Mining atmospheric CO2: Assessing the efficacy of novel carbon sequestration strategies in smelter damaged ecosystems to achieve net zero GHG emissions

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Sudbury, Ontario is one of the world's largest metal mining centres, and historically has been the largest global point source of sulphur dioxide and metal particulate pollution. Through the City of Greater Sudbury's Regreening Program (of which Vale Canada LTD is an important contributor), ecosystem reclamation is a prominent goal. The Regreening Program has substantial evidence informed planning and application by industry, local, national, and global groups. Both the City and Vale have a new goal of net zero carbon (C) by 2050. To achieve this, an integrated industrial emission, energy systems and ecosystem management approach is needed that has been highlighted in the City's Community Energy and Emissions Plan. While regionally over 30,000 ha have been reforested, sequestering an estimated 500,000 Mg of C, there are ~6,000 ha of peatlands that are the densest current and potential C store in this landscape. Yet, many of these peatlands are contaminated with decades of legacy industrial emissions from smelting resulting in degraded functionality and a loss of ~100 years of sequestered C. Notably the keystone Sphagnum "peat mosses" that drive net C sequestration cannot tolerate high levels of metals or sulphur. These normally C-sequestering powerhouses are no longer operating as atmospheric C sinks in this contaminated landscape and there are no current methods to restore contaminated peatlands. Complicating the C storage potential of this landscape is the application of lime to the uplands during reforestation that further disrupts functioning of the naturally acidic peatlands. The impact of upland liming on C sequestration, whether as inadvertent direct application by aircraft or through runoff, is unknown but likely impedes C sequestration and reduces the resiliency of large residual C stocks. We aim to develop novel peatland restoration techniques to address the impacts of industrial contamination and liming and determine modifications to upland regreening efforts to enhance landscape C sequestration potential. This information will be critical to achieve net zero C within the region, and broadly in Canadian and global mining-impacted landscapes.