January 26, 2004

Global Warming - Gulf Stream

From the U.K. Independent comes a alarming tale of Global Warming Cooling and a big scary headline: bq. Global warming will plunge Britain into new ice age 'within decades' Britain is likely to be plunged into an ice age within our lifetime by global warming, new research suggests. And more: bq. Similar events in pre-history are known to have caused sudden "flips" of the climate, bringing ice ages to northern Europe within a few decades. The development - described as "the largest and most dramatic oceanic change ever measured in the era of modern instruments", by the US Woods Hole Oceanographic Institute, which led the research - threatens to turn off the Gulf Stream, which keeps Europe's weather mild. bq. If that happens, Britain and northern Europe are expected to switch abruptly to the climate of Labrador - which is on the same latitude - bringing a nightmare scenario where farmland turns to tundra and winter temperatures drop below -20C. The much-heralded cold snap predicted for the coming week would seem balmy by comparison. And more: bq. Robert Gagosian, the director of Woods Hole, considered one of the world's leading oceanographic institutes, said: "We may be approaching a threshold that would shut down [the Gulf Stream] and cause abrupt climate changes. bq. "Even as the earth as a whole continues to warm gradually, large regions may experience a precipitous and disruptive shift into colder climates." The scientists, who studied the composition of the waters of the Atlantic from Greenland to Tierra del Fuego, found that they have become "very much" saltier in the tropics and subtropics and "very much" fresher towards the poles over the past 50 years. bq. This is alarming because the Gulf Stream is driven by cold, very salty water sinking in the North Atlantic. This pulls warm surface waters northwards, forming the current. And more: bq. When the Gulf Stream abruptly turned off about 12,700 years ago, it brought about a 1,300-year cold period, known as the Younger Dryas. This froze Britain in continuous permafrost, drove summer temperatures down to 10C and winter ones to -20C, and brought icebergs as far south as Portugal. Europe could not sustain anything like its present population. Droughts struck across the globe, including in Asia, Africa and the American west, as the disruption of the Gulf Stream affected currents worldwide. bq. Some scientists say that this is the "worst-case scenario" and that the cooling may be less dramatic, with the world's climate "flickering" between colder and warmer states for several decades. But they add that, in practice, this would be almost as catastrophic for agriculture and civilization. But if you look at information pertaining to the Younger Dryas, it was caused by melt-water from the glaciers in North America after the previous ice age. This torrent of fresh water flowed into the Atlantic and fresh water being lighter, pushed the denser water down effectively blocking the Gulf Stream flow. This is not what is happening now and I think a more moderate outcome is likely. The earth is undergoing a warming trend as we come out of the Little Ice Age and to assign any Human input to this climate change is pure hubris. Medieval Warm Period -- 800 to 1400 Little Ice Age -- 1400 to 1900 Posted by DaveH at January 26, 2004 3:00 PM