Permafrost, or permanently frozen soil, is found continuously in most of the Western Arctic, as well as discontinuously further south (especially in shaded areas and north facing slopes). Studies have shown that permafrost is warming rapidly in both Alaska and western Canada

Permafrost Warming At Healy, Alaska

The Impacts of Global Climate Change in the Bering Sea Region

Subsurface ground temperatures from 1989-1995.

because of increasing temperatures and deeper snow packs. The zone of continuous permafrost has moved about 100 kilometers further north over the last century in Canada. Research in Alaska has concluded that most of the zone of discontinuous permafrost is close to thawing.

Permafrost thawing has profound implications for two major reasons. First, large areas of permafrost (about fifty percent in Alaska) are ice-rich. When this ice melts, the ground above can subside dramatically, up to 10 meters (30 feet) or more in some cases. Since these ice deposits are erratically distributed, permafrost thawing can transform a level ground surface into a jumble of trenches and pits. This ground disruption, called thermokarst, can destroy a forest stand, spark large landslides on river banks or coastal areas, and tear up roads, buildings and pipelines.

Dr. Tom Osterkamp, at the University of Alaska - Fairbanks, has been monitoring the temperature of permafrost at numerous sites along the Trans-Alaska pipeline for several years. He has found dramatic warming at many of these sites, warming clearly associated with increasing average air temperatures and deeper snow packs. The illustration here, showing measurements for Healy, Alaska, is a typical example. His research suggests that much of the permafrost in the discontinuous zone may be close to thawing.

Thermokarst has forced the abandonment of a hospital in Kotzebue, is ruining homes and the local schoolhouse in Kipnuk, has required the reconstruction of roads in Fairbanks and airport runways in Deadhorse, and has created large landslides and ground collapse near Tuktoyaktuk and many other places in the Arctic.

The total economic cost of thermokarst may mount into the billions of dollars. Moreover, ground subsidence, coastal landslides, increased erosion and sea level rise all combine to threaten the very existence of many coastal communities.

The second reason for concern is that organic material in thawing permafrost decays rapidly, releasing large quantities of carbon dioxide and methane. Studies in Alaska have found that the tundra has switched during the last few decades from absorbing carbon dioxide to releasing it. Moreover, large summer methane releases are closely correlated to warming temperatures.