ABSTRACT
Determining the optimal strategy for controlling greenhouse gases requires weighing the costs of abating these pollutants against the damages that the pollutants would otherwise cause. Although reasonably accurate measures of abatement are available for reducing greenhousegas emissions over time-see Tom Kram's paper in this volume on abatement costs-measuring the damages from greenhouse-gas emissions is more elusive. Damage estimates require integrating climate science, ecological responses, human reactions, and social values. The process involves long lags separating emissions from final consequences. The magnitude of the effects will vary across space, improving some areas and making other areas worse off. The impacts affect many sectors of the economy and many aspects of the quality of life. The impact process is dynamic, implying impacts will change over time. The impacts will affect people from many different cultures with widely varying incomes and circumstances. The values to be applied to changes will therefore vary by location, and people will disagree about which values to choose. Not surprisingly, the damages from climate change are controversial. Yet, it is imperative that the world be convinced that substantial benefits arise from controlling greenhouse gases, because there are many political and economic barriers to creating effective control programs.
