Abstract
Climate change and economic inequality are two major related global challenges, and one way climate change worsens inequality is by making heat-exposed workers less productive. While studies find hot and humid regions will lose the most productivity, it is difficult to draw direct conclusions about global economic inequality because both higher and lower-income countries are located in the tropics. We use epidemiological studies of the heat-productivity relationship to examine inequality between countries in a warmer future, with a focus on tropical regions. Climate change will cause significant heat-related productivity losses, particularly in agriculture, which mainly affect lower-income countries. This worsens global economic inequality, and increased future emissions will leave countries even less equal. We also find that inequality in the tropics will get worse even though climatic shifts are relatively similar among tropical countries, because lower-income economies are more dependent on heat-exposed outdoor work. Since labor productivity contributes to wages and economic output, our results suggest that unabated climate change will slow the development of lower-income countries, particularly if efforts are not made to help workers adapt.