V. A Simple Climate Model Used in Economic Studies of Global Change

Analysts need to do a better job of characterizing climate “surprises” — the low-probability but high-consequence scenarios — that are driving much of the international concern about climate change. Currently, most analyses rely on models or projections that assume “smooth behavior” — i.e., the climate responds slowly and predictably, gradually warming as atmospheric GHG concentrations increase. In reality, the global climate is a complex system that could behave quite erratically. The circumstances that could drive such behavior have to do with physical characteristics of the climate system itself, as well as the rate of GHG buildup.