Global Health Effects of Future Atmospheric Mercury Emissions

Abstract

Mercury (Hg) is a potent neurotoxin that poses health risks to the global population. Anthropogenic Hg emissions to the atmosphere are projected to decrease in the future due to enhanced policy efforts such as the Minamata Convention, a legally-binding international treaty entered into force in 2017. To project the health benefits of emission reduction requires considering both primary sources and recycling of previously deposited Hg from the land and ocean. Here we report the development of a comprehensive climate-atmosphere-land-ocean-ecosystem and exposure-risk model framework for Hg and its application to project the health effects of future atmospheric emissions. We find the projected Hg health risk changes nonlinearly with emission changes, and the most optimistic scenario (maximum feasible reduction, MFR) leads to Hg levels in the freshwater and marine biota half of the present-day levels. Our results show that the accumulated health effects associated with Hg exposure during 2010–2050 are $19 (range: 10–27) trillion (2020 USD) realized to 2050 (3% discount rate) for the current policy scenario. The MFR scenario is projected to have a health benefit of $2.4 trillion, while a business-as-usual scenario results in an additional $4.9 trillion health loss. Our results suggest a substantial increase in global human health cost if emission reduction actions are delayed. This comprehensive modeling approach provides a much-needed tool to help parties to evaluate the effectiveness of Hg emission controls as required by the Minamata Convention.