"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 analyze a repeated game in which countries are polluting as well as investing in technologies. While folk theorems point out that the first best can be sustained as a subgame-perfect equilibrium when the players are sufficiently patient, we derive the second best equilibrium when they are...

Climate policy needs to set incentives for actors who face imperfect, distorted markets and large uncertainties about the costs and benefits of abatement. Investors price uncertain assets according to their expected return and risk (carbon beta). We study carbon pricing and financial incentives...