Pipeline bounty includes long-term permafrost research

The trans-Alaska pipeline was a boon for welders, truck drivers and thousands of others who in the ‘70s helped string the silver tube across Alaska. A permafrost scientist also saw in the bonanza a great opportunity for science.

Tom Osterkamp realized that a road traversing Alaska from north to south (to enable building and maintaining the pipeline) would allow a permafrost scientist easy access to the different types of frozen ground in Alaska—the rock-hard soil hundreds of feet thick on the North Slope, the thinner but still plentiful frozen ground north of the Yukon River, the hit-and-miss permafrost south of the Yukon, and the southernmost reaches of frozen ground near Gulkana.

Osterkamp was a permafrost researcher with the Geophysical Institute at the University of Alaska Fairbanks at the time of the pipeline’s construction. He received funding for a network of 100-to-200-feet-deep holes in the soil from Prudhoe Bay southward. Osterkamp drilled most of the 16 holes along that route in 1983. To that network of “permafrost observatories,” Osterkamp added others over the years, the farthest south in Bethel. The holes, and his dutiful years of driving across Alaska to see what they told him, have given us a good snapshot of what Alaska’s permafrost has been doing for the last quarter century.

Permafrost, ground that has remained frozen for at least two years, is a relic of a colder time that has endured in Alaska and other northern places because summer’s warmth still hasn’t overtaken winter’s cold. As Alaska’s air temperatures have warmed in the recent past, Osterkamp and his colleagues have noticed that the permafrost along the pipeline transect and elsewhere in Alaska has responded.

Since 1976-1977, when Alaska climatologists noticed a “regime shift,” after which the state became warmer in most places, Osterkamp captured some of the change on his network of boreholes. Since he installed the observatories, permafrost temperatures warmed from 3-4 degrees Celsius on the coastal plain of the North Slope, increased 1-2 degrees Celsius in the Brooks Range, and rose 0.3-1 degree Celsius south of the Yukon River in Interior Alaska. The warming in the Interior has left much of the permafrost here within one degree of thawing.

Though most of the permafrost in Alaska has gotten warmer during the past quarter century, some have bucked the trend, and Osterkamp is not sure why. Since he drilled boreholes at the Yukon River Bridge and Livengood in the 1980s, permafrost there has gotten colder. Since 1994, permafrost at an Eagle, Alaska borehole has remained stable.

Warmer air is not the only thing that can thaw permafrost, Osterkamp found. In Healy, off the now-famous Stampede Trail, permafrost thawed even though air temperatures cooled. Increased snowcover that traps the heat of the earth was the culprit, he said.

“Snow influences permafrost temperatures big-time,” Osterkamp said. “Warming of the permafrost at Healy during the late 1980s and 1990s was almost entirely due to snow cover effects there. It also played a significant role in warming permafrost along the pipeline.”

These days, Osterkamp no longer drives the Dalton Highway and stops at his boreholes. He retired from UAF in 1997, and now lives in Saint Clair, Missouri. A few years back, he handed over the monitoring of the boreholes to the Geophysical Institute’s Vladimir Romanovsky, who has expanded the program worldwide.

Now, a few decades since the word of a giant pipe across Alaska inspired Osterkamp, he is sharing one of the most valuable resources in science—the knowledge of a person who has studied something for a long time. Since his retirement, he has traveled back to Alaska many times, written 25 papers (including one due in April 2008 upon which I based this column), and three book chapters.