cc: gupta@sdalt.ernet.in, "Jones, Roger" , emilio@ppe.ufrj.br, rik.leemans@rivm.nl, lindam@ucar.edu, naki@iiasa.ac.at, "Pittock,Barrie" , semenov@glasnet.ru, j.skea@psi.org.uk, "Whetton, Peter" , "Leary, Neil (E-mail)" date: Tue, 1 Aug 2000 10:57:30 -0400 from: nleary@usgcrp.gov (Neil Leary) subject: RE: Lisbon - what regional and extreme scenarios are we to use, w to: "Pittock,Barrie" , "'Timothy Carter'" , m.hulme@uea.ac.uk Dear Barrie et al, WGI has adopted a scale for assessing confidence in conclusions that differs from the Schneider/Moss one. It's attached. I'm told that WG1 agreed at their recent authors' meeting that the attached scale would be applied to key conclusions in the SPM and TS of the WG1 report. So we may be getting clearer and more useful statements from WG1 about the likelihood for changes in various kinds of extremes. Perhaps those of you who attended the WG1 meeting can fill us in in Lisbon about the status of work on this. Did WG1 reach any agreement on confidence levels to be assigned to changes in extremes? Neil At 3:19 PM 8/1/00, Pittock,Barrie wrote: >Dear Tim and Mike, > >To reply to both your messages together.... > >I will be in Lisbon and arriving early, and staying on for the Synthesis >Report meeting after. Staying at the hotel Costa Caparica. However, note >that I carry a lot of responsibility for Ch.12, and also now for Ch.19, and >will also be involved in discussion re coral reefs across chapters. So again >I will not be able to be at anything like all of the Ch.3 discussions. Note >also that I will be in Europe after the Lisbon meeting until 4 October. I >sent contact email addresses at Oxford and Friburg (Switzerland) to you >earlier, but I hope that we can get most things settled in Lisbon >(especially so I can revise Ch.12 in Oxford). > >My main concern is that for chapter 12 we have persistent questions re what >regional and extreme event scenarios we use and what confidence can be >attached to them. We are being asked to cross-reference WGI and Chapter 3 on >this, and I am sure other chapters are getting similar comments. Of >particular concern to Ch.12 is scenarios for TC behaviour. We have attached >medium confidence to 0-20% increases in intensity for 2 X CO2 on the basis >of several papers using different methods to reach similar conclusions. We >are told by the US Govt. that we need to justify this as WGI says on page >31, lines 28-29 that "Projected changes in tropical cyclone frequency and >intensity remain inconclusive." (If that is what WGI says, we dispute it, >and the probabilities need to be clarified.) The same source also alleges >that we are attaching too much confidence to regional modelling. We dispute >this also. > >So what we need in Ch.3 is what we tried to put in the GR draft but could >not because it was not in WGI, ie., a concise statement of levels of >confidence in regional scenarios and in changes in ENSO, TCs and extreme >events, which do not assume the need for 95% confidence levels as liked by >pure scientists, but risk levels as in the agreed confidence scale which are >appropriate for applied decisionmaking. The existing Table 3-9 is a first >stab at it, but apparently it is not fully consistent with WGI?. And we do >not have a corresponding table for regional scenarios of mean changes. Peter >Whetton was trying to draw up a table of such for WGI, but I have not seen >the result (Peter went straight to a training week after returning from >Canada). So we urgently need to know what WGI has decided and what we can >put in chapter 3 and reliably use in the ensuing chapters. I suggest that >all LAs should get copies of the relevant concise WGI conclusions in Lisbon >ASAP (with citeable cross-references) so they can digest them. If the WGI >conclusions are too conservative, I suggest we will have to consider an >explanatory statement in Ch.3 as to why impacts people and decsion-makers >need to consider scenarios which WGI say have low confidence, ie., we will >need to justify entries in Table 3-9 and regional table. > >In Ch. 12 we have also been asked why we do not put in maps of regional >rainfall scenarios. I would like to use the Hulme and Sheard (1999) WWF maps >as they plot changes above 1 standard deviation and thus have a reasonable >coverage of likely changes, but the WWF report does not have the standing of >the Carter and Hulme (in press) versions of the same reults which only plot >results above 2 standard deviations, which is too conservative and gives too >poor a coverage. It is probably too late to change this, but it is a pity. > >Cheers, > >Barrie. > >Dr A. Barrie Pittock >Post-Retirement Fellow*, Climate Impact Group >CSIRO Atmospheric Research, PMB 1, Aspendale 3195, Australia >Tel: +61 3 9239 4527, Fax: +61 3 9239 4688, email: > >WWW: http://www.dar.csiro.au/res/cm/impact.htm > >* This means I am working part-time, primarily on writing for the >Intergovernmental Panel on Climate Change. Please refer any matters re the >Climate Impact Group to Dr. Peter Whetton, Group Leader, at >, tel. +61 3 9239 4535. > >"Far better an approximate answer to the right question which is often >vague, than an exact answer to the wrong question which can always be made >precise." J.W. Tukey as cited by R. Lewin, Science 221,636-639. Attachment Converted: "c:\eudora\attach\Agreed terminology.doc" Neil A. Leary, Ph.D. Head, Technical Support Unit Working Group II Intergovernmental Panel on Climate Change 400 Virginia Avenue SW, Suite 750 Washington, DC 20024 USA General number: 1 202 314-2225 Direct number: 1 202 314-2224 Fax: 1 202 488-8678 email: nleary@usgcrp.gov or ipcc@usgcrp.gov