Gulf Stream slowdown & Extreme Weather

[bloom]

When the Ice Melts – Everything Changes

"And now the news. The online edition of the Times of London reported in May that the Gulf Stream slowdown is no longer theoretical, but is already occurring. Peter Wadhams, a professor of ocean physics at Cambridge University, visited the Arctic ice cap on Royal Navy submarines and discovered “that one of the ‘engines’ driving the Gulf Stream – the sinking of supercooled water in the Greenland Sea – has weakened to less than a quarter of its former strength. The weakening, apparently caused by global warming, could herald big changes in the current over the next few years or decades. Paradoxically, it could lead to Britain and northwestern Europe undergoing a sharp drop in temperatures.”

Says Wadhams, “Until recently, we would find giant ‘chimneys’ in the sea where columns of cold, dense water were sinking from the surface to the seabed <1.8 miles> below, but now they have almost disappeared. As the water sank, it was replaced by warm water flowing in from the south, which kept the circulation going. If that mechanism is slowing, it will mean less heat reaching Europe.”

Dr. Gagosian says that a shutting down of the Gulf Stream would mean that “average winter temperatures could drop by five degrees Fahrenheit over much of the United States, and by ten degrees in the northeastern United States and in Europe. That’s enough to send mountain glaciers advancing down from the Alps; to freeze rivers and harbors and bind North Atlantic shipping lanes in ice; to disrupt the operation of ground and air transportation; to cause energy needs to soar exponentially; to force wholesale changes in agricultural practices and fisheries; to change the way we feed our populations. In short, the world, and the world economy, would be drastically different.

...Look at a couple of impacts. Most severe weather takes place when cold air and hot air meet. The tropics are getting warmer, Europe and the northeastern United States and Canada are getting colder. When air masses over the temperate and tropical zones meet, there will be more extreme weather. The water that has been locked into Arctic ice is now merging with the oceans. More water means sea levels rise. That doesn’t even begin to address the impact on the food we eat and where it is grown (and how it gets here), or the wood we use for construction. And then there are the increased costs of energy and transportation systems. So maybe we should start thinking about growing more of our food now, and importing less.”

http://caymannetnews.com/2005/08/907/ecocommentary.shtml

More on Chimneys (with graphics):

http://puddle.mit.edu/~helen/oodc.html