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Re: mass extinction

At 10:35 AM +1000 3/21/06, Dann Pigdon dannj@alphalink.com.au wrote:

>I'd have thought that, given the rapid climate shift at the end of the 
>Pleistocene, extinction rates would have been relatively swift then. Ice core 
>studies suggest that the climate swung from glacial to interglacial within a 
>human lifetime. That's a much greater change in global climate, within a much 
>shorter time span, than us lowly humans have so far been able to manage.

Remember that the Pleistocene lasted over two million years, and during that 
time the flora and fauna had evolved to survive a series of 
glacial/interglacial cycles of varying duration. Successive ice ages did wipe 
out evidence of previous glacial/interglacial cycles, but from what I've read 
and investigated, there isn't much evidence of major megafaunal extinctions 
during previous interglacial thaws. That's an important part of the evidence 
that humans were linked to the Pleistocene extinction -- our widespread 
presence was something that differed from prior interglacials. 

Jeff Hecht, science & technology writer
jeff@jeffhecht.com  http://www.jhecht.net