Thawing Permafrost Threatens Alaska's Foundation

Is Kipnuk sinking?

Eskimo elders in the coastal Alaska village think it might be. Tom Osterkamp thinks he might know one of the reasons why--Alaska's permafrost is warming.

Osterkamp, a Geophysical Institute professor of physics who has studied Alaska's permafrost for 25 years, recently received an e-mail message from a colleague who told him of the Kipnuk elders' concerns.

Kipnuk, located about 100 miles west of Bethel, is a treeless village where about 500 people live. The topographic map for the Kipnuk area looks like Swiss cheese because the village sits amid hundreds of lakes. Kipnuk's elevation is only about five feet above the level of the Bering Sea.

Ian Parks, the principal of Chief Paul Memorial School at Kipnuk, said buildings in the village show signs of an unstable ground surface--walls develop cracks, doors stick, and floors rise and fall.

"If you put a marble on the floor, in one year it'll roll in one direction; in the next year it'll go the other direction," Parks said.

The symptoms Parks described are consistent with those of an area that sits on top of thawing permafrost, Osterkamp said. Permafrost occurs under about 85 percent of Alaska's surface area; patches of permafrost can be found as far south as Anchorage.

If thawing permafrost is Kipnuk's problem, the villagers aren't alone. Osterkamp's recent measurements show that all permafrost south of the Yukon River is warming, and in most cases there isn't one degree left between ice and water.

Osterkamp monitors the temperature of permafrost with a network of one-inch holes drilled in permafrost throughout the state. The holes, located near Fairbanks, Anchorage, Bethel, Glennallen, Eagle, and other towns and villages, have all been telling the same story. Since 1989, each time Osterkamp has checked the temperatures of permafrost at depths from 10 to 25 meters, the permafrost has crept closer to the melting point.

A test site off Stampede Trail in Healy provides an example of what's happening to permafrost south of the Yukon River. In 1989, the permafrost temperature 10 meters under the surface was about -1.27 degrees Celsius.

In 1990, the Stampede Trail permafrost warmed to -1.07 degrees. The permafrost has warmed steadily since. When Osterkamp checked in July, 1996, the permafrost 10 meters deep was about -0.7 degrees Celsius. These tenths of a degree might not seem significant, but Osterkamp pointed out there's not much more warming that can occur before the Stampede Trail permafrost is no longer frozen.

There are two possible reasons why the permafrost has warmed south of the Yukon River, Osterkamp said. Permafrost may be responding to a warmer climate, or it may reflect the amount of snow that insulates the ground. Whatever the cause, permafrost or a sudden lack thereof may catch the attention of many Alaskans in the near future.

"If this (widespread permafrost thaw) comes about, it will change the face of southern Alaska," Osterkamp said. In addition to creating roller coaster roads and tilting buildings, thawing permafrost often causes large sections of forest to collapse, killing trees and other vegetation that live on a foundation of permafrost.

The future of permafrost south of the Yukon River isn't promising, Osterkamp said. He cited computer models that predict a 3- to 5-degree Celsius warming in the next 50 years.

"If that really occurs, it will thaw all of the permafrost south of the Yukon and most of it south of the Brooks Range," he said.

That's a chilling thought.