The climate policy debate has been dominated by economic estimates of the costs of policies to reduce greenhouse gas emissions. Yet the models used to derive those estimates are based on assumptions that have largely gone untested. The conventional approach embodies structural features that rules out alternative market outcomes and possibilities for profitable energy efficiency improvements in industry. The models' characterization of decision-making by individuals and firms is seriously incomplete, and in many cases inconsistent with the empirical evidence. In addition, the pattern of distribution of 'climate rights' is crucial to determining the economic effects of various policies, as well as the economic consequences of different ethical approaches to the problem of intergenerational equity. Bringing these considerations to the forefront shows how domestic and international policy solutions might be found. Stephen J. DeCanio concludes that a much more active approach to climate protection is justified.