Large methane releases lead to strong aerosol forcing and reduced cloudiness

T. Kurten, L. Zhou, R. Makkonen, J. Merikanto, P. Raisanen, M. Boy, N. Richards, A. Rap, S. Smolander, Andrey Sogachev, A. Guenther, G. W. Mann, K. Carslaw, M. Kulmala

    Research output: Contribution to journalJournal articleResearchpeer-review

    211 Downloads (Pure)

    Abstract

    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 (O-3). 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 long-wave radiative forcing ("enhanced greenhouse effect") of the added methane. Together, the indirect CH4-O-3 and CH4-OHaerosol 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.
    Original languageEnglish
    JournalAtmospheric Chemistry and Physics
    Volume11
    Issue number14
    Pages (from-to)6961-6969
    ISSN1680-7316
    DOIs
    Publication statusPublished - 2011

    Bibliographical note

    This work is distributed under the Creative Commons Attribution 3.0 License.

    Keywords

    • Wind power meteorology

    Fingerprint Dive into the research topics of 'Large methane releases lead to strong aerosol forcing and reduced cloudiness'. Together they form a unique fingerprint.

    Cite this