Many poor countries want industrialised nations to make deeper cuts before they consider braking emissions from factories, power plants and cars. They say rich nations have been the source of most greenhouse gases since the Industrial Revolution.

Brazil, in a note before the talks, said it was too early for developing nations to set any limits on heat-trapping emissions from burning fossil fuels.

Any efforts to curb emissions by developing countries "can only be characterized as voluntary and, therefore, cannot be linked or associated to goals, targets or timeframes," it said.

And South Africa said it wanted talks about "positive incentives" to encourage developing nations to curb emissions, including aid and new technology.

"Developing countries have the view that they are waiting for the industrialised countries to demonstrate real leadership in limiting emissions before agreeing to accept binding commitments," said Richard Kinley, acting head of the UN Climate Secretariat, the host of the talks among senior government officials.

"In the industrial world there is a feeling that more action by developing countries is required," he said. Still, he added that there seemed "widespread agreement" that it was not yet time for emissions limits by poor states.

FLOODS, DESERTS

Kyoto backers are meant to cut emissions by an average of 5.2 percent below 1990 levels by 2008-12 as a tiny first step to combat rising temperatures that many scientists say could spur more floods, desertification, more powerful storms and raise world sea levels by almost a metre (yard) by 2100.

The United States pulled out of Kyoto in 2001, saying it would cost jobs and wrongly excluded developing nations from a first round. Washington is instead making big investments in new technologies, ranging from hydrogen to solar power.

After the two-day dialogue between all signatories of the UN Climate Convention, Kyoto backers will also meet from May 17-25 for preliminary talks about how to extend the pact beyond 2012. Those negotiations are likely to last for several years.

Many Kyoto nations say they will struggle to meet emissions cuts even though carbon dioxide prices in a European Union market have plunged to the lowest level in a year on news that most EU members undershot their limits for 2005 emissions.

Canada's Environment Minister Rona Ambrose, who will be chairing the Bonn talks, has suggested that Kyoto should be softened in a second period from 2012 after saying Canada had no chance of reaching its goals.