We suggest that the best constraint on actual climate sensitivity is provided by paleoclimate data that imply a sensitivity 3 ± 1 °C for 2 CO2 [Hansen et al., 1984, 1993, 1997b; Hoffert and Covey, 1992]. (judithcurry.com)
Sory, but this is just another rationalization of the idea that «uncertainty» means we have to put even more resources into the demands of the climate obsessed, as Dr. Levi asserts, «even if those might turn out to cost more than actual climate sensitivity ultimately justifies.» (judithcurry.com)
However, because climate scientists at the time believed a doubling of atmospheric CO2 would cause a larger global heat imbalance than today's estimates, the actual climate sensitivities were approximatly 18 % lower (for example, the «Best» model sensitivity was actually closer to 2.1 °C for doubled CO2). (skepticalscience.com)