The social rate of discount is a crucial driver of the social cost of carbon (SCC), i.e. the expected present discounted value of marginal damages resulting from emitting one ton of carbon today. Policy makers should set carbon prices to the SCC using a carbon tax or a competitive permits...

Under conditions of risk it makes a difference whether the discount rate is determined as an expected present or as an expected future value. This difference which is dubbed as the Weitzman-Gollier puzzle has stimulated an intensive discussion which, however, is somewhat confusing. In this paper...

We discuss the selection of the socially optimal discount rate for public investment projects that entail costs and benefits in the very long run. More specifically, we examine in an expected utility framework how the uncertainty on the growth rate of the GNP per head affects this rate. Under...