Quote:
Originally Posted by modest
If carbon dioxide made up a significant portion of our atmosphere then it's likely earth would be like Venus with average temps well above the melting point of aluminum or lead. Compared to that—I'd say it's the little changes we're interested in.
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There is a limit to the amount of heat that can be trapped by CO2, since it only absorbs a narrow portion of the spectrum. That is why a 50% increase in CO2 over the last 100 years is associated with only a 0.5 to 1 degree rise. Realistically, even if you think CO2 is casual, it would probably not be the ONLY reason for the rise. Further, the main greenhouse gas, water vapor (90% of GG is water vapor, 4% is CO2) absorbs in an overlapping spectrum. Once that spectrum is absorbed, there is not more retention.
The estimates that I saw for an incremental doubling of CO2 predicted a range of 2 to 4 degrees for increased absorption. It is pretty unlikely that CO2 could ever raise us another 10 degrees.
Most of Venus' incremental heat is because it is closer to the sun.
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Few problems are so complex that they cannot be substantially clarified by one more cup of coffee
(or a nice cabernet if it is after 5:00)
Moderator in absentia. Return anticipated. Timing somewhat vague.
