Nearly all discussions about the appropriate consumption discount rate for climate-change policy evaluation assume that a single discount rate concept applies. We argue that two distinct concepts and associated rates apply. We distinguish a social-welfare-equivalent discount rate appropriate for...

We examine the relative attractions of a carbon tax, a “pure” cap-and-trade system, and a “hybrid” option (a cap-and-trade system with a price ceiling and/or price floor). We show that the various options are equivalent along more dimensions than often are recognized. In addition, we...