| Summary: | A climate change impact assessment on the potential permafrost distributions is presented in four research studies that was conducted using various locations along a geographical south-to-north study transect from 52.2°N to 82.5°N within Canada. The transect begins in Lansdowne House, Ontario, and ends at Alert, Nunavut, with intermediate locations at Big Trout Lake, Peawanuck, Fort Severn, Rankin Inlet, Resolute Bay, and Eureka. The first study established the climatic potential for permafrost at Peawanuck from 1959-2011 using the Stefan Frost (Fs) Number index and Stefan equation for active layer thicknesses. Fs and the Stefan depths demonstrated favourable potential for permafrost; however, freezing degree-days were observed to be declining. The second study examined active layers developments at five locations from 2004-2011 using the Xie-Gough Algorithm for multilayered soil profiles. Climate conditions for potential permafrost distributions were assessed and compared using Fs. The third study explored the changes in the potential permafrost using Fs under future climate warming scenarios projected by an ensemble of Global Climate Models for 2011-2100. Climate change projections within the transect indicate warming above the 1971-2000 mean air temperature baseline by +1.5 to +2.4°C for 2011-2040; +2.6 to +4.1°C for 2041-2070; and +3.3 to +7.1°C for 2071-2100. For this century, Fs projections indicate that climate conditions will remain supportive for continuous permafrost distributions at Resolute Bay, Eureka, and Alert. By 2040, conditions for Rankin Inlet indicate change from continuous to discontinuous permafrost. For Peawanuck, conditions by 2100 are projecting to be suitable for sporadic permafrost. The fourth study focuses at Peawanuck and three other locations within northern Ontario, and assessed the behaviour of palsa formation and occurrence in the context of climate change for the 2020s, 2050s, and 2080s. By the end of this century, warming projections support palsa occurrence; however, conditions will no longer support new palsa formation. Ph.D.
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