date: Fri Aug 1 11:24:24 2003 from: Mike Hulme subject: Re: IPCC 4th Assessment Report - inputs to WGI to: "Andrew Watson" Thanks Andy - I've forwarded on these comments, along with some of my own. Mike At 12:48 22/07/2003 +0100, you wrote: Hi Mike I feel that the AR4 planning process should be aware of the problems that have arisen from the TAR WG1 treatment of the ocean carbon cycle. Perhaps Susan Solomon's invitation is a good opportunity to raise this? I'm not sure of the reason why, but the degree of insight on the marine side of the carbon cycle was considerably less than that on the terrestrial or atmospheric side in the TAR. Almost un-noticed, for the TAR, the IPCC moved from the use of ocean carbon cycle models as the primary method of gauging the ocean sink, to the use of atmospheric O2/N2 measurements. They did not notice (or at any rate did not highlight) the significance of the large discrepancy between these two techniques when applied to the period of the 1990s, which was a clear indication of something amiss in the assumptions underlying the O2/N2 method. One result is that their preferred estimates of the size of the land and ocean sinks were out of date before they were published, and quite substantially wrong. This has not enhanced the IPCC's reputation in this area of science. Getting the ocean CO2 fluxes right is important because we are much closer to being able to specify the ocean sink over wide areas from primary measurement and understanding, than is the case for terrestrial sinks and sources. Thus the main constraints on the natural CO2 sinks come from a combination of atmospheric measurements, and ocean studies. Being fully up to speed with what is happening in marine CO2 studies is therefore critical to the IPCC WG1. Cheers Andy Watson ----- Original Message ----- From: "Mike Hulme" To: ; ; ; ; ; ; ; ; ; Cc: Sent: Thursday, July 17, 2003 2:19 PM Subject: IPCC 4th Assessment Report - inputs to WGI > I thought I would circulate this invitation from Susan Solomon (IPCC WGI > Chair) inviting ideas from Convening Lead Authors in the 3rd Assessment for > consideration in the Working Group 1 report of the IPCC 4th > Assessment. You may have received a similar invitation anyway, or have > other routes into the IPCC AR4 scoping process (my apologies if you have), > but before I reply with any thoughts of my own I would be happy to include > suggestions from other senior ENV "climate" scientists about what WGI > should address/emphasise etc. in the next IPCC report (2007) that you feel > has not been well covered in previous reports. > > What Susan is looking for is clear from the attached. If people want to > respond separately, fine ... equally I am happy to collate others ideas > with my own and submit it as a more collective set of views from UEA. 28th > July is the deadline. > > Thanks, > > Mike