More “tilted towns.” More sinking forests. And large amounts of greenhouse gases pumped out of huge expanses of land in the Canadian North.

Those are among the potential fallouts of thawing permafrost that could accelerate warming of the Earth’s climate, says a University of Guelph scientist who co-authored a new international report published today in Nature.

The paper synthesizes results from new studies about the effects of thawing across the planet’s Arctic and subarctic regions. Temperatures there have risen twice as fast as in other parts of the planet over the past 30 years.

The study summarizes data showing that continued thawing will cause prolonged, gradual release of carbon dioxide and methane into the atmosphere.

That ecosystem release will add to the larger carbon emissions caused by human activities such as burning of fossil fuels, said Prof. Merritt Turetsky, Department of Integrative Biology. She said more dire predictions that permafrost thaw will trigger abrupt climate change through rapid release of carbon are unlikely to be borne out.

Perennially frozen soils covering much of Canada’s North hold an estimated 1,330 to 1,580 billion tons of carbon, with potentially even more carbon held deeper in the frozen soil.

“Half of Canada is underlain by permafrost,” said Turetsky. “Canada is a permafrost nation.”

The new paper concludes that “the sheer size of these frozen carbon pools and the rapid changes observed in the permafrost region warrant focused attention on these remote landscapes.”

The study’s authors — from Canada, the United States and Europe — say we need to learn more about rates and amounts of carbon release from permafrost stores, including simulating permafrost processes in climate change models.

The paper also suggests improving models by differentiating between carbon dioxide and methane emissions and by understanding the impacts of gradual warming and “hot spots” of rapid thaw.

Besides the projected increase in atmospheric greenhouse gases, Turetsky said, permafrost thawing will affect resource development and infrastructure in the Arctic and subarctic.

“In Canada and Russia, it is not uncommon to see buildings tilted and sidewalks and roads damaged because of frost heave,” she said. Thawing permafrost will also threaten winter roads needed to transport goods including food and medical supplies to settlements across Canada’s North.

Last month, she was among international authors of another Nature paper that identified permafrost microbes and their role in releasing greenhouse gases under permafrost thaw.

Prof. Merritt Turetsky
Department of Integrative Biology
(519) 824-4120, Ext. 56616