"Prices versus quantities" (Weitzman 1974), a hugely influential paper, is widely cited (and taught) in current debates about the best policy to reduce greenhouse gas emissions. The paper's criterion for ranking policies suggests that technological uncertainty favors taxes over cap and trade....

We introduce a "smart" cap and trade system that eliminates the welfare costs of asymmetric information (“uncertainty”). This cap responds endogenously to technology or macroeconomic shocks, relying on the market price of certificates to aggregate information. It allows policy makers to...

I formally relate the consequences of climate change to the time series variation in weather extensively explored by recent empirical literature. I show that reduced-form fixed effects estimators can recover the effects of climate if agents are myopic, if agents' payoff functions belong to a...