Mercury Co-Benefits of Climate Policy in China

摘要

National commitments on the Minamata Convention on Mercury interact with other global environmental objectives, such as the Paris Agreement on climate change. Understanding the interactions between mercury and other policy interventions can help decision-makers identify more effective policies that can address multiple environmental issues simultaneously. Here, we examine how China's national climate policy focused on decarbonization affects the country's ability to meet its environmental goals related to mercury. To address environmental goals, we assess how mercury co-benefits (positive side effects that are peripheral to a policy's main goal) of a national climate policy in China could contribute to the country's commitments under the Minamata Convention. We examine climate policy scenarios in 2030 corresponding to various levels of carbon intensity reductions in addition to a business-as-usual scenario and a scenario that implements end-of-pipe controls aligned with the requirements of the Minamata Convention. Economic analysis from a computable general equilibrium model of China's economy (C-REM) provides information on changes in economic activity resulting from the climate policy scenarios. Using this economic data, we scale 2007 mercury emissions from the Emissions Database for Global Atmospheric Research (EDGAR) in a variety of sectors to 2030. We then use a global atmospheric transport model (GEOS-Chem) to project changes in mercury deposition at the regional scale in China for each policy scenario, and evaluate the resulting spatial distribution of mercury co-benefits. We find that mercury co-benefits of climate policy can lead to reductions in emissions comparable to end-of-pipe controls. We also find that regions exhibiting the greatest reductions in emissions across the policy scenarios also exhibit the greatest reductions in total mercury deposition.