date: Mon, 08 Sep 2003 13:09:24 +0100 from: Suraje Dessai subject: Fwd: RE: Climate sensitivity PDF to: Mike Hulme 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" To: "Suraje Dessai" 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 Subject: Climate sensitivity PDF Cc: Sarah Raper 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 ___________________________________________________________