cc: "'Timothy Carter'" , nleary@earth.usgcrp.gov, lindam@ucar.edu, "Jones, Roger" , m.hulme@uea.ac.uk, djgriggs@meto.gov.uk, meehl@ncar.ucar.edu, "Whetton, Peter" , tkarl@ncdc.noaa.gov, m.manning@niwa.cri.nz date: Wed, 25 Oct 2000 01:06:22 -0700 (PDT) from: Stephen H Schneider subject: RE: Table 3-10 Version 3b to: "Pittock,Barrie" Hi All. I wish I disagreed with Barrie, but I have little doubt we may have a hassle at the Plenary. But if what we are doing is worthwhile--and we must have this table somewhere as the TAR is written around it already--then missing the Plenary by keeping it out of the SPM but in the TS, say, is good tactics, but I'm not sure about the overall strategy of trying to educate the public and policymakers about relative likelihoods and subjective judgments--issues I know you passionately believe in. So what to do? I've always been a believer in doing what is "right' and damn the torpedoes--why I have so many scars. But for IPCC, that is a tougher call. I'd be very interested in Martin's take on this as a veteran of more Plenaries than I. Now, as to the problem of medium confidence on indifferent outcomes--which have 50% chances if we knew nothing, let me repeat what i said in my last e-mail to all of you--which was a repeat of the guidance paper and many previous reviews few of us ever have the time to fully read: Tim, you are indeed right that medium confidence means indifference to more or less since 50% is the random event. THis is why both in umpteen e-mail reviews of SPMs and TSs (as well as in the guidance paper) I have tried--mostly in vain--to get people to make positive assertions without qualifiers like could. Then medium confidence has much more meaning. For instance, your table goes at least half way--you do specify the year and rough climate scenario. The best thing would be to make a real estimate of what might happen then--like the 10% ncrease in hurricane intensity--or give a range, say, temperature will increase by 2-4 deg C. Then a medium confidence is a pretty affirmative statement of what we think we know. Medium confidence is true, virtually by definition, when we restrict ourselves to predicting just dierction of change and haven't much extra info to push it up or down. Nevertheless, it does make sense to keep it here, since the WG 2 assignment is for consequences, and if it is consequential to have an event that we deem equally likely to happen and it matters, then so be it--this is represented by your last table with the impacted sectors explicit. Of course, it would be more controvrsial and take a sub group months to craft a real range of projections for 2100... In the best of all worlds we'd have had a group of a few dozen of us working on this thing for a year--then running it by decision analytic types, among others. We would not just puti n directions of change, but ranges for given scenarios etc. But, it is the last week before our final drafts must be in and many have written this into their texts. Remember, it isn't wrong, just not ideal. So i guess we stick with it and maybe ask Tim--as if we haven't asked him enough--to put some good discussion into chapter 3 along the lines of our e-mails discussions so the context of the table is clear there at least to the few who'll read that deeply. Finally, I think we should be cautions, but not arbitrarily downgrade stars we believe to be valid state of the science estimates because some like to subtract a star so as to not make the type 2 error. We can all do much better in the FAR!! This has been fun and i too am frustrated that we are about out of time to make it better, but i for one have go to get my chapter finished tomorrow so I'm just burned out trying to make this much better. If only.... Cheers, friends, Steve On Wed, 25 Oct 2000, Pittock,Barrie wrote: > Dear Tim et al., > > I am still trying to finish Ch.12, so I will be brief and perhaps have not > given the new changes enough thought, but, nevertheless: > > 1. The introduction of the underlining for state of the science. With all > due deference to the uncertainties paper and Steve and Roger's views, I find > this at first sight quite confusing. How can one have medium confidence in > something where the science is speculative or with competing explanations. > (Indeed, I have trouble, come to think of it, with the term "competing > explanations" when what I think is meant is competing outcomes.) OK, maybe > it is reasonable, but it will endlessly confuse lay people and critics. > > 2. Personally, I can live with the numbers of stars (maybe), but they will > cause arguments (see below). Let us nod in the direction of the cautious WG1 > colleagues where we can. All I want to see is