Science (15 January 2010), Vol. 327, No. 5963, pp. 322–2325; DOI: 10.1126/science.1175176 |
Reports
Large-scale controls of methanogenesis inferred from methane and gravity spaceborne data
Abstract
Wetlands are the largest individual source of methane (CH4), but the magnitude and distribution of this source are poorly understood on continental scales. We isolated the wetland and rice paddy contributions to spaceborne CH4 measurements over 2003–2005 using satellite observations of gravity anomalies, a proxy for water-table depth 
, and surface temperature analyses TS. We find that tropical and higher-latitude CH4 variations are largely described by and TS variations, respectively. Our work suggests that tropical wetlands contribute 52 to 58% of global emissions, with the remainder coming from the extra-tropics, 2% of which is from Arctic latitudes. We estimate a 7% rise in wetland CH4 emissions over 2003–2007, due to warming of mid-latitude and Arctic wetland regions, which we find is consistent with recent changes in atmospheric CH4.
, and surface temperature analyses TS. We find that tropical and higher-latitude CH4 variations are largely described by and TS variations, respectively. Our work suggests that tropical wetlands contribute 52 to 58% of global emissions, with the remainder coming from the extra-tropics, 2% of which is from Arctic latitudes. We estimate a 7% rise in wetland CH4 emissions over 2003–2007, due to warming of mid-latitude and Arctic wetland regions, which we find is consistent with recent changes in atmospheric CH4.1 School of GeoSciences, University of Edinburgh, Edinburgh, U.K.
2 SRON Netherlands Institute for Space Research, Utrecht, The Netherlands.
*Correspondence e-mail: pip@ed.ac.uk
Link to abstract: http://www.sciencemag.org/cgi/content/abstract/327/5963/322
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