David B. Benson wrote:
> On Apr 11, 6:32 pm, Eric Swanson <[EMAIL PROTECTED]> wrote:
>> ...
>> As I recall (and I admit to being fuzzy about it) the Earth was some 5
>> or 6 C colder and the Tropics also cooled during the last Ice Age at
>> LGM. While lower CO2 levels might have caused that,
>
> A more typical figure for the global temperature during LGM is 6--8 K
> colder than present (1950 CE).
No, I think the earlier figure was better. Not that it matters for the
general point. CO2 can't reasonably account for all the temperature
change but must have contributed a significant proportion. As such, it's
hard to see how the climate can be insensitive to radiative forcing changes.
An increase in dust probably made a significant contribution to the
cooling in the tropics - maybe even more than the GHGs. And there are
vegetation (albedo) changes too. But I still see no reason to single out
CO2 as a credible candidate for having had no effect whatsoever.
James
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