Other
Scientific paper
Dec 2011
adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2011agufm.p24b..04r&link_type=abstract
American Geophysical Union, Fall Meeting 2011, abstract #P24B-04
Other
[5704] Planetary Sciences: Fluid Planets / Atmospheres, [6225] Planetary Sciences: Solar System Objects / Mars, [6296] Planetary Sciences: Solar System Objects / Extra-Solar Planets
Scientific paper
Previous studies have suggested dense CO2-rich atmospheres as warming agents for early Mars and on extrasolar planets. For Mars, 1-D climate models have been unable to explain how global mean surface temperatures could have remained above the freezing point of water. After making several model updates, it is demonstrated that even those results were overly optimistic. The addition of methane produces only a very modest greenhouse effect (~2.5K). So, the best greenhouse warming mechanism for warming early Mars is probably CO2 clouds, as suggested by previous investigators. Despite the difficulties in explaining how early Mars could have been warm, it is shown that leading cold dry Mars hypotheses are untenable. For extrasolar planets, the most interesting question has been the habitability of Gliese 581d. Whereas some 1-D models suggest that a dense CO2-rich atmosphere could keep the mean surface temperature of this planet above freezing, other authors have argued that these same models may overestimate the greenhouse effect of CO2. In agreement with calculations by other investigators, surface temperatures above the freezing point of water are predicted for Gliese 581d, albeit at a very high surface pressure (18 bar). Adding methane only makes the atmosphere cooler because its anti-greenhouse effect is quite pronounced for planets around M stars. The addition of 0.3% CH4 resulted in a surface temperature change of -10 degrees. Conversely, adding 1% CH4 around an F star produced 20K of warming. Clearly, the climatic effect of different infrared-active gases is dependent on spectral class.
Kasting James F.
Ramirez R. M.
No associations
LandOfFree
Greenhouse Warming on Early Mars and Extrasolar Planets plus a Critique of the Martian Valley Impact Hypothesis does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with Greenhouse Warming on Early Mars and Extrasolar Planets plus a Critique of the Martian Valley Impact Hypothesis, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Greenhouse Warming on Early Mars and Extrasolar Planets plus a Critique of the Martian Valley Impact Hypothesis will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-870154