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Contribution of Changing Sources and Sinks to the Growth Rate of Atmospheric Methane Concentrations for the Last Two DecadesIn situ measurements of atmospheric methane concentrations begun in the early 1980s show decadal trends, as well as large interannual variations, in growth rate. Recent research indicates that while wetlands can explain several of the large growth anomalies for individual years, the decadal trend may be the combined effect of increasing sinks, due to increases in tropospheric OH, and stabilizing sources. We discuss new 20-year histories of annual, global source strengths for all major methane sources, i.e., natural wetlands, rice cultivation, ruminant animals, landfills, fossil fuels, and biomass burning. We also present estimates of the temporal pattern of the sink required to reconcile these sources and atmospheric concentrations over this time period. Analysis of the individual emission sources, together with model-derived estimates of the OH sink strength, indicates that the growth rate of atmospheric methane observed over the last 20 years can only be explained by a combination of changes in source emissions and an increasing tropospheric sink. Direct validation of the global sources and the terrestrial sink is not straightforward, in part because some sources/sinks are relatively small and diffuse (e.g., landfills and soil consumption), as well as because the atmospheric record integrates multiple and substantial sources and tropospheric sinks in regions such as the tropics. We discuss ways to develop and test criteria for rejecting and/or accepting a suite of scenarios for the methane budget.
Document ID
20010078968
Acquisition Source
Goddard Space Flight Center
Document Type
Conference Paper
Authors
Matthews, Elaine
(NASA Goddard Inst. for Space Studies New York, NY United States)
Walter, B.
(Columbia Univ. New York, NY United States)
Bogner, J.
(Landfills+, Inc. Wheaton, IL United States)
Sarma, D.
(New York Univ. New York, NY United States)
Portmey, G.
(Arizona Univ. Tucson, AZ United States)
Travis, Larry
Date Acquired
August 20, 2013
Publication Date
January 17, 2001
Subject Category
Environment Pollution
Meeting Information
Meeting: CNES International Workshop on Emissions...
Location: Paris
Country: France
Start Date: June 19, 2001
End Date: June 22, 2001
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.

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