Global warming may cool N. Europe
The powerful ocean currents that transport heat around the globe and keep northern Europe’s weather relatively mild appear to be weakening – a likely and problematic consequence of global warming – a new study by British scientists has concluded.
The currents, like mighty rivers flowing at different depths of the ocean, act like radiator pipes to carry warmth from the tropics to northern latitudes. The best known is the Gulf Stream, which carries warm water from the Gulf of Mexico to the coasts of Britain and France. Other currents return colder water from the poles.
With the prevailing winds, the currents warm the climate of much of Europe by several degrees. Rome, for instance, is at a latitude similar to Boston and would be much cooler if not for the warmth coming from the sea.
In the new study, published today in the journal Nature, a group of British oceanographers surveyed a section of the Atlantic Ocean stretching from Africa to the Bahamas that has been studied periodically since 1957. They found the overall movement of water had slowed 30 percent in the past five decades, particularly in the flow of cold water back to the south.
The report is the first evidence of such a slowdown.
“The result is alarming,” Detlef Quadfasel, a climate expert at the University of Munich, wrote in a commentary accompanying the research.
Scientists differ on the potential effect. Some say weaker currents would cool Europe by several degrees, causing problems for agriculture and ecosystems and ushering in far more severe winters. Others say the cooling would likely balance out the effect of global warming in Europe.