[Coral-List] La Nina, and global warming

Paul Blanchon blanchons at gmail.com
Wed Nov 17 14:22:12 EST 2010

Dear Gene and list,
Here is another geologists take on it:

During the last deglaciation that started 19-18 ka ago, CO2 was not
the trigger for warming but amplified it via positive feedback to
produce a runaway ice-sheet disintegration that transformed a glacial
Earth system into an interglacial one. The trigger for warming was the
minor variation in N. Hemisphere insolation caused by orbital forcing.
This is clearly consistent with CO2 lagging warming in the ice cores
by several hundred years.

By instantaneously injecting 35% more CO2 into the atmosphere than was
present during normal interglacial conditions, humans are presently
mimicking the massive CO2 release by the oceans during deglaciation
and are further amplifying the present warm interglacial conditions,
especially in polar regions. The danger of course is that this polar
amplification will cause further ice-sheet disintegration and lead to
metre-scale sea-level rise.

Given the disturbingly rapid changes in the Arctic, Greenland, and the
West Antarctic, only Tea-Party, Bible-thumping Republicans could claim
these changes are somehow related to natural variability. For the rest
of us it's blindingly obvious.


Paul Blanchon
Marine Geoscience Lab.,
Reef Systems Unit,
Institute of Marine Sciences & Limnology
National Autonomous University of Mexico
Tel. +52  (998) 87-10009 Ext 166
Email. blanchons at gmail.com

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