cc: Simon Tett <REDACTED>
date: Fri, 30 Jun 2000 12:30:43 -0600 (MDT)
from: Tom Wigley <REDACTED>
subject: Re: PRESCIENT: Draft plan -- updated
to: Keith Briffa <REDACTED>

Keith and Simon (and no-one else),

Paleo data cannot inform us *directly* about how the climate sensitivity
(as climate sensitivity is defined). Note the stressed word. The whole
point here is that the text cannot afford to make statements that are
manifestly incorrect. This is *not* mere pedantry. If you can tell me
where or why the above statement is wrong, then please do so.

Quantifying climate sensitivity from real world data cannot even be done
using present-day data, including satellite data. If you think that one
could do better with paleo data, then you're fooling yourself. This is
fine, but there is no need to try to fool others by making extravagant


On Fri, 30 Jun 2000, Keith Briffa wrote:

> Dear all ,
> I should first say that I have communicating directly with Simon on a
> few points, but realize that it is better to send these comments to
> everyone. My only feeling now is that we are tinkering too much at the
> margins and have passed the point of diminishing returns for this effort
> some time ago. As long as the plan does not give a false impression of
> exclusion to some of the community , it is time to get it out. The open
> meeting will provide an opportunity for soliciting the full range of
> potential proposals. The SSC will then have to decide on the balance of
> priorities. The plan expresses the rationale of the Thematic Programme well
> enough now.
> In the area of pedantry, however, I do not like the inclusion of the
> statement
> saying that palaeo -data are not likely to be able to inform us directly about
> climate sensitivity . This is a moot point , and even if true , is not needed.
> However, I do feel we need to put a limit on discussion and issue this call
> now.
> At 04:22 PM 6/30/00 +0100, Simon Tett wrote:
> >Dear All,
> > I got some more faxed comments from Tom and have incorporated
> > them into
> >the draft. I attach it for you all to look at.
> >Tom made two comments which I think need to be drawn to your attention.
> >
> >1) The current draft has a tone that suggests that model development and
> >simulations would not be funded by PRESCIENT. I don't think that was our
> >intention so I've added some text which I hope reduces that danger. Some
> >of that added text is ugly! (it was friday after all!) Please let me
> >know what you think!
> >
> >2) Tom also made a comment about paleo-estimates of climate sensitivity
> >-- the current text reflects (I hope) his faxed comment. However, I
> >don't think I agree with it! Comments please.
> >
> >3) The draft contains various comments which I'd appreciate responses on
> >as well.
> >
> >Simon
> --
> Dr. Keith Briffa, Climatic Research Unit, University of East Anglia,
> Norwich, NR4 7TJ, United Kingdom

Tom M.L. Wigley
Senior Scientist
ACACIA Program Director
National Center for Atmospheric Research
P.O. Box 3000