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| Titel |
Large methane releases lead to strong aerosol forcing and reduced cloudiness |
| VerfasserIn |
T. Kurtén, L. Zhou, R. Makkonen, J. Merikanto, P. Räisänen, M. Boy, N. Richards, A. Rap, S. Smolander, A. Sogachev, A. Guenther, G. W. Mann, K. Carslaw, M. Kulmala  |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1680-7316
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| Digitales Dokument |
URL |
| Erschienen |
In: Atmospheric Chemistry and Physics ; 11, no. 14 ; Nr. 11, no. 14 (2011-07-18), S.6961-6969 |
| Datensatznummer |
250009926
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| Publikation (Nr.) |
 copernicus.org/acp-11-6961-2011.pdf |
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| Zusammenfassung |
| The release of vast quantities of methane into the atmosphere as a result of
clathrate destabilization is a potential mechanism for rapid amplification
of global warming. Previous studies have calculated the enhanced warming
based mainly on the radiative effect of the methane itself, with smaller
contributions from the associated carbon dioxide or ozone increases. Here,
we study the effect of strongly elevated methane (CH4) levels on
oxidant and aerosol particle concentrations using a combination of
chemistry-transport and general circulation models. A 10-fold increase in
methane concentrations is predicted to significantly decrease hydroxyl
radical (OH) concentrations, while moderately increasing ozone (O3).
These changes lead to a 70 % increase in the atmospheric lifetime of
methane, and an 18 % decrease in global mean cloud droplet number
concentrations (CDNC). The CDNC change causes a radiative forcing that is
comparable in magnitude to the longwave radiative forcing ("enhanced
greenhouse effect") of the added methane. Together, the indirect
CH4-O3 and CH4-OH-aerosol forcings could more than double the
warming effect of large methane increases. Our findings may help explain the
anomalously large temperature changes associated with historic methane
releases. |
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