Permafrost in a changing climate: geohazard risk assessment and biogeochemical impacts on the environment.

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Permafrost occupies 40-50% of Canada's landmass and plays a crucial role in cold-climate environments since it affects physical, geomorphological, hydrological, and biological processes. Global warming and permafrost degradation are impacting all aspects of the landscape, including: infrastructure, vegetation productivity (greening and browning), lakes and rivers, and soil biogeochemical cycles. The microbial decomposition of stocks of organic carbon in degrading permafrost is contributing to a positive feedback in the global climate-carbon system. However, the extent of all of these changes is strongly dependent on the presence of ground ice in permafrost sediments. Ground ice (particularly excess ice) controls the rate of permafrost degradation, due to the high latent heat of ice, and the complex nature of potential feedbacks of thawing icy permafrost. Therefore, there is a need to improve our knowledge on the factors influencing the spatial and vertical distribution of ground ice in the complex permafrost system across different landscapes and at different scales to better assess the ongoing environmental changes in polar regions. To contribute to this assessment, my research program is centered on the investigation of physical and (bio)geochemical processes that shape and define the permafrost environments in the Canadian Arctic and Antarctica within a system approach framework. Over the next five years, the main goals of my research are to: (1) Quantify and predict the vertical distribution of ice and heat fluxes in continuous permafrost; (2) Quantify the effects of acid drainage disturbances on temperatures, mobility of water, and biogeochemistry of the active layer and permafrost; (3) Quantify the effect of degrading ice wedge landscapes on local topography, vegetation, hydrology and water quality; and (4) develop a critical mass of highly qualified personnel in permafrost-related topics in Canada. The research will take place mainly at: (1) Tombstone Territorial Park, central Yukon; (2) Eagle Plains, northern Yukon; and (3) Eureka Sound Lowlands on Ellesmere Island, Nunavut. These sites range from warm continuous permafrost in tundra setting to cold continuous permafrost in a polar desert environment. The proposed research program will lead to the production of the first quantitative estimate of the vertical distribution of ground ice in permafrost sediments which could be used to mitigate geohazard risks. A better understanding of the internal feedback of acid drainage and heat released during oxidation of sulphides could help develop proper thermosyphons technology to remove required ground heat to keep hundreds of abandoned tailings frozen and prevent environmental disaster on Indigenous traditional lands. Finally, the research will lead to improved assessment of the water quality from areas affected by degradation of ice wedge polygonal terrain which can help manage water resources in a changing Arctic.