for other mitigation efforts as well. For a real-time earthquake impact alert system, such as U.S. Geological Survey's (USGS) Prompt Assessment of Global Earthquakes for Response (PAGER), (Wald, Earle and others, 2006), we seek to rapidly evaluate potential casualties associated with earthquake ground shaking for any region of the world. The casualty estimation is based primarily on (1) rapid estimation of the ground shaking hazard, (2) aggregating the population exposure within different building types, and (3) estimating the casualties from the collapse of vulnerable buildings. Thus, the

Large methane releases lead to strong aerosol forcing and reduced cloudiness

DEFF Research Database (Denmark)

Kurten, T.; Zhou, L.; Makkonen, R.

2011-01-01

forcing that is comparable in magnitude to the long-wave radiative forcing ("enhanced greenhouse effect") of the added methane. Together, the indirect CH4-O-3 and CH4-OHaerosol forcings could more than double the warming effect of large methane increases. Our findings may help explain the anomalously......The release of vast quantities of methane into the atmosphere as a result of clathrate destabilization is a potential mechanism for rapid amplification of global warming. Previous studies have calculated the enhanced warming based mainly on the radiative effect of the methane itself, with smaller...... contributions from the associated carbon dioxide or ozone increases. Here, we study the effect of strongly elevated methane (CH4) levels on oxidant and aerosol particle concentrations using a combination of chemistry-transport and general circulation models. A 10-fold increase in methane concentrations...

Termites facilitate methane oxidation and shape the methanotrophic community.

Science.gov (United States)

Ho, Adrian; Erens, Hans; Mujinya, Basile Bazirake; Boeckx, Pascal; Baert, Geert; Schneider, Bellinda; Frenzel, Peter; Boon, Nico; Van Ranst, Eric

2013-12-01

Termite-derived methane contributes 3 to 4% to the total methane budget globally. Termites are not known to harbor methane-oxidizing microorganisms (methanotrophs). However, a considerable fraction of the methane produced can be consumed by methanotrophs that inhabit the mound material, yet the methanotroph ecology in these environments is virtually unknown. The potential for methane oxidation was determined using slurry incubations under conditions with high (12%) and in situ (∼0.004%) methane concentrations through a vertical profile of a termite (Macrotermes falciger) mound and a reference soil. Interestingly, the mound material showed higher methanotrophic activity. The methanotroph community structure was determined by means of a pmoA-based diagnostic microarray. Although the methanotrophs in the mound were derived from populations in the reference soil, it appears that termite activity selected for a distinct community. Applying an indicator species analysis revealed that putative atmospheric methane oxidizers (high-indicator-value probes specific for the JR3 cluster) were indicative of the active nest area, whereas methanotrophs belonging to both type I and type II were indicative of the reference soil. We conclude that termites modify their environment, resulting in higher methane oxidation and selecting and/or enriching for a distinct methanotroph population.

Methane clumped isotopes: Progress and potential for a new isotopic tracer

Energy Technology Data Exchange (ETDEWEB)

Douglas, Peter M. J.; Stolper, Daniel A.; Eiler, John M.; Sessions, Alex L.; Lawson, Michael; Shuai, Yanhua; Bishop, Andrew; Podlaha, Olaf G.; Ferreira, Alexandre A.; Santos Neto, Eugenio V.; Niemann, Martin; Steen, Arne S.; Huang, Ling; Chimiak, Laura; Valentine, David L.; Fiebig, Jens; Luhmann, Andrew J.; Seyfried, William E.; Etiope, Giuseppe; Schoell, Martin; Inskeep, William P.; Moran, James J.; Kitchen, Nami

2017-11-01

The isotopic composition of methane is of longstanding geochemical interest, with important implications for understanding hydrocarbon systems, atmospheric greenhouse gas concentrations, the global carbon cycle, and life in extreme environments. Recent analytical developments focusing on multiply substituted isotopologues (‘clumped isotopes’) are opening a potentially valuable new window into methane geochemistry. When methane forms in internal isotopic equilibrium, clumped isotopes can provide a direct record of formation temperature, making this property particularly valuable for identifying different methane origins. However, it has also become clear that in certain settings methane clumped isotope measurements record kinetic rather than equilibrium isotope effects. Here we present a substantially expanded dataset of methane clumped isotope analyses, and provide a synthesis of the current interpretive framework for this parameter. We review different processes affecting methane clumped isotope compositions, describe the relationships between conventional isotope and clumped isotope data, and summarize the types of information that this measurement can provide in different Earth and planetary environments.

Evidence for nitrite-dependent anaerobic methane oxidation as a previously overlooked microbial methane sink in wetlands

Science.gov (United States)

Hu, Bao-lan; Shen, Li-dong; Lian, Xu; Zhu, Qun; Liu, Shuai; Huang, Qian; He, Zhan-fei; Geng, Sha; Cheng, Dong-qing; Lou, Li-ping; Xu, Xiang-yang; Zheng, Ping; He, Yun-feng

2014-01-01

The process of nitrite-dependent anaerobic methane oxidation (n-damo) was recently discovered and shown to be mediated by “Candidatus Methylomirabilis oxyfera” (M. oxyfera). Here, evidence for n-damo in three different freshwater wetlands located in southeastern China was obtained using stable isotope measurements, quantitative PCR assays, and 16S rRNA and particulate methane monooxygenase gene clone library analyses. Stable isotope experiments confirmed the occurrence of n-damo in the examined wetlands, and the potential n-damo rates ranged from 0.31 to 5.43 nmol CO2 per gram of dry soil per day at different depths of soil cores. A combined analysis of 16S rRNA and particulate methane monooxygenase genes demonstrated that M. oxyfera-like bacteria were mainly present in the deep soil with a maximum abundance of 3.2 × 107 gene copies per gram of dry soil. It is estimated that ∼0.51 g of CH4 m−2 per year could be linked to the n-damo process in the examined wetlands based on the measured potential n-damo rates. This study presents previously unidentified confirmation that the n-damo process is a previously overlooked microbial methane sink in wetlands, and n-damo has the potential to be a globally important methane sink due to increasing nitrogen pollution. PMID:24616523

Constraining the relationships between anaerobic oxidation of methane and sulfate reduction under in situ methane concentrations

Science.gov (United States)

Zhuang, G.; Wegener, G.; Joye, S. B.

2017-12-01

The anaerobic oxidation of methane (AOM) is an important microbial metabolism in the global carbon cycle. In marine methane seeps sediment, this process is mediated by syntrophic consortium that includes anaerobic methanotrophic archaea (ANME) and sulfate-reducing bacteria (SRB). Stoichiometrically in AOM methane oxidation should be coupled to sulfate reduction (SR) in a 1:1 ratio. However, weak coupling of AOM and SR in seep sediments was frequently observed from the ex situ rate measurements, and the metabolic dynamics of AOM and SR under in situ conditions remain poorly understood. Here we investigated the metabolic activity of AOM and SR with radiotracers by restoring in situ methane concentrations under pressure to constrain the in situ relationships between AOM and SR in the cold seep sediments of Gulf of Mexico as well as the sediment-free AOM enrichments cultivated from cold seep of Italian Island Elba or hydrothermal vent of Guaymas Basin5. Surprisingly, we found that AOM rates strongly exceeded those of SR when high pressures and methane concentrations were applied at seep sites of GC600 and GC767 in Gulf of Mexico. With the addition of molybdate, SR was inhibited but AOM was not affected, suggesting the potential coupling of AOM with other terminal processes. Amendments of nitrate, iron, manganese and AQDS to the SR-inhibited slurries did not stimulate or inhibit the AOM activity, indicating either those electron acceptors were not limiting for AOM in the sediments or AOM was coupled to other process (e.g., organic matter). In the ANME enrichments, higher AOM rates were also observed with the addition of high concentrations of methane (10mM and 50 mM). The tracer transfer of CO2 to methane, i.e., the back reaction of AOM, increased with increasing methane concentrations and accounted for 1%-5% of the AOM rates. AOM rates at 10 mM and 50 mM methane concentration were much higher than the SR rates, suggesting those two processes were not tightly coupled

Towards Soil and Sediment Inventories of Black Carbon

Science.gov (United States)

Masiello, C. A.

2008-12-01

A body of literature on black carbon (BC) concentrations in soils and sediments is rapidly accumulating, but as of yet, there are no global or regional inventories of BC in either reservoir. Soil and sediment BC inventories are badly needed for a range of fields. For example, in oceanography a global sediment BC inventory is crucial in understanding the role of biomass burning in the development of stable marine carbon reservoirs, including dissolved organic carbon and sedimentary organic carbon. Again in the marine environment, BC likely strongly impacts the fate and transport of anthropogenic pollutants: regional inventories of BC in sediments will help develop better environmental remediation strategies. In terrestrial systems well-constrained natural BC soil inventories would help refine ecological, agricultural, and soil biogeochemical studies. BC is highly sorptive of nutrients including nitrogen and phosphorous. The presence of BC in ecosystems almost certainly alters N and P cycling; however, without soil BC inventories, we cannot know where BC has a significant impact. BC's nutrient sorptivity and water-holding capacity make it an important component of agricultural soils, and some researchers have proposed artificially increasing soil BC inventories to improve soil fertility. Natural soil BC concentrations in some regions are quite high, but without a baseline inventory, it is challenging to predict when agricultural amendment will significantly exceed natural conditions. And finally, because BC is one of the most stable fractions of organic carbon in soils, understanding its concentration and regional distribution will help us track the dynamics of soil organic matter response to changing environmental conditions. Developing effective regional and global BC inventories is challenging both because of data sparsity and methodological intercomparison issues. In this presentation I will describe a roadmap to generating these valuable inventories.

The Impact of Uncertainties in African Biomass Burning Emission Estimates on Modeling Global Air Quality, Long Range Transport and Tropospheric Chemical Lifetimes

Directory of Open Access Journals (Sweden)

Guido R. van der Werf

2012-02-01

Full Text Available The chemical composition of the troposphere in the tropics and Southern Hemisphere (SH is significantly influenced by gaseous emissions released from African biomass burning (BB. Here we investigate how various emission estimates given in bottom-up BB inventories (GFEDv2, GFEDv3, AMMABB affect simulations of global tropospheric composition using the TM4 chemistry transport model. The application of various model parameterizations for introducing such emissions is also investigated. There are perturbations in near-surface ozone (O3 and carbon monoxide (CO of ~60–90% in the tropics and ~5–10% in the SH between different inventories. Increasing the update frequency of the temporal distribution to eight days generally results in decreases of between ~5 and 10% in near-surface mixing ratios throughout the tropics, which is larger than the influence of increasing the injection heights at which BB emissions are introduced. There are also associated differences in the long range transport of pollutants throughout the SH, where the composition of the free troposphere in the SH is sensitive to the chosen BB inventory. Analysis of the chemical budget terms reveals that the influence of increasing the tropospheric CO burden due to BB on oxidative capacity of the troposphere is mitigated by the associated increase in NOx emissions (and thus O3 with the variations in the CO/N ratio between inventories being low. For all inventories there is a decrease in the tropospheric chemical lifetime of methane of between 0.4 and 0.8% regardless of the CO emitted from African BB. This has implications for assessing the effect of inter-annual variability in BB on the annual growth rate of methane.

Methane fluxes from a wet puna ecosystem in the Peruvian Andes

Science.gov (United States)

Jones, Sam; Diem, Torsten; Priscila Huaraca Quispe, Lidia; Quispe Ccahuana, Adan Julian; Meir, Patrick; Arn Teh, Yit

2014-05-01

Discrepancies exist between top-down and bottom-up estimates of the tropical South American atmospheric methane budget. This suggests that current source-sink inventories fail to adequately characterise the landscapes of the region. This may be particularly true of Andean environments where very few field observations have been made. The high tropical Andes, between tree and permanent snow-lines, is home to diverse grass, shrub and giant rosette dominated ecosystems known variously from Venezuela to northern Chile and Argentina as paramo, jalca and puna. In humid regions these are characterised by wet, organic-rich mineral soils, peat-forming wetlands and shallow lakes. Such conditions are likely to promote methane production and potentially represent a regionally significant source to the atmosphere that should be considered. We report on methane fluxes from a bunch-grass dominated puna habitat at 3500 m above sea level in south-eastern Peru. Mean annual temperature and precipitation are 11 °C and 2500 mm, respectively. Temperature is aseasonal but experiences considerable diurnal variations with overnight frosting common-place. In contrast, rainfall is intensely episodic and has a pronounced wet season between September and March. Sampling encompassed a range of topographic features, such as grassland on freely draining, gently inclined or steep slopes and depressions containing bogs, over a 3 ha ridge to basin transition. Monthly sampling was carried out between January 2011 and June 2013 to investigate seasonal variability in methane fluxes. Intensive sampling campaigns were conducted to investigate spatial and short-term variations on a daily basis in two nine-day campaigns during wet and dry season. The site was a net source of methane to the atmosphere during the period of study. Methane fluxes were dominated by emissions from bogs, whereas, freely draining grassland exhibited weak source or marginal sink activity. Temporal variations were most notable at

Significance of dissolved methane in effluents of anaerobically ...

Science.gov (United States)

The need for energy efficient Domestic Wastewater (DWW) treatment is increasing annually with population growth and expanding global energy demand. Anaerobic treatment of low strength DWW produces methane which can be used to as an energy product. Temperature sensitivity, low removal efficiencies (Chemical Oxygen Demand (COD), Suspended Solids (SS), and Nutrients), alkalinity demand, and potential greenhouse gas (GHG) emissions have limited its application to warmer climates. Although well designed anaerobic Membrane Bioreactors (AnMBRs) are able to effectively treat DWW at psychrophilic temperatures (10–30 °C), lower temperatures increase methane solubility leading to increased energy losses in the form of dissolved methane in the effluent. Estimates of dissolved methane losses are typically based on concentrations calculated using Henry's Law but advection limitations can lead to supersaturation of methane between 1.34 and 6.9 times equilibrium concentrations and 11–100% of generated methane being lost in the effluent. In well mixed systems such as AnMBRs which use biogas sparging to control membrane fouling, actual concentrations approach equilibrium values. Non-porous membranes have been used to recover up to 92.6% of dissolved methane and well suited for degassing effluents of Upflow Anaerobic Sludge Blanket (UASB) reactors which have considerable solids and organic contents and can cause pore wetting and clogging in microporous membrane modules. Micro

Quantifying the relative contribution of natural gas fugitive emissions to total methane emissions in Weld County Colorado using δ13CH4 analysis

Science.gov (United States)

Rella, C.; Jacobson, G. A.; Crosson, E.; Sweeney, C.; Karion, A.; Petron, G.

2012-12-01

Fugitive emissions of methane into the atmosphere are a major concern facing the natural gas production industry. Given that the global warming potential of methane is many times greater than that of carbon dioxide (Forster et al. 2007), the importance of quantifying methane emissions becomes clear. Companion presentations at this meeting describe efforts to quantify the overall methane emissions in two separate gas producing areas in Colorado and Utah during intensive field campaigns undertaken in 2012. A key step in the process of assessing the emissions arising from natural gas production activities is partitioning the observed methane emissions between natural gas fugitive emissions and other sources of methane, such as from landfills or agricultural activities. One method for assessing the contribution of these different sources is stable isotope analysis. In particular, the δ13CH4 signature of natural gas (-37 permil) is significantly different that the signature of other significant sources of methane, such as landfills or ruminants (-50 to -70 permil). In this paper we present measurements of δ13CH4 in Colorado in Weld County, a region of intense natural gas production, using a mobile δ13CH4¬ analyzer capable of high-precision measurements of the stable isotope ratio of methane at ambient levels. This analyzer was used to make stable isotope measurements at a fixed location near the center of the gas producing region, from which an overall isotope ratio for the regional emissions is determined. In addition, mobile measurements in the nocturnal boundary layer have been made, over a total distance of 150 km throughout Weld County, allowing spatially resolved measurements of this isotope signature. Finally, this analyzer was used to quantify the isotopic signature of those individual sources (natural gas fugitive emissions, concentrated animal feeding operations, and landfills) that constitute the majority of methane emissions in this region, by making

Methane hydrates in nature - Current knowledge and challenges

Science.gov (United States)

Collett, Timothy S.

2014-01-01

our understanding of methane hydrates in nature. COL assembled a Methane Hydrate Project Science Team with members from academia, industry, and government. This Science Team worked with COL and DOE to develop and host the Methane Hydrate Community Workshop, which surveyed a substantial cross section of the methane hydrate research community for input on the most important research developments in our understanding of methane hydrates in nature and their potential role as an energy resource, a geohazard, and/or as an agent of global climate change. Our understanding of how methane hydrates occur in nature is still growing and evolving, and it is known with certainty that field, laboratory, and modeling studies have contributed greatly to our understanding of hydrates in nature and will continue to be a critical source of the information needed to advance our understanding of methane hydrates.

A record of aerobic methane oxidation in tropical Africa over the last 2.5 Ma

Science.gov (United States)

Spencer-Jones, Charlotte L.; Wagner, Thomas; Talbot, Helen M.

2017-12-01

Methane and CO2 are climatically active greenhouse gases (GHG) and are powerful drivers of rapid global warming. Comparable to the Arctic, the tropics store large volumes of labile sedimentary carbon that is vulnerable to climate change. However, little is known about this labile carbon reservoir, in particular the behaviour of high methane-producing environments (e.g. wetlands), and their role in driving or responding to past periods of global climate change. In this study, we use a microbial biomarker approach that traces continental aerobic methane oxidation (AMO) from sedimentary organic matter in deep-sea fan sediments off the Congo River to reconstruct the link between central African methane cycling and continental export during key periods of global Pleistocene warmth. We use 35-amino bacteriohopanepolyols (BHPs), specifically aminobacteriohopane-31,32,33,34-tetrol (aminotetrol) and 35-aminobacteriohopane-30,31,32,33,34-pentol (aminopentol) as diagnostic molecular markers for AMO (CH4 oxidation markers) and the prevalence of continental wetland environments. BHPs were analysed in sediments from the Congo fan (ODP 1075) dated to 2.5 Ma. High resolution studies of key warm marine isotope stages (MIS) 5, 11 and 13 are included to test the relationship between CH4 oxidation markers in sediments at different levels of elevated global atmospheric GHG. This study presents the oldest reported occurrence, to date, of 35-amino BHPs up to 200 m below sea floor (∼2.5 Ma) with no strong degradation signature observed. Low concentrations of CH4 oxidation markers identified between 1.7 Ma and 1 Ma suggest a reduction in wetland extent in tropical Africa in response to more arid environmental conditions. Correlation of high resolution CH4 oxidation marker signatures with global atmospheric GHG concentrations during MIS 5, 11 and 13 further emphasize periods of enhanced tropical C cycling. However, subsequent analysis would be required to further extrapolate the relative

Methane-oxidizing seawater microbial communities from an Arctic shelf

Science.gov (United States)

Uhlig, Christiane; Kirkpatrick, John B.; D'Hondt, Steven; Loose, Brice

2018-06-01

Marine microbial communities can consume dissolved methane before it can escape to the atmosphere and contribute to global warming. Seawater over the shallow Arctic shelf is characterized by excess methane compared to atmospheric equilibrium. This methane originates in sediment, permafrost, and hydrate. Particularly high concentrations are found beneath sea ice. We studied the structure and methane oxidation potential of the microbial communities from seawater collected close to Utqiagvik, Alaska, in April 2016. The in situ methane concentrations were 16.3 ± 7.2 nmol L-1, approximately 4.8 times oversaturated relative to atmospheric equilibrium. The group of methane-oxidizing bacteria (MOB) in the natural seawater and incubated seawater was > 97 % dominated by Methylococcales (γ-Proteobacteria). Incubations of seawater under a range of methane concentrations led to loss of diversity in the bacterial community. The abundance of MOB was low with maximal fractions of 2.5 % at 200 times elevated methane concentration, while sequence reads of non-MOB methylotrophs were 4 times more abundant than MOB in most incubations. The abundances of MOB as well as non-MOB methylotroph sequences correlated tightly with the rate constant (kox) for methane oxidation, indicating that non-MOB methylotrophs might be coupled to MOB and involved in community methane oxidation. In sea ice, where methane concentrations of 82 ± 35.8 nmol kg-1 were found, Methylobacterium (α-Proteobacteria) was the dominant MOB with a relative abundance of 80 %. Total MOB abundances were very low in sea ice, with maximal fractions found at the ice-snow interface (0.1 %), while non-MOB methylotrophs were present in abundances similar to natural seawater communities. The dissimilarities in MOB taxa, methane concentrations, and stable isotope ratios between the sea ice and water column point toward different methane dynamics in the two environments.

Methane emissions form terrestrial plants

Energy Technology Data Exchange (ETDEWEB)

Bergamaschi, P.; Dentener, F.; Grassi, G.; Leip, A.; Somogyi, Z.; Federici, S.; Seufert, G.; Raes, F. [European Commission, DG Joint Research Centre, Institute for Environment and Sustainability, Ispra (Italy)

2006-07-01

In a recent issue of Nature Keppler et al. (2006) report the discovery that terrestrial plants emit CH4 under aerobic conditions. Until now it was thought that bacterial decomposition of plant material under anaerobic conditions, such as in wetlands and water flooded rice paddies, is the main process leading to emissions from terrestrial ecosystems. In a first attempt to upscale these measurements, the authors estimate that global total emissions may be 149 Tg CH4/yr (62-236 Tg CH4/yr), with the main contribution estimated from tropical forests and grasslands (107 Tg CH4/yr with a range of 46-169 Tg CH4/yr). If confirmed, this new source of emission would constitute a significant fraction of the total global methane sources (estimated 500-600 Tg CH4/yr for present day total natural and anthropogenic sources) and have important implications for the global CH4 budget. To accommodate it within the present budget some sources would need to be re-assessed downwards and/or some sinks re-assessed upwards. Furthermore, also considering that methane is a {approx}23 times more powerful greenhouse gas than CO2, the possible feedbacks of these hitherto unknown CH4 emissions on global warming and their impacts on greenhouse gases (GHG) mitigation strategies need to be carefully evaluated. The merit of the paper is without doubt related to the remarkable discovery of a new process of methane emissions active under aerobic conditions. However, we think that the applied approach of scaling up emissions from the leaf level to global totals by using only few measured data (mainly from herbaceous species) and the Net Primary Productivity of the main biomes is scientifically questionable and tends to overestimate considerably the global estimates, especially for forest biomes. Furthermore, some significant constraints on the upper limit of the global natural CH4 emissions arise from the pre-industrial CH4 budget. Pre-industrial atmospheric CH4 mixing ratios have been measured

METHANE PHYTOREMEDIATION BY VEGETATIVE LANDFILL COVER SYSTEMS

Science.gov (United States)

Landfill gas, consisting of methane and other gases, is produced from organic compounds degrading in landfills, contributes to global climate change, is toxic to various types of vegetation, and may pose a combustion hazard at higher concentrations. New landfills are required to ...

