There is no clear evidence that global warming is an imminent danger to the world, says Rajendra Pachauri, chairman of the United Nations' Intergovernmental Panel on Climate Change.
Even so, it would be good for governments to go further with proposed cuts in greenhouse-gas emissions to deal with dire predictions made in a 2007 panel report, he told the Associated Press in an interview on Tuesday.
"I don't think we should jump to conclusions if we get material that is based on the last one or two years," he said. But governments should rethink their responses to the panel's 2007 report, which predicted sea levels would rise by 40 centimetres to 1.4 metres even if drastic cuts were made in carbon emissions.
Now he has warned that if gigantic ice sheets in Greenland or Antarctica melt, the sea could rise even more, flooding coastal areas and islands and causing widespread environmental disruptions.
The report recommended large drops in carbon emissions after 2015 to contain the changes, but governments should reconsider whether even those targets go far enough, Pachauri said.
He made the comments at a meeting in Poznan, Poland, where more than 10,000 delegates and environmentalists are trying to hammer out an international treaty to cut greenhouse gases. It is intended to to replace the Kyoto Protocol, which expires in 2012.
Pachauri is worried that the negotiators would leave the key decisions to the end of the meeting, producing "a weak agreement that doesn't really address the problem."
Government officials are working on the treaty before politicians arrive to address the issue later this week. Canada's Environment Minister, Jim Prentice, is expected to address the meeting on Thursday.
Prentice has said that he will not agree to the deep emission cuts that environmentalists want.
Canadian environmental organizations and northern indigenous groups want emissions reduced by 25 per cent below 1990 levels by 2020; Prentice said he wants a 20 per cent reduction of 2006 levels to avoid economic damage.
The federal Conservatives have been criticized for substituting lower targets for the level set in the Kyoto deal, signed by not implemented by the Liberals.