Effects of Climate Change and Land Cover Change on Atmospheric Mercury

Abstract:

Mercury is an important pollutant that can be transported globally due to its long lifetime in the atmosphere. Atmosphere-Surface exchange is a major process affecting the cycling of mercury in the global environment. We investigate how the changes in climate and land use/land cover would affect the cycling of mercury as well as its global and regional budgets with a global chemical transport model (GEOS-Chem). On the global scale, climate change will affect the mercury budget mainly through wet deposition while land cover change has more effects on mercury dry deposition. Dry deposition flux of elemental mercury (Hg(0)) increases in most of the continental area; however, change in dry deposition flux of divalent mercury (Hg(II)) shows strong spatial variation reflecting the additional effects associated with mercury chemistry. In addition, climate change leads to decreasing surface concentrations of Hg(0) around the world except for in Southeast Asia and central part of Europe while land cover change decreases Hg(0) concentration all over the world with more in the northern hemisphere.