cc: "'Burgess Jacquelin Prof \(ENV\)'" , date: Mon, 14 Jan 2008 20:08:57 -0000 from: "Tim Lenton" subject: RE: UKCIP08 to: "'Phil Jones'" , Phil, Tim, Thanks for the update. I wasn't criticizing UKCIP08, or at least I wasn't thinking of it at all in my comments, and I was probably over-stating my case. I was criticizing what Hadley Centre and others have claimed they can offer in terms of regional predictions. I do have serious doubts about the merits of down-scaling model output in regions where the pattern of change and therefore the boundary conditions for the regional model are not conserved across an ensemble of global model runs. The key question then is, is the UK one of these regions? (From what I have seen, it looks to be.) In such circumstances I think a probabilistic approach has to be the way to go. Tim -----Original Message----- From: Phil Jones [mailto:p.jones@uea.ac.uk] Sent: 12 December 2007 13:52 To: t.lenton@uea.ac.uk; a.j.watson@uea.ac.uk Cc: Burgess Jacquelin Prof (ENV); t.osborn@uea.ac.uk Subject: UKCIP08 Tim, Andy, Tim Osborn mentioned to me this morning that you were a little skeptical about what UKCIP08 is trying to do. Rather than knock it without knowing, I would be happy to explain it to you. I'm attaching a press release about the first of the reports (one what has happened to climate up to the present). Future climate change is uncertain, and this will be fully expressed in the remaining reports which will come out with the launch in October 08. However, if organizations of whatever kind are to react or do anything, they need to know what is most likely. UKCIP have discussed extensively with user communities across the country and in most cases UKCIP08 will be giving them the best information currently available (with our current range of uncertainties). You will note I've referred to UKCIP and UKCIP08. Between us these are two different things. UKCIP doesn't fully understand what UKCIP08 will provide and this is a problem. UKCIP are going around the country finding out what is wanted and saying what UKCIP08 will provide. UKCIP08 is developing what it will provide trying to incorporate as much as the users want, but if we know we will have no confidence to say anything we won't. UKCIP will have to educate the user community on how to use the UKCIP08 portal and more importantly how the 'output' should be used. No-one at UKCIP realises this. In essence, users want spatially detailed (5km) and high-temporal (sometimes hourly) information that users claim they need. We do ask the obvious questions on what are they using now! The HC produce this at 25km (monthly) from RCM runs, then emulated in the way David Sexton presented at a seminar in ENV back in October. This gives pdfs of variables which the Weather Generator (which CRU and Newcastle are developing) transforms into future weather. Users will then get 100 possible 30 year realizations (they won't be able to get less than this) of the percentile range they choose (e.g. 90th percentile of the single pdf for precip or a joint one with another variable, such as T). So users should then put these data through their impact model (say a crop model for wheat) to develop a pdf of their result (say yield). So from one pdf (precip/temp - depending on emissions scenario) to another pdf (of the effect on yield). This is the bit users will and are finding difficult. There are users, big and small in loads of sectors. With this approach, they will all get consistent scenarios (termed probabilistic projections - but not probabilistic is sense of dice throwing). They need something for planning purposes - it might as well be done by groups best able to do it and explain it. UKCIP08 is only 4 groups and only 4 people who know how and why it is being done the way it is. It is a quantum leap in scenario provision. You're not alone in knocking UKCIP08. The second attachment really is in confidence. I hope you won't be going down to DEFRA to complain about what UKCIP08 is doing. I spent two fruitless hours explaining what UKCIP08 will do to Lenny Smith in November. He clearly didn't listen. Maybe he thinks his expertise will be sidelined by what UKCIP08 will supply, but we need people to interpret to the impacts community what we've done (we don't have much written so far) rather than gripe and say they'll go public if they don't get a piece of the cake! Cheers Phil Prof. Phil Jones Climatic Research Unit Telephone +44 (0) 1603 592090 School of Environmental Sciences Fax +44 (0) 1603 507784 University of East Anglia Norwich Email p.jones@uea.ac.uk NR4 7TJ UK ----------------------------------------------------------------------------