Inventory of Dutch National Research on Global Climate Change: Inside and outside the National Research Programme

International Nuclear Information System (INIS)

Smythe, K.D.; Bernabo, C.; Kingma, J.; Vrakking, W.

1993-04-01

This report contains brief descriptions of research projects in the field of global climate change, performed both within and outside the Dutch National Research Programme on Global Air Pollution and Climate Change (NRP). The descriptions result from a survey of the major research institutions in The Netherlands, conducted by two consultancies (Science and Policy Associates, SPA and Holland Consulting Group, HCG) at the request of the NRP. The inventory had to be completed within a relatively brief period; it is thus unavoidable that one or more projects may sometimes contain inaccuracies. Taken as a whole, this report presents a good picture of the Dutch research activities in this area. The scope and structure of this survey and the contents of this report are based on a request for information from the World Meteorological Organization (WMO) for an intergovernmental meeting on the World Climate Programme (WCP), held on 14-16 April 1993. The WMO request emphasised activities related to the WCP and its associated programmes. The database resulting from this exercise will be a useful tool for organisations which sponsor and conduct research into global climate change in their efforts to stimulate cooperation and to promote coordination between the research groups in The Netherlands and abroad. There are plans to update the inventory in the future and to provide the information to participating organisations in The Netherlands, as well as to research organisations in other countries. An overview of the current research is provided in Volume 1, a list of projects being provided in Annex 3. The projects are presented according to the themes and subthemes which are used in the NRP

Renewable methane from anaerobic digestion of biomass

International Nuclear Information System (INIS)

Chynoweth, D.P.; Owens, J.M.

2001-01-01

Production of methane via anaerobic digestion of energy crops and organic wastes would benefit society by providing a clean fuel from renewable feedstocks. This would replace fossil fuel-derived energy and reduce environmental impacts including global warming and acid rain. Although biomass energy is more costly than fossil fuel-derived energy, trends to limit carbon dioxide and other emissions through emission regulations, carbon taxes, and subsidies of biomass energy would make it cost competitive. Methane derived from anaerobic digestion is competitive in efficiencies and costs to other biomass energy forms including heat, synthesis gases, and ethanol. (author)

Iron-mediated anaerobic oxidation of methane in brackish coastal sediments.

Science.gov (United States)

Egger, Matthias; Rasigraf, Olivia; Sapart, Célia J; Jilbert, Tom; Jetten, Mike S M; Röckmann, Thomas; van der Veen, Carina; Bândă, Narcisa; Kartal, Boran; Ettwig, Katharina F; Slomp, Caroline P

2015-01-06

Methane is a powerful greenhouse gas and its biological conversion in marine sediments, largely controlled by anaerobic oxidation of methane (AOM), is a crucial part of the global carbon cycle. However, little is known about the role of iron oxides as an oxidant for AOM. Here we provide the first field evidence for iron-dependent AOM in brackish coastal surface sediments and show that methane produced in Bothnian Sea sediments is oxidized in distinct zones of iron- and sulfate-dependent AOM. At our study site, anthropogenic eutrophication over recent decades has led to an upward migration of the sulfate/methane transition zone in the sediment. Abundant iron oxides and high dissolved ferrous iron indicate iron reduction in the methanogenic sediments below the newly established sulfate/methane transition. Laboratory incubation studies of these sediments strongly suggest that the in situ microbial community is capable of linking methane oxidation to iron oxide reduction. Eutrophication of coastal environments may therefore create geochemical conditions favorable for iron-mediated AOM and thus increase the relevance of iron-dependent methane oxidation in the future. Besides its role in mitigating methane emissions, iron-dependent AOM strongly impacts sedimentary iron cycling and related biogeochemical processes through the reduction of large quantities of iron oxides.

Estimating dead wood during national forest inventories: a review of inventory methodologies and suggestions for harmonization.

Science.gov (United States)

Woodall, Christopher W; Rondeux, Jacques; Verkerk, Pieter J; Ståhl, Göran

2009-10-01

Efforts to assess forest ecosystem carbon stocks, biodiversity, and fire hazards have spurred the need for comprehensive assessments of forest ecosystem dead wood (DW) components around the world. Currently, information regarding the prevalence, status, and methods of DW inventories occurring in the world's forested landscapes is scattered. The goal of this study is to describe the status, DW components measured, sample methods employed, and DW component thresholds used by national forest inventories that currently inventory DW around the world. Study results indicate that most countries do not inventory forest DW. Globally, we estimate that about 13% of countries inventory DW using a diversity of sample methods and DW component definitions. A common feature among DW inventories was that most countries had only just begun DW inventories and employ very low sample intensities. There are major hurdles to harmonizing national forest inventories of DW: differences in population definitions, lack of clarity on sample protocols/estimation procedures, and sparse availability of inventory data/reports. Increasing database/estimation flexibility, developing common dimensional thresholds of DW components, publishing inventory procedures/protocols, releasing inventory data/reports to international peer review, and increasing communication (e.g., workshops) among countries inventorying DW are suggestions forwarded by this study to increase DW inventory harmonization.

Methane storage capacity of the early martian cryosphere

Science.gov (United States)

Lasue, Jeremie; Quesnel, Yoann; Langlais, Benoit; Chassefière, Eric

2015-11-01

Methane is a key molecule to understand the habitability of Mars due to its possible biological origin and short atmospheric lifetime. Recent methane detections on Mars present a large variability that is probably due to relatively localized sources and sink processes yet unknown. In this study, we determine how much methane could have been abiotically produced by early Mars serpentinization processes that could also explain the observed martian remanent magnetic field. Under the assumption of a cold early Mars environment, a cryosphere could trap such methane as clathrates in stable form at depth. The extent and spatial distribution of these methane reservoirs have been calculated with respect to the magnetization distribution and other factors. We calculate that the maximum storage capacity of such a clathrate cryosphere is about 2.1 × 1019-2.2 × 1020 moles of CH4, which can explain sporadic releases of methane that have been observed on the surface of the planet during the past decade (∼1.2 × 109 moles). This amount of trapped methane is sufficient for similar sized releases to have happened yearly during the history of the planet. While the stability of such reservoirs depends on many factors that are poorly constrained, it is possible that they have remained trapped at depth until the present day. Due to the possible implications of methane detection for life and its influence on the atmospheric and climate processes on the planet, confirming the sporadic release of methane on Mars and the global distribution of its sources is one of the major goals of the current and next space missions to Mars.

Methane airborne measurements and comparison to global models during BARCA

NARCIS (Netherlands)

Beck, Veronika; Chen, Huilin; Gerbig, Christoph; Bergamaschi, Peter; Bruhwiler, Lori; Houweling, Sander; Rockmann, Thomas; Kolle, Olaf; Steinbach, Julia; Koch, Thomas; Sapart, Celia J.; van der Veen, Carina; Frankenberg, Christian; Andreae, Meinrat O.; Artaxo, Paulo; Longo, Karla M.; Wofsy, Steven C.

2012-01-01

Tropical regions, especially the Amazon region, account for large emissions of methane (CH4). Here, we present CH4 observations from two airborne campaigns conducted within the BARCA (Balanco Atmosferico Regional de Carbono na Amazonia) project in the Amazon basin in November 2008 (end of the dry

Methane emissions from oceans, coasts, and freshwater habitats: New perspectives and feedbacks on climate

Science.gov (United States)

Hamdan, Leila J.; Wickland, Kimberly P.

2016-01-01

Methane is a powerful greenhouse gas, and atmospheric concentrations have risen 2.5 times since the beginning of the Industrial age. While much of this increase is attributed to anthropogenic sources, natural sources, which contribute between 35% and 50% of global methane emissions, are thought to have a role in the atmospheric methane increase, in part due to human influences. Methane emissions from many natural sources are sensitive to climate, and positive feedbacks from climate change and cultural eutrophication may promote increased emissions to the atmosphere. These natural sources include aquatic environments such as wetlands, freshwater lakes, streams and rivers, and estuarine, coastal, and marine systems. Furthermore, there are significant marine sediment stores of methane in the form of clathrates that are vulnerable to mobilization and release to the atmosphere from climate feedbacks, and subsurface thermogenic gas which in exceptional cases may be released following accidents and disasters (North Sea blowout and Deepwater Horizon Spill respectively). Understanding of natural sources, key processes, and controls on emission is continually evolving as new measurement and modeling capabilities develop, and different sources and processes are revealed. This special issue of Limnology and Oceanography gathers together diverse studies on methane production, consumption, and emissions from freshwater, estuarine, and marine systems, and provides a broad view of the current science on methane dynamics of aquatic ecosystems. Here, we provide a general overview of aquatic methane sources, their contribution to the global methane budget, and key uncertainties. We then briefly summarize the contributions to and highlights of this special issue.

Climate change. The first national inventory of greenhouse gas emissions by sources and removals by sinks. Final report

International Nuclear Information System (INIS)

1994-01-01

The structure of the present greenhouse gas inventory report follows the order established in the R evised 1996 IPCC Guidelines-Greenhouse Gas Inventory Workbook, volume 2 , which has identified six major economic sectors, as follows: Energy, industrial processes, solvent and other product use, agriculture, land use change and forestry and waste. These guidelines have considered the following greenhouse gases: carbon dioxide, carbon monoxide, nitrogen oxides, nitrous oxide, sulfur dioxide, methane, non methane volatile organic compounds, hydrofluorocarbons, perfluorocarbons and sulfur hexafluoride. It should be noted that the protocol developed for the United Nations framework convention on climate change in the conference of parties 3, held in Kyoto on December 10, 1997 has determined six greenhouse gases to be controlled: CH 4 , CO 2 , N 2 O, HF C, PFC, S F 6 . This report summaries pictures of all important results obtained by the National Inventory team:The emitted amount of each greenhouse in all sectors in Lebanon. Tables and charts have been developed to show the contributions of various sectors to total emissions of gases in Lebanon

Preliminary Evaluation of Method to Monitor Landfills Resilience against Methane Emission

Science.gov (United States)

Chusna, Noor Amalia; Maryono, Maryono

2018-02-01

Methane emission from landfill sites contribute to global warming and un-proper methane treatment can pose an explosion hazard. Stakeholder and government in the cities in Indonesia been found significant difficulties to monitor the resilience of landfill from methane emission. Moreover, the management of methane gas has always been a challenging issue for long waste management service and operations. Landfills are a significant contributor to anthropogenic methane emissions. This study conducted preliminary evaluation of method to manage methane gas emission by assessing LandGem and IPCC method. From the preliminary evaluation, this study found that the IPCC method is based on the availability of current and historical country specific data regarding the waste disposed of in landfills while from the LandGEM method is an automated tool for estimating emission rates for total landfill gas this method account total gas of methane, carbon dioxide and other. The method can be used either with specific data to estimate emissions in the site or default parameters if no site-specific data are available. Both of method could be utilize to monitor the methane emission from landfill site in cities of Central Java.

Artificial electron acceptors decouple archaeal methane oxidation from sulfate reduction.

Science.gov (United States)

Scheller, Silvan; Yu, Hang; Chadwick, Grayson L; McGlynn, Shawn E; Orphan, Victoria J

2016-02-12

The oxidation of methane with sulfate is an important microbial metabolism in the global carbon cycle. In marine methane seeps, this process is mediated by consortia of anaerobic methanotrophic archaea (ANME) that live in syntrophy with sulfate-reducing bacteria (SRB). The underlying interdependencies within this uncultured symbiotic partnership are poorly understood. We used a combination of rate measurements and single-cell stable isotope probing to demonstrate that ANME in deep-sea sediments can be catabolically and anabolically decoupled from their syntrophic SRB partners using soluble artificial oxidants. The ANME still sustain high rates of methane oxidation in the absence of sulfate as the terminal oxidant, lending support to the hypothesis that interspecies extracellular electron transfer is the syntrophic mechanism for the anaerobic oxidation of methane. Copyright © 2016, American Association for the Advancement of Science.

Reducing Open Cell Landfill Methane Emissions with a Bioactive Alternative Daily

Energy Technology Data Exchange (ETDEWEB)

Helene Hilger; James Oliver; Jean Bogner; David Jones

2009-03-31

Methane and carbon dioxide are formed in landfills as wastes degrade. Molecule-for-molecule, methane is about 20 times more potent than carbon dioxide at trapping heat in the earth's atmosphere, and thus, it is the methane emissions from landfills that are scrutinized. For example, if emissions composed of 60% methane and 40% carbon dioxide were changed to a mix that was 40% methane and 60% carbon dioxide, a 30% reduction in the landfill's global warming potential would result. A 10% methane, 90% carbon dioxide ratio will result in a 75% reduction in global warming potential compared to the baseline. Gas collection from a closed landfill can reduce emissions, and it is sometimes combined with a biocover, an engineered system where methane oxidizing bacteria living in a medium such as compost, convert landfill methane to carbon dioxide and water. Although methane oxidizing bacteria merely convert one greenhouse gas (methane) to another (carbon dioxide), this conversion can offer significant reductions in the overall greenhouse gas contribution, or global warming potential, associated with the landfill. What has not been addressed to date is the fact that methane can also escape from a landfill when the active cell is being filled with waste. Federal regulations require that newly deposited solid waste to be covered daily with a 6 in layer of soil or an alternative daily cover (ADC), such as a canvas tarp. The aim of this study was to assess the feasibility of immobilizing methane oxidizing bacteria into a tarp-like matrix that could be used for alternative daily cover at open landfill cells to prevent methane emissions. A unique method of isolating methanotrophs from landfill cover soil was used to create a liquid culture of mixed methanotrophs. A variety of prospective immobilization techniques were used to affix the bacteria in a tarp-like matrix. Both gel encapsulation of methanotrophs and gels with liquid cores containing methanotrophs were readily

Inventory Centralization Decision Framework for Spare Parts

DEFF Research Database (Denmark)

Gregersen, Nicklas; Herbert-Hansen, Zaza Nadja Lee

2018-01-01

Within the current literature, there is a lack of a holistic and multidisciplinary approach to managing spare parts and their inventory configuration. This paper addresses this research gap by examining the key contextual factors which influence the degree of inventory centralization and proposes...... a novel holistic theoretical framework, the Inventory Centralization Decision Framework (ICDF), useful for practitioners. Through an extensive review of inventory management literature, six contextual factors influencing the degree of inventory centralization have been identified. Using the ICDF...... practitioners can assess the most advantageous inventory configuration of spare parts. The framework is tested on a large global company which, as a result, today actively uses the ICDF; thus showing its practical applicability....

Atmospheric methane from organic carbon mobilization in sedimentary basins — The sleeping giant?

Science.gov (United States)

Kroeger, K. F.; di Primio, R.; Horsfield, B.

2011-08-01

The mass of organic carbon in sedimentary basins amounts to a staggering 10 16 t, dwarfing the mass contained in coal, oil, gas and all living systems by ten thousand-fold. The evolution of this giant mass during subsidence and uplift, via chemical, physical and biological processes, not only controls fossil energy resource occurrence worldwide, but also has the capacity for driving global climate: only a tiny change in the degree of leakage, particularly if focused through the hydrate cycle, can result in globally significant greenhouse gas emissions. To date, neither climate models nor atmospheric CO 2 budget estimates have quantitatively included methane from thermal or microbial cracking of sedimentary organic matter deep in sedimentary basins. Recent estimates of average low latitude Eocene surface temperatures beyond 30 °C require extreme levels of atmospheric CO 2. Methane degassing from sedimentary basins may be a mechanism to explain increases of atmospheric CO 2 to values as much as 20 times higher than pre-industrial values. Increased natural gas emission could have been set in motion either by global tectonic processes such as pulses of activity in the global alpine fold belt, leading to increased basin subsidence and maturation rates in the prolific Jurassic and Cretaceous organic-rich sediments, or by increased magmatic activity such as observed in the northern Atlantic around the Paleocene-Eocene boundary. Increased natural gas emission would have led to global warming that was accentuated by long lasting positive feedback effects through temperature transfer from the surface into sedimentary basins. Massive gas hydrate dissociation may have been an additional positive feedback factor during hyperthermals superimposed on long term warming, such as the Paleocene-Eocene Thermal Maximum (PETM). As geologic sources may have contributed over one third of global atmospheric methane in pre-industrial time, variability in methane flux from sedimentary

Global warming: the significance of methane

International Nuclear Information System (INIS)

Dessus, B.; Le Treut, H.; Laponche, B.

2008-01-01

the concept of Global Warming Potential (GWP) indicates the relative contribution to global warming over a given period (for example 100 years) of a pulse emission at the start of the period of 1 kg of a specific greenhouse gas (GHG) in comparison to the contribution, over the same period, of an emission of 1 kg of CO 2 . The GWPs calculated for different time intervals take into account the differences in atmospheric lifetimes of the different GHGs. Using the '100-year GWP' to measure non CO 2 GHG emissions is not well suited to the case of permanent or long lifetime measures whose effectiveness is to be assessed at a given time horizon. In this context, it contributes to significantly playing down the importance of reducing emissions of GHGs with short atmospheric lifetimes. Thus, for example, methane which is not emitted over the period 2020- 2100 as a result of a landfill site being closed in 2020 will have an impact (as opposed to if the site remained in operation) that would be far greater towards 2100 compared to a CO 2 emission source that has also been stopped permanently and whose climate impact is measured in an equivalent manner. Using the GWP is only appropriate if applied year after year to time horizons considered to be of concern or decisive by climate studies, thus in particular 2050, 2100 and 2150. This is all the more significant as climate experts' current concerns lead them not only to advocate long-term stabilisation of GHG concentrations but also to avoid as far as possible intermediate excess of these concentrations over the coming century. Finally, it is noted that CH 4 prevention policies implemented in the short term may continue to have a long-term impact greater than merely taking into account the current GWP would imply. To more or less ignore the impact of CH 4 as it is unsuitable for accounting purposes affects the exclusive character of the link that may exist between the issue of GHGs and that of energy. Furthermore, if the

Carbon and hydrogen isotope composition and C-14 concentration in methane from sources and from the atmosphere: Implications for a global methane budget. Final report, 1 January-30 June 1991

International Nuclear Information System (INIS)

Wahlen, M.

1994-03-01

The topics covered include the following: biogenic methane studies; forest soil methane uptake; rice field methane sources; atmospheric measurements; stratospheric samples; Antarctica; California; and Germany

Fluxed of nitrous oxide and methane in a lake border ecosystem in northern Germany

Energy Technology Data Exchange (ETDEWEB)

Rusch, H.; Rembges, D.; Papke, H.; Rennenberg, H. [Fraunhofer Inst. for Atmospheric Environmental Research, Garmisch-Partenkirchen (Germany)

1995-12-31

Methane and nitrous oxide are radiatively active trace gases. This accounts for approximately 20 % of the total anticipated greenhouse effect. The atmospheric mixing ratio of both gases has increased significantly during the last decades at a rate of 0.25 % yr{sup -l} for N{sub 2}O and a rate of 1 % yr{sup -1} for CH{sub 4}. Whether this increase is caused by enhanced biogenic production of both gases or is due to decreased global sinks, has not been definitely elucidated. Soils are an important source of methane and nitrous oxide. Natural wetlands, e.g., have a similar global source strength of methane as rice paddies. On the other hand, well aerated grasslands have been shown to be a sink for atmospheric methane due to methane oxidation. Nitrous oxide is emitted by a wide range of soil types. Its rate of emission is strongly enhanced by nitrogen fertilization. In the present study, fluxes of methane and nitrous oxide were determined in a lake border ecosystem along a toposequence from reed to dry pasture. The aim of this study was to characterize the influence of soil type, land use and season on the flux rates of these greenhouse gases. (author)

Fluxed of nitrous oxide and methane in a lake border ecosystem in northern Germany

Energy Technology Data Exchange (ETDEWEB)

Rusch, H; Rembges, D; Papke, H; Rennenberg, H [Fraunhofer Inst. for Atmospheric Environmental Research, Garmisch-Partenkirchen (Germany)

1996-12-31

Methane and nitrous oxide are radiatively active trace gases. This accounts for approximately 20 % of the total anticipated greenhouse effect. The atmospheric mixing ratio of both gases has increased significantly during the last decades at a rate of 0.25 % yr{sup -l} for N{sub 2}O and a rate of 1 % yr{sup -1} for CH{sub 4}. Whether this increase is caused by enhanced biogenic production of both gases or is due to decreased global sinks, has not been definitely elucidated. Soils are an important source of methane and nitrous oxide. Natural wetlands, e.g., have a similar global source strength of methane as rice paddies. On the other hand, well aerated grasslands have been shown to be a sink for atmospheric methane due to methane oxidation. Nitrous oxide is emitted by a wide range of soil types. Its rate of emission is strongly enhanced by nitrogen fertilization. In the present study, fluxes of methane and nitrous oxide were determined in a lake border ecosystem along a toposequence from reed to dry pasture. The aim of this study was to characterize the influence of soil type, land use and season on the flux rates of these greenhouse gases. (author)

Danish emission inventory for agriculture. Inventories 1985 - 2009

Energy Technology Data Exchange (ETDEWEB)

Hjorth Mikkelsen, M; Albrektsen, R; Gyldenkaerne, S

2011-02-15

By regulations given in international conventions Denmark is obliged to work out an annual emission inventory and document the methodology. The National Environmental Research Institute (NERI) at Aarhus University (AU) in Denmark is responsible for calculating and reporting the emissions. This report contains a description of the emissions from the agricultural sector from 1985 to 2009. Furthermore, the report includes a detailed description of methods and data used to calculate the emissions, which is based on national methodologies as well as international guidelines. For the Danish emissions calculations and data management an Integrated Database model for Agricultural emissions (IDA) is used. The emission from the agricultural sector includes emission of the greenhouse gases methane (CH{sub 4}), nitrous oxide (N{sub 2}O), ammonia (NH{sub 3}), particulate matter (PM), non-methane volatile organic compounds (NMVOC) and other pollutants related to the field burning of agricultural residue such as NO{sub x}, CO{sub 2}, CO, SO{sub 2}, heavy metals, dioxin and PAH. The ammonia emission from 1985 to 2009 has decreased from 119 300 tonnes of NH{sub 3} to 73 800 tonnes NH{sub 3}, corresponding to a 38 % reduction. The emission of greenhouse gases has decreased by 25 % from 12.9 M tonnes CO{sub 2} equivalents to 9.6 M tonnes CO{sub 2} equivalents from 1985 to 2009. Improvements in feed efficiency and utilisation of nitrogen in livestock manure are the most important reasons for the reduction of both the ammonia and greenhouse gas emissions. (Author)

Methane airborne measurements and comparison to global models during BARCA

NARCIS (Netherlands)

Beck, V.; Chen, H.; Gerbig, C; Bergamaschi, P.; Bruhwiler, L.; Houweling, S.; Röckmann, T.; Kolle, O.; Steinbach, J.; Koch, T.; Sapart, C.J.; van der Veen, C.; Frankenberg, C.; Andreae, M.O.; Artaxo, P.; Longo, K.M.; Wofsy, S.C.

