Tuesday, April 10, 2012


date: Wed Mar 1 16:54:01 2006
from: Keith Briffa <k.briffaatXYZxyz.ac.uk>
subject: Re: Fwd: Re: latest draft of 2000-year section text
to: Jonathan Overpeck <jtoatXYZxyzrizona.edu>

will do
At 16:11 01/03/2006, you wrote:

Just to you - seems you could go a little further and be more clear as Stefan suggests.
Not a major change. Your call, though. Thanks, Peck

X-Sieve: CMU Sieve 2.2
Date: Wed, 01 Mar 2006 15:55:41 +0100
From: Stefan Rahmstorf <rahmstorfatXYZxyzan-klima.de>
X-Accept-Language: en-us, en
To: Fortunat Joos <joosatXYZxyzmate.unibe.ch>
Cc: Jonathan Overpeck <jtoatXYZxyzrizona.edu>,
Tim Osborn <t.osbornatXYZxyz.ac.uk>, Keith Briffa <k.briffaatXYZxyz.ac.uk>,
cddhr@giss.nasa.gov, Eystein Jansen <eystein.jansenatXYZxyz.uib.no>
Subject: Re: latest draft of 2000-year section text
X-Provags-ID: kundenserver.de abuseatXYZxyzdenserver.de
Hi all,
let me add to Fortunat that I feel Keith and Tim have done a tremendous job in very
thorny terrain. And I agree with Peck - science has moved way past the "hockey stick"
debate, and it is great how our chapter shows that.
Nevertheless, we should remember that the Von Storch et al. (2004) critique was a
fundamental methodological critique that applies to *all* (or at least most) proxy
reconstructions - it is not just a Storch vs. Mann quarrel (although it is that as well,
of course). Hence it is worth mentioning their error, else this could still call the
entirety of our conclusions from that section into question.
Currently, our draft just says:

At present, the extent of any such bias in specific reconstructions is uncertain

This is true, but leaves in my view slightly too much room for interpretation - like, it
would still encompass the interpretation that the bias of all reconstructions is
desastrous, so they are all "nonsense" in Von Storch's words.
What about saying something along the lines:
"At present, the extent of any such bias in specific reconstructions is uncertain,
although probably not as large as suggested by Von Storch et al. (2004), whose work was
affected by a calibration error (Wahl, Ritson and Amman, 2006)."
Regards, Stefan
p.s. Tim: Are you convinced the more recent papers by the VS group use the correct
calibration? In those curves that are intended to show the pseudoproxies perform poorly
even when calibrated correctly, as long as you add a lot more noise, I wonder why the
pseudoproxies perform poorly even within the calibration interval, where they now should
be calibrated to properly reproduce the 20th C warming trend, and they don't?


Jonathan T. Overpeck
Director, Institute for the Study of Planet Earth
Professor, Department of Geosciences
Professor, Department of Atmospheric Sciences
Mail and Fedex Address:
Institute for the Study of Planet Earth
715 N. Park Ave. 2nd Floor
University of Arizona
Tucson, AZ 85721
direct tel: +1 520 622-9065
fax: +1 520 792-8795

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

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

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