Ludwig: You are mistaken on 2 counts when you said "In the absence of compelling evidence that AGW is not real or significant, we should err on the side of caution and behave as though it is very significant".

I can show you real evidence that there is NO Warming, whether anthropogenic or not, let me send you my paper showing that(email me tcurtin at bigblue.net.au). Only today A.J. Strata has shown (at WUWT) how CRU and Gistemp fiddle their time series to generate trends that do not exist in the raw data, just like Australia's BoM, as documented by Ken Stewart at Ken's Kingdom. GISS has even taken 0.7 oC off its anomaly for 1998 so that later years like 2005 and 2008 become the hottest ever.

And even if the IPCC were right that atmospheric CO2 at 560 ppm would imply an increase in GMT of 3oC (+/- 1.5), an increase in the UK's mean temperature of 10 oC would be a blessing, and likewise for Canada, much of northern USA, and most of Europe, Russia and northern China, while an extra 3 oC would not be noticeable at any of Khartoum, Dubai, and Darwin, especially when most of the increase is projected to be at night and in higher than lower latitudes, so Darwin would probably only get 2 oC at most. So what's the problem? And remember that Singapore's botanical gardens display far more biodiversity than Melbourne's or Canberra's.