Alaska’s thawing permafrost and the global implications

A mysterious, largely unseen remnant of the last ice age, permafrost is soil that has remained frozen for more than two years. Though rarely obvious on the ground surface, permafrost lies beneath 20 percent of the world’s surface and 80 percent of Alaska. This wide distribution has scientists like UAF’s Vladimir Romanovsky traveling the globe during the International Polar Year to visit existing permafrost observatories, to establish new sites, and to reestablish old ones.

Romanovsky, a professor of geophysics at the Geophysical Institute, was on his way to Greenland in late August 2007, just days after returning from Siberia. He was hustling to install boreholes with thermisters—strings of wires with temperature probes at different depths—in areas that researchers haven’t had time to get to yet, and reestablishing old sites that had gone dormant. He hoped to activate as many as 200 stations by the end of the IPY project, titled “The Permafrost Observatory Project: A Contribution to the Thermal State of Permafrost.”

Scientists want this baseline—worldwide measurements using the same techniques—because permafrost has been warming faster recently. Almost everywhere scientists have looked, permafrost warming has accelerated—permafrost temperatures on a transect along the trans-Alaska pipeline, for example, have increased up to 3 degrees C since 1983. Measurements from Russia, Canada, Greenland, Norway and Asia also show increases.

Much of Alaska has a frozen foundation. North of the Brooks Range, permafrost is generally found everywhere you might dig a hole. Farther south, permafrost is spotty but still plentiful. On Alaska’s North Slope, permafrost ranges in thickness from about 700 to as much as 2,240 feet thick, and may be as cold as minus 8 to minus 10 degrees C. South of the Yukon River, permafrost is much thinner and is just within one-to-two degrees below thawing temperatures—what scientists call “warm permafrost.”

Why should people care about the thawing of frozen soil, especially when most of the time they can’t see it happening? People who live in far-north communities like Fairbanks drive on roads built over permafrost all the time. When permafrost rich with ice thaws beneath roads, the roads slump above the now-empty space. Solid permafrost foundations beneath a good number of homes in Fairbanks can fail the same way.

For years, builders have kept permafrost frozen by raising houses off the ground to keep warmth from seeping into the ground. Engineers have also designed systems with heat exchangers that keep the soil frozen beneath roads and pipelines, but if the climate continues to warm, people may be forced to refrigerate the soil to keep it frozen, as Alyeska Pipeline Service Co. currently does for the pipeline in an area south of the Alaska Range.

Much of the permafrost around Fairbanks—and Alaska-wide south of the Yukon River—is warm permafrost. If a warming trend that began in the 1970s continues, the significant portion of warm permafrost will start to thaw in the next few decades. While getting the ice out of the soil may seem like a welcome relief to those who build roads, houses, bridges and pipelines, it will be a bad thing for the thousands of people who now live on houses above permafrost and use roads, bridges and pipelines built over permafrost. Air temperatures in Fairbanks have increased 1.5 degrees C in the last 20 years. During the same period, Bettles warmed by 1.4 degrees and Gulkana by 1.3 degrees. If the increase is consistent for the next 20 years, residents are going to notice a dramatic difference in Alaska and other northern places, Romanovsky says.

What does permafrost matter to people who don’t live or drive on frozen soil? Scientists consider the far northern portions of the globe as “carbon sink” with more storage of carbon than the amount of carbon emitted. In forms such as methane (CH4) and carbon dioxide (CO2), greenhouse gases make the planet warmer. Since so much carbon is stored within frozen soil, a warmer north could soon be a source of carbon, leaking more greenhouse gases.

Romanovsky has become UAF’s go-to guy when media seeking out global change stories visit Alaska. He has been at UAF since 1992, learning the craft from people like Geophysical Institute professor emeritus Tom Osterkamp, who initiated the series of borehole measurements in sites along the trans-Alaska pipeline, which is strung across the state from north to south. When Osterkamp retired, Romanovsky became the dean of permafrost scientists at UAF. His approachable nature and ability to put science in simple terms have made him a favorite of people like Alan Alda, who interviewed Romanovsky for the PBS television series Scientific American Frontiers.

With a dozen research projects underway involving himself and several postdocs and graduate students, Romanovsky recently received a different $915,000 National Science Foundation grant to initiate a climate model that will help scientists map permafrost changes in Greenland and Alaska and try to predict future changes.

Born in Russia and now a U.S. citizen, the former hockey defenseman at Moscow State University has spoken with or knows of all the permafrost researchers in Siberia and other areas of northern Russia, where scientists who study frozen ground outnumber those who do it in the U.S. Permafrost underlies more than 80 percent of the landscape of Siberia.

Romanovsky received a $945,000 NSF grant for the project to tap into an existing network of permafrost boreholes already drilled in Russia. Many of those boreholes went unstudied after the breakup of the Soviet Union and Romanovsky is hoping to jump-start their revival and the interest of existing and future Russian permafrost scientists.

“We want to develop a new generation of permafrost scientists (with the IPY project),” he says.

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