2012-01-01

Tropical regions, especially the Amazon region, account for large emissions of methane (CH4). Here, we present CH4 observations from two airborne campaigns conducted within the BARCA (Balanço Atmosférico Regional de Carbono na Amazônia) project in the Amazon basin in November 2008 (end of the dry

Monitoring and inventorying of the pollutant emissions from thermal power plants

International Nuclear Information System (INIS)

Vladescu, Gherghina; Iordache, Daniela; Iordache, Victorita; Ciomaga, Carmencita; Matei, Magdalena; Ilie, Ion; Motiu, Cornel

2001-01-01

Pollution due to emissions discharged in atmosphere as a result of human (anthropogenic) activities and the related environmental effects, such as acid depositions, land quality degradation, global warming/climate changes, building degradation, ozone layer depletion required the monitoring and inventorying of the polluting emissions at the local, regional and global levels. The paper briefly presents the international requirements concerning the development of a polluting emission inventory, the European methodologies for air polluting emission inventorying, programs and methodologies used in the Romanian electricity production sector for inventorying the polluting emissions and calculation of the dispersion of the pollutants discharged in the atmosphere. (author)

A correction in the CDM methodological tool for estimating methane emissions from solid waste disposal sites.

Science.gov (United States)

Santos, M M O; van Elk, A G P; Romanel, C

2015-12-01

Solid waste disposal sites (SWDS) - especially landfills - are a significant source of methane, a greenhouse gas. Although having the potential to be captured and used as a fuel, most of the methane formed in SWDS is emitted to the atmosphere, mainly in developing countries. Methane emissions have to be estimated in national inventories. To help this task the Intergovernmental Panel on Climate Change (IPCC) has published three sets of guidelines. In addition, the Kyoto Protocol established the Clean Development Mechanism (CDM) to assist the developed countries to offset their own greenhouse gas emissions by assisting other countries to achieve sustainable development while reducing emissions. Based on methodologies provided by the IPCC regarding SWDS, the CDM Executive Board has issued a tool to be used by project developers for estimating baseline methane emissions in their project activities - on burning biogas from landfills or on preventing biomass to be landfilled and so avoiding methane emissions. Some inconsistencies in the first two IPCC guidelines have already been pointed out in an Annex of IPCC latest edition, although with hidden details. The CDM tool uses a model for methane estimation that takes on board parameters, factors and assumptions provided in the latest IPCC guidelines, while using in its core equation the one of the second IPCC edition with its shortcoming as well as allowing a misunderstanding of the time variable. Consequences of wrong ex-ante estimation of baseline emissions regarding CDM project activities can be of economical or environmental type. Example of the first type is the overestimation of 18% in an actual project on biogas from landfill in Brazil that harms its developers; of the second type, the overestimation of 35% in a project preventing municipal solid waste from being landfilled in China, which harms the environment, not for the project per se but for the undue generated carbon credits. In a simulated landfill - the same

Impact of Peat Mining and Restoration on Methane Turnover Potential and Methane-Cycling Microorganisms in a Northern Bog.

Science.gov (United States)

Reumer, Max; Harnisz, Monika; Lee, Hyo Jung; Reim, Andreas; Grunert, Oliver; Putkinen, Anuliina; Fritze, Hannu; Bodelier, Paul L E; Ho, Adrian

2018-02-01

Ombrotrophic peatlands are a recognized global carbon reservoir. Without restoration and peat regrowth, harvested peatlands are dramatically altered, impairing their carbon sink function, with consequences for methane turnover. Previous studies determined the impact of commercial mining on the physicochemical properties of peat and the effects on methane turnover. However, the response of the underlying microbial communities catalyzing methane production and oxidation have so far received little attention. We hypothesize that with the return of Sphagnum spp. postharvest, methane turnover potential and the corresponding microbial communities will converge in a natural and restored peatland. To address our hypothesis, we determined the potential methane production and oxidation rates in natural (as a reference), actively mined, abandoned, and restored peatlands over two consecutive years. In all sites, the methanogenic and methanotrophic population sizes were enumerated using quantitative PCR (qPCR) assays targeting the mcrA and pmoA genes, respectively. Shifts in the community composition were determined using Illumina MiSeq sequencing of the mcrA gene and a pmoA -based terminal restriction fragment length polymorphism (t-RFLP) analysis, complemented by cloning and sequence analysis of the mmoX gene. Peat mining adversely affected methane turnover potential, but the rates recovered in the restored site. The recovery in potential activity was reflected in the methanogenic and methanotrophic abundances. However, the microbial community composition was altered, being more pronounced for the methanotrophs. Overall, we observed a lag between the recovery of the methanogenic/methanotrophic activity and the return of the corresponding microbial communities, suggesting that a longer duration (>15 years) is needed to reverse mining-induced effects on the methane-cycling microbial communities. IMPORTANCE Ombrotrophic peatlands are a crucial carbon sink, but this environment

Gas hydrates: entrance to a methane age or climate threat?

International Nuclear Information System (INIS)

Krey, Volker; Nakicenovic, Nebojsa; Grubler, Arnulf; O'Neill, Brian; Riahi, Keywan; Canadell, Josep G; Abe, Yuichi; Andruleit, Harald; Archer, David; Hamilton, Neil T M; Johnson, Arthur; Kostov, Veselin; Lamarque, Jean-Francois; Langhorne, Nicholas; Nisbet, Euan G; Riedel, Michael; Wang Weihua; Yakushev, Vladimir

2009-01-01

Methane hydrates, ice-like compounds in which methane is held in crystalline cages formed by water molecules, are widespread in areas of permafrost such as the Arctic and in sediments on the continental margins. They are a potentially vast fossil fuel energy source but, at the same time, could be destabilized by changing pressure-temperature conditions due to climate change, potentially leading to strong positive carbon-climate feedbacks. To enhance our understanding of both the vulnerability of and the opportunity provided by methane hydrates, it is necessary (i) to conduct basic research that improves the highly uncertain estimates of hydrate occurrences and their response to changing environmental conditions, and (ii) to integrate the agendas of energy security and climate change which can provide an opportunity for methane hydrates-in particular if combined with carbon capture and storage-to be used as a 'bridge fuel' between carbon-intensive fossil energies and zero-emission energies. Taken one step further, exploitation of dissociating methane hydrates could even mitigate against escape of methane to the atmosphere. Despite these opportunities, so far, methane hydrates have been largely absent from energy and climate discussions, including global hydrocarbon assessments and the Fourth Assessment Report of the Intergovernmental Panel on Climate Change.

Environmental impact of coal mine methane emissions and responding strategies in China

Energy Technology Data Exchange (ETDEWEB)

Cheng, Y.P.; Wang, L.; Zhang, X.L. [China University of Mining & Technology, Xuzhou (China)

2011-01-15

The impact on global climate change from coal mine methane emissions in China has been drawing attention as coal production has powered its economic development. Data on coal mine methane emissions from the State Administration of Coal Mine Safety of China has been analyzed. It is estimated that the methane emission from coal mining in China reached 20 billions of cubic meters in 2008, most of which comes from state-owned coal mines with high-gas content. China releases six times as much of methane from coal mines as compared to the United States. However, Chinese methane emission from coal production accounts for only a very small proportion on the environmental impact when compared to emissions of carbon dioxide from fossil fuel consumption. The Chinese government has shown environmental awareness and resolution on the mitigation and utilization of coal mine methane emissions. Measures have been taken to implement the programs of mitigation and utilization of coal mine methane, and at the same time, to ensure mining safety. Nearly 7.2 billions of cubic meters of methane were drained from the coal mines, and 32% of it was utilized in 2008. The slow advancement of technologies for the drainage and utilization of low-concentration methane from ventilation air hinders the progress of mitigation of atmospheric methane and the utilization of coal mine methane emissions.

Near-source mobile methane emission estimates using EPA Method33a and a novel probabilistic approach as a basis for leak quantification in urban areas

Science.gov (United States)

Albertson, J. D.

2015-12-01

Methane emissions from underground pipeline leaks remain an ongoing issue in the development of accurate methane emission inventories for the natural gas supply chain. Application of mobile methods during routine street surveys would help address this issue, but there are large uncertainties in current approaches. In this paper, we describe results from a series of near-source (< 30 m) controlled methane releases where an instrumented van was used to measure methane concentrations during both fixed location sampling and during mobile traverses immediately downwind of the source. The measurements were used to evaluate the application of EPA Method 33A for estimating methane emissions downwind of a source and also to test the application of a new probabilistic approach for estimating emission rates from mobile traverse data.

MethaneSat: Detecting Methane Emissions in the Barnett Shale Region

Science.gov (United States)

Propp, A. M.; Benmergui, J. S.; Turner, A. J.; Wofsy, S. C.

2017-12-01

In this study, we investigate the new information that will be provided by MethaneSat, a proposed satellite that will measure the total column dry-air mole fraction of methane at 1x1 km or 2x2 km spatial resolution with 0.1-0.2% random error. We run an atmospheric model to simulate MethaneSat's ability to characterize methane emissions from the Barnett Shale, a natural gas province in Texas. For comparison, we perform observation system simulation experiments (OSSEs) for MethaneSat, the National Oceanic and Atmospheric administration (NOAA) surface and aircraft network, and Greenhouse Gases Observing Satellite (GOSAT). The results demonstrate the added benefit that MethaneSat would provide in our efforts to monitor and report methane emissions. We find that MethaneSat successfully quantifies total methane emissions in the region, as well as their spatial distribution and steep gradients. Under the same test conditions, both the NOAA network and GOSAT fail to capture this information. Furthermore, we find that the results for MethaneSat depend far less on the prior emission estimate than do those for the other observing systems, demonstrating the benefit of high sampling density. The results suggest that MethaneSat would be an incredibly useful tool for obtaining detailed methane emission information from oil and gas provinces around the world.

Boreal Inundation Mapping with SMAP Radiometer Data for Methane Studies

Science.gov (United States)

Kim, Seungbum; Brisco, Brian; Poncos, Valentin

2017-04-01

Inundation and consequent anoxic condition induce methane release, which is one of the most potent greenhouse gases. Boreal regions contain large amounts of organic carbon, which is a potentially major methane emission source under climatic warming conditions. Boreal wetlands in particular are one of the largest sources of uncertainties in global methane budget. Wetland spatial extent together with the gas release rate remains highly unknown. Characterization of the existing inundation database is poor, because of the inundation under clouds and dense vegetation. In this work, the inundation extent is derived using brightness temperature data acquired by the L-band Soil Moisture Active Passive (SMAP) satellite, which offers the L-band capabilities to penetrate clouds and vegetation at 3-day revisit. The fidelity of the SMAP watermask is assessed as a first step in this investigation by comparing with the following data sets: 3-m resolution maps derived using Radarsat synthetic aperture radar (SAR) data in northern Canada and multi-sensor climatology over Siberia. Because Radarsat coverages are limited despite its high spatial resolution, at the time and location where Radarsats are not available, we also compare with 3-km resolution SMAP SAR data that are concurrent with the SMAP radiometer data globally until July 2015. Inundation extents were derived with Radarsat, SMAP SAR, and SMAP radiometer over the 60 km x 60km area at Peace Athabasca Delta (PAD), Canada on 6 days in spring and summer 2015. The SMAP SAR results match the locations of Radarsat waterbodies. However, the SMAP SAR underestimates the water extent, mainly over mixed pixels that have subpixel land presence. The threshold value (-3 dB) applied to the SMAP SAR was determined previously over the global domain. The threshold is dependent on the type of local landcover within a mixed pixel. Further analysis is needed to locally optimize the threshold. The SMAP radiometer water fraction over Peace

Reducing the environmental impact of methane emissions from dairy farms by anaerobic digestion of cattle waste.

Science.gov (United States)

Marañón, E; Salter, A M; Castrillón, L; Heaven, S; Fernández-Nava, Y

2011-08-01

Four dairy cattle farms considered representative of Northern Spain milk production were studied. Cattle waste was characterised and energy consumption in the farms was inventoried. Methane emissions due to slurry/manure management and fuel consumption on the farms were calculated. The possibility of applying anaerobic digestion to the slurry to minimise emissions and of using the biogas produced to replace fossil fuels on the farm was considered. Methane emissions due to slurry management (storage and use as fertiliser) ranged from 34 to 66kg CH(4)cow(-1)year(-1) for dairy cows and from 13 to 25kg CH(4)cow(-1)year(-1) for suckler calves. Cattle on these farms are housed for most of the year, and the contribution from emissions from manure dropped in pastures is insignificant due to the very low methane conversion factors. If anaerobic digestion were implemented on the farms, the potential GHG emissions savings per livestock unit would range from 978 to 1776kg CO(2)eq year(-1), with the main savings due to avoided methane emissions during slurry management. The methane produced would be sufficient to supply digester heating needs (35-55% of the total methane produced) and on-farm fuel energy requirements. Copyright © 2011 Elsevier Ltd. All rights reserved.

Biologically Produced Methane as a Renewable Energy Source.

Science.gov (United States)

Holmes, D E; Smith, J A

2016-01-01

Methanogens are a unique group of strictly anaerobic archaea that are more metabolically diverse than previously thought. Traditionally, it was thought that methanogens could only generate methane by coupling the oxidation of products formed by fermentative bacteria with the reduction of CO 2 . However, it has recently been observed that many methanogens can also use electrons extruded from metal-respiring bacteria, biocathodes, or insoluble electron shuttles as energy sources. Methanogens are found in both human-made and natural environments and are responsible for the production of ∼71% of the global atmospheric methane. Their habitats range from the human digestive tract to hydrothermal vents. Although biologically produced methane can negatively impact the environment if released into the atmosphere, when captured, it can serve as a potent fuel source. The anaerobic digestion of wastes such as animal manure, human sewage, or food waste produces biogas which is composed of ∼60% methane. Methane from biogas can be cleaned to yield purified methane (biomethane) that can be readily incorporated into natural gas pipelines making it a promising renewable energy source. Conventional anaerobic digestion is limited by long retention times, low organics removal efficiencies, and low biogas production rates. Therefore, many studies are being conducted to improve the anaerobic digestion process. Researchers have found that addition of conductive materials and/or electrically active cathodes to anaerobic digesters can stimulate the digestion process and increase methane content of biogas. It is hoped that optimization of anaerobic digesters will make biogas more readily accessible to the average person. Copyright © 2016 Elsevier Inc. All rights reserved.

Methane and Root Dynamics in Arctic Soil

DEFF Research Database (Denmark)

D'Imperio, Ludovica

on the global climate. We investigated two aspects of arctic ecosystem dynamics which are not well represented in climatic models: i) soil methane (CH4) oxidation in dry heath tundra and barren soils and ii) root dynamics in wetlands. Field measurements were carried out during the growing season in Disko Island...

A high-resolution regional emission inventory of atmospheric mercury and its comparison with multi-scale inventories: a case study of Jiangsu, China

Directory of Open Access Journals (Sweden)

H. Zhong

2016-12-01

Full Text Available A better understanding of the discrepancies in multi-scale inventories could give an insight into their approaches and limitations as well as provide indications for further improvements; international, national, and plant-by-plant data are primarily obtained to compile those inventories. In this study we develop a high-resolution inventory of Hg emissions at 0.05°  ×  0.05° for Jiangsu, China, using a bottom-up approach and then compare the results with available global/national inventories. With detailed information on individual sources and the updated emission factors from field measurements applied, the annual Hg emissions of anthropogenic origin in Jiangsu in 2010 are estimated at 39 105 kg, of which 51, 47, and 2 % were Hg0, Hg2+, and Hgp, respectively. This provincial inventory is thoroughly compared to three downscaled national inventories (NJU, THU, and BNU and two global ones (AMAP/UNEP and EDGARv4.tox2. Attributed to varied methods and data sources, clear information gaps exist in multi-scale inventories, leading to differences in the emission levels, speciation, and spatial distributions of atmospheric Hg. The total emissions in the provincial inventory are 28, 7, 19, 22, and 70 % larger than NJU, THU, BNU, AMAP/UNEP, and EDGARv4.tox2, respectively. For major sectors, including power generation, cement, iron and steel, and other coal combustion, the Hg contents (HgC in coals/raw materials, abatement rates of air pollution control devices (APCDs and activity levels are identified as the crucial parameters responsible for the differences in estimated emissions between inventories. Regarding speciated emissions, a larger fraction of Hg2+ is found in the provincial inventory than national and global inventories, resulting mainly from the results by the most recent domestic studies in which enhanced Hg2+ were measured for cement and iron and steel plants. Inconsistent information on large power and industrial plants is

Two Mechanisms for Methane Release at the Paleocene/Eocene Boundary

Science.gov (United States)

Katz, M. E.; Cramer, B. S.; Mountain, G. S.; Mountain, G. S.; Katz, S.; Miller, K. G.; Miller, K. G.

2001-12-01

The rapid global warming of the Paleocene/Eocene thermal maximum (PETM) has been attributed to a massive methane release from marine gas hydrate reservoirs. Two mechanisms have been proposed for this methane release. The first relies on a deepwater circulation change and water temperature increase that was sufficiently large and rapid to trigger massive thermal dissociation of gas hydrate frozen beneath the seafloor (Dickens et al., 1995). The second relies on slope failure (via erosion or seismic activity) of the oversteepened continental margins of the western North Atlantic to allow methane to escape from gas reservoirs trapped between the hydrate-bearing sediments and the underlying reef front (Katz et al., in press). We evaluate thermal dissociation by modeling heat flow through the sediments to show the effect of the temperature change on the gas hydrate stability zone through time. We use Paleocene bottom water temperatures (constrained by isotope records) and assume an instantaneous water temperature increase (i.e., no time allotted for ocean circulation change and water mass mixing). This yields an end-member minimum estimate of >2350 years necessary to melt all gas hydrate at locations shallower than 1570m; gas hydrates at greater depths remain frozen. We also use this model to predict the amount of C12-enriched methane that could have contributed to the carbon isotope excursion (CIE). Using reasonable methane distributions within sediments, we conclude that thermal dissociation alone cannot account for the full magnitude of the CIE. We propose that thermal dissociation did not initiate the CIE; rather, a different mechanism injected a large amount of carbon into the atmosphere, causing global greenhouse warming that could have led to subsequent thermal dissociation. Methane remains a plausible source for this initial carbon injection; however, initial release would have resulted from mechanical disruption of sediments rather than thermal dissociation

Methane - quick fix or tough target? New methods to reduce emissions.

Science.gov (United States)

Nisbet, E. G.; Lowry, D.; Fisher, R. E.; Brownlow, R.

