Briffa advises colleague not to let Michael Mann 'push you (us) beyond what we know is right'

Climategate 2.0: 1922.txt

cc: Eystein Jansen
date: Wed, 15 Feb 2006 11:57:07 -0700
from: Jonathan Overpeck
subject: Bullet debate number 2
to: Keith Briffa

   Hi again - as for bullet issue number 2, I agree that we don't need to go with the suggest
   stuff on solar/forcing, BUT, I agree w/ Susan that we should try to put more in the bullet
   about "Subsequent evidence" Would you pls send a new bullet that has your suggested changes
   below, and that includes something like:

   "Subsequent evidence, including x, y and z, reinforces this conclusion." Need to convince
   readers that there really has been an increase in knowledge - more evidence. What is it?
   The bullet can be longer if needed.

   Thanks, Peck

     Second
     Simply make "1000"   "1300 years. "  and delete "and unusually warm compared with the
     last 2000 years."
     It is certainly NOT our job to be discussing attribution in the 20th century - this is
     Chapter 9 - and we had no room (or any published material) to allow a discussion of
     relative forcing contributions in earlier time. Therefore a vague statement about
     "perhaps due to solar forcing" seems unjustified.
     Third
     I suggest this should be
     Taken together , the sparse evidence of Southern Hemisphere temperatures prior to the
     period of instrumental records indicates that overall warming has occurred during the
     last 350 years, but the even fewer longer regional records indicate earlier periods that
     are as warm, or warmer than, 20th century means.
     Fourth
     fine , though perhaps "warmth" instead of "warming"?
     and need to see EMIC text
     Fifth
     suggest delete
     Sixth
     suggest delete
     Peck, you have to consider that since the TAR , there has been a lot of argument re
     "hockey stick" and the real independence of the inputs to most subsequent analyses is
     minimal. True, there have been many different techniques used to aggregate and scale
     data - but the efficacy of these is still far from established. We should be careful not
     to push the conclusions beyond what we can securely justify - and this is not much other
     than a confirmation of the general conclusions of the TAR . We must resist being pushed
     to present the results such that we will be accused of bias - hence no need to attack
     Moberg . Just need to show the "most likely"course of temperatures over the last 1300
     years - which we do well I think. Strong confirmation of TAR is a good result, given
     that we discuss uncertainty and base it on more data.  Let us not try to over egg the
     pudding.
     For what it worth , the above comments are my (honestly long considered) views - and I
     would not be happy to go further . Of course this discussion now needs to go to the
     wider Chapter authorship, but do not let Susan (or Mike [Mann]) push you (us) beyond where we
     know is right.
     --
     Professor Keith Briffa,
     Climatic Research Unit
     University of East Anglia
     Norwich, NR4 7TJ, U.K.
     Phone: +44-1603-593909
     Fax: +44-1603-507784
     http://www.cru.uea.ac.uk/cru/people/briffa/

--

   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
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   University of Arizona
   Tucson, AZ 85721
   direct tel: +1 520 622-9065
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   http://www.geo.arizona.edu/