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 [Manager, Climate Change Scenarios, Hadley Centre, Met Office]
Hat tip: H. Miller