I offer a selective review of discounting and climate policy. Analytic and numerical models show that different assumptions greatly change the degree to which decisions about climate policy depend on the discount rate. I discuss a claim that standard models exaggerate the current generation's...

“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...

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...

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...