Rapid rise in Arctic methane shocks scientists – ‘Some plumes are 1 kilometer or more wide’
By Steve Connor
14 December 2011 Dramatic and unprecedented plumes of methane – a greenhouse gas 20 times more potent than carbon dioxide – have been seen bubbling to the surface of the Arctic Ocean by scientists undertaking an extensive survey of the region. 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, Dr Igor Semiletov, of the Far Eastern branch of the Russian Academy of Sciences, said that he had 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 1000m in diameter. It’s amazing,” Semiletov said. “I was most impressed by the sheer scale and high density of the plumes. Over a relatively small area, we found more than 100 but, over a wider area, there should be thousands.” Scientists estimate that there are hundreds of millions of tonnes of methane gas locked away beneath the Arctic permafrost, which extends from the mainland into the seabed of the relatively shallow sea of the East Siberian Arctic Shelf. One of the greatest fears is that with the disappearance of the Arctic sea-ice in summer, and rapidly rising temperatures across the entire region, which are already melting the Siberian permafrost, the trapped methane could be suddenly released into the atmosphere, leading to rapid and severe climate change. Semiletov’s team published a study last year estimating that the methane emissions from this region were about 8 million tonnes a year, but the latest expedition suggests this is a significant underestimate of the phenomenon. In late northern summer, the Russian research vessel Academician Lavrentiev conducted an extensive survey of about 25,900sq km of sea off the East Siberian coast. Scientists deployed four highly sensitive instruments, seismic and acoustic, to monitor the “fountains” – or plumes – of methane bubbles rising to the sea surface from beneath the seabed. “In a very small area, less than [25,900sq km], we have counted more than 100 fountains, or torch-like structures, bubbling through the water column and injected directly into the atmosphere from the seabed,” Semiletov said. “We carried out checks at about 115 stationary points and discovered methane fields of a fantastic scale – I think on a scale not seen before. Some plumes were 1km or more wide and the emissions went directly into the atmosphere – the concentration was 100 times higher than normal.” Semiletov released his findings for the first time last week at the American Geophysical Union meeting in San Francisco.
Theoretically, a vigorous methane plume can lower the density of the water enough to sink a ship.
If the methane gets trapped under the ice or there is an exceptionally windless day, and some brave soul ignites it *and* someone takes a good pic of it, you think people will then take this seriously?
Perhaps if they lit a match…
The methane would ignite and convert to CO2 – something less damaging.
The crudest form of geo-engineering…
Oh forget it..
When is the media going to stop using "20x more . . ." figure? Even the 2007 IPCC uses "72x more than CO2 over 20 years. . ." Over the first five years the figure is 105x.
The first thing I thought when I saw this was that the media finally got a hold of the paper, by the same scientists mentioned here, last year which claimed that 3.5 gigatons (not kidding) of annual methane releases were observed (seems to be the same paper that estimated 8 million tons, mentioned in the article here).
http://symposium2010.serdp-estcp.org/content/download/8914/107496/version/3/file/1A_Shakhova_Final.pdf
On page 33, they estimate 8 million tons (8 Tg) per year; on the next page, they say "directly observed fluxes exceed estimated by up [to] 3 orders of magnitude; Interpretation of acoustical data recorded with deployed multibeam sonar allowed moderate quantification of bottom fluxes as high as 44 g/m2/d (Leifer et al., in preparation). Prorating these numbers to the areas of hot spots (210×103 km2) adds 3.5Gt to annual methane release from the ESAS. This is enough to trigger abrupt climate change (Archer, 2005)."
Anon. Yes, it is time they started updating their statements on the GW potential of methane. I am usually the lone voice pointing this out. Glad to see someone else pitching in.
Michael, that was the Shakhova presentation from last year. The latter figure I took to mean "this is what will happen if the most intense plumes grow and spread."
I believe Shakhova was along on the latest scientific mission to the area with Semiletov–they are associates.
But this is based on new readings, not a rehash of that older data.
An international team of scientists was rushed up to the Arctic 'on short notice' in September to study a reported 'dramatic' increase in methane release. It is sounding as if the releases were dramatic indeed.
Corroborating evidence now seems to be showing up in some of the closest (buts still quite distant) monitoring stations such as Barrow, Alaska which show a very large spike in methane concentrations, and Cold Bay, which, along with Barrow, shows more moderate increases in CO2, what methane immediately starts to oxidize into.
http://www.esrl.noaa.gov/gmd/dv/iadv/graph.php?code=BRW&program=ccgg&type=ts
It would be a vast understatement to say that this is a worrying development.