cc: wg1-ar4-ch06@joss.ucar.edu
date: Fri, 22 Jul 2005 11:59:29 -0600 (MDT)
from: Bette Otto-Bliesner <ottobli@ucar.edu>
subject: Re: [wg1-ar4-ch06] Updated 6.1 (inc. Bette's comments)
to: David Rind <drind@giss.nasa.gov>

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Looking more closely at the PRISM data set on the web, I would be more 
comfortable with the following changes and additions to the text:

1.  In paragraph 3, temperatures warmer (estimated by GCMs to be 2-3C 
above preindustrial).  The uneven and geographically sparse nature of the 
data cores makes me uneasy including a global warming estimate based on 
the data.

2.  In paragraph 4, I would like to see numbers (with uncertainties) of 
high-latitude and tropical warming from the data.  This is important since
we contend that the Pliocene response is different than what models
project for the future.

I think in addition to Jim Zachos we should have Alan Haywood look at this 
box ahay@bas.ac.uk.

Bette

______________________________________________
Bette L. Otto-Bliesner
Climate Change Research
National Center for Atmospheric Research
1850 Table Mesa Drive / P.O. Box 3000
Boulder, Colorado  80307
Phone:	303-497-1723
Fax:	303-497-1348
Email:	ottobli@ncar.ucar.edu
______________________________________________

On Fri, 22 Jul 2005, David Rind wrote:

> Hi  Eyestein,
>
> Thanks for your comments. With respect to the suggested changes in paragraphs 
> 1,2 and 4, they seem fine to me. However, I think we need to include in 
> paragraph 5 potential reasons as to why the substantial (and not just 
> significant) high latitude warming that appears in the mid-Pliocene record is 
> not produced in GCMs in response to higher CO2, in general - otherwise we 
> leave the reader with a big question and no possible solution. The tendency 
> of GCM simulations for the future climate to produce an NADW decrease forces 
> those simulations to have minimal high latitude warming in the North 
> Atlantic, exactly opposite the inference from the Pliocene paleo-record 
> (which is quite robust in this respect at least). If the Pliocene record is 
> indicating the opposite of what current models are predicting, it may be 
> offering us a valuable clue...
>
> The suggested reasons also include the comment that the lack of land ice at 
> high northern latitudes might be a strong contributing cause - which would 
> make it a no-analog situation, and hence not fully a GCM problem.
>
> I would favor leaving those two sentences as they were.
>
> David
>
>
> At 5:19 PM +0200 7/22/05, Eystein Jansen wrote:
>> Hi,
>> see enclosed some comments to the last version of the deep time box. I 
>> propose some deletions and some toning down of language. What do you think?
>> 
>> Eystein
>> --
>> ______________________________________________________________
>> Eystein Jansen
>> Professor/Director
>> Bjerknes Centre for Climate Research and
>> Dep. of Earth Science, Univ. of Bergen
>> Allgaten 55
>> N-5007 Bergen
>> NORWAY
>> e-mail: eystein.jansen@geo.uib.no
>> Phone:	+47-55-583491  -  Home: +47-55-910661
>> Fax: 	+47-55-584330
>> 
>> Attachment converted: Toltec:IPCC Box 6.1_latest_EJcomm.doc (WDBN/IC) 
>> (1BE54183)
>
>
> -- 
> ///////////////////////////////////////////////////////////////////////////
>
> ///////////////////////////////////////////////////////////////////////////
>
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