Overlapping Generations and Environmental Policy: An Introduction

A small but growing body of literature uses overlapping generations (OLG) models to study environmental policy for long-lived problems such as climate change. An OLG model, unlike the infinitely lived representative agent model, distinguishes between impatience with respect to one¡¯s own future utility, and attitudes toward successors' utility. I discuss the problem of time inconsistency, the role of Markov perfection, and show that a class of OLG models can be studied using methods developed to analyze models of non-constant discounting. An example illustrates the techniques and determines the conditions underwhich, in equilibrium, there is under-investment or over-investment in natural capital.