Permafrost Degradation

Ground temperatures are warming even faster than air temperatures in much of the Arctic and Subarctic - a 3 degree average increase has been observed in western Canada and Alaska. [17]

This rapid ground warming raises the concern that permafrost, the permanently frozen ground that underlies much of the Arctic and Subarctic, may be severely degraded. In fact, a recent study by the Geological Survey of Canada shows that the zone of continuous permafrost has retreated about 100 kilometres north over the last century. [18]

In ice-rich areas, warming ground tempera-tures may cause ice melting followed by rapid ground collapse and the creation of an irregular landscape of channels, pits, ponds lakes and "drunken" forest (trees leaning in random directions) called thermokarst. [19] If this collapse occurs under buildings or other infrastructure, it would cause severe property damage, and possibly death or injury. A special concern is the ice-rich area of Norman Wells, where Exxon operates oil production facilities. [20]

Environment Canada warns that "The slow melting of the permafrost layer which underlies much of the Arctic tundra could turn the ground into a messy quagmire. This could affect northern transportation since in many areas surface travel is possible only when the ground is frozen solid. Buildings and other structures such as pipelines built directly on permafrost may become unstable as well. The way of life of tens of thousands of northern Canadians could be affected." [21]

Permafrost degradation can also cause landslides. A recent survey of the Mackenzie Basin by the Geological Survey of Canada has catalogued some 3400 landslides, many caused by extreme climatic events. [22] Landslides can choke rivers and streams with sediment, and can threaten buildings and other infrastructure. Most notably, the Mackenzie Valley pipeline, carrying crude oil from Norman Wells to Yellowknife on Great Slave Lake, is at risk.

Besides the dramatic impacts of sudden ground collapse and landslides, permafrost degradation can convert once solid ground into swampy wetlands releasing large quantities of methane, a greenhouse gas some 20-90 times more powerful than carbon dioxide. This has already been observed - during the unusually warm summers of 1987 and 1989, for example, methane emissions at observed sites on Alaska's North Slope increased more than three times and two times respectively. [23]