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Observational constraints on recent increases in the atmospheric CH 4 burden
Measurements of atmospheric CH 4 from air samples collected weekly at 46 remote surface sites show that, after a decade of near‐zero growth, globally averaged atmospheric methane increased during 2007 and 2008. During 2007, CH 4 increased by 8.3 ± 0.6 ppb. CH 4 mole fractions averaged over polar nor...
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Published in: | Geophysical research letters 2009-09, Vol.36 (18) |
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Main Authors: | , , , , , , , , , , |
Format: | Article |
Language: | English |
Citations: | Items that this one cites Items that cite this one |
Online Access: | Get full text |
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Summary: | Measurements of atmospheric CH
4
from air samples collected weekly at 46 remote surface sites show that, after a decade of near‐zero growth, globally averaged atmospheric methane increased during 2007 and 2008. During 2007, CH
4
increased by 8.3 ± 0.6 ppb. CH
4
mole fractions averaged over polar northern latitudes and the Southern Hemisphere increased more than other zonally averaged regions. In 2008, globally averaged CH
4
increased by 4.4 ± 0.6 ppb; the largest increase was in the tropics, while polar northern latitudes did not increase. Satellite and in situ CO observations suggest only a minor contribution to increased CH
4
from biomass burning. The most likely drivers of the CH
4
anomalies observed during 2007 and 2008 are anomalously high temperatures in the Arctic and greater than average precipitation in the tropics. Near‐zero CH
4
growth in the Arctic during 2008 suggests we have not yet activated strong climate feedbacks from permafrost and CH
4
hydrates. |
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ISSN: | 0094-8276 1944-8007 |
DOI: | 10.1029/2009GL039780 |