By Alex Kirby
BBC News Online environment correspondent
The blockbuster climate disaster movie The Day After Tomorrow contains badly flawed science and ignores the laws of physics, leading UK scientists believe.
Dramatic licence: It won't happen like this, scientists say
But many of them have welcomed the film as a dramatic and popular way to raise people's awareness of climate change.
Sir David King, the government's chief scientific adviser, said he hoped many ordinary Americans would see the film.
And the former US Vice-President Al Gore said the risks the film portrayed were a threat to our common future.
Beyond the science
Speaking in London, Sir David described The Day After Tomorrow as "a spectacular action film" which portrayed the switching off of the Gulf Stream and the Northern Hemisphere's subsequent plunge into a new Ice Age.
The scientific consensus was that climate change might lead to a weakening of the thermohaline circulation (THC), the phenomenon that drives the Gulf Stream; but it was not expected to cause its complete halting, as in the film.
Sir David said the present global atmospheric carbon dioxide concentration of 379 parts per million, the highest for at least 420,000 years, was "very significantly higher" than during previous warm periods.
But that did not mean the THC, which keeps north-western Europe about 5C warmer than it would be otherwise, would switch off at all, and certainly not as quickly as The Day After Tomorrow suggested.
The film "unrealistically concertinas into a few weeks a scenario which, if it did occur, would take decades or a century".
Sir David said: "The film brings events together into a highly unlikely or even impossible scenario. It's very difficult to explain the physics of it.
"But what's good is that while my colleagues and I have just spent half an hour presenting you with the scientific understanding of climate change, the movie gets the basic message across in a few sentences of dialogue. It's a beautiful piece of script-writing.
Ignoring the facts
"I hope US audiences will see it. It's very important that we all take cognisance of what science is saying, and that includes American politicians."
He said there had been 21,000 extra fatalities in Europe's heatwave in 2003 that had been attributable to climate change, but few had made the link.
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Sir David said: "There's a problem in dramatising these events, because even when they happen in the real world we don't seem to take much notice of them."
One of his colleagues was Dr Geoff Jenkins, head of climate prediction at the Met Office's Hadley Centre for Climate Prediction and Research.
He said: "It's a movie, and we shouldn't get too po-faced about it. Hollywood's not going to make money out of a bunch of scientists discussing uncertainties."
Dr Jenkins said scientists thought a collapse of the THC was a low-probability but high-impact event. But they did not know how low the probability was, and in principle it could happen.
Dr David Viner, of the Climatic Research Unit at the University of East Anglia, told BBC News Online: "The film got a lot of the detail wrong, and the direction of change as well - cooling of this sort is very unlikely with global warming.
"But the fact that The Day After Tomorrow raises awareness about climate change must be a good thing."
Images copyright 2004 Twentieth Century Fox.