2016-12-01

Methane is a cost-effective target for greenhouse gas reduction efforts. The UK's MOYA project is designed to improve understanding of the global methane budget and to point to new methods to reduce future emissions. Since 2007, methane has been increasing rapidly: in 2014 and 2015 growth was at rates last seen in the 1980s. Unlike 20thcentury growth, primarily driven by fossil fuel emissions in northern industrial nations, isotopic evidence implies present growth is driven by tropical biogenic sources such as wetlands and agriculture. Discovering why methane is rising is important. Schaefer et al. (Science, 2016) pointed out the potential clash between methane reduction efforts and food needs of a rising, better-fed (physically larger) human population. Our own work suggests tropical wetlands are major drivers of growth, responding to weather changes since 2007, but there is no acceptable way to reduce wetland emission. Just as sea ice decline indicates Arctic warming, methane may be the most obvious tracker of climate change in the wet tropics. Technical advances in instrumentation can do much in helping cut urban and industrial methane emissions. Mobile systems can be mounted on vehicles, while drone sampling can provide a 3D view to locate sources. Urban land planning often means large but different point sources are typically clustered (e.g. landfill or sewage plant near incinerator; gas wells next to cattle). High-precision grab-sample isotopic characterisation, using Keeling plots, can separate source signals, to identify specific emitters, even where they are closely juxtaposed. Our mobile campaigns in the UK, Kuwait, Hong Kong and E. Australia show the importance of major single sources, such as abandoned old wells, pipe leaks, or unregulated landfills. If such point sources can be individually identified, even when clustered, they will allow effective reduction efforts to occur: these can be profitable and/or improve industrial safety, for example in the

Characterization of Methane Degradation and Methane-Degrading Microbes in Alaska Coastal Water

Energy Technology Data Exchange (ETDEWEB)

Kirchman, David L. [Univ. of Delaware, Lewes, DE (United States)

2012-03-29

The net flux of methane from methane hydrates and other sources to the atmosphere depends on methane degradation as well as methane production and release from geological sources. The goal of this project was to examine methane-degrading archaea and organic carbon oxidizing bacteria in methane-rich and methane-poor sediments of the Beaufort Sea, Alaska. The Beaufort Sea system was sampled as part of a multi-disciplinary expedition (Methane in the Arctic Shelf or MIDAS) in September 2009. Microbial communities were examined by quantitative PCR analyses of 16S rRNA genes and key methane degradation genes (pmoA and mcrA involved in aerobic and anaerobic methane degradation, respectively), tag pyrosequencing of 16S rRNA genes to determine the taxonomic make up of microbes in these sediments, and sequencing of all microbial genes (metagenomes ). The taxonomic and functional make-up of the microbial communities varied with methane concentrations, with some data suggesting higher abundances of potential methane-oxidizing archaea in methane-rich sediments. Sequence analysis of PCR amplicons revealed that most of the mcrA genes were from the ANME-2 group of methane oxidizers. According to metagenomic data, genes involved in methane degradation and other degradation pathways changed with sediment depth along with sulfate and methane concentrations. Most importantly, sulfate reduction genes decreased with depth while the anaerobic methane degradation gene (mcrA) increased along with methane concentrations. The number of potential methane degradation genes (mcrA) was low and inconsistent with other data indicating the large impact of methane on these sediments. The data can be reconciled if a small number of potential methane-oxidizing archaea mediates a large flux of carbon in these sediments. Our study is the first to report metagenomic data from sediments dominated by ANME-2 archaea and is one of the few to examine the entire microbial assemblage potentially involved in

Compilation and evaluation of a Paso del Norte emission inventory

Energy Technology Data Exchange (ETDEWEB)

Funk, T.H.; Chinkin, L.R.; Roberts, P.T. [Sonoma Technology, Inc., 1360 Redwood Way, Suite C, 94954-1169 Petaluma, CA (United States); Saeger, M.; Mulligan, S. [Pacific Environmental Services, 5001 S. Miami Blvd., Suite 300, 27709 Research Triangle Park, NC (United States); Paramo Figueroa, V.H. [Instituto Nacional de Ecologia, Avenue Revolucion 1425, Nivel 10, Col. Tlacopac San Angel, Delegacion Alvaro Obregon, C.P., 01040, D.F. Mexico (Mexico); Yarbrough, J. [US Environmental Protection Agency - Region 6, 1445 Ross Avenue, Suite 1200, 75202-2733 Dallas, TX (United States)

2001-08-10

Emission inventories of ozone precursors are routinely used as input to comprehensive photochemical air quality models. Photochemical model performance and the development of effective control strategies rely on the accuracy and representativeness of an underlying emission inventory. This paper describes the tasks undertaken to compile and evaluate an ozone precursor emission inventory for the El Paso/Ciudad Juarez/Southern Dona Ana region. Point, area and mobile source emission data were obtained from local government agencies and were spatially and temporally allocated to a gridded domain using region-specific demographic and land-cover information. The inventory was then processed using the US Environmental Protection Agency (EPA) recommended Emissions Preprocessor System 2.0 (UAM-EPS 2.0) which generates emissions files compatible with the Urban Airshed Model (UAM). A top-down evaluation of the emission inventory was performed to examine how well the inventory represented ambient pollutant compositions. The top-down evaluation methodology employed in this study compares emission inventory ratios of non-methane hydrocarbon (NMHC)/nitrogen oxide (NO{sub x}) and carbon monoxide (CO)/NO{sub x} ratios to corresponding ambient ratios. Detailed NMHC species comparisons were made in order to investigate the relative composition of individual hydrocarbon species in the emission inventory and in the ambient data. The emission inventory compiled during this effort has since been used to model ozone in the Paso del Norte airshed (Emery et al., CAMx modeling of ozone and carbon monoxide in the Paso del Norte airshed. In: Proc of Ninety-Third Annual Meeting of Air and Waste Management Association, 18-22 June 2000, Air and Waste Management Association, Pittsburgh, PA, 2000)

Methane Feedbacks to the Global Climate System in a Warmer World

Science.gov (United States)

Dean, Joshua F.; Middelburg, Jack J.; Röckmann, Thomas; Aerts, Rien; Blauw, Luke G.; Egger, Matthias; Jetten, Mike S. M.; de Jong, Anniek E. E.; Meisel, Ove H.; Rasigraf, Olivia; Slomp, Caroline P.; in't Zandt, Michiel H.; Dolman, A. J.

2018-03-01

Methane (CH4) is produced in many natural systems that are vulnerable to change under a warming climate, yet current CH4 budgets, as well as future shifts in CH4 emissions, have high uncertainties. Climate change has the potential to increase CH4 emissions from critical systems such as wetlands, marine and freshwater systems, permafrost, and methane hydrates, through shifts in temperature, hydrology, vegetation, landscape disturbance, and sea level rise. Increased CH4 emissions from these systems would in turn induce further climate change, resulting in a positive climate feedback. Here we synthesize biological, geochemical, and physically focused CH4 climate feedback literature, bringing together the key findings of these disciplines. We discuss environment-specific feedback processes, including the microbial, physical, and geochemical interlinkages and the timescales on which they operate, and present the current state of knowledge of CH4 climate feedbacks in the immediate and distant future. The important linkages between microbial activity and climate warming are discussed with the aim to better constrain the sensitivity of the CH4 cycle to future climate predictions. We determine that wetlands will form the majority of the CH4 climate feedback up to 2100. Beyond this timescale, CH4 emissions from marine and freshwater systems and permafrost environments could become more important. Significant CH4 emissions to the atmosphere from the dissociation of methane hydrates are not expected in the near future. Our key findings highlight the importance of quantifying whether CH4 consumption can counterbalance CH4 production under future climate scenarios.

Urban sources and emissions of nitrous oxide and methane in southern California, USA

Science.gov (United States)

Townsend-Small, A.; Pataki, D.; Tyler, S. C.; Czimczik, C. I.; Xu, X.; Christensen, L. E.

2012-12-01

Anthropogenic activities have resulted in increasing levels of greenhouse gases, including carbon dioxide, methane, and nitrous oxide. While global and regional emissions sources of carbon dioxide are relatively well understood, methane and nitrous oxide are less constrained, particularly at regional scales. Here we present the results of an investigation of sources and emissions of methane and nitrous oxide in Los Angeles, California, USA, one of Earth's largest urban areas. The original goal of the project was to determine whether isotopes are useful tracers of agricultural versus urban nitrous oxide and methane sources. For methane, we found that stable isotopes (carbon-13 and deuterium) and radiocarbon are good tracers of biogenic versus fossil fuel sources. High altitude observations of methane concentration, measured continuously using tunable laser spectroscopy, and isotope ratios, measured on discrete flask samples using mass spectrometry, indicate that the predominant methane source in Los Angeles is from fossil fuels, likely from "fugitive" emissions from geologic formations, natural gas pipelines, oil refining, or power plants. We also measured nitrous oxide emissions and isotope ratios from urban (landscaping and wastewater treatment) and agricultural sources (corn and vegetable fields). There was no difference in nitrous oxide isotope ratios between the different types of sources, although stable isotopes did differ between nitrous oxide produced in oxic and anoxic wastewater treatment tanks. Our nitrous oxide flux data indicate that landscaped turfgrass emits nitrous oxide at rates equivalent to agricultural systems, indicating that ornamental soils should not be disregarded in regional nitrous oxide budgets. However, we also showed that wastewater treatment is a much greater source of nitrous oxide than soils regionally. This work shows that global nitrous oxide and methane budgets are not easily downscaled to regional, urban settings, which has

Gathering pipeline methane emissions in Fayetteville shale pipelines and scoping guidelines for future pipeline measurement campaigns

Directory of Open Access Journals (Sweden)

Daniel J. Zimmerle

2017-11-01

Full Text Available Gathering pipelines, which transport gas from well pads to downstream processing, are a sector of the natural gas supply chain for which little measured methane emissions data are available. This study performed leak detection and measurement on 96 km of gathering pipeline and the associated 56 pigging facilities and 39 block valves. The study found one underground leak accounting for 83% (4.0 kg CH4/hr of total measured emissions. Methane emissions for the 4684 km of gathering pipeline in the study area were estimated at 402 kg CH4/hr [95 to 1065 kg CH4/hr, 95% CI], or 1% [0.2% to 2.6%] of all methane emissions measured during a prior aircraft study of the same area. Emissions estimated by this study fall within the uncertainty range of emissions estimated using emission factors from EPA’s 2015 Greenhouse Inventory and study activity estimates. While EPA’s current inventory is based upon emission factors from distribution mains measured in the 1990s, this study indicates that using emission factors from more recent distribution studies could significantly underestimate emissions from gathering pipelines. To guide broader studies of pipeline emissions, we also estimate the fraction of the pipeline length within a basin that must be measured to constrain uncertainty of pipeline emissions estimates to within 1% of total basin emissions. The study provides both substantial insight into the mix of emission sources and guidance for future gathering pipeline studies, but since measurements were made in a single basin, the results are not sufficiently representative to provide methane emission factors at the regional or national level.

Emission of Methane From Enteric Fermentation: National Contribution and Factors Affecting it in Livestock

Directory of Open Access Journals (Sweden)

Budi Haryanto

2009-12-01

Full Text Available Changing in atmosphere condition is affected by the quantity of gases produced from all activities on the earth. Gases that have effects on global warming are CO2, N2O, H2O, and CH4 (methane. Among other sources of methane are enteric fermentation of organic material from ruminants and feces decomposition. Methane production from ruminants is affected by several factors such as breed/type of animal, feed quality, environmental temperature and physiological status of the animal. Energy as methane in ruminants may reach 2 to 15% of the total energy consumption. To reduce the emission of methane from ruminants, it is necessary to apply a strategic feeding system for more efficient utilization of feed.

Anaerobic digestion of sewage sludge: French inventory and state of the art

International Nuclear Information System (INIS)

Reverdy, A.L.; Dieude-Fauvel, E.; Baudez, J.C.; Ferstler, V.

2012-01-01

Following the Kyoto Protocol and the 'Grenelle de l'environnement', France committed itself to develop renewable energies. Methanization is a process which falls within this objective. Anaerobic digestion of organic material generates biogas made of methane (CH 4 ), carbon dioxide (CO 2 ) and water (H 2 O). In 2009, electricity generation from biogas represented only 0, 93% of the renewable electricity production in France. An inventory of facilities and a state of the art of the methanization of sewage sludge on wastewater treatment plants with the inhabitant equivalent of more than 30.000 were realized. They were done with bibliography and surveys. In France, 68 installations of sewage sludge methanization were counted. The primary technology used is a mix reactor in which sewage sludge, heated at deg. C 37, are introduced. Biogas is mainly valued to warm those sludges. Electrical valorization is poor, especially on old installations. Anaerobic digestion of sewage sludge is generally accepted by managers, mainly because of its capacity to reduce sewage sludge quantity and odors. Methanization as listed in France is quite basic. It is performed with digestion series modification, with pretreatments or with co-digestion. Given the quantity of sewage sludge which could be digested, France could increase renewable energies via biogas. However this technology is perfectible in many units because biogas is burned in flares. (authors)

Methane Recycling During Burial of Methane Hydrate-Bearing Sediments

Science.gov (United States)

You, K.; Flemings, P. B.

2017-12-01

We quantitatively investigate the integral processes of methane hydrate formation from local microbial methane generation, burial of methane hydrate with sedimentation, and methane recycling at the base of the hydrate stability zone (BHSZ) with a multiphase multicomponent numerical model. Methane recycling happens in cycles, and there is not a steady state. Each cycle starts with free gas accumulation from hydrate dissociation below the BHSZ. This free gas flows upward under buoyancy, elevates the hydrate saturation and capillary entry pressure at the BHSZ, and this prevents more free gas flowing in. Later as this layer with elevated hydrate saturation is buried and dissociated, the large amount of free gas newly released and accumulated below rapidly intrudes into the hydrate stability zone, drives rapid hydrate formation and creates three-phase (gas, liquid and hydrate) equilibrium above the BHSZ. The gas front retreats to below the BHSZ until all the free gas is depleted. The shallowest depth that the free gas reaches in one cycle moves toward seafloor as more and more methane is accumulated to the BHSZ with time. More methane is stored above the BHSZ in the form of concentrated hydrate in sediments with relatively uniform pore throat, and/or with greater compressibility. It is more difficult to initiate methane recycling in passive continental margins where the sedimentation rate is low, and in sediments with low organic matter content and/or methanogenesis reaction rate. The presence of a permeable layer can store methane for significant periods of time without recycling. In a 2D system where the seafloor dips rapidly, the updip gas flow along the BHSZ transports more methane toward topographic highs where methane gas and elevated hydrate saturation intrude deeper into the hydrate stability zone within one cycle. This could lead to intermittent gas venting at seafloor at the topographic highs. This study provides insights on many phenomenon associated with

Methane emissions from global wetlands: An assessment of the uncertainty associated with various wetland extent data sets

Science.gov (United States)

Zhang, Bowen; Tian, Hanqin; Lu, Chaoqun; Chen, Guangsheng; Pan, Shufen; Anderson, Christopher; Poulter, Benjamin

2017-09-01

A wide range of estimates on global wetland methane (CH4) fluxes has been reported during the recent two decades. This gives rise to urgent needs to clarify and identify the uncertainty sources, and conclude a reconciled estimate for global CH4 fluxes from wetlands. Most estimates by using bottom-up approach rely on wetland data sets, but these data sets show largely inconsistent in terms of both wetland extent and spatiotemporal distribution. A quantitative assessment of uncertainties associated with these discrepancies among wetland data sets has not been well investigated yet. By comparing the five widely used global wetland data sets (GISS, GLWD, Kaplan, GIEMS and SWAMPS-GLWD), it this study, we found large differences in the wetland extent, ranging from 5.3 to 10.2 million km2, as well as their spatial and temporal distributions among the five data sets. These discrepancies in wetland data sets resulted in large bias in model-estimated global wetland CH4 emissions as simulated by using the Dynamic Land Ecosystem Model (DLEM). The model simulations indicated that the mean global wetland CH4 emissions during 2000-2007 were 177.2 ± 49.7 Tg CH4 yr-1, based on the five different data sets. The tropical regions contributed the largest portion of estimated CH4 emissions from global wetlands, but also had the largest discrepancy. Among six continents, the largest uncertainty was found in South America. Thus, the improved estimates of wetland extent and CH4 emissions in the tropical regions and South America would be a critical step toward an accurate estimate of global CH4 emissions. This uncertainty analysis also reveals an important need for our scientific community to generate a global scale wetland data set with higher spatial resolution and shorter time interval, by integrating multiple sources of field and satellite data with modeling approaches, for cross-scale extrapolation.

Methane cycling in peat bogs: Environmental relevance of methano-Trophs revealed by microbial lipid chemistry

NARCIS (Netherlands)

van Winden, J.F.

2011-01-01

Global warming is continuing without delay and this is caused by the accumulation of greenhouse gases in the atmosphere. Methane is a strong greenhouse gas, 25 times stronger compared to CO2. The increase in methane concentrations in the atmosphere is largely the result of human influences, but

Shallow Gas Migration along Hydrocarbon Wells-An Unconsidered, Anthropogenic Source of Biogenic Methane in the North Sea.

Science.gov (United States)

Vielstädte, Lisa; Haeckel, Matthias; Karstens, Jens; Linke, Peter; Schmidt, Mark; Steinle, Lea; Wallmann, Klaus

2017-09-05

Shallow gas migration along hydrocarbon wells constitutes a potential methane emission pathway that currently is not recognized in any regulatory framework or greenhouse gas inventory. Recently, the first methane emission measurements at three abandoned offshore wells in the Central North Sea (CNS) were conducted showing that considerable amounts of biogenic methane originating from shallow gas accumulations in the overburden of deep reservoirs were released by the boreholes. Here, we identify numerous wells poking through shallow gas pockets in 3-D seismic data of the CNS indicating that about one-third of the wells may leak, potentially releasing a total of 3-17 kt of methane per year into the North Sea. This poses a significant contribution to the North Sea methane budget. A large fraction of this gas (∼42%) may reach the atmosphere via direct bubble transport (0-2 kt yr -1 ) and via diffusive exchange of methane dissolving in the surface mixed layer (1-5 kt yr -1 ), as indicated by numerical modeling. In the North Sea and in other hydrocarbon-prolific provinces of the world shallow gas pockets are frequently observed in the sedimentary overburden and aggregate leakages along the numerous wells drilled in those areas may be significant.

Need for a marginal methodology in assessing natural gas system methane emissions in response to incremental consumption.

Science.gov (United States)

Mac Kinnon, Michael; Heydarzadeh, Zahra; Doan, Quy; Ngo, Cuong; Reed, Jeff; Brouwer, Jacob

2018-05-17

Accurate quantification of methane emissions from the natural gas system is important for establishing greenhouse gas inventories and understanding cause and effect for reducing emissions. Current carbon intensity methods generally assume methane emissions are proportional to gas throughput so that increases in gas consumption yield linear increases in emitted methane. However, emissions sources are diverse and many are not proportional to throughput. Insights into the causal drivers of system methane emissions, and how system-wide changes affect such drivers are required. The development of a novel cause-based methodology to assess marginal methane emissions per unit of fuel consumed is introduced. The carbon intensities of technologies consuming natural gas are critical metrics currently used in policy decisions for reaching environmental goals. For example, the low-carbon fuel standard in California uses carbon intensity to determine incentives provided. Current methods generally assume methane emissions from the natural gas system are completely proportional to throughput. The proposed cause-based marginal emissions method will provide a better understanding of the actual drivers of emissions to support development of more effective mitigation measures. Additionally, increasing the accuracy of carbon intensity calculations supports the development of policies that can maximize the environmental benefits of alternative fuels, including reducing greenhouse gas emissions.

Assessing the Gap Between Top-down and Bottom-up Measured Methane Emissions in Indianapolis, IN.

Science.gov (United States)

Prasad, K.; Lamb, B. K.; Cambaliza, M. O. L.; Shepson, P. B.; Stirm, B. H.; Salmon, O. E.; Lavoie, T. N.; Lauvaux, T.; Ferrara, T.; Howard, T.; Edburg, S. L.; Whetstone, J. R.

2014-12-01

Releases of methane (CH4) from the natural gas supply chain in the United States account for approximately 30% of the total US CH4 emissions. However, there continues to be large questions regarding the accuracy of current emission inventories for methane emissions from natural gas usage. In this paper, we describe results from top-down and bottom-up measurements of methane emissions from the large isolated city of Indianapolis. The top-down results are based on aircraft mass balance and tower based inverse modeling methods, while the bottom-up results are based on direct component sampling at metering and regulating stations, surface enclosure measurements of surveyed pipeline leaks, and tracer/modeling methods for other urban sources. Mobile mapping of methane urban concentrations was also used to identify significant sources and to show an urban-wide low level enhancement of methane levels. The residual difference between top-down and bottom-up measured emissions is large and cannot be fully explained in terms of the uncertainties in top-down and bottom-up emission measurements and estimates. Thus, the residual appears to be, at least partly, attributed to a significant wide-spread diffusive source. Analyses are included to estimate the size and nature of this diffusive source.

Controls on tree species stem transport and emission of methane from tropical peatlands

Science.gov (United States)

Van Haren, J. L. M.; Cadillo-Quiroz, H.

2016-12-01

Methane emissions from wetlands dominate the global budget and are most likely responsible for the annual variability in emissions. Methane is produced and consumed by microbial activity and then transported to the atmosphere. Plants have been shown to facilitate the transport of methane to significant amounts, but broad surveys across multiple sites have been lacking. We present data collected from multiple peatland and wetland sites south of Iquitos Peru and varzea sites from Santarem Brazil and compare our results to the limited literature of tree stem fluxes. The survey suggests that methane stem emissions might be conserved at the genera level, but not the family level. Large emitters exist in the Aracaceae, Euphorbiaceae, and Sapotaceae, however, other genera within the same families do not emit any methane. Certain genera are consistent pan-tropical methane emitters. The methane emission from the stems decreases generally with height, suggesting a diffusion constrained stem flux. Further constraints on the methane emissions from tree stems involve soil methane concentration and wood density, which is likely an indicator for stem conductivity. Diurnal cycles, flooding level and tree leaves appear to have less of an influence on the tree methane emissions though flooding can lead to a translocation of emissions up the stem to above the flooding level. Methane emissions and the plant transport pathways appear to be constrained at the genera level within wetlands.

Are termite mounds biofilters for methane? - Challenges and new approaches to quantify methane oxidation in termite mounds

Science.gov (United States)

Nauer, Philipp A.; Hutley, Lindsay B.; Bristow, Mila; Arndt, Stefan K.

2015-04-01

Methane emissions from termites contribute around 3% to global methane in the atmosphere, although the total source estimate for termites is the most uncertain among all sources. In tropical regions, the relative source contribution of termites can be far higher due to the high biomass and relative importance of termites in plant decomposition. Past research focused on net emission measurements and their variability, but little is known about underlying processes governing these emissions. In particular, microbial oxidation of methane (MOX) within termite mounds has rarely been investigated. In well-studied ecosystems featuring an oxic matrix above an anoxic methane-producing habitat (e.g. landfills or sediments), the fraction of oxidized methane (fox) can reach up to 90% of gross production. However, conventional mass-balance approaches to apportion production and consumption processes can be challenging to apply in the complex-structured and almost inaccessible environment of a termite mound. In effect, all field-based data on termite-mound MOX is based on one study that measured isotopic shifts in produced and emitted methane. In this study a closed-system isotope fractionation model was applied and estimated fox ranged from 10% to almost 100%. However, it is shown here that by applying an open-system isotope-pool model, the measured isotopic shifts can also be explained by physical transport of methane alone. Different field-based methods to quantify MOX in termite mounds are proposed which do not rely on assumptions of physical gas transport. A simple approach is the use of specific inhibitors for MOX, e.g. difluoromethane (CH2F2), combined with chamber-based flux measurements before and after their application. Data is presented on the suitability of different inhibitors and first results of their application in the field. Alternatively, gas-tracer methods allow the quantification of methane oxidation and reaction kinetics without knowledge of physical gas

Permafrost degradation and methane: low risk of biogeochemical climate-warming feedback

International Nuclear Information System (INIS)

Gao Xiang; Adam Schlosser, C; Sokolov, Andrei; Anthony, Katey Walter; Zhuang Qianlai; Kicklighter, David

2013-01-01

Climate change and permafrost thaw have been suggested to increase high latitude methane emissions that could potentially represent a strong feedback to the climate system. Using an integrated earth-system model framework, we examine the degradation of near-surface permafrost, temporal dynamics of inundation (lakes and wetlands) induced by hydro-climatic change, subsequent methane emission, and potential climate feedback. We find that increases in atmospheric CH 4 and its radiative forcing, which result from the thawed, inundated emission sources, are small, particularly when weighed against human emissions. The additional warming, across the range of climate policy and uncertainties in the climate-system response, would be no greater than 0.1 ° C by 2100. Further, for this temperature feedback to be doubled (to approximately 0.2 ° C) by 2100, at least a 25-fold increase in the methane emission that results from the estimated permafrost degradation would be required. Overall, this biogeochemical global climate-warming feedback is relatively small whether or not humans choose to constrain global emissions. (letter)

Thermochemical performance analysis of solar driven CO_2 methane reforming

International Nuclear Information System (INIS)

Fuqiang, Wang; Jianyu, Tan; Huijian, Jin; Yu, Leng

2015-01-01

Increasing CO_2 emission problems create urgent challenges for alleviating global warming, and the capture of CO_2 has become an essential field of scientific research. In this study, a finite volume method (FVM) coupled with thermochemical kinetics was developed to analyze the solar driven CO_2 methane reforming process in a metallic foam reactor. The local thermal non-equilibrium (LTNE) model coupled with radiative heat transfer was developed to provide more temperature information. A joint inversion method based on chemical process software and the FVM coupled with thermochemical kinetics was developed to obtain the thermochemical reaction parameters and guarantee the calculation accuracy. The detailed thermal and thermochemical performance in the metal foam reactor was analyzed. In addition, the effects of heat flux distribution and porosity on the solar driven CO_2 methane reforming process were analyzed. The numerical results can serve as theoretical guidance for the solar driven CO_2 methane reforming application. - Highlights: • Solar driven CO_2 methane reforming process in metal foam reactor is analyzed. • FVM with chemical reactions was developed to analyze solar CO_2 methane reforming. • A joint inversion method was developed to obtain thermochemical reaction parameters. • Results can be a guidance for the solar driven CO_2 methane reforming application.

