cc: "Phil Jones" date: Tue, 16 Oct 2007 13:43:11 +0100 from: "Jenkins, Geoff" subject: RE: Romans in Britain to: "Stott, Peter" Thanks. I think I will say: "Anecdotal evidence, for example the growing of grapes in the medieval period, has been used to imply that current warm temperatures in England have not been influenced by human activities. However, the popularity of grape growing is related to many other factors apart from temperature, and the longest temperature record in existence (that for the Low Countries (van Engelen, refernce??)) indicates a medieval warm period that was cooler than current temperatures". OK? I am not very convinced by it myself, but it's the best I can think of. Realclimate points out that "attribution doesn't depend on previous climates changes", which I have used myself, but doesnt seem to apply here, does it, because you use the lack of any natural warming from obs/model as the way to rule out natural causes for the last 50 years. van Engelen (Fig 6 in UKCIP02) seems to show sustained warmings as big as 1970-2000 in the 1300s. Change of subject. In K&S you say "....it is likely that there has been a sig human influence on the recent warming of CET...". I is the word "likely" meant to have IPCC connotations ie GT 66%? BTW I didn't think much of the 9 errors article on realclimate, particularly the points on SLR and on Kilimanjaro. Much too defensive of Gore. Geoff -----Original Message----- From: Stott, Peter Sent: 16 October 2007 13:10 To: Jenkins, Geoff Cc: Jones, Gareth S Subject: Re: Romans in Britain Geoff, http://www.realclimate.org/index.php?p=322 has an extensive discussion of English wine growing. Also http://www.realclimate.org/index.php/archives/2006/11/english-vineyards- again/ Socio economic factors are more important than climate. Phil Jones can tell you all about Vine Street in London which isn't anything to do with vineyards I gather. The observed variability on the 200 years we looked at in Karoly and Stott agreed with the modelled variability - in fact the unforced control model had about the same variability as the (presumably naturally forced) observed variability, indicating the model had too much (not too little) variability. If there was greater unforced variability pre 1700 than post 1700 than that could I suppose invalidate our conclusions but I don't know any evidence there was, during the last 2000 years or so. A whole industry of bloggers out there are debating the 9 "errors" and now realclimate has weighed in. http://www.realclimate.org/ Peter On Tue, 2007-10-16 at 11:09 +0100, Jenkins, Geoff wrote: > Peter > > What is the line to take, please, on "It was warmer in England in > Roman times - grapes etc - so the Karoly & Stott attribution of recent > CET warming to man is rubbish". > > Thanks > > Geoff > > Dr Geoff Jenkins > Manager, Climate Change Scenarios > Hadley Centre > Met Office > FitzRoy Road, EXETER, EX1 3PB, UK > tel: +44 (0) 787 966 1136 > geoff.jenkins@metoffice.gov.uk > www.metoffice.gov.uk >