The objective of this research is to characterize the dependence of optimal near-term decisions about policies to abate global climate change on two potentially important factors that have received inadequate attention in current integrated-assessment efforts: (1) selection of the evaluation endpoint and parametric form of the damage function (relating economic losses to climate change), and (2) decision making about adaptation to reduce damages. The analysis will use a combination of analytic and integrated-assessment models to evaluate the effects of changes in these factors on optimal greenhouse-gas emission paths and to develop an understanding of the reasons for these effects. The Harvard Center for Risk Analysis (HCRA) Integrated Assessment Model will be used for exploratory modeling. Compared with other integrated assessment models, the HCRA model is relatively simple and flexible, characteristics which permit rapid modification to incorporate new specifications and solutions for optimal greenhouse-gas emission trajectories. The results of this research should provide an initial understanding of the importance for climate-abatement policy of variations in the choice of endpoint and/or damage function and the magnitude and control of opportunities for adaptation. Exploration of the effect of these factors will provide information about the importance of including them in other integrated assessment activities and will help to suggest which aspects warrant greatest attention.
