Thawing permafrost speeding up global warming

Permafrost thaw will speed up global warming, study says

CBC News,

September 11, 2012

A polar bear wanders along the Hudson Bay. New research suggets that permafrost soils in Canada's Arctic are melting at a rate that will significantly speed up global warming. (iStock)

Permafrost soils in Canada's Arctic are melting at a rate that will significantly speed up global warming, according to new research from the University of Victoria.

The study, published this week in Nature Geoscience, predicts that the thawing permafrost will release between 68 billion and 508 billion tonnes of carbon into the atmosphere by the year 2100.

As a result of those carbon emissions, researchers say the Earth's temperature will rise by more than 0.5 C by the end of the century.

Although seemingly insignificant, that amount is in addition to the two degrees the Earth's temperature is expected to rise because of global warming from industrial sources.

Andrew Weaver, a climate scientist at the University of Victoria and one of the study's authors, warns that once the planet warms by more than two degrees, the impact could be dire.

"Warming much beyond that puts an unacceptably high probability that we're committed to Greenland melting," Weaver said in an interview. "Rather large percentages of existing species become committed to extinction."

Experts estimate that permafrost soils contain 1,700 billion tonnes of carbon, about four times the amount emitted since the industrial revolution.

As the permafrost thaws because of warmer climates, trapped carbon is released into the atmosphere. This interplay between the increasing carbon emissions and increasing temperatures is a process called feedback.

Now that this process has started, not much can be done to stop it, said Weaver.

"It's like a slow, creeping cancer," he said. "Once you've set it in motion, it continues on and on and on and gains momentum."

The Arctic is undergoing a number of changes because of global warming. Last month, the amount of sea ice cover in the region melted to a record low, with experts predicting that the Arctic Ocean could become ice-free by 2030.

http://www.cbc.ca/news/technology/story/2012/09/11/science-uvic-permafrost-carbon.html