Welcome! This site contains an interactive global mercury (Hg) box modeling tool developed as a companion: “Cumulative Anthropogenic Impacts of Past and Future Releases on the Global Mercury Cycle [DOI TBA] .”
The pull-down menus on the left allow you to explore and visualize how different rates proposed in the literature and varying primary anthropogenic Hg emissions and release scenarios affect the global Hg cycle.
Users interested in research applications of this model are encouraged to use the python version, available on GitHub [link pending]. For questions, troubleshooting issues, or feedback, please contact us at thackray@seas.harvard.edu.

The site has two components: a control bar (left side) and an output panel (right side). The control bar allows users to adjust key model inputs as detailed below. The output panel presents figures showing the results of user settings.

Dropdown Menus

• Compartment to plot: controls the global reservoir selected for display in the Reservoir Mass Trend and Perturbation Response plots.

• Historical releases: controls the magnitude of historical anthropogenic Hg releases (1510 – 2010). Estimates are from Streets et al. (2019), with “Best Estimate” reflecting the central value and “Low Scenario” and “High Scenario” reflecting the 80% confidence interval.

• Future releases: controls the magnitude of future anthropogenic Hg releases (2010 – 2300). Projections are based on Shared Socioeconomic Pathway (SSP) scenarios as described in Geyman et al. (2024). “SSP1-2.6” represents a lower emission bound and “SSP5-8.5” represents an upper bound among the scenarios considered.

Slider Bars

• Rates of exchange: controls the rates of key processes in the global Hg cycle. A rate is defined as F/M, where M is the mass of Hg in a source reservoir and F is the specified flux out of that reservoir. For each slider, there is also an associated dropdown menu to assign a rate from the recent literature. The complete model contains many more processes than the subset presented here.

• Natural releases: controls geogenic Hg fluxes to the atmosphere and deep ocean.

Co-authorship is appropriate if your paper benefits significantly from use of this model/code. Citation is appropriate if use of this model/code has only a marginal impact on your work or if the work is a second generation application of the model/code. Citations should refer to the original manuscript:

Geyman, B.M., Streets, D.G., Olson, C.I., Thackray, C.P., Olson, C.L., Krabbenhoft, D.P., & Sunderland, E.M. (2025). Cumulative Anthropogenic Impacts of Past and Future Releases on the Global Mercury Cycle [DOI pending]

Historical estimates are from Streets et al. (2019) with sector definitions adjusted for consistency with future projections. Future projections are based on Shared Socioeconomic Pathway (SSP) scenarios described in Geyman et al. (2024). Note that these releases reflect settings chosen in the control panel.

Historical and projected Hg burden for the selected reservoir from different sources. Sources include anthropogenic contributions from fossil fuel combustion (black), mercury production and use (red), gold and silver production (yellow), other metals production (light grey), as well as natural contributions from subaerial volcanism (orange) and deep sea hydrothermal vents (blue).

This diagram depicts global Hg budget circa the year 2010, including reservoir masses (bold) and gross fluxes between reservoirs (Gg a-1; arrows). Red arrows represent primary anthropogenic releases, and orange arrows represent natural geogenic fluxes.

This plot compares simulated values (black diamonds) against observationally constrained ranges for three key categories:

• (I) present average seawater Hg concentrations for the upper ocean (0 – 1500 m; light blue) and deep ocean (>1500 m; dark blue).
• (II) present atmospheric Hg mass (2010 - 2015; orange)
• (III) lake sediment enrichment factors describing ratios between the 20th century peak in anthropogenic Hg deposition (20thCmax; 1950 - 1990) and the pre-industrial period (1800 - 1880) and between the 20thCmax and the pre-anthropogenic natural steady state

If your selected combination of flux rates and emissions causes the model output to fall outside the observational ranges, the model configuration is likely inconsistent with real-world measurements. Observational constraints are from Shah et al. (2021) and Feinberg et al. (2022) for the atmosphere, Li et al. (2020) for sediment enrichment factors and Geyman et al. (2025) for the ocean.

