North-Western Europe could be in for some sudden climatic surprises in the future.

North-Western Europe is kept warm by an ocean current known as the North Atlantic Current, an extension of the Gulf Stream which brings warm water from the tropics to the north. This current is sensitive to global warming and could slow down, or even break down as a result of increasing global temperatures. Studies of Earth's ancient climate show that the North Atlantic Current has changed repeatedly and dramatically in the past, resulting in massive and sudden regional climate changes [ice ages]. >from *Future climate change in North-Western Europe may come as a shock*. January 15, 2004.

"The rate and extent of change, especially since the 1950s is unprecedented," says Dr Will Steffen, Executive Director of the International Geosphere-Biosphere Programme and lead author of the book "Global Change and the Earth System: A planet under pressure", a view of a rapidly changing planet presented by hundreds of scientists from around the world. "We are changing the very life support system on which we depend and its future is highly unpredictable."

One of the concerns raised by the book is that many of the changes occurring to the Earth remain 'invisible' for long periods until critical thresholds are crossed and large changes follow. "Some changes may be irreversible on any time scale meaningful to humans", says Steffen." >from *New policies needed to combat Global Change*. January 20, 2004

related context
> new study reports large-scale salinity changes in the oceans. saltier tropical oceans and fresher ocean waters near the poles are further signs of global warming's impacts on the planet... continue to freshen northern north atlantic ocean waters -- to a point that could disrupt ocean circulation and trigger further climate changes. december 17, 2003
> electrokinetic cells: new source of energy. november 17, 2003
> earth 'will expire by 2050': living planet report. july 12, 2002
> global warming: u.s. climate action report 2002. june 12, 2002

imago
> ice age coming?

Now the Pentagon tells Bush: climate change will destroy us. Secret report warns of rioting and nuclear war; Britain will be 'Siberian' in less than 20 years; Threat to the world is greater than terrorism .From The Guardian, february 22, 2004
http://www.guardian.co.uk/climatechange/story/0,12374,1153530,00.html

The original report: An Abrupt Climate Change Scenario and Its Implications for United States National Security. October 2003. By Peter Schwartz and Doug Randall
http://www.greenpeace.org/multimedia/download/1/417492/0/pentagon-on-climate-change.pdf

By disturbing a massive ocean current, melting Arctic sea ice might trigger colder weather in Europe and North America. Global warming could plunge North America and Western Europe into a deep freeze, possibly within only a few decades.That's the paradoxical scenario gaining credibility among many climate scientists. The thawing of sea ice covering the Arctic could disturb or even halt large currents in the Atlantic Ocean. Without the vast heat that these ocean currents deliver--comparable to the power generation of a million nuclear power plants--Europe's average temperature would likely drop 5 to 10°C (9 to 18°F), and parts of eastern North America would be chilled somewhat less. Such a dip in temperature would be similar to global average temperatures toward the end of the last ice age roughly 20,000 years ago.

Some scientists believe this shift in ocean currents could come surprisingly soon--within as little as 20 years, according to Robert Gagosian, president and director of the Woods Hole Oceanographic Institution. Others doubt it will happen at all. Even so, the Pentagon is taking notice. Andrew Marshall, a veteran Defense Department planner, recently released an unclassified report detailing how a shift in ocean currents in the near future could compromise national security.

From "A Chilling Possibility". science@nasa, march 5, 2004
http://science.nasa.gov/headlines/y2004/05mar_arctic.htm?list77294

"We have not made significant progress in curbing global warming in the last decade. In fact, the latest scientific reports indicate that global warming is worsening," said Dr. Jonathan Pershing, director of WRI's Climate, Energy and Pollution Program. "We are quickly moving to the point where the damage will be irreversible. Unless we act now, the world will be locked in to temperatures that would cause irreparable harm. To stabilize the atmospheric concentrations of the greenhouse gases that lead to global warming, we must ultimately bring net emissions of these gases to near zero." From "World Resources Institute warns of worsening warming as Climate Treaty Celebrates tenth year" March 11, 2004 http://newsroom.wri.org/newsrelease_text.cfm?NewsReleaseID=277

Climate scientists have been stirred to ridicule claims in an upcoming Hollywood blockbuster that global warming could trigger a new ice age, a scenario also put forward in a controversial report to the US military...

Andrew Weaver of the University of Victoria in British Columbia, Canada, surveys the current research and concludes "it is safe to say that global warming will not lead to the onset of a new ice age".

Wallace Broecker of Columbia University, New York, US, who has warned for two decades that the Atlantic circulation is "the Achilles heel of our climate system", seriously questions both the speed and severity of the changes proposed.

In a letter to Science, he accuses the DoD authors of making exaggerated claims that "only intensify the existing polarisation over global warming". He adds: "What is needed is not more words but rather a means to shut down CO2 emissions." Such action could avert any Gulf Stream shutdown in the next 100 years. From Scientists stirred to ridicule ice age claims. april 15, 2004
http://www.newscientist.com/news/news.jsp?id=ns99994888