Sunday, December 18, 2011

1122126027.txt

From: Eystein Jansen <eystein.jansen@geo.uib.no>
To: David Rind <drind@giss.nasa.gov>
Subject: Ad: Re: [wg1-ar4-ch06] Updated 6.1 (inc. Bette's comments)
Date: Sat, 23 Jul 2005 09:40:27 +0200
Reply-to: Eystein Jansen <eystein.jansen@geo.uib.no>
Cc: wg1-ar4-ch06@joss.ucar.edu

Hi David,
thanks for the reply. I think your arguments to add some comments of explanation re Pliocene warmth are convincing and that there is potential relevance for IPCC concerning lat. heat transport in a world with less land and sea ice. My concern is that I don't think the text should be interpreted to imply that the Mid Pliocene was free of Arctic sea ice and Greenland was ice free. There is evidence from the recent IODP Central Arctic Drilling (have to check what ref. to use) of sea ice cover through the Pliocene. I have publishet on IRD evidence for a Greenland ice sheet of some sort. Concerning THC, N Atlantic data indicate strong presence of NADW akin to now, but we cannot constrain overturning rate. Both Nordic Seas an Arctic Ocean was poorly ventilated and deep water formation to feed overflows was shallover, perhaps due to higher temperature?
Instead of deleting the section I proposed, I suggest changing it as follows: After (Rind and Chadler 1991) add , "for which available proxy data are inconclusive", and
Instead of writing "absence of land ice", write " reduced extent of land and sea ice". I will find the best refs for this on Monday.
Cheers
Eystein


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