Tuesday, May 22, 2012


date: Wed, 04 May 2005 09:53:42 -0400
from: "Michael E. Mann" <mannatXYZxyzginia.edu>
subject: Re: Past Millennia Reconstructions
to: Christoph Kull <christoph.kullatXYZxyzes.unibe.ch>, rbradley@geo.umass.edu, k.briffa@uea.ac.uk, tcrowleyatXYZxyze.edu

Dear Christoph,
Thanks--this looks good. Only one thing I would want to take issue with; that's the 2nd
bullet under "Accepted Robust Findings":
"There is evidence for periods of cooling (e.g. LIA) and warming (e.g. MWP)."
This statement is somewhat problematic For one thing, it's a tautology, because there "has"
to be both a warmest and coldest interval in any regional or hemispheric reconstruction,
but as many of us have pointed out in past work, it is not very useful to simply label
these "MWP" and "LIA" when they vary from region to region.
Even the hemispheric reconstructions are not even in agreement as to what the precise
timing was of the warmest or coldest periods (compare Esper et al, Moberg et al, Jones et
al, etc.). Moreover, spatial reconstructions and hemispheric reconstructions do not agree
on the timing of the minima/maxima, and so its not clear what we mean by "LIA" and "MWP" if
we're not absolutely specific (Europe, Northern Hemisphere mean? Southern Hemisphere
I suggest deleting this bullet, as it doesn't add anything.
The relevant points, in my opinion, are already raised in the "background" and accompanying
I'd be interested in what others' thoughts are,
At 09:25 AM 5/4/2005, Christoph Kull wrote:

Dear all,
After having already received some feedbacks to the message below, I would
like to ask you about your comments.
If possible, we would appreciate your input to the attached draft document
on "Proxy based climate reconstructions and modeling A PAGES view and a
basis for future activities" by end of May.
Thanks a lot for your effort, all the best and greetings from Bern,
> Dear all,
> After discussing the issue of past climate variability during the past years,
> this topic remained a burning issue for PAGES, CLIVAR, the wider scientific
> community and the public.
> Especially the fact, that the late 20th century warmth is most probably
> anomalous in the context of the past 1,000-2,000 years fuelled this
> discussion. Significant differences and uncertainties exist, however, between
> various estimates with regard to both empirical reconstructions and model
> simulations.
> PAGES gets often contacted in order to make a statement on those different
> approaches, results and related implications. In fact, it is impossible to
> have a short answer prepared and quite often, our reply remains a statement
> about the different approaches used and the range of conclusions.
> The PAGES IPO would therefore like to promote and prepare a widely agreed
> statement on that topic, thereby not judging the different approaches, but
> extracting the robust findings, their degree of (un)certainty, still open
> questions, and especially strategies for future activities to answer them.
> It is the idea to have this statement finally signed by the key-players in
> this field (e.g. you! And others). This short note would afterwards be
> available as the PAGES viewpoint to the different published results.
> Furthermore, this "general agreement" could be used as a basis for discussions
> for future related activities.
> The PAGES IPO in Bern prepared a first DRAFT (attached) while discussing
> this issue with the University of Bern scientists.
> We would highly acknowledge your edits, comments etc. on the attached document
> in order to finally have a broadly accepted statement available on our
> web-page.
> Thanks a lot for your research and finally your related effort for
> All the best and greetings from Bern,
> Christoph
Christoph Kull
Science Officer
Sulgeneckstrasse 38
CH-3007 Bern
phone: +4131 312 31 53/33
fax: +4131 312 31 68

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

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