Just-released analysis of atmospheric methane above the Arctic. Top photo: November 2010. Bottom photo: November 2011.
For those who have been following the studies focused on methane release in the Arctic, these pictures may be sobering - but hardly surprising. We read the reports from Natalia Shakhova and Igor Semiletov in 2010, describing a potentially dangerous new development - perforations in the permafrost on the floor of the East Siberian Arctic Shelf, which could allow a rapid release of methane from below:
A section of the Arctic Ocean seafloor that holds vast stores of frozen methane is showing signs of instability and widespread venting of the powerful greenhouse gas, according to the findings of an international research team led by University of Alaska Fairbanks scientists Natalia Shakhova and Igor Semiletov.
The research results, published in the March 5 edition of the journal Science, show that the permafrost under the East Siberian Arctic Shelf, long thought to be an impermeable barrier sealing in methane, is perforated and is starting to leak large amounts of methane into the atmosphere.
Release of even a fraction of the methane stored in the shelf could trigger abrupt climate warming.
"The amount of methane currently coming out of the East Siberian Arctic Shelf is comparable to the amount coming out of the entire world's oceans," said Shakhova, a researcher at UAF's International Arctic Research Center. "Subsea permafrost is losing its ability to be an impermeable cap."
..."Our concern is that the subsea permafrost has been showing signs of destabilization already," she said. "If it further destabilizes, the methane emissions may not be teragrams, it would be significantly larger."
Then, just last September, Shakhova and Semiletov put together a hastily-organized mission back to the Eastern Arctic. There, they "discovered methane fields of a fantastic scale", and "torch-like structures, bubbling through the water column and injected directly into the atmosphere from the seabed".
The scale and volume of the methane release has astonished the head of the Russian research team who has been surveying the seabed of the East Siberian Arctic Shelf off northern Russia for nearly 20 years.
In an exclusive interview with The Independent, Igor Semiletov of the International Arctic Research Centre at the University of Alaska Fairbanks, who led the 8thjoint US-Russia cruise of the East Siberian Arctic seas, said that he has never before witnessed the scale and force of the methane being released from beneath the Arctic seabed.
"Earlier we found torch-like structures like this but they were only tens of metres in diameter. This is the first time that we've found continuous, powerful and impressive seeping structures more than 1,000 metres in diameter. It's amazing," Dr Semiletov said.
...Dr Semiletov's team published a study in 2010 estimating that the methane emissions from this region were in the region of 8 million tons a year but the latest expedition suggests this is a significant underestimate of the true scale of the phenomenon.
Methane is a powerful greenhouse gas, which has been linked to abrupt changes in the Earth's climate before. During the PETM, a deadly thermal maximum event 55 million years ago, the Earth warmed very rapidly - 5C to 8C in 20,000 years. Methane is considered to be the most likely driver of this rapid climate change.
And in 2008, Lawrence Berkley National Laboratory identified potential methane releases in the Arctic as one the most serious scenarios for abrupt climate change:
... in the Arctic, methane hydrate deposits exist near the edge of the safe temperature-pressure zone; in these locales, methane release could be abrupt.
The resultant rapid warming would trigger yet more releases of methane: permafrost would melt, the deep sea would become a dead zone, the hole in the Arctic ozone would grow bigger and occur more frequently.
Back in 2008, Shakhova and Semiletov concluded that "release of up to 50 Gt of predicted amount of hydrate storage [is] highly possible for abrupt release at any time". That would result in "∼12-times increase of modern atmospheric methane burden with consequent catastrophic greenhouse warming."
Are these new pictures confirmation that an abrupt release of methane is imminent?
We may know soon - Shakhova and Semiletovplan to publish their findings from the 2011 mission next month.