Climate Forcing by Aerosols--a Hazy Picture

Abstract
Anthropogenic aerosol emissions are believed to have counteracted the global-warming effect of greenhouse gases over the past century. However, the magnitude of this cooling effect is highly uncertain. In their Perspective, Anderson et al. argue that the magnitude and uncertainty of aerosol forcing may be larger than is usually considered in models. This would have important implications for the total climate forcing by anthropogenic emissions, and hence for predicting future global warming.