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

J. G. Levine*, E. W. Wolff, A. E. Jones, L. C. Sime, P. J. Valdes, A. T. Archibald, G. D. Carver, N. J. Warwick, J. A. Pyle

*Corresponding author for this work

Research output: Contribution to journalArticle (Academic Journal)peer-review

30 Citations (Scopus)

Abstract

We know from the ice record that the concentration of atmospheric methane, [CH 4], at the Last Glacial Maximum (LGM) was roughly half that in the pre-industrial era (PI), but how 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 wetlandsthe dominant, natural methane source; and the possible recycling of OH consumed in isoprene oxidationthe 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), implying the change in [CH 4] was almost entirely source drivena conclusion that, though subject to significant uncertainties, can be reconciled with recent methane source estimates.

Original languageEnglish
Article numberL23804
JournalGeophysical Research Letters
Volume38
Issue number23
DOIs
Publication statusPublished - 19 Dec 2011

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