Linking this to anything is
premature. We do not know if this is
even a new event. Besides, a reduction
in the sea ice should have no impact deep in the ocean bed itself. Even a noticeably warmer layer of surface
water should have no effect. The heat
has to pass through the permafrost to get anywhere bedsides.
The hemisphere has warmed over
the past half century and a range of effects have been observed. Yet I am loath to include this effect as even
a part of the observed warming.
Again methane is singled out as a
greenhouse gas which is technically true but practically this is not so as the
gas rises swiftly out of the lower atmosphere.
Shock as retreat of Arctic sea ice releases deadly greenhouse gas
Russian research team astonished after finding 'fountains' of methane
bubbling to surface
TUESDAY 13 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
In an exclusive interview with The Independent, Igor Semiletov, of the
Far Eastern branch of the Russian
Academy
"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. "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 of
them."
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.
Dr Semiletov's team published a study in 2010 estimating that the
methane emissions from this region were about eight million tonnes a year, but
the latest expedition suggests this is a significant underestimate of the phenomenon.
In late summer, the Russian research vessel Academician Lavrentiev
conducted an extensive survey of about 10,000 square miles of sea off the East
Siberian coast. Scientists deployed four highly sensitive instruments, both
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 10,000 square miles, 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,"
Dr 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 a kilometre or more wide and the emissions went
directly into the atmosphere – the concentration was a hundred times higher
than normal."
Dr Semiletov released his findings for the first time last week at the
American Geophysical Union meeting in San
Francisco
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