cc: Phil Jones ,Mike Salmon , Keith Briffa ,Clare Goodess , "Aurelie Persechino" , date: Thu, 13 Jul 2006 12:36:23 +0100 from: Tim Osborn subject: Re: BA festival - Global Warming to: "Laura Middleton" Dear Laura, here is the next graph for the BA exhibit. This one is from the IPCC TAR 2001 summary for policymakers (fig SPM-2) if you want to read the detailed caption. This is the "attribution modelling plot" listed under the "Instrumental climate record" part of the CRU outline. Some explanation of this graph: ----------------------- The purpose is to see if we can understand the causes of past temperature changes (the measured/observed changes are shown in red in all cases). The grey band in each panel are the range of temperatures simulated by a climate model. In the top left, the climate model is responding only to natural changes in the sun's output and volcanic "dust". It is clear that the observed warming cannot be explained by these natural changes. In the top right, the climate model is responding only to human-related changes ("anthropogenic"), principally increasing greenhouse gas concentrations. The overall amount of observed warming appears to be explained by these human-related effects, but the timing of when the warming took place is not explained by these human-related effects alone. In the bottom panel, the climate model is responding to both natural and human-related changes. It provides an excellent explanation of the observed changes in temperature. ----------------------- Cheers Tim Attachment Converted: "c:\eudora\attach\understandingpastwarming.png" Dr Timothy J Osborn, Academic Fellow Climatic Research Unit School of Environmental Sciences, University of East Anglia Norwich NR4 7TJ, UK e-mail: t.osborn@uea.ac.uk phone: +44 1603 592089 fax: +44 1603 507784 web: http://www.cru.uea.ac.uk/~timo/ sunclock: http://www.cru.uea.ac.uk/~timo/sunclock.htm **Norwich -- City for Science: **Hosting the BA Festival 2-9 September 2006