cc: j.turnpenny@uea.ac.uk date: Mon Mar 11 17:51:39 2002 from: Mike Hulme subject: unresolved issue to: wilkins_diana,jenkins_geoff Diana and Geoff, There is one issue remaining unresolved re. the Briefing Report. This concerns the Box on p.13 about levels of confidence. - DEFRA/UKCIP want the box, ideally to also include statements with M and L status also. - Hadley don't think it really works unless DIRECTION is included Tyndall therefore suggest the version below (there is just not space to include M and L statements and remember, we spent a lot more time on this than in the UKCIP98 version (p.57) which was highly arbitrary. If we cannot get agreement the demands of space would suggest we drop it! We have negotiated an extra 24 hours with the designers so please let me have your views Tuesday. Mike ____________________________________________________ Levels of confidence In the scientific report for the UKCIP02 scenarios we adopt a scale of relative confidence High, Medium and Low when presenting summary statements about future changes in UK climate. These are expert judgements made by the authors based on our understanding of the physical reasoning involved, consistency between models and statistical significance of the results. It should be emphasised that these are relative rather than absolute judgements. We summarise here the statements regarding the direction of change in which we have High Confidence (annual results unless stated): Average temperature increases Summer temperature increases more in the southeast than the northwest High temperature extremes increase in frequency Low temperature extremes decrease in frequency Sea-surface temperature warms Thermal growing season lengthens Heating degree days reduce Cooling degree days increase Winter precipitation increases Winter precipitation intensity increases Snowfall decreases Summer soil moisture decreases Specific humidity increases Sea-level rises