• We are grateful to Scott Barrett, Alan Hamlin, Alan Ingham, Charles Kolstad, two anonymous referees, an associate editor, the editor and participants at seminars in Dublin, Stirling, Maastricht, University College London for comments on earlier versions of this paper. We are also grateful to David Maddison, Ray O'Brien and Laura Valentini for support for the empirical work. The usual disclaimer applies.


A number of economists have argued that the literature on the irreversibility effect implies that current abatement of greenhouse gas emissions should be greater when there is the possibility of obtaining better information in the future about the potential damages from global warming than when there is no possibility of obtaining better information. In this paper we show that even the simplest model of global warming does not satisfy either of Epstein's (1980) sufficient conditions, so it is not possible to use Epstein's analysis to tell whether the irreversibility effect applies to models of global warming. We derive an alternative sufficient condition for the irreversibility effect to hold.