Ecosystem damages in integrated assessment models of climate change

The impacts on biodiversity and ecosystems are among the key reasons for concern about climate change. Integrated assessment models are the main tools used to estimate the global economic benefits of policies that would address climate change, but these models typically include only a partial accounting and idiosyncratic treatment of ecosystem impacts. This report reviews several recent studies of the impacts of climate change on biodiversity. We also review recent quantitative estimates of the rate of species extinctions, the impact of climate change on biodiversity, and the value of biodiversity loss. Based on these estimates, we re-calibrate the biodiversity loss function in the FUND integrated assessment model, and we develop a new global biodiversity nonuse value function. These could serve as replacements for the functions currently used in FUND, or as a preliminary ecosystem damage function in a new integrated assessment model. We also highlight areas where further research is needed for developing more comprehensive and reliable forecasts of ecosystem damages as a result of climate change.