Methane dynamics in Northern Wetlands: Significance of vascular plants

Energy Technology Data Exchange (ETDEWEB)

Joabsson, Anna

2001-09-01

The studies presented illustrate several different aspects of the impact of vascular plants on methane emissions from northern natural wetlands. The subject has been approached on different scales, ranging from the study of microbial substrates in the vicinity of a single plant root, to an attempt to extrapolate some of the results to the entire northern hemisphere north of 50 meridian. The main overall conclusions from the papers are that vascular plants affect net methane emissions 1) by offering an efficient route of transport to the atmosphere so that methane oxidation in oxic surface soils is avoided, and 2) by being sources of methanogenic substrate. The degree to which vascular wetland plants affect methane emissions seems to be dependent on species-specific differences in both the capacity to act as gas conduits and the exudation of labile carbon compounds to the soil. An intimate coupling between vascular plant production and methane emission was found in an Arctic tundra wetland, although other environmental variables (water table, temperature) also contributed significantly to the explained variation in methane exchange. Studies of vascular plant extidation of organic acids suggest that the available pool of methanogenic substrates is both qualitatively and quantitatively correlated to vascular plant production (photosynthetic rate). On global scales, vascular plant production as a single factor does not seem to be sufficient to explain the majority of variation in methane flux patterns. Based on comparable experiments at five different sites in the northwestern Eurasian and Greenlandic North, we suggest that mean seasonal soil temperature is the best predictor of methane exchange on broad spatial and temporal scales.

Quantifying, Assessing, and Mitigating Methane Emissions from Super-emitters in the Oil and Gas Supply Chain

Science.gov (United States)

Lyon, David Richard

Methane emissions from the oil and gas (O&G) supply chain reduce potential climate benefits of natural gas as a replacement for other fossil fuels that emit more carbon dioxide per energy produced. O&G facilities have skewed emission rate distributions with a small fraction of sites contributing the majority of emissions. Knowledge of the identity and cause of these high emission facilities, referred to as super-emitters or fat-tail sources, is critical for reducing supply chain emissions. This dissertation addresses the quantification of super-emitter emissions, assessment of their prevalence and relationship to site characteristics, and mitigation with continuous leak detection systems. Chapter 1 summarizes the state of the knowledge of O&G methane emissions. Chapter 2 constructs a spatially-resolved emission inventory to estimate total and O&G methane emissions in the Barnett Shale as part of a coordinated research campaign using multiple top-down and bottom-up methods to quantify emissions. The emission inventory accounts for super-emitters with two-phase Monte Carlo simulations that combine site measurements collected with two approaches: unbiased sampling and targeted sampling of super-emitters. More comprehensive activity data and the inclusion of super-emitters, which account for 19% of O&G emissions, produces a emission inventory that is not statistically different than top-down regional emission estimates. Chapter 3 describes a helicopter-based survey of over 8,000 well pads in seven basins with infrared optical gas imaging to assess high emission sources. Four percent of sites are observed to have high emissions with over 90% of observed sources from tanks. The occurrence of high emissions is weakly correlated to site parameters and the best statistical model explains only 14% of variance, which demonstrates that the occurrence of super-emitters is primarily stochastic. Chapter 4 presents a Gaussian dispersion model for optimizing the placement of

Estimating U.S. Methane Emissions from the Natural Gas Supply Chain. Approaches, Uncertainties, Current Estimates, and Future Studies

Energy Technology Data Exchange (ETDEWEB)

Heath, Garvin [Joint Inst. for Strategic Energy Analysis, Golden, CO (United States); Warner, Ethan [Joint Inst. for Strategic Energy Analysis, Golden, CO (United States); Steinberg, Daniel [Joint Inst. for Strategic Energy Analysis, Golden, CO (United States); Brandt, Adam [Stanford Univ., CA (United States)

2015-08-01

A growing number of studies have raised questions regarding uncertainties in our understanding of methane (CH₄) emissions from fugitives and venting along the natural gas (NG) supply chain. In particular, a number of measurement studies have suggested that actual levels of CH₄ emissions may be higher than estimated by EPA" tm s U.S. GHG Emission Inventory. We reviewed the literature to identify the growing number of studies that have raised questions regarding uncertainties in our understanding of methane (CH₄) emissions from fugitives and venting along the natural gas (NG) supply chain.

Further evaluation of wetland emission estimates from the JULES land surface model using SCIAMACHY and GOSAT atmospheric column methane measurements

Science.gov (United States)

Hayman, Garry; Comyn-Platt, Edward; McNorton, Joey; Chipperfield, Martyn; Gedney, Nicola

2016-04-01

The atmospheric concentration of methane began rising again in 2007 after a period of near-zero growth [1,2], with the largest increases observed over polar northern latitudes and the Southern Hemisphere in 2007 and in the tropics since then. The observed inter-annual variability in atmospheric methane concentrations and the associated changes in growth rates have variously been attributed to changes in different methane sources and sinks [2,3]. Wetlands are generally accepted as being the largest, but least well quantified, single natural source of CH4, with global emission estimates ranging from 142-284 Tg yr-1 [3]. The modelling of wetlands and their associated emissions of CH4 has become the subject of much current interest [4]. We have previously used the HadGEM2 chemistry-climate model to evaluate the wetland emission estimates derived using the UK community land surface model (JULES, the Joint UK Land Earth Simulator) against atmospheric observations of methane, including SCIAMACHY total methane columns [5] up to 2007. We have undertaken a series of new HadGEM2 runs using new JULES emission estimates extended in time to the end of 2012, thereby allowing comparison with both SCIAMACHY and GOSAT atmospheric column methane measurements. We will describe the results of these runs and the implications for methane wetland emissions. References [1] Rigby, M., et al.: Renewed growth of atmospheric methane. Geophys. Res. Lett., 35, L22805, 2008; [2] Nisbet, E.G., et al.: Methane on the Rise-Again, Science 343, 493, 2014; [3] Kirschke, S., et al.,: Three decades of global methane sources and sinks, Nature Geosciences, 6, 813-823, 2013; [4] Melton, J. R., et al.: Present state of global wetland extent and wetland methane modelling: conclusions from a model inter-comparison project (WETCHIMP), Biogeosciences, 10, 753-788, 2013; [5] Hayman, G.D., et al.: Comparison of the HadGEM2 climate-chemistry model against in situ and SCIAMACHY atmospheric methane data, Atmos. Chem

Emission inventory: An urban public policy instrument and benchmark

International Nuclear Information System (INIS)

D'Avignon, Alexander; Azevedo Carloni, Flavia; Lebre La Rovere, Emilio; Burle Schmidt Dubeux, Carolina

2010-01-01

Global concern with climate change has led to the development of a variety of solutions to monitor and reduce emissions on both local and global scales. Under the United Nations Framework Convention on Climate Change (UNFCCC), both developed and emerging countries have assumed responsibility for developing and updating national inventories of greenhouse gas emissions from anthropic sources. This creates opportunities and incentives for cities to carry out their own local inventories and, thereby, develop air quality management plans including both essential key players and stakeholders at the local level. The aim of this paper is to discuss the role of local inventories as an urban public policy instrument and how this type of local instrument may bring advantages countrywide in enhancing the global position of a country. Local inventories have been carried out in many cities of the world and the main advantage of this is that it allows an overview of emissions produced by different municipal activities, thereby, helps decision makers in the elaboration of efficient air quality management plans. In that way, measures aimed at the reduction of fossil fuel consumption to lower local atmospheric pollution levels can also, in some ways, reduce GHG emissions.

Methane penetration in DIII-D ELMing H-mode plasmas

International Nuclear Information System (INIS)

West, W.P.; Lasnier, C.J.; Whyte, D.G.; Isler, R.C.; Evans, T.E.; Jackson, G.L.; Rudakov, D.; Wade, M.R.; Strachan, J.

2003-01-01

Carbon penetration into the core plasma during midplane and divertor methane puffing has been measured for DIII-D ELMing H-mode plasmas. The methane puffs are adjusted to a measurable signal, but global plasma parameters are only weakly affected (line average density, e > increases by E , drops by 6+ density profiles in the core measured as a function of time using charge exchange recombination spectroscopy. The methane penetration factor is defined as the difference in the core content with the puff on and puff off, divided by the carbon confinement time and the methane puffing rate. In ELMing H-mode discharges with ion ∇B drift direction into the X-point, increasing the line averaged density from 5 to 8x10 19 m -3 dropped the penetration factor from 6.6% to 4.6% for main chamber puffing. The penetration factor for divertor puffing was below the detection limit (<1%). Changing the ion ∇B drift to away from the X-point decreased the penetration factor by more than a factor of five for main chamber puffing

A new approach to estimate fugitive methane emissions from coal mining in China

Energy Technology Data Exchange (ETDEWEB)

Ju, Yiwen, E-mail: juyw03@163.com [Key Laboratory of Computational Geodynamics of Chinese Academy Sciences, Beijing 100049 (China); College of Earth Science, University of Chinese Academy Sciences, Beijing 100049 (China); Sun, Yue [Key Laboratory of Computational Geodynamics of Chinese Academy Sciences, Beijing 100049 (China); College of Earth Science, University of Chinese Academy Sciences, Beijing 100049 (China); Sa, Zhanyou [Department of Safety Engineering, Qingdao Technological University, Qingdao 266520 (China); Pan, Jienan [School of Resources and Environment, Henan Polytechnic University, Jiaozuo 454000 (China); Wang, Jilin [School of Resources and Geosciences, China University of Mining and Technology, Xuzhou 221116 (China); Hou, Quanlin; Li, Qingguang; Yan, Zhifeng [Key Laboratory of Computational Geodynamics of Chinese Academy Sciences, Beijing 100049 (China); College of Earth Science, University of Chinese Academy Sciences, Beijing 100049 (China); Liu, Jie [Department of Safety Engineering, Qingdao Technological University, Qingdao 266520 (China)

2016-02-01

Developing a more accurate greenhouse gas (GHG) emissions inventory draws too much attention. Because of its resource endowment and technical status, China has made coal-related GHG emissions a big part of its inventory. Lacking a stoichiometric carbon conversion coefficient and influenced by geological conditions and mining technologies, previous efforts to estimate fugitive methane emissions from coal mining in China has led to disagreeing results. This paper proposes a new calculation methodology to determine fugitive methane emissions from coal mining based on the domestic analysis of gas geology, gas emission features, and the merits and demerits of existing estimation methods. This new approach involves four main parameters: in-situ original gas content, gas remaining post-desorption, raw coal production, and mining influence coefficient. The case studies in Huaibei–Huainan Coalfield and Jincheng Coalfield show that the new method obtains the smallest error, + 9.59% and 7.01% respectively compared with other methods, Tier 1 and Tier 2 (with two samples) in this study, which resulted in + 140.34%, + 138.90%, and − 18.67%, in Huaibei–Huainan Coalfield, while + 64.36%, + 47.07%, and − 14.91% in Jincheng Coalfield. Compared with the predominantly used methods, this new one possesses the characteristics of not only being a comparably more simple process and lower uncertainty than the “emission factor method” (IPCC recommended Tier 1 and Tier 2), but also having easier data accessibility, similar uncertainty, and additional post-mining emissions compared to the “absolute gas emission method” (IPCC recommended Tier 3). Therefore, methane emissions dissipated from most of the producing coal mines worldwide could be more accurately and more easily estimated. - Highlights: • Propose a new method to estimate fugitive methane emissions from coal mining. • New method has accurate prediction for CMM emissions without activity data updating. • Mining

Methane feedbacks to the global climate system in a warmer world

NARCIS (Netherlands)

Dean, Joshua F.; Middelburg, Jack J.; Röckmann, Thomas; Aerts, Rien; Blauw, Luke G.; Egger, Matthias; Jetten, Mike S.M.; de Jong, Anniek E.E.; Meisel, Ove H.; Rasigraf, Olivia; Slomp, Caroline P.; in't Zandt, Michiel H.; Dolman, A. J.

Methane (CH4) is produced in many natural systems that are vulnerable to change under a warming climate, yet current CH4 budgets, as well as future shifts in CH4 emissions, have high uncertainties. Climate change has the potential to increase CH4 emissions from critical systems such as wetlands,

Landslide risk reduction strategies: an inventory for the Global South

Science.gov (United States)

Maes, Jan; Kervyn, Matthieu; Vranken, Liesbet; Dewitte, Olivier; Vanmaercke, Matthias; Mertens, Kewan; Jacobs, Liesbet; Poesen, Jean

2015-04-01

Landslides constitute a serious problem globally. Moreover, landslide impact remains underestimated especially in the Global South. It is precisely there where the largest impact is experienced. An overview of measures taken to reduce risk of landslides in the Global South is however still lacking. Because in many countries of the Global South disaster risk reduction (DRR) is at an emerging stage, it is crucial to monitor the ongoing efforts (e.g. discussions on the Post-2015 Framework for DRR). The first objective of this study is to make an inventory of techniques and strategies that are applied to reduce risk from landslides in tropical countries. The second objective is to investigate what are the main bottlenecks for implementation of DRR strategies. In order to achieve these objectives, a review of both scientific and grey literature was conducted, supplemented with expert knowledge. The compilation of recommended and implemented DRR measures from landslide-prone tropical countries is based on an adapted classification proposed by the SafeLand project. According to Vaciago (2013), landslide risk can be reduced by either reducing the hazard, the vulnerability, the number or value of elements at risk or by sharing the residual risk. In addition, these measures can be combined with education and/or awareness raising and are influenced by governance structures and cultural beliefs. Global landslide datasets have been used to identify landslide-prone countries, augmented with region-specific datasets. Countries located in the tropics were selected in order to include landslide-prone countries with a different Human Development Index (HDI) but with a similar climate. Preliminary results support the statement made by Anderson (2013) that although the importance of shifting from post-disaster emergency actions to pre-disaster mitigation is acknowledged, in practice this paradigm shift seems rather limited. It is expected that this is especially the case in countries

Forests and methane - at the intersection of science and politics, experimentation and extrapolation, objectivity and subjectivity

International Nuclear Information System (INIS)

Peyron, Jean-Luc

2005-01-01

According to recent information, vegetation is thought to be a major source of methane. This phenomenon had not been contemplated until now and still remains to be explained. According to the authors and on the basis of rough extrapolations, it may cast light on some missing pieces in the global methane balance. The initial reaction by commentators following this discovery was to discuss its consequences on the strategy to fight the greenhouse effect considering methane's considerable impact on global warming. However, a preliminary analysis based on opinions from a range of experts underscores three aspects - the experimental discovery needs to be confirmed and explained before drawing any hasty conclusions; extrapolations performed so far on a global scale are highly inadequate and probably overestimated; implications for fighting the greenhouse effect are limited because the phenomenon in question is a natural one and not extensive enough to offset the benefits of forests as a sink for carbon dioxide. (authors)

Modeling methane emissions by cattle production systems in Mexico

Science.gov (United States)

Castelan-Ortega, O. A.; Ku Vera, J.; Molina, L. T.

2013-12-01

Methane emissions from livestock is one of the largest sources of methane in Mexico. The purpose of the present paper is to provide a realistic estimate of the national inventory of methane produced by the enteric fermentation of cattle, based on an integrated simulation model, and to provide estimates of CH4 produced by cattle fed typical diets from the tropical and temperate climates of Mexico. The Mexican cattle population of 23.3 million heads was divided in two groups. The first group (7.8 million heads), represents cattle of the tropical climate regions. The second group (15.5 million heads), are the cattle in the temperate climate regions. This approach allows incorporating the effect of diet on CH4 production into the analysis because the quality of forages is lower in the tropics than in temperate regions. Cattle population in every group was subdivided into two categories: cows (COW) and other type of cattle (OTHE), which included calves, heifers, steers and bulls. The daily CH4 production by each category of animal along an average production cycle of 365 days was simulated, instead of using a default emission factor as in Tier 1 approach. Daily milk yield, live weight changes associated with the lactation, and dry matter intake, were simulated for the entire production cycle. The Moe and Tyrrell (1979) model was used to simulate CH4 production for the COW category, the linear model of Mills et al. (2003) for the OTHE category in temperate regions and the Kurihara et al. (1999) model for the OTHE category in the tropical regions as it has been developed for cattle fed tropical diets. All models were integrated with a cow submodel to form an Integrated Simulation Model (ISM). The AFRC (1993) equations and the lactation curve model of Morant and Gnanasakthy (1989) were used to construct the cow submodel. The ISM simulates on a daily basis the CH4 production, milk yield, live weight changes associated with lactation and dry matter intake. The total daily CH

Methane emissions from natural gas infrastructure and use in the urban region of Boston, Massachusetts.

Science.gov (United States)

McKain, Kathryn; Down, Adrian; Raciti, Steve M; Budney, John; Hutyra, Lucy R; Floerchinger, Cody; Herndon, Scott C; Nehrkorn, Thomas; Zahniser, Mark S; Jackson, Robert B; Phillips, Nathan; Wofsy, Steven C

2015-02-17

Methane emissions from natural gas delivery and end use must be quantified to evaluate the environmental impacts of natural gas and to develop and assess the efficacy of emission reduction strategies. We report natural gas emission rates for 1 y in the urban region of Boston, using a comprehensive atmospheric measurement and modeling framework. Continuous methane observations from four stations are combined with a high-resolution transport model to quantify the regional average emission flux, 18.5 ± 3.7 (95% confidence interval) g CH4 ⋅ m(-2) ⋅ y(-1). Simultaneous observations of atmospheric ethane, compared with the ethane-to-methane ratio in the pipeline gas delivered to the region, demonstrate that natural gas accounted for ∼ 60-100% of methane emissions, depending on season. Using government statistics and geospatial data on natural gas use, we find the average fractional loss rate to the atmosphere from all downstream components of the natural gas system, including transmission, distribution, and end use, was 2.7 ± 0.6% in the Boston urban region, with little seasonal variability. This fraction is notably higher than the 1.1% implied by the most closely comparable emission inventory.

Inventory of volatile organic compound emissions in Finland, 1985

International Nuclear Information System (INIS)

Mroueh, U.M.

1988-01-01

The aim of the study was to compile an inventory of the emissions of volatile organic compounds in Finland for the year 1985. The report was prepared for the ECE Task Force on Emissions of Volatile Organic Compounds from Stationary Sources according to the classification given by the Task Force. It considers anthropogenic as well as natural sources. Mobile sources are excluded. The quantities as well as the main components are listed, as far as possible. The values given exclude methane which according to the present understanding is regarded as unreactive

A tiered observational system for anthropogenic methane emissions

Science.gov (United States)

Duren, R. M.; Miller, C. E.; Hulley, G. C.; Hook, S. J.; Sander, S. P.

2014-12-01

Improved understanding of anthropogenic methane emissions is required for closing the global carbon budget and addressing priority challenges in climate policy. Several decades of top-down and bottom-up studies show that anthropogenic methane emissions are systematically underestimated in key regions and economic sectors. These uncertainties have been compounded by the dramatic rise of disruptive technologies (e.g., the transformation in the US energy system due to unconventional gas and oil production). Methane flux estimates derived from inverse analyses and aircraft-based mass balance approaches underscore the disagreement in nationally and regionally reported methane emissions as well as the possibility of a long-tail distribution in fugitive emissions spanning the US natural gas supply chain; i.e. a small number of super-emitters may be responsible for most of the observed anomalies. Other studies highlight the challenges of sectoral and spatial attribution of fugitive emissions - including the relative contributions of dairies vs oil and gas production or disentangling the contributions of natural gas transmission, distribution, and consumption or landfill emissions in complex urban environments. Limited observational data remains a foundational barrier to resolving these challenges. We present a tiered observing system strategy for persistent, high-frequency monitoring over large areas to provide remote detection, geolocation and quantification of significant anthropogenic methane emissions across cities, states, basins and continents. We describe how this would both improve confidence in methane emission estimates and expedite resolution of fugitive emissions and leaks. We summarize recent prototype field campaigns that employ multiple vantage points and measurement techniques (including NASA's CARVE and HyTES aircraft and PanFTS instrument on Mt Wilson). We share preliminary results of this tiered observational approach including examples of individual

Methane emissions from paddy cultivation and livestock farming in Sarawak, Malaysia

Directory of Open Access Journals (Sweden)

Peng E.K.

