I was reading a blog entry on Kate's blog.

Quote:
New research
...concludes that the Earth’s climate is only about one-third as sensitive to carbon dioxide as the IPCC assumes. [...]

According to Schwartz’s results, which are based on the empirical relationship between trends in surface temperature and ocean heat content, doubling the CO2 concentration in the atmosphere would result in a 1.1oC increase in average temperature (0.1–2.1oC, two standard deviation uncertainty range). Schwartz’s result is 63% lower than the IPCC’s estimate of 3oC for a doubling of CO2 (2.0–4.5oC, 2SD range).