On Feb 21, 6:21 pm, Hank Roberts <[email protected]> wrote:
> PS, David, I'm aware of the 500-million-year decline you point to, but
> that's not what I was talking about. Each warming has had active
> biological cycling.
>
> Evolution has worked quickly compared to the pace of the ice ages;
> each ice age cycle has had newly evolved organisms involved in the
> cycling of carbon
Color me confused.
First of all, due to my browser,
please use short lines as the ends of longer ones
are cut off.
Second, the entire Quatenary is an ice age with
about 1.5 million years of cyclying between stades
and interstades followed by about 1 million years
of cycling between glacials and interglacials. The
previous ice age seems to have been
http://en.wikipedia.org/wiki/Snowball_Earth
a very long time ago.
Third, modern climate condtions were set sometime
between 5 and 3 million years ago by the closure of
the Isthmus of Panama. So AFAIK modern climate sensitivity
is thought to have reamined about the same since then.
Fourth, AFAIK there has been relatively evolution during
the Quaternary. Some of course, including us:
http://en.wikipedia.org/wiki/Quaternary
So at this point I am simply baffled about your questions(s).
I have no idea of the time frame of the deVargas study
but the other is set at the P/E boundary, when the world
was a very dfferent place.
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