For each study, the net ocean and net terrestrial emissions are combined with the anthropogenic emissions to show the total emissions used in the analysis. The “net terrestrial” values shown represent the sum of net Hg(0) emissions from soil/vegetation, biomass burning, geogenic processes, and prompt reemission. In the Kikuchi et al. study (2013), several variations were presented in addition to the base case: M1 (with a new soil-emissions parameterization); M2-1 (with O₃ as an atmospheric oxidant); M2-2 (same as M2-1 but with a different treatment of polar emissions). The base case (1A) and other variations shown for this work are described in more detail in the text and involve variations in the rates of certain Hg(0) oxidation reactions, the extent of prompt Hg(II) reduction in plumes, and emissions.