date: Mon, 08 Sep 2003 13:09:24 +0100
from: Suraje Dessai <s.dessai@uea.ac.uk>
subject: Fwd: RE: Climate sensitivity PDF
to: Mike Hulme <m.hulme@uea.ac.uk>

   some rather critical comments from Richard Tol on our paper ... I sent the paper around to
   the people who sent me their climate sensitivity PDFs, hence the e-mail.
   Suraje

     From: "Richard Tol" <tol@dkrz.de>
     To: "Suraje Dessai" <s.dessai@uea.ac.uk>
     Subject: RE: Climate sensitivity PDF
     Date: Mon, 8 Sep 2003 14:10:12 +0200
     X-Mailer: Microsoft Outlook IMO, Build 9.0.2416 (9.0.2910.0)
     Importance: Normal
     Hi Suraje,

     I must say that I find the working paper disturbing. The main question "are
     probabilities necessary?" has been answered a long time ago: one can support decisions
     without probabilities, but the quality of the decision necessarily increases with the
     information available. (Probabilities are information.) This is undisputed with solitary
     decision makers, and the exceptions for moral hazards and public goods are
     well-documented. Climate change is not a special problem, so all this applies.

     Your title is misleading, because you write about adaptation rather than climate change
     in general. Your quotes in your "case against probabilities" are misinterpreted; these
     people argue that other types of research have a higher priority, not that probabilities
     would not be handy in adaptation research; besides, their proposed shift in emphasis is
     towards the type of research that they would like to do, and should therefore be
     discounted.

     Best

     Richard


     Dr. Richard S.J. Tol
     Michael Otto Professor of Sustainability and Global Change
     Hamburg, Vrije and Carnegie Mellon Universities
     ZMK, Troplowitzstrasse 7, 22529 Hamburg, Germany
     +49 40 428387007/8 (voice) +49 40 428387009 (fax) tol@dkrz.de
     [1]http://www.uni-hamburg.de/Wiss/FB/15/Sustainability/tol.html

          -----Original Message-----
          From: Suraje Dessai [[2]mailto:s.dessai@uea.ac.uk]
          Sent: Saturday, September 06, 2003 6:42 PM
          To: jonathan.gregory@metoffice.com; ceforest@MIT.EDU; wigley@ucar.edu;
          knutti@climate.unibe.ch; tol@dkrz.de; schlesin@atmos.uiuc.edu
          Cc: Sarah Raper
          Subject: Fwd: Climate sensitivity PDF
          Dear all,
          Following on from the e-mail below, I attach the working paper where we published
          the climate sensitivity PDF figure. Of course this is only a snapshot in time, as
          Chris and Reto already have revised values since their papers were published. I
          assume IPCC or someone else will collect these values in the future. It would be
          interesting to have an article discussing just the climate sensitivity figure and I
          sent an outline to EOS (AGU's newsletter), but they never got back to me. If you
          think this is worthwhile pursuing let me know.
          Comments on the working paper are most welcome.
          Best wishes,
          Suraje

          Date: Tue, 11 Mar 2003 18:22:18 +0000
          To: jonathan.gregory@metoffice.com, ceforest@MIT.EDU, wigley@ucar.edu,
          knutti@climate.unibe.ch, tol@dkrz.de, schlesin@atmos.uiuc.edu
          From: Suraje Dessai <s.dessai@uea.ac.uk>
          Subject: Climate sensitivity PDF
          Cc: Sarah Raper <s.raper@uea.ac.uk>
          Dear all,
          Many thanks for the various climate sensitivity PDFs you sent me. I have plotted
          them and attached it at the request of some of you. It should be self-explanatory.
          For the purposes of my literature review on "whether climate policy needs
          probabilities or not", I interpreted the figure as follows: Essentially, different
          value judgements about which techniques to use (e.g., optimal fingerprinting,
          bootstrapping or Bayesian techniques), which GCMs/models to employ or which
          parameters to include (e.g., sulphate aerosols, solar forcing, ocean temperature,
          etc.) yield significantly different curves. Probabilities of climate change will
          remain subjective so it is extremely important for researchers to be explicit about
          their assumptions.
          I'm interested to know if you agree with this interpretation (of course data
          constraints are also a major issue) and if you have any further thoughts on this
          comparison figure. Also, have I missed out any other major studies on climate
          sensitivity PDFs?
          Best regards,
          Suraje
          ___________________________________________________________
          Suraje Dessai
          PhD Researcher
          Tyndall Centre for Climate Change Research
          School of Environmental Sciences
          University of East Anglia
          Norwich, NR4 7TJ
          United Kingdom
          Tel: + 44 (0)1603 593911
          Fax: + 44 (0)1603 593901
          E-mail: s.dessai@uea.ac.uk
          Web: [3]http://www.tyndall.ac.uk
          ___________________________________________________________

