The moment of truth is approaching. We've been discussing climate change for 10 years

Olivier Deleuze, Belgian energy minister

On Saturday, the head of the European Union delegation at the talks called for negotiations to end soon.

Olivier Deleuze, the Belgian energy minister, said: "The moment of truth is approaching. We've been discussing climate change for 10 years.

"We shouldn't prolong the discussions for years more, or even months.

"We've been talking long enough, and meanwhile the problem of climate change gets worse and worse. The process is speeding up."

Discussions continued until the small hours, and resumed on Sunday morning.

Sticking points

Japan, Russia, Canada and Australia want to be allowed to make much wider use of carbon sinks in reaching their emissions reduction targets under the climate treaty, the Kyoto Protocol, than the EU is happy to see.

It fears they will allow countries to avoid real cuts in emissions from industry and transport.

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Another contentious issue is whether industrialised countries should be allowed to fund nuclear power projects in the developing world, and count the carbon savings they achieve towards their own reduction targets.

Mr Deleuze said: "I wouldn't say that I'm over-optimistic. Truth is about willingness to have an agreement that's environmentally sound.

"The EU is prepared to compromise on sinks, but not on nuclear power."

Mr Pronk's draft concedes the EU's demand by excluding nuclear projects from developing country aid.

The third main problem area is how to ensure countries comply with the protocol if it does enter into force, and here the EU is not prepared to give ground to those arguing for a voluntary approach.

The EU environment commissioner, Margot Wallstrom, said: "Compliance remains an absolute must for the EU."

She did however say that the atmosphere at the talks was "good and promising".

Push for agreement

There is a will to reach an agreement.

Members of both the Canadian and the Japanese delegations have said they cannot go home empty-handed again, as they did from last November's failed talks in The Hague.

There is a growing feeling that Bonn should reach a decision and not defer "the moment of truth" to the next round of talks, due to take place in Morocco in October.

"As time passes", one delegate told BBC News Online, "things can only get worse".