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The El Niño–Southern Oscillation and wetland methane interannual variability
Author(s) -
Hodson E. L.,
Poulter B.,
Zimmermann N. E.,
Prigent C.,
Kaplan J. O.
Publication year - 2011
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2011gl046861
Subject(s) - wetland , environmental science , el niño southern oscillation , boreal , methane , climatology , atmospheric methane , atmospheric sciences , methane emissions , geography , ecology , geology , archaeology , biology
Global measurements of atmospheric methane (CH 4 ) concentrations continue to show large interannual variability whose origin is only partly understood. Here we quantify the influence of the El Niño–Southern Oscillation (ENSO) on wetland CH 4 emissions, which are thought to be the dominant contributor to interannual variability of the CH 4 sources. We use a simple wetland CH 4 model that captures variability in wetland extent and soil carbon to model the spatial and temporal dynamics of wetland CH 4 emissions from 1950–2005 and compare these results to an ENSO index. We are able to explain a large fraction of the global and tropical variability in wetland CH 4 emissions through correlation with the ENSO index. We find that repeated El Niño events throughout the 1980s and 1990s were a contributing factor towards reducing CH 4 emissions and stabilizing atmospheric CH 4 concentrations. An increase in emissions from the boreal region would likely strengthen the feedback between ENSO and interannual variability in global wetland CH 4 emissions. Our analysis emphasizes that climate variability has a significant impact on wetland CH 4 emissions, which should be taken into account when considering future trends in CH 4 sources.