Doubt, uncertainty and ignorance
The word “doubt” has a bad connotation in the climate debate owing to the merchants of doubt meme. Richard Feynman puts the word “doubt” into the appropriate perspective in the context of science:
When a scientist doesn’t know the answer to a problem, he is ignorant. When he has a hunch as to what the result is, he is uncertain. And when he is pretty damn sure of what the result is going to be, he is still in some doubt. We have found it of paramount importance that in order to progress, we must recognize our ignorance and leave room for doubt. Scientific knowledge is a body of statements of varying degrees of certainty — some most unsure, some nearly sure, but none absolutely certain.
I became outspoken on the subject of uncertainty following the release of the CRU emails. I was hardly the first “mainstream” climate scientist to emphasize uncertainty. Steve Schneider has been generally regarded as the IPCC’s “uncertainty cop.” However Steve Schneider’s vision of climate uncertainty was that of statistical uncertainty, that could be managed in a subjective Bayesian approach using the judgment of experts.
My vision of climate uncertainty includes greater levels of uncertainty, including scenario uncertainty and ignorance. In the broader context of science and the philosophy of science, my view of uncertainty is not unusual at all. However, climate scientists have clung to Steve Schneider’s vision in an ever tightening spiral of reducing uncertainty and increasing confidence levels. I can only hope that my writings on this subject are influencing climate scientists. In any event, it seems that the science journalists are paying attention to the issue of uncertainty.