Learning about climate change and its implications for near-term policy

Climate change is a problem with a time scale of centuries and significant uncertainties. Current debates over appropriate greenhouse gas emission reductions, both over potential U.S. domestic action and future international accords after the Kyoto commitment period ends in 2012, focus on the overall level of reductions needed. Arguments for undertaking only very minimal steps (e.g. $7-12 per ton CO2),

1 or delaying reductions altogether remain prominent in these debates. Among the justifications for the delayed approach is that we should wait until the uncertainty about the climate system is reduced.