158 - Co-benefits of Reducing Atmospheric Mercury Emission and Deposition under 1.5 ℃ Pathways in China

Achieving carbon neutrality before 2060 newly announced in China are expected to substantially affect atmospheric mercury pollution. Pathways for China to achieve 1.5℃ climate target have been comprehensively explored in recent researches. Here we selected four typical and widely accepted 1.5℃ pathways to calculate the potential Hg emission reductions with end-of-pipe control scenarios that meet China’s commitments under the Minamata Convention. Hg deposition flux in 2030 (the target year of carbon peak) and 2060 (the target year of carbon neutrality) are then simulated with GEOS-Chem model. Finally, we include two health endpoints in benefit estimates: decrement in IQ of newborns and fatal heart attack (FHA). We find that China can reduce at least 65t Hg from 2020 to 2030 only driven by 1.5℃ climate target; Different 1.5 ℃ pathways can drive additional 60t reduction; 143t can be furtherly mitigated by the strictest Minamata Convention policy. As a hopeful result, China will achieve the surface mean of Hg deposition flux in Northern Hemisphere (25 μg m-2 yr-1) by 2030. In 2060, at least 190t Hg can be reduced due to climate policy; 87t can be additional mitigated by different 1.5 ℃ pathways; with the strictest Minamata Convention policy, 43t Hg will be furtherly reduced. Finally, ambitious climate mitigation efforts for China’s carbon neutrality goals can achieve Hg deposition flux to widely below 20 μg m-2 yr-1 by 2060. The accumulated health impacts associated with Hg exposure during 2020~2060 are about $8 trillion (2020 USD), wherein $2.5 trillion are from different 1.5 ℃ pathways.