Climate effects of aerosols reduce economic inequality

The climate effects of anthropogenic aerosols have masked some of the warming induced by GHGs(1) along with some impacts of that warming(2). These temperature effects may be beneficial but are almost certainly overwhelmed by aerosols' negative health impacts(3). Recent analyses of economic impacts have concluded that warming harms economies in warm climates, but provides economic benefits in cold climates(4). Here we investigate whether aerosol-induced cooling would have a positive effect on less wealthy economies in hotter regions and a negative effect on wealthier economies in colder regions. Climate simulations over the historical period both with and without anthropogenic aerosol emissions, using a fully coupled ocean and atmosphere climate model, indicate that in year 2010 anthropogenic aerosol emissions were cooling the Earth by 0.72 +/- 0.02 degrees C relative to a scenario without such emissions. Due to opposing economic impacts in different regions, the net economic impact of aerosol-induced cooling is likely to be small at the global scale. However, these results suggest that the cooling effects of anthropogenic aerosols benefit developing tropical economies while harming developed high-latitude economies, and thus the temperature effects of past aerosol emissions have probably diminished global economic inequality.