A.D. 2012

The End of Time

  Slowdown In Ocean Currents
May Bring Ice Age To Britain

By Roger Highfield
Science Editor
The Telegraph - UK
4-16-4

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.

 

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.

 

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.

 

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.

 

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.

 

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.

 

Nor is it clear whether the slowdown will mean major changes in Atlantic circulation.

 

The 1990s was one of the most active periods of climate change during the past century in northern latitudes.

 

"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.