reason to consider the > possible impacts of changes, not high confidence which may be disputed. > > 3. I would not want the table in the SPM to be approved, or disapproved, > line by line by others. It will cause horrendous delays and possibly worse. > What we need in the SPM is a general statement re changes in some important > extremes, and about their importance to impacts, perhaps singling out those > in which we have high confidence. I am inclined to duck (like WG1) in the > SPM. Maybe you can persuade me otherwise. A seriously cut down table may be > OK, but the present SPM version will cause problems. > > 4. Re TCs, I did NOT ask to downgrade TC intensity increases from 4 to 3 > stars (I have checked my email). I asked to downgrade increased frequency > from 3 stars to 2 stars. You have now made them all 3 stars. I am sure that > increased intensity is more likely than increased global numbers, and that > that relative confidence is widely supported by the TC experts. > > 5. Re a more El Nino-like mean state, I stick to wanting 3 stars. The other > worry with this one is what it means (this was behind the questions in WG1 > reported by Tim). All we are talking about is a reduced east-west > temperature gradient across the tropical Pacific. It does not necessarily > mean that everything presently correlated with ENSO will change in the same > way as in present year-to-year variability. More available water vapour may > change those observed associations in an EGH world. The more stars it has, > the more important it is to be careful about what it implies. It may need a > further footnote? > > Sorry Tim. You are doing a great job and I am sure glad you are there doing > it. > > 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. > > > -----Original Message----- > > From: Timothy Carter [SMTP:tim.carter@vyh.fi] > > Sent: Tuesday, October 24, 2000 10:50 PM > > To: nleary@earth.usgcrp.gov; shs@stanford.edu; > > barrie.pittock@dar.csiro.au; lindam@ucar.edu; roger.jones@dar.csiro.au; > > m.hulme@uea.ac.uk; djgriggs@meto.gov.uk; meehl@ncar.ucar.edu; > > peter.whetton@dar.csiro.au; tkarl@ncdc.noaa.gov; m.manning@niwa.cri.nz > > Subject: Table 3-10 Version 3b > > > > Dear colleagues, > > > > I have responded to some of the comments received to come up with a second > > attempt at Version 3. The main changes are: > > > > (1) Addition of a supplementary state of knowledge indicator for each > > entry. This was suggested by Roger and hinted at by others. I chose to > > lump > > together the "speculative" and "competing explanations", to avoid making > > the choices even more difficult than they already were. But my choices for > > all three may differ from those of others, and we are now adding a new > > layer of subjectivity to the assignment of these ratings. > > > > For example, do we regard the observed evidence or the future projections > > of intense precipitation events as "well established" or "established but > > incomplete" ..... or something else? > > > > It really needs several of us to go through all of these and suggest > > qualifiers for each one. > > > > These can easily be removed, but I thought I should try them out on you > > now. They certainly have the potential to provide useful additional > > information for the reader, but is it too late to include these now? > > > > (2) I have downgraded both categories of TC intensity to 3 stars, as > > Barrie > > suggested. > > > > (3) I retained ENSO mean state at 4 stars, although Barrie suggested > > downgrading to 3 stars. I would appreciate other views on this. Otherwise, > > all of the complex events from mid-lat storms downwards will have 3 stars > > (i.e. 50:50). Is this a fair reflection of our expectations/knowledge? > > > > (4) Some changes are included in the caption and some hail/lightning > > references plus fine tuning added to the footnotes. > > > > (5) I have converted Table 3-10 into Table 1 of the SPM and shortened the > > title and footnotes. I even managed to squeeze it onto one page. Again, > > the > > state of knowledge underlinings can be removed if we want. > > > > Are we all agreed that this should be included in the SPM? I am cautious > > about this because if it is included, I'm the one who will presumably get > > all the flak in B. Aires! > > > > Finally, is there to be a face-to-face meeting to finalise the WG II SPM > > like WG I had in NY? Some of these details could be ironed out by the SPM > > team at such a meeting. > > > > Regards, > > > > Tim > > > > <> both in word/IPCC chapter 3 > ------ Stephen H. Schneider Dept. of Biological Sciences Stanford University Stanford, CA 94305-5020 U.S.A. Tel: (650)725-9978 Fax: (650)725-4387 shs@leland.stanford.edu