Robert Pindyck of MIT talks with EconTalk host Russ Roberts about the challenges of global warming for policy makers. Pindyck argues that while there is little doubt about the existence of human-caused global warming via carbon emissions, there is a great deal of doubt about the size of the effects on temperature and the size of the economic impact of warmer climate. This leads to a dilemma for policy-makers over how to proceed. Pindyck suggests that a tax or some form of carbon emission reduction is a good idea as a precautionary measure, despite the uncertainty.