2017-01-01

Full Text Available In this study, implementation of Tier 1 methodology of 2006 IPCC (Intergovernmental Panel on Climate Change Guidelines in paddy cultivation and livestock farming has been applied to estimate methane emissions in Sarawak, Malaysia within the years from 1998 to 2009. Methane emission inventory has been developed in this study, based on volume 4, 2006 IPCC Guidelines. Based on cultivation area and livestock population data as input to Tier 1 methodology, variations in paddy cultivation area and amount of livestock has been identified as the main contributor to emissions of methane. Methane emissions increased from 1.61 to 1.72 Gg CH4/year during 1998 to 1999. Based on results obtained, the outcomes show that there would be a significant drop of methane emission from buffalo and sheep. Although there are gain and loss in emissions from enteric fermentation, drastic reduction is observed from 0.65 Gg CH4/year in 1998 to 0.44 Gg CH4/year in 2009 as well as 0.05 Gg CH4/year to 0.02 Gg CH4/year for buffalo and sheep respectively. Simultaneously, methane emissions from manure management of buffalo has decreased from 0.024 Gg CH4/year in 1998 to 0.016 Gg CH4/year in 2009 while for sheep, its emission from manure management dropped from 0.002 Gg CH4/year in 1998 to 0.0007 Gg CH4/year in 2009. Overall emission from paddy cultivation can be considered in upward trend due to gain from 1998 at 1.61 Gg CH4/year to 1.67 Gg CH4/year in 2009. As an addition, significant rise in methane emission by 0.24 Gg CH4/year from 2000 to 2006 as well as 0.1 Gg CH4/year from 2007 to 2009 show momentum gaining in enteric fermentation of cattle. It also indicates future increment in methane emission from cattle which coherently affects the state’s emission level. As for emissions from manure management, emissions from cattle, goat and deer are gaining momentum in Sarawak.

Systematic arrangement of global environment measure technology. 3. Current status of methane generation and its effective utilization; Chikyu kankyo taisaku gijutsu no taikeiteki seiri. 2. Methane no hassei jokyo to sono yuko riyo no genjo

Energy Technology Data Exchange (ETDEWEB)

NONE

1997-03-01

The status of the methane generation due to landfill with waste has been analyzed to investigate the actual circumstances of effective utilization of methane in the world and its possibility. The artificial generation of methane is 375 Tg per year among the total methane generation in the world, 535 Tg per year. The methane generation from the landfill with waste is 40 Tg per year, which becomes a rather large contribution. The methane generation from the landfill with waste in Japan is estimated to be from 130 to 520 Gg per year, which is a rather low value as a share in the world. This is caused by the sub-aerobic property of landfill in Japan, and the methane generation can be suppressed. Accordingly, there are no systems using recovered methane as energy source in Japan. In the USA, profitability of energy recovery can be established in 600 to 700 landfills among about 6,000 landfills. The methane recovery is practically conducted at more than 120 landfills. The recovered methane is used as a power generation fuel. 45 refs., 43 figs., 27 tabs.

Biomass Assessment. Assessment of global biomass potentials and their links to food, water, biodiversity, energy demand and economy. Inventory and analysis of existing studies. Supporting document

International Nuclear Information System (INIS)

Dornburg, V.; Faaij, A.; Verweij, P.; Banse, M.; Van Diepen, K.; Van Keulen, H.; Langeveld, H.; Meeusen, M.; Van de Ven, G.; Wester, F.; Alkemade, R.; Ten Brink, B.; Van den Born, G.J.; Van Oorschot, M.; Ros, J.; Smout, F.; Van Vuuren, D.; Van den Wijngaart, R.; Aiking, H.; Londo, M.; Mozaffarian, H.; Smekens, K.; Lysen, E.

2008-01-01

This supporting document contains the result from the inventory phase of the biomass assessment of global biomass potentials and their links to food, water, biodiversity, energy demand and economy. This study provides a comprehensive assessment of global biomass potential estimates, focusing on the various factors affecting these potentials, such as food supplies, water use, biodiversity, energy demands and agro-economics

Methane fluxes from tropical coastal lagoons surrounded by mangroves, Yucatán, Mexico

Science.gov (United States)

Chuang, P.-C.; Young, M. B.; Dale, A. W.; Miller, L. G.; Herrera-Silveira, J. A.; Paytan, A.

2017-05-01

Methane concentrations in the water column and emissions to the atmosphere were determined for three tropical coastal lagoons surrounded by mangrove forests on the Yucatán Peninsula, Mexico. Surface water dissolved methane was sampled at different seasons over a period of 2 years in areas representing a wide range of salinities and anthropogenic impacts. The highest surface water methane concentrations (up to 8378 nM) were measured in a polluted canal associated with Terminos Lagoon. In Chelem Lagoon, methane concentrations were typically lower, except in the polluted harbor area (1796 nM). In the relatively pristine Celestún Lagoon, surface water methane concentrations ranged from 41 to 2551 nM. Methane concentrations were negatively correlated with salinity in Celestún, while in Chelem and Terminos high methane concentrations were associated with areas of known pollution inputs, irrespective of salinity. The diffusive methane flux from surface lagoon water to the atmosphere ranged from 0.0023 to 15 mmol CH4 m-2 d-1. Flux chamber measurements revealed that direct methane release as ebullition was up to 3 orders of magnitude greater than measured diffusive flux. Coastal mangrove lagoons may therefore be an important natural source of methane to the atmosphere despite their relatively high salinity. Pollution inputs are likely to substantially enhance this flux. Additional statistically rigorous data collected globally are needed to better consider methane fluxes from mangrove-surrounded coastal areas in response to sea level changes and anthropogenic pollution in order to refine projections of future atmospheric methane budgets.

Observed correlation between the depth to base and top of gas hydrate occurrence from review of global drilling data

Science.gov (United States)

Riedel, M.; Collett, T. S.

2017-07-01

A global inventory of data from gas hydrate drilling expeditions is used to develop relationships between the base of structure I gas hydrate stability, top of gas hydrate occurrence, sulfate-methane transition depth, pressure (water depth), and geothermal gradients. The motivation of this study is to provide first-order estimates of the top of gas hydrate occurrence and associated thickness of the gas hydrate occurrence zone for climate-change scenarios, global carbon budget analyses, or gas hydrate resource assessments. Results from publically available drilling campaigns (21 expeditions and 52 drill sites) off Cascadia, Blake Ridge, India, Korea, South China Sea, Japan, Chile, Peru, Costa Rica, Gulf of Mexico, and Borneo reveal a first-order linear relationship between the depth to the top and base of gas hydrate occurrence. The reason for these nearly linear relationships is believed to be the strong pressure and temperature dependence of methane solubility in the absence of large difference in thermal gradients between the various sites assessed. In addition, a statistically robust relationship was defined between the thickness of the gas hydrate occurrence zone and the base of gas hydrate stability (in meters below seafloor). The relationship developed is able to predict the depth of the top of gas hydrate occurrence zone using observed depths of the base of gas hydrate stability within less than 50 m at most locations examined in this study. No clear correlation of the depth to the top and base of gas hydrate occurrences with geothermal gradient and sulfate-methane transition depth was identified.

Light-Dependent Aerobic Methane Oxidation Reduces Methane Emissions from Seasonally Stratified Lakes

Science.gov (United States)

Oswald, Kirsten; Milucka, Jana; Brand, Andreas; Littmann, Sten; Wehrli, Bernhard; Kuypers, Marcel M. M.; Schubert, Carsten J.

2015-01-01

Lakes are a natural source of methane to the atmosphere and contribute significantly to total emissions compared to the oceans. Controls on methane emissions from lake surfaces, particularly biotic processes within anoxic hypolimnia, are only partially understood. Here we investigated biological methane oxidation in the water column of the seasonally stratified Lake Rotsee. A zone of methane oxidation extending from the oxic/anoxic interface into anoxic waters was identified by chemical profiling of oxygen, methane and δ13C of methane. Incubation experiments with 13C-methane yielded highest oxidation rates within the oxycline, and comparable rates were measured in anoxic waters. Despite predominantly anoxic conditions within the zone of methane oxidation, known groups of anaerobic methanotrophic archaea were conspicuously absent. Instead, aerobic gammaproteobacterial methanotrophs were identified as the active methane oxidizers. In addition, continuous oxidation and maximum rates always occurred under light conditions. These findings, along with the detection of chlorophyll a, suggest that aerobic methane oxidation is tightly coupled to light-dependent photosynthetic oxygen production both at the oxycline and in the anoxic bottom layer. It is likely that this interaction between oxygenic phototrophs and aerobic methanotrophs represents a widespread mechanism by which methane is oxidized in lake water, thus diminishing its release into the atmosphere. PMID:26193458

High Time Resolution Measurements of Methane Fluxes From Enteric Fermentation in Cattle Rumen

Science.gov (United States)

Floerchinger, C. R.; Herndon, S.; Fortner, E.; Roscioli, J. R.; Kolb, C. E.; Knighton, W. B.; Molina, L. T.; Zavala, M.; Castelán, O.; Ku Vera, J.; Castillo, E.

2013-12-01

Methane accounts for roughly 20% of the global radiative climate forcing in the last two and a half centuries. Methane emissions arise from a number of anthropogenic and biogenic sources. In some areas enteric fermentation in livestock produces over 90% of agricultural methane. In the spring of 2013, as a part of the Short Lived Climate Forcer-Mexico field campaign, the Aerodyne Mobile Laboratory in partnership with the Molina Center for the Environment studied methane production associated with enteric fermentation in the rumen of cattle. A variety of different breeds and stocks being raised in two agricultural and veterinary research facilities located in different areas of Mexico were examined. Methane fluxes were quantified using two methods: 1) an atmospherically stable gaseous tracer release was collocated with small herds in a pasture, allowing tracer ratio flux measurements; 2) respiratory CO2 was measured in tandem with methane in the breath of individual animals allowing methane production to be related to metabolism. The use of an extensive suite of very high time response instruments allows for differentiation of individual methane producing rumination events and respiratory CO2 from possible background interferences. The results of these studies will be presented and compared to data from traditional chamber experiments.

Mitigation of methane emission from an old unlined landfill in Klintholm, Denmark using a passive biocover system

DEFF Research Database (Denmark)

Scheutz, Charlotte; Pedersen, Rasmus Broen; Petersen, Per Haugsted

2014-01-01

Methane generated at landfills contributes to global warming and can be mitigated by biocover systems relying on microbial methane oxidation. As part of a closure plan for an old unlined landfill without any gas management measures, an innovative biocover system was established. The system was de...

Reducing Methane Emissions: The Other Climate Change Challenge

International Nuclear Information System (INIS)

Dessus, Benjamin; Laponche, Bernard

2008-08-01

, comparing the climate impact of a 30% reduction in global CH_4 emissions between 2010 and 2030 and of a 40% reduction in CO_2 emissions over the same period shows that the effectiveness of the CH_4 programme is 50% of that of the CO_2 programme in 2030, around 40% in 2050 and 20% in 2150. Contrary to widely accepted belief, the effect of rapidly implemented CH_4 emission reduction measures is highly significant in short- and medium-term climate strategies. The breakdown of global methane emissions by sector is as follows: agriculture (38%), energy systems (33%), household waste landfill sites and waste water treatment (23%), industry and forest fires (6%). The different possibilities for reducing these emissions are presented for each sector. It is thus estimated that the short-term reduction potential is around 30%. Interesting possibilities to go beyond this exist but they require more in-depth research and studies. Concrete CH_4 emission reduction programmes are presented: capturing methane from landfill sites in France and a comparison with certain CO_2 emission reduction programmes; a comparison of recent methane emission reduction policies of Germany and France; reducing methane emissions from the energy system in Tunisia and from household waste in Mexico; expected results of methane emission reductions by capturing firedamp in coal mines under China's Climate Plan by 2010. In the current context of fossil fuel prices, a significant proportion of the emission reduction potential can be cost-effectively harnessed simply by recovering the methane for energy production purposes. For the remaining potential, regulatory or fiscal incentives are required. Seeking to massively and rapidly decouple methane emissions from GDP growth should therefore provide a major opportunity for countries with emerging economies to put themselves on a path towards controlling increases in their greenhouse gas emissions in the medium term. This is particularly true since the corresponding

Effects of Inventory Bias on Landslide Susceptibility Calculations

Science.gov (United States)

Stanley, T. A.; Kirschbaum, D. B.

2017-01-01

Many landslide inventories are known to be biased, especially inventories for large regions such as Oregon's SLIDO or NASA's Global Landslide Catalog. These biases must affect the results of empirically derived susceptibility models to some degree. We evaluated the strength of the susceptibility model distortion from postulated biases by truncating an unbiased inventory. We generated a synthetic inventory from an existing landslide susceptibility map of Oregon, then removed landslides from this inventory to simulate the effects of reporting biases likely to affect inventories in this region, namely population and infrastructure effects. Logistic regression models were fitted to the modified inventories. Then the process of biasing a susceptibility model was repeated with SLIDO data. We evaluated each susceptibility model with qualitative and quantitative methods. Results suggest that the effects of landslide inventory bias on empirical models should not be ignored, even if those models are, in some cases, useful. We suggest fitting models in well-documented areas and extrapolating across the study region as a possible approach to modeling landslide susceptibility with heavily biased inventories.

Short communication: Genetic study of methane production predicted from milk fat composition in dairy cows.

Science.gov (United States)

van Engelen, S; Bovenhuis, H; Dijkstra, J; van Arendonk, J A M; Visker, M H P W

2015-11-01

Dairy cows produce enteric methane, a greenhouse gas with 25 times the global warming potential of CO2. Breeding could make a permanent, cumulative, and long-term contribution to methane reduction. Due to a lack of accurate, repeatable, individual methane measurements needed for breeding, indicators of methane production based on milk fatty acids have been proposed. The aim of the present study was to quantify the genetic variation for predicted methane yields. The milk fat composition of 1,905 first-lactation Dutch Holstein-Friesian cows was used to investigate 3 different predicted methane yields (g/kg of DMI): Methane1, Methane2, and Methane3. Methane1 was based on the milk fat proportions of C17:0anteiso, C18:1 rans-10+11, C18:1 cis-11, and C18:1 cis-13 (R(2)=0.73). Methane2 was based on C4:0, C18:0, C18:1 trans-10+11, and C18:1 cis-11 (R(2)=0.70). Methane3 was based on C4:0, C6:0, and C18:1 trans-10+11 (R(2)=0.63). Predicted methane yields were demonstrated to be heritable traits, with heritabilities between 0.12 and 0.44. Breeding can, thus, be used to decrease methane production predicted based on milk fatty acids. Copyright © 2015 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

Effect of improving Diet Quality by Feeding Supplements on Methane Emission in different Production Systems of Beef Cattle in Brazil

NARCIS (Netherlands)

Geraldo De Lima, J.; Bannink, A.; Pol - Van Dasselaar, Van Den A.; Barioni, L.G.; Menezes Santos, P.

2014-01-01

In Brazil, the national inventories on methane emission are carried out using the Tier 2 approach published by the Intergovernmental Panel on Climate Change (IPCC). Although, IPCC recommends the use of a more specific Tier 3 approach, this is hampered by a lack of consolidated data for development,

Alternatives for methane emission mitigation in livestock systems

OpenAIRE

Lascano,Carlos E.; Cárdenas,Edgar

2010-01-01

Human activities are contributing to Global Climate Change through the production of Green House Gases (GHG), which result in increased air, land and ocean temperatures and extreme changes in precipitation in regions of low and high rainfall. The most important GHG's are carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O). It is estimated that 18 % of the annual GHG emissions come from different types of livestock and that 37% of CH4, with higher global warming potential (23) relative...

Options for cost-effectively reducing atmospheric methane concentrations from anthropogenic biomass sources

International Nuclear Information System (INIS)

Roos, K.F.; Jacobs, C.; Orlic, M.

1993-01-01

Methane is a major greenhouse gas, second only to carbon dioxide in its contribution to future global warming. Methane concentrations have more than doubled over the last two centuries and continue to rise annually. These increases are largely correlated with increasing human populations. Methane emissions from human related activities currently account for about 70 percent of annual emissions. Of these human related emissions, biomass sources account for about 75 percent and non-biomass sources about 25 percent. Because methane has a shorter lifetime than other major greenhouse gases, efforts to reduce methane emissions may fairly quickly be translated into lower atmospheric concentrations of methane and lower levels of radiative forcing. This fairly quick response would have the benefit of slowing the rate of climate change and hence allow natural ecosystems more time to adapt. Importantly, methane may be cost-effectively reduced from a number of biomass and non-biomass sources in the United States and worldwide. Methane is a valuable fuel, not just a waste by-product, and often systems may be reconfigured to reap the fuel value of the methane and more than justify the necessary expenditures. Such options for reducing methane emission from biomass sources exist for landfills, livestock manures, and ruminant livestock, and have been implemented to varying degrees in countries around the world. However, there are a number of barriers that hinder the more widespread use of technologies, including institutional, financial, regulatory, informational, and other barriers. This paper describes an array of available options that may be cost-effectively implemented to reduce methane emissions from biomass sources. This paper also discusses a number of programs that have been developed in the United States and internationally to promote the implementation of these methane reduction options and overcome existing barriers

Influence of Large Lakes on Methane Greenhouse Forcing in the Early Eocene

Science.gov (United States)

Whiteside, J. H.; Granberg, D. L.; Kasprak, A. H.; Taylor, K. W.; Pancost, R. D.

2011-12-01

Long-duration elevated global temperatures and increased atmospheric pCO2 levels (~1000-2000 ppm) characterized the earliest portion of the Eocene (Ypressian; ~55 to 49 Ma). This extended period of global warmth was also punctuated by a series of short (sub-precessional) hyperthermal events in which atmospheric CO2 (>2000 ppm) and global temperatures rose with unprecedented and (as of yet) unexplained rapidity. This interval is perhaps the best temporal analog for assessing contemporary response of the biosphere and global carbon cycle to increased CO2 emissions. Although these hyperthermals appear paced by 100 Ka and 1 Ma scale orbital (eccentricity) cycles in the marine realm, high frequency forcing processes have not yet been examined, and long continental records have yet to be explored for their expression. To identify sub-eccentricity (Messel Shale, (Darmstadt, Germany.) We demonstrate that in addition to the expected 100 Ka eccentricity cycle, the 40 Ka cycle of obliquity is also an important component of climate variability as reflected in the lacustrine carbon cycle and hence a potential driver of global carbon cycling. We further investigated carbon cycle dynamics by examining biomarker evidence for changes in the terrestrial methane cycle during this time interval. Due to their increased volumes (>60,000 km2), highly stratified and cyclically anoxic lakes of the Eocene could have provided enough methane to alter global radiative forcing. This is consistent with our data, which demonstrate that the GRF and Messel Shale both exhibit strongly reducing conditions as well as abundant methanogen and methanotroph biomarkers. Further, the GRF lacustrine environment was highly stratified with, at times, euxinic waters extending into the photic zone, as inferred from the presence of isorenieratene derivatives. Thus, the GRF was likely an area of elevated methanogenic activity during this time. Increasing input of terrestrial matter into the GRF correlates with

Canada`s greenhouse gas emissions inventory

Energy Technology Data Exchange (ETDEWEB)

Jaques, A. [Environment Canada, Ottawa, ON (Canada)

1998-09-01

In 1994, Canada was the seventh largest global emitter of CO{sub 2}. The Kyoto Protocol has made it necessary to continue to improve methods for developing emissions inventories. An emissions inventory was defined as `a comprehensive account of air pollutant emissions and associated data from sources within the inventory area over a specified time frame that can be used to determine the effect of emissions on the environment`. The general approach is to compile large-scale emission estimates under averaged conditions for collective sources and sectors, using data that is available on a sectoral, provincial and national basis. Ideally, continuous emission monitors should be used to develop emissions inventories. Other needed improvements include additional research on emissions data, and increased support for international negotiations on reporting policies and related methodologies, verification procedures and adjustments. 1 ref., 5 figs.

Methane production from coal by a single methanogen

Science.gov (United States)

Sakata, S.; Mayumi, D.; Mochimaru, H.; Tamaki, H.; Yamamoto, K.; Yoshioka, H.; Suzuki, Y.; Kamagata, Y.

2017-12-01

production, suggesting that AmaM produced methane from MACs in the media not analyzed this time and/or MACs bound to the coal surface. In conclusion, the contribution of methoxydotrophic methanogenesis may be important not only to the formation of CBM but also to the global carbon cycle.

Sensitivity of wetland methane emissions to model assumptions: application and model testing against site observations

Directory of Open Access Journals (Sweden)

L. Meng

2012-07-01

Full Text Available Methane emissions from natural wetlands and rice paddies constitute a large proportion of atmospheric methane, but the magnitude and year-to-year variation of these methane sources are still unpredictable. Here we describe and evaluate the integration of a methane biogeochemical model (CLM4Me; Riley et al., 2011 into the Community Land Model 4.0 (CLM4CN in order to better explain spatial and temporal variations in methane emissions. We test new functions for soil pH and redox potential that impact microbial methane production in soils. We also constrain aerenchyma in plants in always-inundated areas in order to better represent wetland vegetation. Satellite inundated fraction is explicitly prescribed in the model, because there are large differences between simulated fractional inundation and satellite observations, and thus we do not use CLM4-simulated hydrology to predict inundated areas. A rice paddy module is also incorporated into the model, where the fraction of land used for rice production is explicitly prescribed. The model is evaluated at the site level with vegetation cover and water table prescribed from measurements. Explicit site level evaluations of simulated methane emissions are quite different than evaluating the grid-cell averaged emissions against available measurements. Using a baseline set of parameter values, our model-estimated average global wetland emissions for the period 1993–2004 were 256 Tg CH₄ yr⁻¹ (including the soil sink and rice paddy emissions in the year 2000 were 42 Tg CH₄ yr⁻¹. Tropical wetlands contributed 201 Tg CH₄ yr⁻¹, or 78% of the global wetland flux. Northern latitude (>50 N systems contributed 12 Tg CH₄ yr⁻¹. However, sensitivity studies show a large range (150–346 Tg CH₄ yr⁻¹ in predicted global methane emissions (excluding emissions from rice paddies. The large range is

Methane production and methane consumption: a review of processes underlying wetland methane fluxes.

NARCIS (Netherlands)

Segers, R.

