Thursday, September 13, 2007

Peat and Forests Slow Permafrost Melt

A recent study at McMaster University indicates that global warming may not melt the permafrost as quickly as computer models have predicted.

About 42% of Canada is covered in permafrost - frozen soil that remains at or below 0°C for at least two consecutive years.

Studies using the U.S. National Center for Atmospheric Research Community Climate Model have predicted that only a million square kilometres of the currently estimated 10.5-million square kilometres of permafrost would remain by the end of this century. But Altaf Arain, associate professor in Geography & Earth Sciences at McMaster, states that computer models have not figured in peat and vegetation.

Peat and vegetation in northern areas may help protect permafrost from the effects of climate change, according to Arain.

"A layer of peat above the permafrost acts as insulation by trapping air pockets, which reduce heat transfer and helps permafrost retention," he says. "Vegetation can also help slow the rate at which permafrost melts because it shades the ground."

The study, entitled Impacts of peat and vegetation on permafrost degradation under climate warming, was published in Geophysical Research Letters in August and also appeared in Nature Geosciences this month.

McMaster University

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