KEY POINTS:
Leading climate-change experts have warned of the "Hollywoodisation" of global warming and criticised American scientists for exaggerating the message of climate change.
Professors Paul Hardaker and Chris Collier of Britain's Royal Meteorological Society said scientists, campaign groups, politicians and the media were making out that catastrophic events were more likely to happen when this could not be proved by scientists.
They also criticised the tendency to say that individual extreme events - such as a typhoon or floods - were certain evidence of climate change.
They singled out a report last month by the American Association for the Advancement of Science, which said intensification of droughts, heatwaves, floods, wildfires and storms were "early warning signs of even more devastating damage to come".
"It's certainly a very strong statement," said Collier. "To make the blanket assumption that all extreme weather events are increasing is a bit too early yet."
Media coverage of the report by the United Nations International Panel on Climate Change was also criticised, especially the use of words not in the report, such as "catastrophic", "shocking", "terrifying" and "devastating".
"Campaigners, media and some scientists seem to be appealing to fear to generate a sense of urgency," said Professor Mike Hulme, director of the Tyndall Centre for Climate Change Research at the University of East Anglia and a contributor to the report.
"If they want to engage the public in responding to climate change, this is unreliable at best, and counter-productive at worst."
The report, Making Sense of the Weather and Climate, was launched at a conference organised by the charity Sense About Science. The authors said they firmly believe global warming was occurring and man-made emissions of greenhouse gases were partly to blame.
Some scientists also acknowledged that dramatic warnings about climate change had helped to generate public debate and support for action.
But Hardaker warned that exaggeration of the problems confused the public and made it easier for sceptics to argue that scientists were wrong.
A low-probability event given too much weight was the risk of the Gulf Stream, which keeps the North Atlantic relatively warm, "switching off" and plunging the region into an ice age, the scenario dramatised by the film The Day After Tomorrow.
Scientists had to be more honest about the uncertainties surrounding climate change prediction to avoid losing public trust, said Hardaker.
Their comments were backed by other leading figures in the debate. Dr Peter Stott, manager of understanding and attributing climate change at the Hadley Centre for Climate Change, said scientists had to make it clear there was a long way to go until we know how bad climate change will be.
"There is a lot more research to do to understand about exactly what effects it's going to have in the future."
He welcomed a growing public awareness about the dangers, brought about by films and headlines, but said informed debate was vital.
"It would be unfortunate if people got the impression that there is nothing we can do about it, because there is a lot we can do to change the future of climate change," he said.
Al Gore, who has been praised for his Oscar-winning environmental film An Inconvenient Truth, has also attracted criticism from scientists.
"I don't want to pick on Al Gore," Don J. Easterbrook, an emeritus professor of geology at Western Washington University, told hundreds of experts at the annual meeting of the Geological Society of America.
"But there are a lot of inaccuracies in the statements we are seeing, and we have to temper that with real data."
Gore, in an email exchange about the critics, said his work made "the most important and salient points" about climate change.
"The degree of scientific consensus on global warming has never been stronger. I am trying to communicate the essence of it in the lay language that I understand."
- OBSERVER
In perspective
Claim: More frequent El Ninos
Reality: El Nino is a warming of the tropical Pacific Ocean that occurs every three to seven years. The cause of El Nino is not fully understood but its frequency is not linked to global warming and it has been documented since the 16th century.
Claim: Extreme weather events such as the one-in-400-years floods in Boscastle, Cornwall, in 2004 are more and more frequent.
Reality: It can sound alarming to know that a major flood such as this may happen two years running, but that translates into a 0.25 per cent chance of a flood happening in any one year; the chance remains the same whatever happened in the previous 12 months.
Claim: The disappearing snows of Kilimanjaro are due to global warming.
Reality: This may not have much to do with man's activities. It appears to have begun in the 1880s and the most likely explanation seems to be the change to drier conditions in East Africa.
There is little evidence that the retreating glaciers can be blamed on rising temperatures and hence on human activity.
* Source: Sense about Science charitable trust.
