Climate Model Response Uncertainty in Projections of Climate Change Impacts on Air Quality

Abstract

Uncertainties in climate simulations can strongly propagate to estimates of climate change impacts, including its effects on air pollution. Here we use a coupled modeling framework to evaluate the role of climate model response in projections of climate-induced impacts on air quality. Within integrated economic, climate, and air pollution projections, climate model response is altered by modifying the climate sensitivity of the framework’s Earth system component. We find that variations in climate sensitivity ranging from 2.0 to 4.5 °C per doubling of CO2 can change projections of the climate penalty on O3 and PM2.5 pollution in the U.S. by more than 2 ppb and 0.5 µg m−3. The impact of uncertainty due to climate model response can be as important as that related to greenhouse gas emissions scenario or natural variability.