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 between a social-welfare-equivalent discount rate...

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...

Distinguishing the two rates helps resolve arguments as to whether the choice of discount rate should be based on ethical considerations or empirical information (such as market interest rates), and about whether the discount rate should serve a prescriptive or descriptive role. Separating out...