This plot shows the fate of a hypothetical “pulse” of Hg introduced to the selected reservoir at time t=0. The panel shows how the Hg is redistributed among global compartments as a function of time. Note that the x-axis has a logarithmic scale. Figure adapted from Amos et al. (2013).

Amos, H. M., Jacob, D. J., Streets, D. G., & Sunderland, E. M. (2013). Legacy impacts of all‐time anthropogenic emissions on the global mercury cycle. Global Biogeochemical Cycles, 27(2), 410–421. https://doi.org/10.1002/gbc.20040

Feinberg, A., Dlamini, T., Jiskra, M., Shah, V., & Selin, N. E. (2022). Evaluating atmospheric mercury (Hg) uptake by vegetation in a chemistry-transport model. Environmental Science: Processes & Impacts, 24(9), 1303–1318. https://doi.org/10.1039/D2EM00032F

Geyman, B.M., Streets, D.G., Olson, C.I., Thackray, C.P., Olson, C.L., Krabbenhoft, D.P., and E.M. Sunderland. (2025). Cumulative Anthropogenic Impacts of Past and Future Releases on the Global Mercury Cycle. [DOI pending]

Geyman, B. M., Streets, D. G., Thackray, C. P., Olson, C. L., Schaefer, K., & Sunderland, E. M. (2024). Projecting Global Mercury Emissions and Deposition Under the Shared Socioeconomic Pathways. Earth’s Future, 12(4), e2023EF004231. https://doi.org/10.1029/2023EF004231

Li, C., Sonke, J. E., Le Roux, G., Piotrowska, N., Van der Putten, N., Roberts, S. J., et al. (2020). Unequal Anthropogenic Enrichment of Mercury in Earth’s Northern and Southern Hemispheres. ACS Earth and Space Chemistry, 4(11), 2073–2081. https://doi.org/10.1021/acsearthspacechem.0c00220

Shah, V., Jacob, D. J., Thackray, C. P., Wang, X., Sunderland, E. M., Dibble, T. S., et al. (2021). Improved Mechanistic Model of the Atmospheric Redox Chemistry of Mercury. Environmental Science & Technology, 55(21), 14445–14456. https://doi.org/10.1021/acs.est.1c03160

Streets, D. G., Horowitz, H. M., Lu, Z., Levin, L., Thackray, C. P., & Sunderland, E. M. (2019). Five hundred years of anthropogenic mercury: spatial and temporal release profiles. Environmental Research Letters, 14(8), 084004. https://doi.org/10.1088/1748-9326/ab281f

Rate references

Friedli et al. 2009 This paper estimates Hg biomass burning emissions using a carbon emission database and Hg:C ratios.

Smith-Downey et al. 2010 This paper presents a terrestrial model for Hg.

Soerensen et al. 2010 This paper presents oceanic uptake and evasion rates of Hg0.

Amos et al. (2013). Model rates are from the GEOS-Chem atmospheric CTM (Holmes et al., 2010), the Global Terrestrial Mercury Model (GTMM, Smith-Downey et al., 2010), and two ocean simulations (Soerensen et al., 2010; Sunderland and Mason, 2007).

Amos et al. 2014 Model rates are from Amos et al. (2013) with the addition of a coastal burial term and an updated terrestrial mercury sink.

Horowitz et al. 2017 This paper presents changes to the atmospheric Hg redox cycle and uses a coupled atmosphere and ocean model.

Kumar et al. 2018 This paper estimates Hg wildfire emissions using global land use, vegetation and fire activity data.

Sonke et al. 2023 This review proposes a surface budget for Hg cycling.

Zhang et al. 2023 This paper presents a surface budget from a coupled atmosphere-land-ocean model.

Zhang et al. 2024 This paper proposes new rates for oceanic uptake and evasion of Hg0.