Thawing Permafrost Poses Much Greater Climate Threat Than Previously Known

by Duane Nichols on July 23, 2017

Mackenzie River Delta in Canada as seen by satellite (NASA)

Methane Seeps Out as Arctic Permafrost Starts to Resemble Swiss Cheese

From an Article by Bob Berwyn, InsideClimate News, July 19, 2017

PHOTO: In parts of northern Canada’s Mackenzie River Delta, seen here by satellite, scientists are finding high levels of methane near deeply thawed pockets of permafrost.

Global warming may be unleashing new sources of heat-trapping methane from layers of oil and gas that have been buried deep beneath Arctic permafrost for millennia. As the Earth’s frozen crust thaws, some of that gas appears to be finding new paths to the surface through permafrost that’s starting to resemble Swiss cheese in some areas, scientists said.

In a study released today, the scientists used aerial sampling of the atmosphere to locate methane sources from permafrost along a 10,000 square-kilometer swath of the Mackenzie River Delta in northwestern Canada, an area known to have oil and gas desposits.

Deeply thawed pockets of permafrost, the research suggests, are releasing 17 percent of all the methane measured in the region, even though the emissions hotspots only make up 1 percent of the surface area, the scientists found.

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—which suggests the methane is likely also coming from geological sources, seeping up along faults and cracks in the permafrost, and from beneath lakes.

The findings suggest that global warming will “increase emissions of geologic methane that is currently still trapped under thick, continuous permafrost, as new emission pathways open due to thawing permafrost,” the authors wrote in the journal Scientific Reports. Along with triggering bacterial decomposition in permafrost soils, global warming can also trigger stronger emissions of methane from fossil gas, contributing to the carbon-climate feedback loop, they concluded.

“This is another methane source that has not been included so much in the models,” said the study’s lead author, Katrin Kohnert, a climate scientist at the GFZ German Research Centre for Geosciences in Potsdam, Germany. “If, in other regions, the permafrost becomes discontinuous, more areas will contribute geologic methane,” she said.

Similar Findings Near Permafrost Edges

The findings are based on two years of detailed aerial atmospheric sampling above the Mackenzie River Delta. It was one of the first studies to look for sources of deep methane across such a large region.

Previous site-specific studies in Alaska have looked at single sources of deep methane, including beneath lakes. A 2012 study made similar findings near the edge of permafrost areas and around melting glaciers.

Now, there is more evidence that “the loss of permafrost and glaciers opens conduits for the release of geologic methane to the atmosphere, constituting a newly identified, powerful feedback to climate warming,” said the 2012 study’s author, Katey Walter Anthony, a permafrost researcher at the University of Alaska Fairbanks.

“Together, these studies suggest that the geologic methane sources will likely increase in the future as permafrost warms and becomes more permeable,” she said.

“I think another critical thing to point out is that you do not have to completely thaw thick permafrost to increase these geologic methane emissions,” she said. “It is enough to warm permafrost and accelerate its thaw. Permafrost that starts to look like Swiss cheese would be the type that could allow substantially more geologic methane to escape in the future.”

Róisín Commane, a Harvard University climate researcher, who was not involved with the study but is familiar with Kohnert’s work, said, “The fluxes they saw are much larger than any biogenic flux … so I think a different source, such as a geologic source of methane, is a reasonable interpretation.”

Commane said the study makes a reasonable assumption that the high emissions hotspots are from geologic sources, but that without more site-specific data, like isotope readings, it’s not possible to extrapolate the findings across the Arctic, or to know for sure if the source is from subsurface oil and gas deposits.

“There doesn’t seem to be any evidence of these geogenic sources at other locations in the Arctic, but it’s something that should be considered in other studies,” she said. There may be regions with pockets of underground oil and gas similar to the Mackenzie River Delta that haven’t yet been mapped.

Speed of Methane Release Remains a Question

The Arctic is on pace to release a lot more greenhouse gases in the decades ahead. In Alaska alone, the U.S. Geological Survey recently estimated that 16-24 percent of the state’s vast permafrost area would melt by 2100.

In February, another research team documented rapidly degrading permafrost across a 52,000-square-mile swath of the northwest Canadian Arctic.

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. Most recent studies suggest a more gradual increase in releases, but the new research adds a missing piece of the puzzle, according Ted Schuur, a permafrost researcher at Northern Arizona University.

Since the study only covered two years, it doesn’t show long-term trends, but it makes a strong argument that there is significant methane escaping from trapped layers of oil and gas, Schuur said.

“As for current and future climate impact, what matters is the flux to the atmosphere and if it is changing … if there is methane currently trapped by permafrost, we could imagine this source might increase as new conduits in permafrost appear,” he said.

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Jeremy Plester July 23, 2017 at 11:37 am

All hell breaks loose as the tundra thaws in Siberia

From an Article by Jeremy Plester, The Guardian, July 20, 2017

Strange things have been happening in the frozen tundra of northern Siberia. Last August a boy died of anthrax in the remote Yamal Peninsula, and 20 other infected people were treated and survived. Anthrax hadn’t been seen in the region for 75 years, and it’s thought the recent outbreak followed an intense heatwave in Siberia, temperatures reaching over 30C that melted the frozen permafrost.

Long dormant spores of the highly infectious anthrax bacteria frozen in the carcass of an infected reindeer rejuvenated themselves and infected herds of reindeer and eventually local people.

More recently, a huge explosion was heard in June in the Yamal Peninsula. Reindeer herders camped nearby saw flames shooting up with pillars of smoke and found a large crater left in the ground. Melting permafrost was again suspected, thawing out dead vegetation and erupting in a blowout of highly flammable methane gas.

Over the past three years, 14 other giant craters have been found in the region, some of them truly massive – the first one discovered was around 50m (160ft) wide and about 70m (230ft) deep, with steep sides and debris spread all around.

There have also been cases of the ground trembling in Siberia as bubbles of methane trapped below the surface set the ground wobbling like an airbed. Even more dramatic, setting fire to methane released from frozen lakes in both Siberia and Alaska causes some impressive flames to erupt.

Methane is of huge concern. It is more than 20 times more potent a greenhouse gas than carbon dioxide, and a massive release of methane in the Arctic could pose a significant threat to the global climate, driving worldwide temperatures even higher.

Source: https://www.theguardian.com/environment/2017/jul/20/hell-breaks-loose-tundra-thaws-weatherwatch?utm_content=bufferf9f5e&utm_medium=social&utm_source=twitter.com&utm_campaign=buffer

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