University of Oxford
Friday, October 7, 2005
Mesa Laboratory, Damon Room
Estimating the odds on a high climate sensitivity
Climate sensitivity, or the final equilibrium warming resulting from a doubling of carbon dioxide levels, cannot be measured directly, since the real climate system will never be subjected to a carbon dioxide doubling and then allowed to come into equilibrium. Because we can neither observe sensitivity directly nor find observable quantities that are directly proportional to it over the full ranges of values that are consistent with current observations, any estimate of the probability that a given greenhouse gas stabilisation level might result in a "dangerous" equilibrium warming turns out to be dependent on subjective prior assumptions of the investigators and not purely on constraints provided by actual climate observations.