Science academies back Kyoto
A warming world will mean "increased risk of drought"
By BBC News Online's environment correspondent Alex Kirby Seventeen national science academies have urged politicians to implement the Kyoto Protocol on climate change.
In a joint statement, they say human activities are worsening the problem.
They say the world cannot continue as it is, and everyone should work to reduce greenhouse gas emissions.
And they say they see no reason to doubt the growing agreement on the science of climate change.
The statement is published as an editorial in the current issue of the journal Science (a full list of signatories appears below).
It endorses the work of the Intergovernmental Panel on Climate Change (IPCC), which it says "represents the consensus of the international scientific community".
Unwarranted doubts
It says: "We recognise the IPCC as the world's most reliable source of information on climate change and its causes, and we endorse its method of achieving this consensus.
"Despite increasing consensus, doubts have been expressed recently about the need to mitigate the risks posed by global climate change. We do not consider such doubts justified.
The scientists say seas will rise
"We support the IPCC's conclusion that it is at least 90% certain that temperatures will continue to rise, with average global surface temperature projected to increase by between 1.4 and 5.8 degrees Celsius above 1990 levels by 2100.
"This increase will be accompanied by rising sea levels; more intense precipitation events in some countries and increased risk of drought in others; and adverse effects on agriculture, health and water balance.
"It is now evident that human activities are already contributing adversely to global climate change. Business as usual is no longer a viable option.
Small step
"The balance of the scientific evidence demands effective steps now to avert damaging changes to the earth's climate."
The signatories say ratifying the Kyoto Protocol, the international climate treaty, would be "a small but essential first step".
President Bush has been widely criticised for saying the US will not implement the protocol, which commits developed countries to cut their greenhouse emissions by an average of 5.2% over the next decade.
Sir Robert May is president of the UK's Royal Society, one of the academies to sign the statement.
He said: "Some people have unjustifiably sought to undermine the work of the IPCC, but governments should be left in no doubt that it offers the best source of expertise in climate change.
"The developed countries have been responsible for more than two-thirds of emissions over the last 200 years, and it is morally right that they should lead the way."
Dissent welcome
Sir Robert told BBC News Online: "The initiative for this statement came from the Royal Society, and everyone we approached agreed to sign it except the US National Academy of Sciences (NAS).
"They've been asked by the administration to conduct a review of this area, and felt they couldn't pre-empt it. But they'll be making a statement of their own in June.
Despite President Bush, Kyoto "is essential"
"Undermining the IPCC is unjustifiable. For scientists to dissent from mainstream opinion on climate is something one has to welcome - that's how science works.
"But what is unjustifiable is statements from put-together lobby groups funded by people like the oil industry."
Glenn Kelly, of the US-based Global Climate Coalition, told BBC News Online: "We certainly agree that individuals, businesses and government should work aggressively to reduce greenhouse gases.
Cynical
"But we feel new technologies will have a far greater impact than the Kyoto Protocol could ever hope to have."
Richard Lindzen is professor of meteorology at Massachusetts Institute of Technology.
He told BBC News Online: "To endorse the consensus process of the IPCC borders on the cynical.
"When they say they've asked thousands of scientists about something, they never ask 99.5% of them.
"And the IPCC operates to lower standards than the NAS."
The statement in Science has been signed by the academies of Australia, Belgium, Brazil, Canada, the Caribbean, China, France, Germany, India, Indonesia, Ireland, Italy, Malaysia, New Zealand, Sweden, Turkey and the UK.