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| Titel |
The significance of shortwave methane forcing for climate change |
| VerfasserIn |
William Collins, Christopher Algieri |
| Konferenz |
EGU General Assembly 2010
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 12 (2010) |
| Datensatznummer |
250042718
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| Zusammenfassung |
| The radiative effects of methane are computed for the current climate.
The longwave radiative forcing due to anthropogenic methane is the
second largest forcing from the long-lived greenhouse gases (LLGHGs).
We calculate the shortwave and longwave radiative forcing by methane at
the top of atmosphere, tropopause, and surface. The shortwave forcing by
methane has, to date, been omitted from models used in the assessments
of global warming by the Intergovernmental Panel on Climate Change
(IPCC). However, our results show that the shortwave and longwave
surface forcings due to the increase in methane from pre-industrial to
present-day concentrations are comparable in magnitude. The surface
shortwave forcing from anthropogenic methane exceeds that of
anthropogenic carbon dioxide. The spectral variations in the shortwave
effects of water vapor, methane, and other LLGHGs are compared using
line-by-line models. Global forcings are determined using the Rapid
Radiative Transfer Method for GCMs (RRTMG) combined with the
Community Climate System Model (CCSM). These calculations
demonstrate that the shortwave forcing by methane is an important
perturbation to the energy budget of the Earth's surface. The effects of
methane on solar insolation should be included in future projections of
climate change and simulations of paleoclimatic conditions. |
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