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Scientists find highest-ever 'flares' of methane in Arctic waters

Methane is a powerful greenhouse gas

ARCTIC OCEAN - Russian scientists studying Arctic waters found the most powerful ever methane jets shooting up from the seabed to the water's surface, they said.

Igor Semiletov, the chief scientist aboard a vessel carrying 65 scientists on a 40-day research voyage, told CNN via satellite phone that he found amounts of methane in the air over the East Siberian Sea up to nine times the global average.

Methane is a powerful greenhouse gas, with a significantly greater global warming potential than carbon dioxide, according to NASA. The methane emissions in the Arctic, fueled by the melting of permafrost on the sea floor, are one driver of climate change, NASA said.

The emissions are presenting a growing risk.

Methane levels Semiletov's team found in the air above the seawater were "extremely high," he said. "Nobody has detected these concentrations."

 

Levels are highest seen in decades of research

 

Semiletov, a professor at Tomsk Polytechnic University in Siberia, said the ship full of scientists reached the East Siberian Sea around the beginning of October.

The water is usually tough to get through due to it being "covered in ice," but Semiletov said this year was different. The water was "fully open."

The team studied more than 60 sites known to have had methane emissions at the water's surface in the past.

Each emission site varies in size. Some spread across 100 square meters of sea surface. Others can cover a square kilometer.

When the plumes of methane reach the surface, the water looks like it's boiling. The researchers take samples of the air above the bubbling columns to determine how much methane is coming out of the sea, and its potential to alter the atmosphere.

In previous trips, Semiletov said he found methane at 3, 4 or 5 parts per million at these sites, well above the average atmospheric methane concentration of 1.7 parts per million. On this trip, some of the measurements were up to 16 parts per million.

Semiletov said he embarked on 30 to 35 expeditions over the past 15 years, but on this one there were some surprises.

He said the methane emissions, which look like torches or flares, are "all increasing."

 

Building on a legacy of breakthroughs

 

Semiletov and his colleague Natalia Shakhova raised an alarm with their 2010 paper in the journal Science showing that underwater permafrost on the seabed of the Arctic shelf could melt and release methane into the ocean.

Prior to that, scientists thought the sub-sea permafrost was essentially an impermeable barrier keeping methane at bay.

In a 2012 interview published by the European Geophysical Union, Shakhova said the hydrocarbons buried beneath the Arctic shelf have potential to be a major contributor to climate change.

As permafrost on the seabed melts, it could dramatically change Earth's atmosphere, she said, noting the release of only 1% of the gas could make an impact.

"The very shallow water column and weakening permafrost" could lead to the doubling of methane in the atmosphere in "a matter of decades," Shakhova suggested.

In past trips, the scientists found the methane seeps growing year by year and summarized decades of results earlier this year in the journal Geosciences.

"It's crucially important to study the change in size of the seeps," Semiletov said.

 

The methane releases contribute to global warming

 

Semiletov said so far the increasing methane emissions are a "significant contribution" to global warming, "but not catastrophic."

However, "The public should know it would affect climate in the near future if there are increases in the rate of permafrost degradation," he said.

The scientists are expected to return to port by the end of the month and they'll have plenty of new data to process. Semiletov felt confident they'd have enough to publish "a couple of papers" based on the recent voyage.

One major takeaway, he emphasized, was the need to focus global scientific attention on the methane seeps.

"This goes beyond geo-political considerations," he said. "We need to think about how to combine our efforts to study this, because it affects everyone."


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