A TREATY to cut greenhouse gas emissions could hinge on the US Congress passing a climate change bill by December, after its chief climate negotiator warned it would struggle to commit to an emissions target without it.
US deputy special envoy for climate change Jonathan Pershing said it would be ''extraordinarily difficult'' for the US to offer what was expected under a Copenhagen agreement without legislation to support it.
The comment comes less than a week after President Barack Obama's director of climate policy, Carol Browner, cautioned it was not likely the bill now before the Senate could become law this year.
''We're actually not working on that eventuality,'' Dr Pershing said.''We're still focused on the notion that we can get where we need to go. I don't really have an answer for the alternative hypothetical in which it's not done,'' he said.
''I think it would be extraordinarily difficult for the US to commit to a specific [emissions reduction] number in the absence of action from Congress. That doesn't mean that the deal is not possible. Nor does it mean we won't have a number for the conference … the question is open to how much we could do.''
The comments came as the latest round of United Nations talks in Bangkok ended with entrenched divisions between wealthy and developing nations.
UN climate chief Yvo de Boer warned the negotiations could not progress without fully costed promises from rich nations on how they would generate the money needed to help the developing world deal with climate change.
''I believe that people around the world, people everywhere, have a right to know exactly what their governments will do to address dangerous climate change,'' he said.
Australia was attacked by aid agency Oxfam, which accused it of joining the US, Canada, the European Union and Japan in blocking the negotiations.
Oxfam senior climate adviser Antonio Hill said rich countries had not put serious money on the table for a climate finance plan - seen as crucial to a deal being signed - or boosted emissions targets.
Climate scientists say the rich must cut emissions by at least 25-40 per cent by 2020 to give the world an even money-chance of avoiding a two-degree warming. Current targets add up to 10-24 per cent.
Mr Hill said the world's most vulnerable countries faced an impossible choice - accepting an agreement that failed to reduce climate change risks, or hold out for a better deal and walk away from Copenhagen with nothing.
''It is grossly unfair to force these poorer countries to choose between no deal and a suicide pact,'' he said.
Although Australia was praised by green and welfare groups for its proposals to cut emissions from aviation and shipping and a system for distributing a global climate fund, the proposals were said to lack credibility because they were not backed by a funding plan.
Alden Meyer, director of the US-based Union of Concerned Scientists, said: ''If the industrialised countries don't put their cards on the table very soon on climate finance, there's not going to be a card game in Copenhagen. The table's going to be kicked over, there's not going to be a deal,'' he said.
A spokeswoman for Australian Climate Change Minister Penny Wong said negotiations in Bangkok had made progress on issues including forest carbon and financing, but added: ''We are a long way from where we need to be and we don't have much time … What each country does at home also matters, including for Australia. We need to come to the negotiating table in Copenhagen with a plan to deliver our targets.''
WHEN IS IT & WHAT WILL HAPPEN?
December 7-18. The 192 UN countries will try to thrash out a climate treaty to start in 2013.
WHAT IS THE KYOTO PROTOCOL?
Thirty-seven industrialised countries agreed to cut emissions to 6 per cent below 1990 levels by 2012. The US signed, but did not ratify. Developing countries have no commitments. Targets vary. Australia is allowed to increase emissions by 8 per cent.
HOW WOULD A COPENHAGEN TREATY BUILD ON THIS?
It must include commitments from the rich, including the US, and the developing poor: China, India, Brazil, Indonesia, Mexico and South Africa. The rich must boost targets. They agreed in Bali two years ago that they needed to make a combined cut by 2020 of 25-40 per cent. The emerging giants must have plans to slow down emissions growth. Just as crucial is a plan to help pay the huge cost of combating climate change. The World Bank estimates the bill could reach $US470 billion ($A521 billion) a year.
COMMITMENTS SO FAR?
The G8 and 17-member Major Economies Forum, which includes Australia, agree global warming must be limited to 2 degrees. It is now about 0.7 degrees hotter than before the industrial revolution. Estimates suggest targets put forward by wealthy nations add up to a 10-24 per cent cut. Australia's target is equivalent to 4-24 per cent below 1990. The developing world says it isn't enough. China will have a carbon intensity target, dictating how much can be emitted for every yuan of GDP generated. India has promised a ''broadly indicative'' target, possibly covering energy efficiency and renewable power. Little has been proposed on climate finance. Britain has a proposal that would generate $US100 billion a year.
ARE THERE OTHER STICKING POINTS?
Developing countries want the Kyoto Protocol to continue beyond 2012. The EU has proposed collapsing it into a new agreement that would cover all major players. The G77 developing block says this is trying to ''kill'' Kyoto. The US won't have a bar of Kyoto - there is no way its Congress would agree to it. It doesn't care if Kyoto continues as long as it is covered by something else. But a disagreement is brewing over the US wanting to be bound by domestic law only. Australia's proposal is ''Kyoto plus''. Rich countries would meet emissions targets. Developing nations would be bound to introduce climate-friendly laws.
IS THAT IT?
Hardly. Side issues include:
■A deal on how to reduce emissions from deforestation and forest degradation.
■How to share clean technology and its intellectual property.
■How to structure an offsets system that allows rich nations to meet targets by paying for emissions cuts in poor countries.