Tuesday, December 20, 2011


From: Stefan Rahmstorf <rahmstorf@ozean-klima.de>
To: Fortunat Joos <joos@climate.unibe.ch>
Subject: Re: latest draft of 2000-year section text
Date: Wed, 01 Mar 2006 15:55:41 +0100
Cc: Jonathan Overpeck <jto@u.arizona.edu>, Tim Osborn <t.osborn@uea.ac.uk>, Keith Briffa <k.briffa@uea.ac.uk>, cddhr@giss.nasa.gov, Eystein Jansen <eystein.jansen@geo.uib.no>

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?

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