1998-01-01

Potential rates of both methane production and methane consumption vary over three orders of magnitude and their distribution is skew. These rates are weakly correlated with ecosystem type, incubation temperature, in situ aeration, latitude, depth and distance to oxic/anoxic interface. Anaerobic

MERLIN: A French-German Space Lidar Mission Dedicated to Atmospheric Methane

Directory of Open Access Journals (Sweden)

Gerhard Ehret

2017-10-01

Full Text Available The MEthane Remote sensing Lidar missioN (MERLIN aims at demonstrating the spaceborne active measurement of atmospheric methane, a potent greenhouse gas, based on an Integrated Path Differential Absorption (IPDA nadir-viewing LIght Detecting and Ranging (Lidar instrument. MERLIN is a joint French and German space mission, with a launch currently scheduled for the timeframe 2021/22. The German Space Agency (DLR is responsible for the payload, while the platform (MYRIADE Evolutions product line is developed by the French Space Agency (CNES. The main scientific objective of MERLIN is the delivery of weighted atmospheric columns of methane dry-air mole fractions for all latitudes throughout the year with systematic errors small enough (<3.7 ppb to significantly improve our knowledge of methane sources from global to regional scales, with emphasis on poorly accessible regions in the tropics and at high latitudes. This paper presents the MERLIN objectives, describes the methodology and the main characteristics of the payload and of the platform, and proposes a first assessment of the error budget and its translation into expected uncertainty reduction of methane surface emissions.

Atmospheric methane isotopic record favors fossil sources flat in 1980s and 1990s with recent increase

Science.gov (United States)

Rice, Andrew L.; Butenhoff, Christopher L.; Teama, Doaa G.; Röger, Florian H.; Khalil, M. Aslam K.; Rasmussen, Reinhold A.

2016-09-01

Observations of atmospheric methane (CH4) since the late 1970s and measurements of CH4 trapped in ice and snow reveal a meteoric rise in concentration during much of the twentieth century. Since 1750, levels of atmospheric CH4 have more than doubled to current globally averaged concentration near 1,800 ppb. During the late 1980s and 1990s, the CH4 growth rate slowed substantially and was near or at zero between 1999 and 2006. There is no scientific consensus on the drivers of this slowdown. Here, we report measurements of the stable isotopic composition of atmospheric CH4 (13C/12C and D/H) from a rare air archive dating from 1977 to 1998. Together with more modern records of isotopic atmospheric CH4, we performed a time-dependent retrieval of methane fluxes spanning 25 y (1984-2009) using a 3D chemical transport model. This inversion results in a 24 [18, 27] Tg y-1 CH4 increase in fugitive fossil fuel emissions since 1984 with most of this growth occurring after year 2000. This result is consistent with some bottom-up emissions inventories but not with recent estimates based on atmospheric ethane. In fact, when forced with decreasing emissions from fossil fuel sources our inversion estimates unreasonably high emissions in other sources. Further, the inversion estimates a decrease in biomass-burning emissions that could explain falling ethane abundance. A range of sensitivity tests suggests that these results are robust.

Global Warming: How Much and Why?

Science.gov (United States)

Lanouette, William

1990-01-01

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

Life cycle inventory analysis of fossil energies in Japan

International Nuclear Information System (INIS)

Yoon Sungyee; Yamada, Tatsuya

1999-01-01

Given growing concerns over global warming problems in recent years, a matter of great importance has been to grasp GHG emissions from fossil energy use as accurately as possible by figuring out how much GHGs result from a life cycle (production, transportation and consumption) of various fossil energies. The objective of this study is to make a life cycle inventory (LCI) analysis of major fossil energies (coal, oil, LNG, LPG) consumed in Japan pursuant to ISO 14040. On these fossil energies imported to Japan in 1997, LCI analysis results of GHG emissions (specifically carbon dioxide and methane) put CO 2 intensity during their combustion stage (gross heat value basis) at 100:121:138:179 among LNG:LPG:oil:coal. But, in life cycle terms, the ratios turned to be 100:110:120:154. The world average (gross heat value basis) gained from IPCC data, among others, puts the ratios among LNG:LPG:oil:coal at 100:105:110:151. In comparison, our study that focused on Japan found their corresponding figures at 100:110:120:154. COP 3 set forth country-by-country targets. Yet, global warming, that is a worldwide problem, also requires a more comprehensive assessment based on a life cycle analysis (LCA). The estimation results of our study can be of some help in shaping some criteria when considering energy and environmental policies from a global viewpoint. In addition, our study results suggest the importance of the best energy mix that is endorsed by LCI analysis results, if global warming abatement efforts should successfully be in advance. As specific institutional designs of Kyoto Mechanism are currently under examination, the introduction of LCI method deserves to be considered in discussing the baseline issue of joint implementation and clean development mechanism. In the days ahead, by gathering and analysing detailed-ever data, and through fossil-energy LCA by use, we had better consider supply and demand of the right energies in the right uses. (author)

Annual net ecosystem exchanges of carbon dioxide and methane from a temperate brackish marsh: should the focus of marsh restoration be on brackish environments?

Science.gov (United States)

Windham-Myers, L.; Anderson, F. E.; Bergamaschi, B. A.; Ferner, M. C.; Schile, L. M.; Spinelli, G.

2015-12-01

The exchange and transport of carbon in tidally driven, saline marsh ecosystems provide habitat and trophic support for coastal wildlife and fisheries, while potentially accumulating and storing carbon at some of the highest rates compared to other ecosystems. However, due to the predicted rise in sea level over the next century, the preservation and restoration of estuarine habitats is necessary to compensate for their expected decline. In addition, restoration of these marsh systems can also reduce the impacts of global climate change as they assimilate as much carbon as their freshwater counterparts, while emitting less methane due to the higher concentrations of sulfate in seawater. Unfortunately, in brackish marshes, with salinity concentrations less than 18 parts per thousand (ppt), simple relationships between methane production, salinity and sulfate concentrations are not well known. Here we present the net ecosystem exchange (NEE) of carbon dioxide and methane, as calculated by the eddy covariance method, from a brackish marsh ecosystem in the San Francisco Estuary where salinity ranges from oligohaline (0.5-5 ppt) to mesohaline (5-18 ppt) conditions. Daily rates of carbon dioxide and methane NEE ranged from approximately 10 gC-CO2 m-2 d-1 and 0 mgC-CH4 m-2 d-1, during the winter to -15 gC-CO2 m-2 d-1 and 30 mgC-CH4 m-2 d-1, in the summer growing season. A comparison between similar measurements made from freshwater wetlands in the Sacramento-San Joaquin Delta found that the daily rates of carbon dioxide NEE were similar, but daily rates of methane NEE were just a small fraction (0-15%). Our research also shows that the daily fluxes of carbon dioxide and methane at the brackish marsh were highly variable and may be influenced by the tidal exchanges of seawater. Furthermore, the observed decline in methane production from summer to fall may have resulted from a rise in salinity and/or a seasonal decline in water and air temperatures. Our research goals are

New Tropical Peatland Gas and Particulate Emissions Factors Indicate 2015 Indonesian Fires Released Far More Particulate Matter (but Less Methane than Current Inventories Imply

Directory of Open Access Journals (Sweden)

Martin J. Wooster

2018-03-01

Full Text Available Deforestation and draining of the peatlands in equatorial SE Asia has greatly increased their flammability, and in September–October 2015 a strong El Niño-related drought led to further drying and to widespread burning across parts of Indonesia, primarily on Kalimantan and Sumatra. These fires resulted in some of the worst sustained outdoor air pollution ever recorded, with atmospheric particulate matter (PM concentrations exceeding those considered “extremely hazardous to health” by up to an order of magnitude. Here we report unique in situ air quality data and tropical peatland fire emissions factors (EFs for key carbonaceous trace gases (CO2, CH4 and CO and PM2.5 and black carbon (BC particulates, based on measurements conducted on Kalimantan at the height of the 2015 fires, both at locations of “pure” sub-surface peat burning and spreading vegetation fires atop burning peat. PM2.5 are the most significant smoke constituent in terms of human health impacts, and we find in situ PM2.5 emissions factors for pure peat burning to be 17.8 to 22.3 g·kg−1, and for spreading vegetation fires atop burning peat 44 to 61 g·kg−1, both far higher than past laboratory burning of tropical peat has suggested. The latter are some of the highest PM2.5 emissions factors measured worldwide. Using our peatland CO2, CH4 and CO emissions factors (1779 ± 55 g·kg−1, 238 ± 36 g·kg−1, and 7.8 ± 2.3 g·kg−1 respectively alongside in situ measured peat carbon content (610 ± 47 g-C·kg−1 we provide a new 358 Tg (± 30% fuel consumption estimate for the 2015 Indonesian fires, which is less than that provided by the GFEDv4.1s and GFASv1.2 global fire emissions inventories by 23% and 34% respectively, and which due to our lower EFCH4 produces far less (~3× methane. However, our mean in situ derived EFPM2.5 for these extreme tropical peatland fires (28 ± 6 g·kg−1 is far higher than current emissions inventories assume, resulting in our total

Methane excess in Arctic surface water-triggered by sea ice formation and melting.

Science.gov (United States)

Damm, E; Rudels, B; Schauer, U; Mau, S; Dieckmann, G

2015-11-10

Arctic amplification of global warming has led to increased summer sea ice retreat, which influences gas exchange between the Arctic Ocean and the atmosphere where sea ice previously acted as a physical barrier. Indeed, recently observed enhanced atmospheric methane concentrations in Arctic regions with fractional sea-ice cover point to unexpected feedbacks in cycling of methane. We report on methane excess in sea ice-influenced water masses in the interior Arctic Ocean and provide evidence that sea ice is a potential source. We show that methane release from sea ice into the ocean occurs via brine drainage during freezing and melting i.e. in winter and spring. In summer under a fractional sea ice cover, reduced turbulence restricts gas transfer, then seawater acts as buffer in which methane remains entrained. However, in autumn and winter surface convection initiates pronounced efflux of methane from the ice covered ocean to the atmosphere. Our results demonstrate that sea ice-sourced methane cycles seasonally between sea ice, sea-ice-influenced seawater and the atmosphere, while the deeper ocean remains decoupled. Freshening due to summer sea ice retreat will enhance this decoupling, which restricts the capacity of the deeper Arctic Ocean to act as a sink for this greenhouse gas.

Methane and compost from straw. Final report

Energy Technology Data Exchange (ETDEWEB)

Rijkens, B A

1982-01-01

A concept is developed in which the farmer collects the straw and ferments it anaerobically to compost and methane at the farm. The methane can be used for heating and for production of mechanical energy, while the compost can be returned to the land at any suitable moment. This way of processing conserves part of the energy, present in the straw, that would otherwise be lost by the field-burning or the ploughing-in. In the meantime it solves the field-burning and environmental problems and it provides the possibility to recycle the organic matter in the humus, as well as all the fertilizing compounds K, P, Mg and nitrogen. There are indications that the arable land will need a restocking with humus that has been lost during many years of (modern) farming, leading to loss in structure and production capacity. This study collects the global technical and economical data, enabling us to indicate under which circumstances and local conditions the methane and compost concept would be feasible and would be an alternative to field-burning, ploughing-in or to the purely energetic use of the straw.

A global inventory of aircraft NO{sub x} emissions (ANCAT/EC 2). A revised inventory (1996) by the ECAC/ANCAT and EC working group

Energy Technology Data Exchange (ETDEWEB)

Gardner, R M [Great Minister House, London (United Kingdom). Dept. of Transfert London

1998-12-31

Results of the ANCAT/EC 2 inventory produced by the European ANCAT/EC emissions inventory group is reported. The base year inventory has been completed and is currently being written up for report publication. The ANCAT/EC 2 inventory in the base year, 1991/92, has accounted for a total fuel burn of 132.5 Tg/yr and a NO{sub x} mass of 1.82 Tg/yr. The civil subsonic fleet average emissions index is EI NO{sub x} 13.9. The inventory has accounted for 80% of the IEA refined jet fuel total for 1992. The forecast 2015 inventory accounts for 289.4 Tg/yr fuel and 3.48 Tg/yr NO{sub x}, increases of 118% and 91% respectively. Both datasets will be reported fully in the next few months. (author) 5 refs.

A global inventory of aircraft NO{sub x} emissions (ANCAT/EC 2). A revised inventory (1996) by the ECAC/ANCAT and EC working group

Energy Technology Data Exchange (ETDEWEB)

Gardner, R.M. [Great Minister House, London (United Kingdom). Dept. of Transfert London

1997-12-31

Results of the ANCAT/EC 2 inventory produced by the European ANCAT/EC emissions inventory group is reported. The base year inventory has been completed and is currently being written up for report publication. The ANCAT/EC 2 inventory in the base year, 1991/92, has accounted for a total fuel burn of 132.5 Tg/yr and a NO{sub x} mass of 1.82 Tg/yr. The civil subsonic fleet average emissions index is EI NO{sub x} 13.9. The inventory has accounted for 80% of the IEA refined jet fuel total for 1992. The forecast 2015 inventory accounts for 289.4 Tg/yr fuel and 3.48 Tg/yr NO{sub x}, increases of 118% and 91% respectively. Both datasets will be reported fully in the next few months. (author) 5 refs.

Atmospheric methane removal by methane-oxidizing bacteria immobilized on porous building materials.

Science.gov (United States)

Ganendra, Giovanni; De Muynck, Willem; Ho, Adrian; Hoefman, Sven; De Vos, Paul; Boeckx, Pascal; Boon, Nico

2014-04-01

Biological treatment using methane-oxidizing bacteria (MOB) immobilized on six porous carrier materials have been used to mitigate methane emission. Experiments were performed with different MOB inoculated in building materials at high (~20 % (v/v)) and low (~100 ppmv) methane mixing ratios. Methylocystis parvus in autoclaved aerated concrete (AAC) exhibited the highest methane removal rate at high (28.5 ± 3.8 μg CH₄ g⁻¹ building material h⁻¹) and low (1.7 ± 0.4 μg CH₄ g⁻¹ building material h⁻¹) methane mixing ratio. Due to the higher volume of pores with diameter >5 μm compared to other materials tested, AAC was able to adsorb more bacteria which might explain for the higher methane removal observed. The total methane and carbon dioxide-carbon in the headspace was decreased for 65.2 ± 10.9 % when M. parvus in Ytong was incubated for 100 h. This study showed that immobilized MOB on building materials could be used to remove methane from the air and also act as carbon sink.

Global emissions inventories

International Nuclear Information System (INIS)

Dignon, J.

1995-07-01

Atmospheric chemistry determines the concentrations of most of the important greenhouse gases except for carbon dioxide. The rate of removal of the greenhouse gases from the atmosphere is also controlled by atmospheric chemistry. The indirect effects of chemical forcing resulting from the chemical interactions of other species can also affect the concentrations of radiatively important gases such as ozone. In order to establish the contribution of any possible climatic change attributable to individual greenhouse gases, spatially and temporally resolved estimates of their emissions need to be established. Unfortunately, for most of the radiatively important species the global magnitudes of their individual fluxes are not known to better than a factor of two and their spatial distributions are even more poorly characterized. Efforts to estimate future projections of potential impacts and to monitor international agreements will require continued research to narrow the uncertainties of magnitude and geographical distribution of emissions

Quantification of methane emissions from 15 Danish landfills using the mobile tracer dispersion method

Energy Technology Data Exchange (ETDEWEB)

Mønster, Jacob [Department of Environmental Engineering, Technical University of Denmark, Miljøvej – Building 113, DK-2800 Lyngby (Denmark); Samuelsson, Jerker, E-mail: jerker.samuelsson@fluxsense.se [Chalmers University of Technology/FluxSense AB, SE-41296 Göteborg (Sweden); Kjeldsen, Peter [Department of Environmental Engineering, Technical University of Denmark, Miljøvej – Building 113, DK-2800 Lyngby (Denmark); Scheutz, Charlotte, E-mail: chas@env.dtu.dk [Department of Environmental Engineering, Technical University of Denmark, Miljøvej – Building 113, DK-2800 Lyngby (Denmark)

2015-01-15

Highlights: • Quantification of whole landfill site methane emission at 15 landfills. • Multiple on-site source identification and quantification. • Quantified methane emission from shredder waste and composting. • Large difference between measured and reported methane emissions. - Abstract: Whole-site methane emissions from 15 Danish landfills were assessed using a mobile tracer dispersion method with either Fourier transform infrared spectroscopy (FTIR), using nitrous oxide as a tracer gas, or cavity ring-down spectrometry (CRDS), using acetylene as a tracer gas. The landfills were chosen to represent the different stages of the lifetime of a landfill, including open, active, and closed covered landfills, as well as those with and without gas extraction for utilisation or flaring. Measurements also included landfills with biocover for oxidizing any fugitive methane. Methane emission rates ranged from 2.6 to 60.8 kg h{sup −1}, corresponding to 0.7–13.2 g m{sup −2} d{sup −1}, with the largest emission rates per area coming from landfills with malfunctioning gas extraction systems installed, and the smallest emission rates from landfills closed decades ago and landfills with an engineered biocover installed. Landfills with gas collection and recovery systems had a recovery efficiency of 41–81%. Landfills where shredder waste was deposited showed significant methane emissions, with the largest emission from newly deposited shredder waste. The average methane emission from the landfills was 154 tons y{sup −1}. This average was obtained from a few measurement campaigns conducted at each of the 15 landfills and extrapolating to annual emissions requires more measurements. Assuming that these landfills are representative of the average Danish landfill, the total emission from Danish landfills were calculated at 20,600 tons y{sup −1}, which is significantly lower than the 33,300 tons y{sup −1} estimated for the national greenhouse gas inventory for

Rain increases methane production and methane oxidation in a boreal thermokarst bog

Science.gov (United States)

Neumann, R. B.; Moorberg, C.; Turner, J.; Wong, A.; Waldrop, M. P.; Euskirchen, E. S.; Edgar, C.; Turetsky, M. R.

2017-12-01

Bottom-up biogeochemical models of wetland methane emissions simulate the response of methane production, oxidation and transport to wetland conditions and environmental forcings. One reason for mismatches between bottom-up and top-down estimates of emissions is incomplete knowledge of factors and processes that control microbial rates and methane transport. To advance mechanistic understanding of wetland methane emissions, we conducted a multi-year field investigation and plant manipulation experiment in a thermokarst bog located near Fairbanks, Alaska. The edge of the bog is experiencing active permafrost thaw, while the center of the bog thawed 50 to 100 years ago. Our study, which captured both an average year and two of the wettest years on record, revealed how rain interacts with vascular vegetation and recently thawed permafrost to affect methane emissions. In the floating bog, rain water warmed and oxygenated the subsurface, but did not alter soil saturation. The warmer peat temperatures increased both microbial methane production and plant productivity at the edge of the bog near the actively thawing margin, but minimally altered microbial and plant activity in the center of the bog. These responses indicate processes at the edge of the bog were temperature limited while those in the center were not. The compounding effect of increased microbial activity and plant productivity at the edge of the bog doubled methane emissions from treatments with vascular vegetation during rainy years. In contrast, methane emissions from vegetated treatments in the center of the bog did not change with rain. The oxygenating influence of rain facilitated greater methane oxidation in treatments without vascular vegetation, which offset warming-induced increases in methane production at the edge of the bog and decreased methane emissions in the center of the bog. These results elucidate the complex and spatially variable response of methane production and oxidation in

Historical methane hydrate project review

Science.gov (United States)

Collett, Timothy; Bahk, Jang-Jun; Frye, Matt; Goldberg, Dave; Husebo, Jarle; Koh, Carolyn; Malone, Mitch; Shipp, Craig; Torres, Marta

2013-01-01

Blake Ridge in the Atlantic Ocean in 1995, have also contributed greatly to our understanding of the geologic controls on the formation, occurrence, and stability of gas hydrates in marine environments. For the most part methane hydrate research expeditions carried out by the ODP and IODP provided the foundation for our scientific understanding of gas hydrates. The methane hydrate research efforts under ODP-­‐IODP have mostly dealt with the assessment of the geologic controls on the occurrence of gas hydrate, with a specific goal to study the role methane hydrates may play in the global carbon cycle.Over the last 10 years, national led methane hydrate research programs, along with industry interest have led to the development and execution of major methane hydrate production field test programs. Two of the most important production field testing programs have been conducted at the Mallik site in the Mackenzie River Delta of Canada and in the Eileen methane hydrate accumulation on the North Slope of Alaska. Most recently we have also seen the completion of the world’s first marine methane hydrate production test in the Nankai Trough in the offshore of Japan. Industry interest in gas hydrates has also included important projects that have dealt with the assessment of geologic hazards associated with the presence of hydrates.The scientific drilling and associated coring, logging, and borehole monitoring technologies developed in the long list of methane hydrate related field studies are one of the most important developments and contributions associated with methane hydrate research and development activities. Methane hydrate drilling has been conducted from advanced scientific drilling platforms like the JOIDES Resolution and the D/V Chikyu, which feature highly advanced integrated core laboratories and borehole logging capabilities. Hydrate research drilling has also included the use of a wide array of industry, geotechnical and multi-­‐service ships. All of

The MOYA aircraft campaign: First measurements of methane, ethane and C-13 isotopes from West African biomass burning and other regional sources using the UK FAAM aircraft

Science.gov (United States)

Allen, Grant; Pitt, Joseph; Lee, James; Hopkins, James; Young, Stuart; Bauguitte, Stéphane; Gallagher, Martin; Fisher, Rebecca; Lowry, David; Nisbet, Euan

2017-04-01

Global methane concentrations continue to rise due to an imbalance between sources and sinks. There remains little consensus on the relative components of the manifold source types and their geographical origin. The Global Methane Budget and Yearly Assessments (MOYA) project is tasked with better characterising the global methane budget through an augmented global measurement and modelling programme. As part of MOYA, the UK's Facility for Airborne Atmospheric Measurement (FAAM), will fly four campaigns based out of West Africa and Ascension Island in the period 2017-2019, to focus on the important role of tropical sources. The first of these, to be conducted in late February 2017, will focus on the biomass burning season in West Africa. This paper will present the plan for future FAAM MOYA campaigns and report on our first aircraft data gathered in the West African region. The new addition of an interband cascade laser spectrometer to the FAAM aircraft, flown in this campaign for the first time, promises to provide the first real-time, continuous, and simultaneous, airborne measurements of methane, ethane and methane C-13 isotopologues. Together, these measurements, when interpreted in combination with other trace gases and aerosol measured on the aircraft, will serve as case studies to inform modelling of regional and global fluxes through their isotopic fingerprints.

