- A crucial "cog" in the circulation of the North
Atlantic is slowing down, which could signal a major upheaval in the climate
of Britain, according to a study published today.
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- The report in Science comes as Hollywood prepares to
release a film on the same theme, The Day After Tomorrow, in which snowstorms
batter New Delhi and tornadoes strike Los Angeles after global warming
disrupts ocean circulation patterns.
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- It seems logical that a gradual build-up of greenhouse
gases will lead to an equally gradual change in climate. But this has been
overturned by evidence found in ice and sediments which reveal that the
global climate can lurch from warm to cold in a few decades when ocean
circulation patterns change.
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- Water, even when moving sluggishly, carries significant
heat and the tightly-linked Arctic and North Atlantic regions play a key
role in the delicately balanced global ocean circulation system that warms
the UK with the Gulf Stream. Disrupt it, and the UK could suffer drastic
and unpredictable changes in temperature and rainfall, even an ice age,
within a timescale ranging from a decade to a century.
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- Today in Science, a team reports that satellite measurements
of sea surface height show there has been a slowdown in the anticlockwise
circulation of surface water just below the Arctic Circle in the North
Atlantic over the past decade.
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- Whether this slowdown is a consequence of basic global
warming or part of a mid-term climate cycle it is too early to know, said
Prof Peter Rhines of the University of Washington, Seattle.
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- Nor is it clear whether the slowdown will mean major
changes in Atlantic circulation.
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- The 1990s was one of the most active periods of climate
change during the past century in northern latitudes.
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- "The question is, how much 're-plumbing' of the
ocean circulation is required to push the coupled atmosphere-ocean system
over a threshold?" said Prof Rhines.
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- © Copyright of Telegraph Group Limited 2004. http://www.telegraph.co.uk/news/main.jhtml?xml=/news/2004/04/
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