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Reconciling the changes in atmospheric-methane sources and sinks between the Last Glacial Maximum and the pre-industrial era

Levine, J.G.; Wolff, E.W.; Jones, A.E.; Sime, L.C.; Valdes, P.J.; Archibald, A.T.; Carver, G.D.; Warwick, N.J.; Pyle, J.A.. 2011 Reconciling the changes in atmospheric-methane sources and sinks between the Last Glacial Maximum and the pre-industrial era. Geophysical Research Letters, 38 (23), L23804. 6, pp. 10.1029/2011GL049545

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Abstract/Summary

We know from the ice record that the concentration of atmospheric methane, [CH4], at the Last Glacial Maximum (LGM) was roughly half that in the pre-industrial era (PI), buthow much of the difference was source-driven, and how much was sink-driven, remains uncertain. Recent developments include: a higher estimate of the LGM-PI change in methane emissions from wetlands―the dominant, natural methane source; and the possible recycling of OH consumed in isoprene oxidation―the principal methane sink. Here, in view of these developments, we use an atmospheric chemistry-transport model to re-examine the main factors affecting OH during this period: changes in air temperature and emissions of non-methane volatile organic compounds from vegetation. We find that their net effect was negligible(with and without an OH recycling mechanism), implyingthe change in [CH4] was almost entirely source driven―a conclusion that, though subject to significant uncertainties,can be reconciled with recent methane source estimates.

Item Type: Publication - Article
Digital Object Identifier (DOI): 10.1029/2011GL049545
Programmes: BAS Programmes > Polar Science for Planet Earth (2009 - ) > Chemistry and Past Climate
ISSN: 0094-8276
NORA Subject Terms: Atmospheric Sciences
Chemistry
Date made live: 25 Jan 2012 14:52
URI: http://nora.nerc.ac.uk/id/eprint/16505

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