After posing four-broad questions about uncertainty and climate change, Part 1 of this paper provides a review of basic ideas about uncertainty and its treatment in quantitative policy analysis. Part 2 reports very briefly on a series of expert elicitations of climate experts which the author and his colleagues have conducted. The final portion of the paper uses integrated assessment of climate change as a vehicle to explore some limitations to conventional policy analysis and the treatment of uncertainty. Because the climate problem is global in scope, involving many societies, and because it will involve large changes that unfold on a time-scale of several centuries, many standard analytic methods for policy analysis cannot be appropriately applied. Several such difficulties are identified and explored. Strategies for addressing a few of them are discussed. The paper closes by offering answers to the four opening questions.