Opportunities to reduce methane emissions in the natural gas industry

Energy Technology Data Exchange (ETDEWEB)

Cowgill, R.M. [Radian Corporation, Austin, TX (United States)

1995-12-31

The U.S. Environmental Protection Agency (EPA) and the Gas Research Institute (GRI) cofunded a project to quantify methane (CH{sub 4}) emissions from the U.S. natural gas industry. Methane, the major constituent of natural gas, is a potent greenhouse gas that is believed to increase the effect of global warming when released to the atmosphere. Reducing emissions from natural gas systems would lessen the greenhouse gas effect attributable to atmospheric CH{sub 4}. Further, mitigation methods to reduce emissions of natural gas, a marketable resource, could save money and increase energy efficiency. This presentation summarizes the major sources and quantity of methane being emitted to the atmosphere for all segments of the U.S. gas industry: production; processing; storage; transmission; and distribution. A description of how those emissions were determined is included here, as well as a discussion of which sources are potential candidates for reducing emissions. (author)

Opportunities to reduce methane emissions in the natural gas industry

Energy Technology Data Exchange (ETDEWEB)

Cowgill, R M [Radian Corporation, Austin, TX (United States)

1996-12-31

The U.S. Environmental Protection Agency (EPA) and the Gas Research Institute (GRI) cofunded a project to quantify methane (CH{sub 4}) emissions from the U.S. natural gas industry. Methane, the major constituent of natural gas, is a potent greenhouse gas that is believed to increase the effect of global warming when released to the atmosphere. Reducing emissions from natural gas systems would lessen the greenhouse gas effect attributable to atmospheric CH{sub 4}. Further, mitigation methods to reduce emissions of natural gas, a marketable resource, could save money and increase energy efficiency. This presentation summarizes the major sources and quantity of methane being emitted to the atmosphere for all segments of the U.S. gas industry: production; processing; storage; transmission; and distribution. A description of how those emissions were determined is included here, as well as a discussion of which sources are potential candidates for reducing emissions. (author)

Opportunities to reduce methane emissions in the natural gas industry

International Nuclear Information System (INIS)

Cowgill, R.M.

1995-01-01

The U.S. Environmental Protection Agency (EPA) and the Gas Research Institute (GRI) cofunded a project to quantify methane (CH 4 ) emissions from the U.S. natural gas industry. Methane, the major constituent of natural gas, is a potent greenhouse gas that is believed to increase the effect of global warming when released to the atmosphere. Reducing emissions from natural gas systems would lessen the greenhouse gas effect attributable to atmospheric CH 4 . Further, mitigation methods to reduce emissions of natural gas, a marketable resource, could save money and increase energy efficiency. This presentation summarizes the major sources and quantity of methane being emitted to the atmosphere for all segments of the U.S. gas industry: production; processing; storage; transmission; and distribution. A description of how those emissions were determined is included here, as well as a discussion of which sources are potential candidates for reducing emissions. (author)

The social cost of methane: theory and applications.

Science.gov (United States)

Shindell, D T; Fuglestvedt, J S; Collins, W J

2017-08-24

Methane emissions contribute to global warming, damage public health and reduce the yield of agricultural and forest ecosystems. Quantifying these damages to the planetary commons by calculating the social cost of methane (SCM) facilitates more comprehensive cost-benefit analyses of methane emissions control measures and is the first step to potentially incorporating them into the marketplace. Use of a broad measure of social welfare is also an attractive alternative or supplement to emission metrics focused on a temperature target in a given year as it incentivizes action to provide benefits over a broader range of impacts and timescales. Calculating the SCM using consistent temporal treatment of physical and economic processes and incorporating climate- and air quality-related impacts, we find large SCM values, e.g. ∼$2400 per ton and ∼$3600 per ton with 5% and 3% discount rates respectively. These values are ∼100 and 50 times greater than corresponding social costs for carbon dioxide. Our results suggest that ∼110 of 140 Mt of identified methane abatement via scaling up existing technology and policy options provide societal benefits that outweigh implementation costs. Within the energy sector, renewables compare far better against use of natural gas in electricity generation when incorporating these social costs for methane. In the agricultural sector, changes in livestock management practices, promoting healthy diets including reduced beef and dairy consumption, and reductions in food waste have been promoted as ways to mitigate emissions, and these are shown here to indeed have the potential to provide large societal benefits (∼$50-150 billion per year). Examining recent trends in methane and carbon dioxide, we find that increases in methane emissions may have offset much of the societal benefits from a slowdown in the growth rate of carbon dioxide emissions. The results indicate that efforts to reduce methane emissions via policies spanning a wide

Research on estimation of methane generated in paddy field and release mechanism of the gas into the atmosphere. Suiden ni okeru methane hasseiryo no hyoka to sono hoshutsu kiko ni kansuru kenkyu

Energy Technology Data Exchange (ETDEWEB)

Minami, K; Nouchi, I; Yagi, K [National Institute of Agro-Environmental Science, Tsukuba (Japan)

1991-11-25

Research and estimation have been carried out on a mechanism to generate methane in paddy fields, which relates closely to global warming. For methane flux measurement, the chamber method was used. The result revealed that with paddy fields mixed with organic substances, methane generation was abundant in the order of raw rice straw mixed area > rice straw compost mixed area > chemical fertilizer mixed area. At the Ryugasaki test area, the raw rice straw and fertilizer mixed areas have generated methane annually at 27.0 gm[sup [minus]2] and 8.2 gm[sup [minus]2], respectively. With regard to soil types, the order was peat soil > gley soil > Kuroboku soil > light-colored Kuroboku soil, where the peat soil generated about 40 times as much of methane as the light-colored Kuroboku soil. As regards the influence from drainage adjustment, normally water-filled field, wet field, and dry field generated methane at 9.25, 4.79, and 0.34 gm[sup [minus]1] y[sup [minus]1], respectively. Amount of methane generated annually from paddy fields over the whole world was estimated at 22 to 73[times]10[sup 12] g. It was determined from the above facts that methane generation may be reduced if organic substance mixing and water in paddy fields are controlled properly. 8 refs., 5 figs., 1 tab.

Quantification of the Potential Gross Economic Impacts of Five Methane Reduction Scenarios

Energy Technology Data Exchange (ETDEWEB)

Keyser, David [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Warner, Ethan [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Curley, Christina [Colorado State Univ., Fort Collins, CO (United States)

2015-04-23

Methane (CH4) is a potent greenhouse gas that is released from the natural gas supply chain into the atmosphere as a result of fugitive emissions1 and venting2 . We assess five potential CH4 reduction scenarios from transmission, storage, and distribution (TS&D) using published literature on the costs and the estimated quantity of CH4 reduced. We utilize cost and methane inventory data from ICF (2014) and Warner et al. (forthcoming) as well as data from Barrett and McCulloch (2014) and the American Gas Association (AGA) (2013) to estimate that the implementation of these measures could support approximately 85,000 jobs annually from 2015 to 2019 and reduce CH4 emissions from natural gas TS&D by over 40%. Based on standard input/output analysis methodology, measures are estimated to support over $8 billion in GDP annually over the same time period and allow producers to recover approximately $912 million annually in captured gas.

Tandem Gravimetric and Volumetric Apparatus for Methane Sorption Measurements

Science.gov (United States)

Burress, Jacob; Bethea, Donald

Concerns about global climate change have driven the search for alternative fuels. Natural gas (NG, methane) is a cleaner fuel than gasoline and abundantly available due to hydraulic fracturing. One hurdle to the adoption of NG vehicles is the bulky cylindrical storage vessels needed to store the NG at high pressures (3600 psi, 250 bar). The adsorption of methane in microporous materials can store large amounts of methane at low enough pressures for the allowance of conformable, ``flat'' pressure vessels. The measurement of the amount of gas stored in sorbent materials is typically done by measuring pressure differences (volumetric, manometric) or masses (gravimetric). Volumetric instruments of the Sievert type have uncertainties that compound with each additional measurement. Therefore, the highest-pressure measurement has the largest uncertainty. Gravimetric instruments don't have that drawback, but can have issues with buoyancy corrections. An instrument will be presented with which methane adsorption measurements can be performed using both volumetric and gravimetric methods in tandem. The gravimetric method presented has no buoyancy corrections and low uncertainty. Therefore, the gravimetric measurements can be performed throughout an entire isotherm or just at the extrema to verify the results from the volumetric measurements. Results from methane sorption measurements on an activated carbon (MSC-30) and a metal-organic framework (Cu-BTC, HKUST-1, MOF-199) will be shown. New recommendations for calculations of gas uptake and uncertainty measurements will be discussed.

Design considerations for tropical forest inventories

Directory of Open Access Journals (Sweden)

Ronald Edward McRoberts

2013-06-01

Full Text Available Forests contribute substantially to maintaining the global greenhouse gas balance, primarily because among the five economic sectors identified by the United Nations Framework Convention on Climate Change, only the forestry sector has the potential to remove greenhouse gas emissions from the atmosphere. In this context, development of national forest carbon accounting systems, particularly in countries with tropical forests, has emerged as an international priority. Because these systems are often developed as components of or in parallel with national forest inventories, a brief review of statistical issues related to the development of forest ground sampling designs is provided. This overview addresses not only the primary issues of plot configurations and sampling designs, but also to a lesser extent the emerging roles of remote sensing and uncertainty assessment. Basic inventory principles are illustrated for two case studies, the national forest inventory of Brazil with special emphasis on the state of Santa Catarina, and an inventory for Tanzania.

Biogeographical distribution and diversity of microbes in methane hydrate-bearing deep marine sediments, on the Pacific Ocean Margin

DEFF Research Database (Denmark)

Inagaki, F.; Nunoura, T.; Nakagawa, S.

2006-01-01

The deep subseafloor biosphere is among the least-understood habitats on Earth, even though the huge microbial biomass therein plays an important role for potential long-term controls on global biogeochemical cycles. We report here the vertical and geographical distribution of microbes and their ......The deep subseafloor biosphere is among the least-understood habitats on Earth, even though the huge microbial biomass therein plays an important role for potential long-term controls on global biogeochemical cycles. We report here the vertical and geographical distribution of microbes...... of the uncultivated Deep-Sea Archaeal Group were consistently the dominant phylotype in sediments associated with methane hydrate. Sediment cores lacking methane hydrates displayed few or no Deep-Sea Archaeal Group phylotypes. Bacterial communities in the methane hydrate-bearing sediments were dominated by members...

Sensitivity of Global Methane Bayesian Inversion to Surface Observation Data Sets and Chemical-Transport Model Resolution

Science.gov (United States)

Lew, E. J.; Butenhoff, C. L.; Karmakar, S.; Rice, A. L.; Khalil, A. K.

2017-12-01

Methane is the second most important greenhouse gas after carbon dioxide. In efforts to control emissions, a careful examination of the methane budget and source strengths is required. To determine methane surface fluxes, Bayesian methods are often used to provide top-down constraints. Inverse modeling derives unknown fluxes using observed methane concentrations, a chemical transport model (CTM) and prior information. The Bayesian inversion reduces prior flux uncertainties by exploiting information content in the data. While the Bayesian formalism produces internal error estimates of source fluxes, systematic or external errors that arise from user choices in the inversion scheme are often much larger. Here we examine model sensitivity and uncertainty of our inversion under different observation data sets and CTM grid resolution. We compare posterior surface fluxes using the data product GLOBALVIEW-CH4 against the event-level molar mixing ratio data available from NOAA. GLOBALVIEW-CH4 is a collection of CH4 concentration estimates from 221 sites, collected by 12 laboratories, that have been interpolated and extracted to provide weekly records from 1984-2008. Differently, the event-level NOAA data records methane mixing ratios field measurements from 102 sites, containing sampling frequency irregularities and gaps in time. Furthermore, the sampling platform types used by the data sets may influence the posterior flux estimates, namely fixed surface, tower, ship and aircraft sites. To explore the sensitivity of the posterior surface fluxes to the observation network geometry, inversions composed of all sites, only aircraft, only ship, only tower and only fixed surface sites, are performed and compared. Also, we investigate the sensitivity of the error reduction associated with the resolution of the GEOS-Chem simulation (4°×5° vs 2°×2.5°) used to calculate the response matrix. Using a higher resolution grid decreased the model-data error at most sites, thereby

MICROBIAL DIVERSITY AS A CONTROLLING FACTOR OF AEROBIC METHANE CONSUMPTION

NARCIS (Netherlands)

Bodelier, P.L.E.; Meima-Franke, M.; Hordijk, C.A.; Steenbergh, A.K.

2010-01-01

Background. Aerobic methane oxidizing bacteria (MOB) play a vital role in the global climate by degrading the greenhouse gas CH4. The process of CH4 consumption is sensitive to disturbance leading to strong variability in CH4 emission from ecosystems. Mechanistic explanations for variability in CH4

Quantification of methane and nitrous oxide emissions from various waste treatment facilities by tracer dilution method

Science.gov (United States)

Mønster, Jacob; Rella, Chris; Jacobson, Gloria; Kjeldsen, Peter; Scheutz, Charlotte

2013-04-01

Urban activities generate solid and liquid waste, and the handling and aftercare of the waste results in the emission of various compounds into the surrounding environment. Some of these compounds are emitted as gasses into the atmosphere, including methane and nitrous oxide. Methane and nitrous oxide are strong greenhouse gases and are considered to have 25 and 298 times the greenhouse gas potential of carbon dioxide on a hundred years term (Solomon et al. 2007). Global observations of both gasses have shown increasing concentrations that significantly contribute to the greenhouse gas effect. Methane and nitrous oxide are emitted from both natural and anthropogenic sources and inventories of source specific fugitive emissions from the anthropogenic sources of methane and nitrous oxide of are often estimated on the basis of modeling and mass balance. Though these methods are well-developed, actual measurements for quantification of the emissions is a very useful tool for verifying the modeling and mass balance as well as for validation initiatives done for lowering the emissions of methane and nitrous oxide. One approach to performing such measurements is the tracer dilution method (Galle et al. 2001, Scheutz et al. 2011), where the exact location of the source is located and a tracer gas is released at this source location at a known flow. The ratio of downwind concentrations of the tracer gas and the methane and nitrous oxide gives the emissions rates of the greenhouse gases. This tracer dilution method can be performed using both stationary and mobile measurements and in both cases, real-time measurements of both tracer and quantified gas are required, placing high demands on the analytical detection method. To perform the methane and nitrous oxide measurements, two robust instruments capable of real-time measurements were used, based on cavity ring-down spectroscopy and operating in the near-infrared spectral region. One instrument measured the methane and

Utilization of coalbed methane

Energy Technology Data Exchange (ETDEWEB)

Gustavson, J.B. [Gustavson Associates Inc., Boulder, CO (United States)

1996-02-01

Substantial progress has been made in capturing coalbed methane (CBM gas), which constitutes a valuable source of clean burning energy. It is of importance to study the various potential uses of coalbed methane and to understand the various technologies required, as well as their economics and any institutional constraints. In industrialised countries, the uses of coalbed methane are almost solely dependent on microeconomics; coalbed methane must compete for a market against natural gas and other energy sources - and frequently, coalbed methane is not competitive against other energy sources. In developing countries, on the other hand, particularly where other sources of energy are in short supply, coalbed methane economics yield positive results. Here, constraints to development of CBM utilization are mainly lack of technology and investment capital. Sociological aspects such as attitude and cultural habits, may also have a strong negative influence. This paper outlines the economics of coalbed methane utilization, particularly its competition with natural gas, and touches upon the many different uses to which coalbed methane may be applied. 24 refs., 4 figs.

Doses from radioactive methane

International Nuclear Information System (INIS)

Phipps, A.W.; Kendall, G.M.; Fell, T.P.; Harrison, J.D.

1990-01-01

A possible radiation hazard arises from exposure to methane labelled with either a 3 H or a 14 C nuclide. This radioactive methane could be released from a variety of sources, e.g. land burial sites containing radioactive waste. Standard assumptions adopted for vapours would not apply to an inert alkane like methane. This paper discusses mechanisms by which radioactive methane would irradiate tissues and provides estimates of doses. Data on skin thickness and metabolism of methane are discussed with reference to these mechanisms. It is found that doses are dominated by dose from the small fraction of methane which is inhaled and metabolised. This component of dose has been calculated under rather conservative assumptions. (author)

2000 emission inventory for the Lower Fraser Valley airshed

International Nuclear Information System (INIS)

2002-10-01

This emissions inventory is a compilation of all emissions in the Lower Fraser Valley International Airshed. Its objective is to harmonize the inventory data of Canada's Greater Vancouver Regional District (GVRD), the Fraser Valley Regional District (FVRD) and Whatcom County in the United States. It provides an idea of the current state of air emissions on both sides of the Canada-United States border. This inventory provides information regarding the types of emissions sources in the region, their location and the amount of air pollution emitted within a given time frame. It is designed to help manage air quality by identifying sectors which need to be more vigilant. The common air pollutants addressed in the inventory include total particulate matter, nitrogen oxides, sulphur oxides, volatile organic compounds, carbon monoxide, and ammonia. The greenhouse gases include carbon dioxide, methane, and nitrous oxide. The inventory distinguishes between point, area, and mobile sources. Carbon monoxide emissions are found to be dominated by cars, trucks and non-road engines. Nitrogen oxide emissions are also dominated by cars, trucks, marine vessels and non-road engines. Natural sources such as trees and vegetation contribute to volatile organic compounds, as do cars, lights trucks and solvent evaporation from industrial, commercial and consumer products. Marine vessels are the largest contributors of sulphur oxide emissions in the region. In addition, the petroleum industry emits 26 per cent of sulphur oxide emissions in the region. Significant amounts of particulate matter come from area sources such as wind erosion in the agricultural sector. Point sources for PM include bulk shipping terminals and the wood products industry. Agriculture contributes the largest amount of ammonia in the region. refs., tabs., figs

Seasonal variability in distribution and fluxes of methane in the Arabian Sea

Digital Repository Service at National Institute of Oceanography (India)

Patra, P.K.; Lal, S.; Venkataramani, S.; Gauns, M.; Sarma, V.V.S.S.

Methane, a biogeochemically important gas in Earth's atmosphere was measured in the water column and air in the Arabian Sea in different seasons, viz., northeast monsoon, intermonsoon, and southwest monsoon, as part of the Joint Global Ocean Flux...

2010-2015 methane trends over Canada, the United States, and Mexico observed by the GOSAT satellite: contributions from different source sectors

Science.gov (United States)

Sheng, J. X.; Jacob, D.; Turner, A. J.; Maasakkers, J. D.; Benmergui, J. S.; Bloom, A. A.; Arndt, C.; Gautam, R.; Zavala Araiza, D.; Hamburg, S.; Boesch, H.; Parker, R.

2017-12-01

We use six years (2010-2015) of methane column data from the GOSAT satellite to examine trends in atmospheric methane over North America and infer trends in emissions. Local methane enhancements above background are diagnosed in the GOSAT data on a 0.5°x0.5° grid by estimating the local background as the low (10th-25th) quantile of the deseasonalized frequency distributions of the data for individual years. Trends in methane enhancements on the 0.5°x0.5° grid are then aggregated nationally and for individual source sectors, using information from state-of-science bottom-up inventories, to increase statistical power. We infer that US methane emissions increased by 1.9% a-1 over the six-year period, with contributions from both oil/gas systems (possibly unconventional gas production) and from livestock in the Midwest (possibly swine production). Mexican emissions show a decrease that can be attributed to a decreasing cattle population. Canadian emissions show interannual variability driven by wetlands emissions and correlated with wetland areal extent. The US emission trends inferred from the GOSAT data are within the constraint provided by surface observations from the North American Carbon Program network.

Mitigating global warming potentials of methane and nitrous oxide gases from rice paddies under different irrigation regimes.

Science.gov (United States)

Ali, Muhammad Aslam; Hoque, M Anamul; Kim, Pil Joo

2013-04-01

A field experiment was conducted in Bangladesh Agricultural University Farm to investigate the mitigating effects of soil amendments such as calcium carbide, calcium silicate, phosphogypsum, and biochar with urea fertilizer on global warming potentials (GWPs) of methane (CH4) and nitrous oxide (N2O) gases during rice cultivation under continuous and intermittent irrigations. Among the amendments phosphogypsum and silicate fertilizer, being potential source of electron acceptors, decreased maximum level of seasonal CH4 flux by 25-27 % and 32-38 % in continuous and intermittent irrigations, respectively. Biochar and calcium carbide amendments, acting as nitrification inhibitors, decreased N2O emissions by 36-40 % and 26-30 % under continuous and intermittent irrigations, respectively. The total GWP of CH4 and N2O gases were decreased by 7-27 % and 6-34 % with calcium carbide, phosphogypsum, and silicate fertilizer amendments under continuous and intermittent irrigations, respectively. However, biochar amendments increased overall GWP of CH4 and N2O gases.

An estimate of the terrestrial carbon budget of Russia using inventory-based, eddy covariance and inversion methods

Directory of Open Access Journals (Sweden)

A. J. Dolman

2012-12-01

Full Text Available We determine the net land to atmosphere flux of carbon in Russia, including Ukraine, Belarus and Kazakhstan, using inventory-based, eddy covariance, and inversion methods. Our high boundary estimate is −342 Tg C yr⁻¹ from the eddy covariance method, and this is close to the upper bounds of the inventory-based Land Ecosystem Assessment and inverse models estimates. A lower boundary estimate is provided at −1350 Tg C yr⁻¹ from the inversion models. The average of the three methods is −613.5 Tg C yr⁻¹. The methane emission is estimated separately at 41.4 Tg C yr⁻¹.

These three methods agree well within their respective error bounds. There is thus good consistency between bottom-up and top-down methods. The forests of Russia primarily cause the net atmosphere to land flux (−692 Tg C yr⁻¹ from the LEA. It remains however remarkable that the three methods provide such close estimates (−615, −662, −554 Tg C yr^–1 for net biome production (NBP, given the inherent uncertainties in all of the approaches. The lack of recent forest inventories, the few eddy covariance sites and associated uncertainty with upscaling and undersampling of concentrations for the inversions are among the prime causes of the uncertainty. The dynamic global vegetation models (DGVMs suggest a much lower uptake at −91 Tg C yr⁻¹, and we argue that this is caused by a high estimate of heterotrophic respiration compared to other methods.