Natural Science Forum / Earth Science / Oceanography / November 2006

http://environment.guardian.co.uk/climatechange/story/0,,1932761,00.html

Most alarmingly, the data reveal that a part of the current, which is
usually 60 times more powerful than the Amazon river, came to a temporary
halt during November 2004.

The nightmare scenario of a shutdown in the meridional ocean current which
drives the Gulf stream was dramatically portrayed in The Day After Tomorrow.
The climate disaster film had Europe and North America plunged into a new
ice age practically overnight.

Although no scientist thinks the switch-off could happen that quickly, they
do agree that even a weakening of the current over a few decades would have
profound consequences.

Warm water brought to Europe's shores raises the temperature by as much as
10C in some places and without it the continent would be much colder and
drier.

Researchers are not sure yet what to make of the 10-day hiatus. "We'd never
seen anything like that before and we don't understand it. We didn't know it
could happen," said Harry Bryden, at the National Oceanography Centre, in
Southampton, who presented the findings to a conference in Birmingham on
rapid climate change.

Is it the first sign that the current is stuttering to a halt? "I want to
know more before I say that," Professor Bryden said.

Lloyd Keigwin, a scientist at the Woods Hole Oceanographic Institution, in
Massachusetts, in the US, described the temporary shutdown as "the most
abrupt change in the whole [climate] record".

He added: "It only lasted 10 days. But suppose it lasted 30 or 60 days, when
do you ring up the prime minister and say let's start stockpiling fuel? How
can we rule out a longer one next year?"