Thursday, June 7, 2012


cc:,,, Keith Alverson <>,
date: Mon, 17 Dec 2001 14:35:38 -0500
from: "Michael E. Mann" <>
to: Keith Briffa <>, Jean-Claude Duplessy <>

Dear Jean-Claude et al,
Been travelling (AGU meeting) hence the delay in my response.
I think that such a meeting is, of course, a wonderful idea, and a natural followup to the
previous PAGES/CLIVAR meeting we held last March in Charlottesville on this/related topic.
I'm happy to help w/ the organization of this...
Coincidentally, the Charlottesville meeting report apparently just appeared in the latest
Eos (I haven't received mine yet, but I did get a reprint request) and the list of
questions/issues that were raised in the meeting report would be a natural starting place
for this workshop. Indeed, this list (see attached copy of the preprint of the Eos report)
overlaps significantly many of the points that Keith raises below, which are points that
many of us are working hard to address as completely as possible. For example, It will be
very worthwhile to discuss the results of experiments using models and synthetic
'pseudoproxy' networks that many of us are now actively engaged in.
Healthy skepticism should be welcome w/ open arms, and I look forward to Keith's
involvement in helping organize this meeting.
Please let me know what we need to do to move forward on this!
At 03:39 PM 12/11/01 +0000, Keith Briffa wrote:

At 10:23 AM 12/11/01 +0100, Jean-Claude Duplessy wrote:
Dear Jean-Claude and Peck (and the rest of you)
Here is hoping you are all battling against life's irritants and soon will find time for
a soothing and satisfying Christmas. Perhaps I am biased but I agree that the subject
you suggest is a good one - and still not one that has been sufficiently covered ( and
certainly not over exposed ). Therefore ,
I would be happy to collaborate on such a venture. Possible areas of focus include -
*trying to penetrate the mist of large regional and complex multivariate transfer
functions - and the danger of over calibration
*Timescale dependent bias in calibration ( and unrealistic extrapolation)
*potential inconsistencies in spatial as opposed to temporal field calibration
*realistic ( or not) inference from verification statistics
*calculation of (time-scale and time dependent ) reconstruction error
*Scaling from regional (and seasonal) reconstructions to hemispheric (annual) series
*anthropogenic "compromising" of climate inference
With Mike's cleverness and my cynicism , we might make an interesting meeting!
best wishes

Hi Michael and Keith,
I write you as members of the PAGES-CLIVAR WG. You certainly remember that the
WG has endorsed to address a small number of IPCC questions.
In this context, Peck and I suggest that the PAGES-CLIVAR WG promote the
organization of a meeting on the overlap between instrumental and paleo data in order to
firmly establish the degree to which paleo data are useful in the context of
instrumental observations. This new goal would be a contribution to IPCC objectives and
provides a clear answer to skeptics who have often said that proxy data are not reliable
(e.g., because some records do not exhibit evidence of recent warming).
We hope that you would be able to help in launching this action, because, among
the members of the PAGES-CLIVER WG, you have the stronger involvement in this topic.
Obviously, we shall ask help of the whole WG and other scientists who had to face
concerted actions of skeptics, but your own experience makes your help and your
involvement absolutely necessary to the success of this action.
At present, everything is open and we would greatly appreciate to have your
comments and suggestions.
Best regards
Jean-Claude DUPLESSY
laboratoire des Sciences du Climat et de l'Environnement
Laboratoire mixte CNRS-CEA
F - 91198 Gif sur Yvette cedex
- tel (33) 01 69 82 35 26
- fax (33) 01 69 82 35 68
- e-mail :

Professor Keith Briffa,
Climatic Research Unit
University of East Anglia
Norwich, NR4 7TJ, U.K.

Phone: +44-1603-593909
Fax: +44-1603-507784

Professor Michael E. Mann
Department of Environmental Sciences, Clark Hall
University of Virginia
Charlottesville, VA 22903
e-mail: Phone: (434) 924-7770 FAX: (434) 982-2137
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