From: Stefan Rahmstorf <rahmstorf@ozean-klima.de>
To: Tim Osborn <t.osborn@uea.ac.uk>
Subject: Re: latest draft of 2000-year section text
Date: Tue, 28 Feb 2006 18:32:25 +0100
Cc: Keith Briffa <k.briffa@uea.ac.uk>, jto@u.arizona.edu, eystein.jansen@geo.uib.no, Fortunat Joos <joos@climate.unibe.ch>, drind@giss.nasa.gov

   Hi Tim,
   my simplistic interpretation as an outside observer of this field is:
   VS04 published a high-profile analysis in Science concluding that the performance of the
   MBH method is disastrously bad. Subsequently, VS in the media called the MBH result
   "nonsense", accused Nature of putting their sales interests above peer review when
   publishing MBH, and called the IPCC "stupid" and "irresponsible" for highlighting the
   results of MBH. This had *major* political impact - I know this e.g. from EU negotiators
   who were confronted with this stuff by their US colleagues.
   Then it turns out that they implemented the method incorrectly. If it is done as MBH did,
   variance is still somewhat underestimated in the same pseudoproxy test, but only a little,
   within the error bars given by MBH and shown by IPCC. Certainly nothing dramatic - one
   could conclude that the method works reasonably well but needs improvement. This would have
   been a technical discussion with not much political impact.
   What VS and their colleagues are doing now, rather than publishing a correction of their
   mistake, is saying: "well, but if we add a lot more noise, or use red noise, then the MBH
   method is still quite bad..."
   The question here is: should our IPCC chapter say something to correct the wrong impression
   which had the political impact, namely that the MBH method is disastrously bad? This is not
   the same as the legitimate discussion about the real errors in proxy reconstructions, which
   accepts that these reconstructions have some errors but are still quite useful, rather than
   being "nonsense".
   Cheers, Stefan
--
To reach me directly please use: [1]rahmstorf@ozean-klima.de
(My former addresses @pik-potsdam.de are read by my assistant Brigitta.)

Stefan Rahmstorf
[2]www.ozean-klima.de
[3]www.realclimate.org

References

   1. mailto:rahmstorf@ozean-klima.de
   2. http://www.ozean-klima.de/
   3. http://www.realclimate.org/

