Smith, S.L. and Burgess, M.M., 2000. Ground temperature database for northern Canada; Geological Survey of Canada Open File Report #3954, 57 p.

Permafrost, permanently frozen ground, can be found in a significant portion of the western Arctic. In the southern part of the N.W.T. and Yukon, permafrost is discontinuous and may only be present beneath 10% of the land area. Farther north, the proportion of land affected by permafrost increases and permafrost is continuous occurring everywhere except beneath deep lakes. The temperature of permafrost is within only a few degrees of 0°C in a large part of the N.W.T. and Yukon. If climate warms by up to 5°C in the next 50 to 100 years, seasonal thaw will increase, permafrost will become thinner or ultimately disappear.

Permafrost soils over a large portion of the Mackenzie Valley and Delta may contain high amounts of ice. Thawing of these soils can result in unstable ground and settlement of the ground surface. This can cause foundations for buildings and other infrastructure to become unstable. Travel may also become more difficult especially in areas serviced by winter roads which take advantage of the stability of frozen ground. As temperatures warm, the period of time over which such roads may be used will become shorter.

Over the last decade, the Geological Survey of Canada has been monitoring the depth of summer thaw in areas affected by permafrost in the Mackenzie Delta and Valley. The depth of thaw has increased with the largest increase occurring during the summer of 1998.

Nixon, F.M., Geological Survey of Canada, pers. comm. Wolfe, S.A., Kotler, E. and Nixon, F.M. 2000. Recent warming impacts in the Mackenzie Delta, Northwest Territories, and northern Yukon Territory coastal areas; Geological Survey of Canada, Current Research 2000-B1, 9 p.

The impact of climate warming on permafrost will need to be considered in the design of future structures to prevent damage. Many techniques are currently used to ensure the stability of structures if the ground thaws beneath them. For example, buildings are often built on piles anchored in permafrost or bedrock. Artificial refrigeration such as that provided by thermosyphons may have to be used to maintain stable permafrost foundations beneath a wide range of structures.

Dyke, L.D., Aylsworth, J.M., Burgess, M.M., Nixon, F.M. and Wright, F., 1997. Permafrost in the Mackenzie Basin, its influences on land-altering processes, and its relationship to climate change; in Mackenzie Basin Impact Study (MBIS), Final Report, Environmental Adaptation Research Group, Environment Canada, p. 112-117.

Smith, S.L., Burgess, M.M. and Heginbottom, J.A. (in press), Permafrost in Canada, a challenge to northern development; in G.R. Brooks (ed.), A Synthesis of Geological Hazards in Canada, Geological Survey of Canada Bulletin 548.

More information on permafrost can be found on the Geological Survey of Canada's permafrost Site and the State of the Canadian Cryosphere web site.