Wednesday, 22 December 2010

Snow falls in Westminster, so climate change called into doubt

All right, so a heavy snowfall in England and Wales is unusual before Christmas, but, as Marcus Brigstocke drove  home in his typically confrontational fashion on the latest "Now Show", what is happening on  ones own doorstep is not indicative of the rest of the world. Global temperatures are continuing to rise, as the Weather Club and  web sites like this  indicate.

There was a time, as people of my generation will remember, when there was some snow every winter, sometimes at least as severe as the current situation: early 1963, for instance,  or 1947/48 when the opposition attacked the government for lack of preparedness. Some things do not change.

Paradoxically,  one of the predictions of climate scientists is that, as the North Atlantic warms up, Britain will get cooler in winter because the Gulf Stream/North Atlantic Drift will move westwards as the Greenland ice sheet retreats. This particular bad winter for us is down to La Nina and fluctuations in the jet-stream as I understand it, but perhaps we had better prepare for more frequent severe winters in future as well as hotter springs.

As to how far global warming is caused by man - well, that's another matter.

Update 2010/12/27: Another contributory factor is said to be the loss of ice-cover in north European seas, as reported in this Independent article:

"Say the ocean is at zero degrees Celsius (32 degrees Fahrenheit)," said Stefan Rahmstorf, a climate scientist at the Potsdam Institute for Climate Impact Research in Germany.
"That is a lot warmer than the overlying air in the polar area in winter, so you get a major heat flow heating up the atmosphere from below which you don't have when it is covered by ice. That's a massive change," he told AFP in an interview.
The result, according to a modelling study published earlier this month the Journal of Geophysical Research, is a strong high-pressure system over the newly-exposed sea which brings cold polar air, swirling counter-clockwise, into Europe.
"Recent severe winters like last year's or the one of 2005-2006 do not conflict with the global warming picture, but rather supplement it," explained Vladimir Petoukhov, lead author of the study and a physicist at the Potsdam Institute.

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