Economists and Ecologists: Different Frames of Reference for Global Climate Change

Economists and ecologists, in general, have offered differing opinions about the seriousness of climate change and the need for rapid reductions in greenhouse gas emissions. Economists have tended to urge caution, focusing on the potential for large-scale cutbacks to upset the economy. Ecologists have tended to focus on the potential for catastrophic losses from climate change, and have urged extensive shifts in policy. This paper uses the tools of cost benefit analysis and the decision sciences to examine why members of the two disciplines often reach different conclusions. First, economists and ecologists start from different perspectives about what is the point of reference against which policies should be judged. Second, economists and ecologists tend to apply different discount rates to future impacts of climate change. Third, economists and ecologists are likely to interpret differently the substantive findings and expressed uncertainties of formal cost-benefit analysis. Using a simplified version of the DICE model of climate change, this paper explores how these different viewpoints can be expressed in practice.