Warming ocean contributes to global warming

Aug 14, 2009

The warming of an Arctic current over the last 30 years has triggered the release of methane, a potent greenhouse gas, from methane hydrate stored in the sediment beneath the seabed.

Scientists at the National Centre Southampton working in collaboration with researchers from the University of Birmingham, Royal Holloway London and IFM-Geomar in Germany have found that more than 250 plumes of bubbles of gas are rising from the seabed of the West Spitsbergen continental margin in the Arctic, in a depth range of 150 to 400 metres.

Methane released from gas hydrate in submarine sediments has been identified in the past as an agent of . The likelihood of methane being released in this way has been widely predicted.

The data were collected from the royal research ship RRS James Clark Ross, as part of the Natural Environment Research Council's International Polar Year Initiative. The bubble plumes were detected using sonar and then sampled with a water-bottle sampling system over a range of depths.

The results indicate that the warming of the northward-flowing West Spitsbergen current by 1° over the last thirty years has caused the release of methane by breaking down methane hydrate in the sediment beneath the seabed.

Professor Tim Minshull, Head of the University of Southampton's School of Ocean and Earth Science based at that the National Oceanography Centre, says: "Our survey was designed to work out how much methane might be released by future ocean warming; we did not expect to discover such strong evidence that this process has already started."

Methane hydrate is an ice-like substance composed of water and methane which is stable in conditions of high pressure and low temperature. At present, methane hydrate is stable at water depths greater than 400 metres in the ocean off Spitsbergen. However, thirty years ago it was stable at water depths as shallow as 360 metres.

This is the first time that such behaviour in response to climate change has been observed in the modern period.

While most of the methane currently released from the seabed is dissolved in the seawater before it reaches the atmosphere, methane seeps are episodic and unpredictable and periods of more vigorous outflow of methane into the atmosphere are possible. Furthermore, methane dissolved in the seawater contributes to ocean acididfication.

Graham Westbrook Professor of Geophysics at the University of Birmingham, warns: "If this process becomes widespread along Arctic continental margins, tens of megatonnes of methane per year - equivalent to 5-10% of the total amount released globally by natural sources, could be released into the ."

The team is carrying out further investigations of the plumes; in particular they are keen to observe the behaviour of these gas seeps over time.

More information: Westbrook, G. K. et al. Escape of methane gas from the seabed along the West Spitsbergen continental margin. Geophysical Research Letters doi:10.1029/2009GL039191 , 2009

Source: National Oceanography Centre, Southampton

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User comments : 6

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NeilFarbstein
2.3 / 5 (3) Aug 14, 2009
The runaway greenhouse effect might take place afer all.
If it happens its the worst news, ever.
axemaster
3 / 5 (2) Aug 14, 2009
"Warming ocean contributes to global warming"

Successful Troll is Successful.

;)
nighmare
not rated yet Aug 15, 2009
could it lead to another ice age? i wanna know
PPihkala
4 / 5 (1) Aug 15, 2009
How about collecting that methane and burning it to CO2, that is lesser GHG effector? And get some energy for consumption while doing so?
dachpyarvile
5 / 5 (1) Aug 15, 2009
That would be a great idea, PPihkala. Unfortunately, it would neither be cost effective nor would the greenies want to take money from their programs to push gigatons of GHGs 17,000 times more potent than CO2 into atmosphere as part of the manufacturing and maintenance of solar cells and panels. :)
glgist
not rated yet Aug 29, 2009
Could someone explain why this research team decided to investigate the ocean 150 feet down at this location? Is it assumed that over the last 30 years this test had been undertaken at consistent intervals so that any rate of change of methane release could be verified.

Further, how is methane, a covalent hydrocarbon, soluble in and ionic compound such as sea water - higher pressure at depth? Not sure.

Finally, what acid does methane contribute to in sea water.

My basic science does not cover any of these inconsistencies and the article was of no help.

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