What are the likely changes in mercury concentration in the Arctic atmosphere and ocean under future emissions scenarios?
What are the likely changes in mercury concentration in the Arctic atmosphere and ocean under future emissions scenarios?
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在未来的排放情景下，北极大气和海洋中的汞浓度可能会发生什么变化？
DOI：
10.1016/j.scitotenv.2022.155477
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发表时间：
2022
影响因子：
9.8
通讯作者：
Selin, Noelle E.
中科院分区：
文献类型：
--
作者：
Schartup, Amina T.;Soerensen, Anne L.;Angot, Hélène;Bowman, Katlin;Selin, Noelle E.
北极汞浓度对人为汞排放和环境变化的变化作出反应。这份手稿是为2021年北极监测和评估方案汞评估编写的，探讨了北冰洋汞浓度对不断变化的初级汞排放、不断变化的海冰覆盖、河流输入和净初级生产的响应。为此，我们使用2015年汞清单和未来人为汞排放情景进行了模型分析。我们模拟未来的大气汞沉积到海洋表面作为一个通量的表面水或海冰使用三种方案：没有行动，新政策（NP），和最大可行的减少（MFR）。然后，我们使用这些情景和文献衍生的气候变量强制建立北冰洋汞循环的五室箱模型来模拟环境变化。到2050年，“不采取行动”将使汞沉积率提高51%，同时使地表水中的汞浓度增加22%，深层水中的汞浓度增加<9%。在2020年或2035年实施的两种“行动”方案（自然保护方案和最低生产率方案），到2050年，汞沉积量将减少7%（自然保护方案推迟到2035年实施）至30%（最低生产率方案在2020年实施）。在最后一种情况下，海洋汞浓度在表层下降14%，在深层下降4%。我们发现，海冰覆盖的下降施加最强的汞减少强迫北冰洋，而河流流量增加汞浓度增加。综合修正后的气候情景显示，到2050年，北冰洋的汞含量将下降≤5%。因此，我们表明，排放引起的北冰洋未来变化的幅度很可能是巨大的气候引起的影响相比。此外，这项研究强调，需要采取迅速和雄心勃勃的行动来改变北极地区的汞浓度，因为将不太雄心勃勃的减排措施（如NP）推迟到2035年可能会被2035年前排放的汞所抵消。
Arctic mercury (Hg) concentrations respond to changes in anthropogenic Hg emissions and environmental change. This manuscript, prepared for the 2021 Arctic Monitoring and Assessment Programme Mercury Assessment, explores the response of Arctic Ocean Hg concentrations to changing primary Hg emissions and to changing sea-ice cover, river inputs, and net primary production. To do this, we conduct a model analysis using a 2015 Hg inventory and future anthropogenic Hg emission scenarios. We model future atmospheric Hg deposition to the surface ocean as a flux to the surface water or sea ice using three scenarios: No Action, New Policy (NP), and Maximum Feasible Reduction (MFR). We then force a five-compartment box model of Hg cycling in the Arctic Ocean with these scenarios and literature-derived climate variables to simulate environmental change. No Action results in a 51% higher Hg deposition rate by 2050 while increasing Hg concentrations in the surface water by 22% and <9% at depth. Both “action” scenarios (NP and MFR), implemented in 2020 or 2035, result in lower Hg deposition ranging from 7% (NP delayed to 2035) to 30% (MFR implemented in 2020) by 2050. Under this last scenario, ocean Hg concentrations decline by 14% in the surface and 4% at depth. We find that the sea-ice cover decline exerts the strongest Hg reducing forcing on the Arctic Ocean while increasing river discharge increases Hg concentrations. When modified together the climate scenarios result in a ≤5% Hg decline by 2050 in the Arctic Ocean. Thus, we show that the magnitude of emissions-induced future changes in the Arctic Ocean is likely to be substantial compared to climate-induced effects. Furthermore, this study underscores the need for prompt and ambitious action for changing Hg concentrations in the Arctic, since delaying less ambitious reduction measures–like NP–until 2035 may become offset by Hg accumulated from pre-2035 emissions.