As this year's UN climate summit opens, some of the developing world's biggest greenhouse gas emitters are bidding to delay talks on a new global agreement.
To the anger of small islands states, India and Brazil have joined rich nations in wanting to start talks on a legal deal no earlier than 2015.
The EU and climate-vulnerable blocs want to start as soon as possible, and have the deal finalised by 2015.
The UN summit, in Durban, South Africa, may make progress in a few areas.
"We are in Durban with one purpose: to find a common solution that will secure a future to generations to come," said Maite Nkoana-Mashabane, South Africa's minister of international relations, who is chairing the summit.
But the process of finding that common solution, in the form of an agreement that can constrain greeenhouse gas emissions enough to keep the global average temperature rise below 2C, will entail some complex and difficult politics.
Developing countries will certainly target rich governments such as Japan, Canada and Russia over their refusal to commit to new emission cuts under the Kyoto Protocol, whose current targets expire at the end of next year.
They see this as a breach of previous commitments and of trust.
But some observers say small island states may begin "naming and shaming" developing countries that are also delaying progress.
They say the impasse should not delay talks on a new deal, arguing that to do so would be, in one delegate's wording, "the politics of mutually-assured destruction".
"They're on the edge of a mess," another delegate told BBC News, "and they may not be able to resolve this mess".
The politics of the UN climate process are undergoing something of a fundamental transformation.
Increasingly, countries are dividing into one group that wants a new global treaty as soon as possible - the EU plus lots of developing countries - and another that prefers a delay and perhaps something less rigorous than a full treaty.
The divide was evident earlier this month at the Major Economies Forum (MEF) meeting in Arlington, US - the body that includes 17 of the world's highest-polluting nations.
There, the UK and others argued that the Durban summit should agree to begin work on a new global agreement immediately, to have it in place by 2015, and operating by 2020 at the very latest.
The US, Russia and Japan were already arguing for a longer timeframe.
But BBC News has learned that at the MEF meeting, Brazil and India took the same position.
Brazil wants the period 2012-15 to be a "reflection phase", while India suggested it should be a "technical/scientific period".
China, now the world's biggest emitter, is said by sources to be more flexible, though its top priority for Durban is the Kyoto Protocol.
"The planet has no other sustainable alternative other than to ensure the continuity of the Kyoto Protocol, through a second commitment period starting in 2013," said Jorge Arguello, leader of the Argentinian delegation, which this year chairs the powerful G77/China bloc of 131 nations.
"The adoption of a second commitment period for the reduction of greenhouse gases emissions under the Kyoto Protocol is not only a political imperative and a historical responsibility, but a legal obligation that must be faced as such."
Although the EU does not oppose a second commitment period, other developed nations do.
And as the US left the protocol years ago, nations still signed on account only for about 15% of global emissions - which is why there is so much emphasis on a new instrument, with some legal force, covering all countries.
The US, Russia, Japan and Canada have all argued for delaying negotiations on this for various domestic political reasons.
But the news that big developing countries are also lobbying for a delay is likely to lead to fireworks in Durban.
Many of the countries most at risk from climate impacts want to cut emissions fast enough to hold the global average temperature rise from pre-industrial times under 1.5C.
Scientific assessments say that for this to happen, global emissions should peak and begin to fall before 2020, adding urgency to these nations' quest for a new and effective global agreement.
President Nasheed of the Maldives is virtually the only leader who has spoken openly of the need for major developing countries to begin cutting emissions soon.
Equating the need to develop with the right to emit greenhouse gases is, he has said, "rather silly".
But sources in Durban indicate that delegates from other small developing countries may join him before the fortnight elapses, and demand more of the big developing nations.
China, Brazil and India are also being blamed for blocking moves to phase out the climate-warming industrial HFC gases, which small island states tabled at the Montreal Protocol meeting in Bali last week.
"The global response to climate change simply does not have time for advancing self-serving national interests," said Mark Roberts, international policy advisor for the Environmental Investigation Agency (EIA).
Sources say, however, that there is real prospect of agreement in Durban on rules and mechanisms for a Green Climate Fund.
This would raise and disburse sums, rising to $100bn per year by 2020, to developing nations.
There is no agreement on where the money should come from.
Developing countries say the public coffers of industrialised nations should be the main source, whereas western governments say the bulk must come from private sector sources.
That is unlikely to be resolved until the end of next year.
But finalising the fund's rules in Durban would be a concrete step forward.
Tim Gore, Oxfam's chief policy adviser, said UK Climate Minister Chris Huhne must push for "getting the money flowing through the Green Climate Fund that poor people need to fight climate change now.
"A deal to raise resources from international transport could be on the table, and Huhne must convince other ministers to strike it," he said.
However, there is widespread scepticism about the much smaller funds - $10bn per year - that developed nations are already supposed to be contributing under the Fast Start Finance agreement made in 2009.
Developing countries say only a small fraction of what has been pledged is genuinely "new and additional", as it is meant to be; and that little has actually materialised.
The summit may also see a row over the EU's imminent integration of aviation into the Emission Trading Schemen, which India and some other developing nations oppose.
Follow Richard on Twitter