Thawing Permafrost Begins Venting Methane in Canada’s Mackenzie River Basin
Climate-busting methane is beginning to seep from thawing permafrost in Canada’s Mackenzie River Basin that is “starting to resemble Swiss cheese in some areas,” InsideClimate News reports, citing a two-year aerial sampling study published this week in the journal Scientific Reports.
“Deeply thawed pockets of permafrost, the research suggests, are releasing 17% of all the methane measured in the region, even though the emissions hotspots only make up 1% of the surface area,” ICN states. “In those areas, the peak concentrations of methane emissions were found to be 13 times higher than levels usually caused by bacterial decomposition—a well-known source of methane emissions from permafrost,” suggesting the dangerous, short-term greenhouse gas is also reaching the atmosphere from geological sources.
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“This is another methane source that has not been included so much in the models,” said lead author, Katrin Kohnert of the GFZ German Research Centre for Geosciences. “If, in other regions, the permafrost becomes discontinuous, more areas will contribute geologic methane.”
A study in Alaska in 2012 reached similar conclusions, based on sampling at the edges of permafrost areas and around melting glaciers, writes ICN correspondent Bob Berwyn.
“Together, these studies suggest that the geologic methane sources will likely increase in the future as permafrost warms and becomes more permeable,” said University of Alaska Fairbanks permafrost specialist Katey Walter Anthony, who wrote the 2012 study. “Another critical thing to point out is that you do not have to completely thaw thick permafrost to increase these geologic methane emissions,” she added. “It is enough to warm permafrost and accelerate its thaw.”
InsideClimate cites several past studies that look at the pace of permafrost degradation, with the U.S. Geological Survey projecting that 16 to 24% of Alaska’s permafrost will melt by 2100. “What’s not clear yet is whether the rapid climate warming in the Arctic will lead to a massive surge in releases of methane, a greenhouse gas that is about 28 times more powerful at trapping heat as carbon dioxide but does not persist as long in the atmosphere,” Berwyn writes. “Most recent studies suggest a more gradual increase in releases, but the new research adds a missing piece of the puzzle.”