On Frozen Ground

January 27, 2010

Dr. Vladimir Romanovsky, director of the Permafrost Laboratory at the University of Alaska, Fairbanks, conducts permafrost research on the North Slope of Alaska. Photo: courtesy Dr. Romanovsky

By Marcy Davis

Scientists have long known the importance of permafrost, a layer of frozen soil in circumpolar regions that is one of the first victims of a warming climate. For more than 50 years, researchers have dropped temperature sensors into boreholes at various depths all around the world to track the state of the permafrost. But much of this data remains isolated and unpublished, inaccessible to anyone hoping to track global temperature change.

But if Dr. Vladimir Romanovsky, director of the Permafrost Laboratory at the University of Alaska, Fairbanks, Geophysical Institute, has his way, an international collaboration between the United States and Russia could produce the first international permafrost network. Call it the Cold Cooperation, the scientific opposite of the Cold War.

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As one of 35 National Science Foundation-supported Arctic Observing Network (AON) projects, Romanovsky’s work will integrate 80 Alaskan borehole sites—locations where researchers study permafrost, with about 160 Russian borehole sites. This initial step will provide the baseline temperature estimates necessary to evaluate future rates of change, according to Romanovsky.

“Permafrost data is beneficial to any ecological or carbon cycle study,” said Romanovsky. “Providing our data to other studies is important. In turn, we want to know about ecosystems, and have to be able to take into account hydrology and vegetation changes. Establishing this network will facilitate better communication and data sharing.”

Improved Modeling

In addition, the network will make permafrost data more available to climate modelers, which should improve researchers’ abilities to predict and understand the interaction between permafrost and climate.

Permafrost

Permafrost, defined as any earth material at or below 0°C for two or more consecutive years typically forms in the Arctic, subarctic, Antarctica, and in high alpine regions. It can vary in extent and thickness, and the largest area of continuous permafrost underlies the Tibetan Plateau in China with an area totaling 2.5 million square kilometers, more than twice the size of Alaska. Eastern Siberia holds the record for thickest permafrost at 1400 meters.

Domestically, permafrost in the Rocky Mountains of North America is laterally discontinuous, or patchy, with thicknesses ranging from less than one to several meters. Where temperatures are consistently colder, the permafrost is thicker.

Along Alaska’s North Slope, permafrost is continuous except under big lakes and rivers, which do not freeze completely to the bottom in winter; water acts as a source of heat to the ground below. At Prudhoe Bay, permafrost is 660 m thick. In Alaska’s interior, permafrost is discontinuous, found mostly in stands of black spruce and in low valleys where moss and peat are prevalent; Aspen groves and south-facing slopes rarely have permafrost.

Changes To Frozen Ground

Romanovsky has observed temperature changes in Alaskan permafrost, but added that interpreting those changes is difficult. Natural oscillations that last multiple decades show the same patterns; researchers need more time to understand whether or not their results result from longer-term, global climate change.

“The cycle seems on an upward trend,” he said. “What we see could be global warming, or could just be a longer natural oscillation. What are interesting are the hemispherical similarities between Alaska and Russia. Models can help explain past temperatures and future projections regionally and globally. So, we need to keep making measurements.”

Threats To Permafrost

One of the biggest concerns about warming permafrost is that greenhouse gases such as methane now sequestered in permafrost may be released back into the atmosphere, thereby creating a positive feedback for future climate warming. Another worry stems from the potential impacts of thawing permafrost on the communities, which could include localized but important changes in ecosystems and infrastructure.

Romanovsky says, “We are seeing changes in permafrost, but they are slowly evolving changes. There could be dangers for people who live in permafrost regions so they should be aware of the problem, but should not panic. Instead, we need to focus on mitigation, and working together. We have some ways to tackle these problems, but it takes time and money.”


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