Some of the developing world’s biggest greenhouse gas emitters are bidding to delay talks on a new climate agreement.
To the anger of small islands and other vulnerable countries, India and Brazil are joining rich nations such as the US and Japan 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 climate summit opens on Monday in Durban, South Africa.
Some observers say small island states, which traditionally aim their criticism at the industrialised world’s big emitters, may begin “naming and shaming” developing countries that are also delaying progress.
“They’re on the edge of a mess,” one experienced delegate told BBC News, “and they may not be able to resolve this mess”.
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 of the most vulnerable nations 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”.
However, on one of the summit’s other main topics – financial aid for poor countries – there is a strong chance of progress at the fortnight-long summit.
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.
see also Benny Peiser: Durban Downbeat