Warming of Arctic could 'turn off' Gulf stream

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08 April 2000 Saturday 02 Muharram 1421

Warming of Arctic could 'turn off' Gulf stream

By Tim Radford

LONDON: Warming in the Arctic could be about to "turn off" the warm Gulf stream with catastrophic consequences for the climate of northern Europe in the long term, scientists warned on Thursday.

Peter Wadhams, of the Scott Polar Research Institute in the UK, said that for the fifth winter in the last seven years, a huge tongue of shelf ice had failed to form in the Greenland sea. Arctic ice is both thinning and dwindling.

The loss of ice in the Arctic could have dramatic knock-on effects because its formation is an important part of the ocean "conveyor belt" which sends cold salty water plunging to the seabed and heading south, allowing warm water to flood in from the tropics.

One US climate scientist has warned that if the Gulf stream was turned off, Britain and Ireland would experience temperatures familiar on the Arctic island of Spitsbergen.

"That was too dramatic," said Dr Wadhams. Temperatures in Britain would drop about 5C and Norway would suffer a 10C fall.

The Gulf stream flows north from the Caribbean, keeping Britain at least 5C warmer than expected at its latitude. Britain's chief scientist, Sir Robert May, once calculated that it delivered 27,000 times the warmth that all Britain's power stations could supply.

It merges with the north Atlantic current and the encounter of this giant, warm surface river with the Arctic winter ice is a powerful part of the convection machine which keeps the ocean swirling.

Ice is fresh water - so the sea that remains is increasingly cold, salty and dense. It sinks, beginning a kind of submarine river, 30 times the volume of the Amazon, flowing south again. But the Arctic ice cover is in retreat - shrinking by an area the size of the Netherlands every year. It is also thinning, from more than three metres thick to less than two metres in 30 years.-Dawn/The Guardian News Service

http://www.dawn.com/2000/04/08/int8.htm

-- Martin Thompson (mthom1927@aol.com), April 08, 2000


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