Goulder and Stavins reply

We agree with Caldeira's view that it would be unfair to require future generations to pay the present generation for the costs of current climate policy. Our example was meant to illustrate complications that arise in evaluating policy options involving winners and losers.

Caldeira goes on to claim that discounting (and benefit–cost analysis) is not useful for problems with intergenerational impacts. Here we differ. The aggregate policy-generated gains and losses, translated by discounting into comparable units, are highly relevant for assessing public policies. But we emphasize here, as in our essay, that other considerations — including attention to other criteria of fairness — are important in policy evaluation.