cc: Rwatson@worldbank.org, "'Houghton, Sir John'" , "'Yihui, Ding'" , "'Ramaswamy'" , "'Cubasch, Ulrich'" , "'Meehl, Jerry'" , "'Raper, Sarah'" , "'Wigley, Tom'" , "'Joos, Fortunat'" , "Jenkins, Geoff" , "'Leemans, Rik'" , "'Sundararaman, Ram'" , "Noguer, Maria" , "Hulme, Mike" date: Thu, 17 Jun 1999 17:17:10 -0600 from: Tom Wigley subject: Re: Simple model as a policy tool to: "Griggs, Dave" Dave, As you know, our (Sarah Raper, me and Mike Hulme) MAGICC model does all of the things you want in a user-friendly shell. Early versions included CO, NOx, VOCs and individual halocarbons, but the current version has essentially turned off the user options to tweak these emissions---for scientifically justifiable reasons. As I have noted previously, another reason for making such a model more generally available is to get away from dependence on GWPs. Papers by myself (GRL 25, 2285-2288, 1998) and myself and Steve Smith (Climatic Change, in press) have shown how flawed GWPs are when applied to realistic emissions control issues. Sarah (with people at the Hadley Ctr.) has been looking carefully at the performance of MAGICC vis a vis O/AGCMs and it is likely that improvements will be made over the next few months. Sarah is really the lead player in MAGICC currently. As a final point, you may not realize or remember that some of the early development work on MAGICC was funded by the UK Dept. of the Environment (at that time, MAGICC was called "STUGE"). Significant funding support since then has come from the EC, the US Dept. of Energy, and the US National Science Foundation. Cheers, Tom "Griggs, Dave" wrote on 06/17/99 06:03:17 AM > > To: "'Houghton, Sir John'" , "'Yihui, Ding'" > , 'Ramaswamy' , "'Cubasch, Ulrich'" > , "'Meehl, Jerry'" , "'Raper, > Sarah'" , "'Wigley, Tom'" , > "'Joos, Fortunat'" , "Jenkins, Geoff" > , "'Leemans, Rik'" > cc: Robert T. Watson-Env, "'Sundararaman, Ram'" , > "Noguer, Maria" > > Subject: Simple model as a policy tool > > ------------------------------------------------------------------------ > > Simple climate model as a policy tool > > To: Sir John Houghton > Ding Yihui > V Ramaswamy > Ulrich Cubasch > Jerry Meehl > Sarah Raper > Tom Wigley > Fortunat Joos > Geoff Jenkins > Rik Leemans > > cc. Bob Watson > N Sundararaman > M Noguer > > A subject was raised in the margins of the recent SBSTA meeting, namely > would it be possible for IPCC to produce or endorse a Simple Climate Model > (SCM) for use by the policy-making community. I believe this idea was first > raised by Tom Wigley shortly after completion of the Second Assessment > Report but at that time there was no obvious way of implementing it > (especially to achieve IPCC endorsement) and the idea was never acted upon. > However, there is clearly a need for the policy-making community to be able > to study quickly and simply the effects of various scenarios for emissions > (reductions) rather than just using GWPs. As we are in the process of > producing the TAR we have the opportunity to include such a model in the TAR > and hence to have it receive IPCC acceptance for its use as a policy tool. > However, there are a number of questions and complications to doing this, > some of which are: > > 1) If we are going to do this we need to include a section something > like "A Simple Climate Model as a Policy Tool" in one of the TAR chapters, > presumably in Chapter 9. > > 2) How do we choose one model to receive IPCC endorsement. It could be > what is considered to be the most suitable existing model for the purpose or > a hybrid model with features chosen from existing models. > > 3) What complications or difficulties might this present to owners of > simple models. > > 4) What are the inputs and outputs which the SCM would have to be of > maximum utility for the policy-making community. The details of the SCM > requirements can be worked out once we have agreed it should be included in > the TAR but the following gives an idea of the kind of possible inputs and > outputs plus data which should be available for comparison purposes: > > Inputs: > > Global emissions from CO2, CH4, N2O, CFCs, HFCs, PF6 etc > > Dates: 1760 to 2100 > > Climate sensitivity > > Other parameters which "tune" the model (recommended values > and ranges of values could be suppied). > > Outputs (at any date): > > Global mean surface temperature > > Global mean sea level > > Global rate of temperature increase > > Radiative forcing? > > Comparison data: > > Historical emissions 1760 to present day > > IS92 and SRES emissions scenarios > > S and WRE stabilisation scenarios > > 5) How will we make the chosen SCM suitable for use by the > policy-making community. At the very least IPCC would have to pay for > someone to design a user-interface and guidance material so that the model > is easy to use. > > 6) How will IPCC disseminate the model, presumably it could be put on a > web site and distributed on CD-ROM. > > If we are able to overcome any difficulties it would certainly be another > way in which IPCC could be of use to the Convention process. I would be > grateful for your views on how we might implement this proposal, > particularly 1 ñ 4 as 5 and 6 would come after the TAR has been accepted. > > I look forward to hearing from you. > > Regards > > Dave > > ------------------------------------------------------ > Dr David Griggs > IPCC WGI Technical Support Unit > Hadley Centre > Met Office > London Road > Bracknell > Berks, RG12 2SY > > Tel: +44 (0)1344 856615 > Fax: +44 (0)1344 856912 > e-mail: djgriggs@meto.gov.uk > ------------------------------------------------------