Historic Change in Permafrost Distribution in Northern British Columbia and Southern Yukon Territory, Canada

• Main Author: James, Megan
• Format: Thesis
• Language: English
• Published: Université d'Ottawa / University of Ottawa 2010
• Subjects: Physical Geography.; Geomorphology.; Paleoclimate Science.; Yukon; Canada; British Columbia; Fort St. John; permafrost; Whitehorse; Alaska
• Online Access: https://dx.doi.org/10.20381/ruor-19376; http://www.ruor.uottawa.ca/handle/10393/28657

The impact of recent climate change on permafrost distribution was evaluated by repeating the 1964 survey of Roger Brown along the Alaska Highway from Whitehorse, YT to Fort St. John, BC in August 2007 and 2008. Results demonstrate that: (1) significant degradation of permafrost has occurred over the past four decades, especially in the southernmost part of the route where 67% of the permafrost sites in 1964 no longer exhibit perennially frozen conditions; (2) the mapped southern limit of discontinuous permafrost appears to have shifted roughly 75 km northward; (3) most of the permafrost still present in the study area is in peat or under thick organic mats, which probably relates to a large thermal offset or to the latent heat requirements of thawing permafrost; and (4) that where permafrost has persisted, it is very thin, discontinuous, at temperatures just below 0°C, and its location may relate in part to the existence of atmospheric temperature inversions in the region. Changes in permafrost are attributed to significant climatic warming, primarily in winter, at rates of 0.4°C to 0.5°C per decade from 1965-2008. The results augment the very limited number of field studies of long-term change to permafrost in Canada, and are relevant to northern residents who must adapt to changing permafrost conditions.