As President Obama and high-level representatives of other nations converge in Anchorage, Alaska on August 30-31 for the Conference on Global Leadership in the Arctic: Cooperation, Innovation, Engagement and Resilience (GLACIER), hosted by the U.S. Department of State, top U.S. climate scientists urge policymakers to address the critical problem of the thawing permafrost in the Arctic region.

Arctic permafrost - ground that has been frozen for many thousands of years - is now thawing because of global climate change, and the results could be disastrous and irreversible.

"The release of greenhouse gases resulting from thawing Arctic permafrost could have catastrophic global consequences," said Dr. Max Holmes, a Senior Scientist at the Woods Hole Research Center (WHRC) who has been advising State Department officials on the problem.

Thawing permafrost releases greenhouse gases (carbon dioxide and methane) into the atmosphere, which accelerates climate change, which in turn causes more thawing of the permafrost. This potentially unstoppable and self-reinforcing cycle could constitute a calamitous "tipping point."

WHRC scientists have counseled the State Department on policies that could control this problem, including reducing global carbon emissions from fossil fuel use and deforestation, and limiting emissions of "black carbon," sooty particles that darken snow and ice and hasten Arctic warming.

"Despite the importance and urgency of this problem, until now it has received little attention from policymakers," said Dr. Sue Natali, another WHRC scientist. A study published earlier this year by Dr. Natali and WHRC scientists estimated that greenhouse gases released from thawing permafrost could make it much more difficult to meet the widely held goal of limiting global warming to 2 degrees Celsius.

"The United States must lead a large-scale effort to find the tipping point - at what level of warming will the cycle of warming and permafrost thawing become impossible to stop," said Dr. Holmes. "The real and imminent threat posed by permafrost thawing must be communicated clearly and broadly to the general public and the policy community."

The key science points, implications and recommendations can be found in the WHRC Policy Brief, "Permafrost and Global Climate Change."