The environment and the long run: a comparison of different criteria

We use growth models with natural resources to study the consequences of a ranking of intertemporal paths, due to Chichilnisky, which places weight on their very long run or limiting characteristics as well as on their characteristics over any finite period. This criterion shows more intertemporal symmetry or egalitarianism than the discounted utilitarian approach, which clearly emphasizes the immediate future at the expense of the long run. In this respect it captures the concenrs of those who argue for sustainability and for a heightened sense of responsibility to the future. In some of the examples that we consider, the long-run characteristics of paths optimal by this criterion are a mixture of those of utilitarian paths and the “green golden rule” (the configuration which maximizes long-run sustainable utility from consumption and environment).