The first round of UN climate talks since December's bitter Copenhagen summit opens in Bonn on Friday with the future of the process uncertain.
Developing countries are adamant that the UN climate convention is the right forum for negotiating a global deal and want it done by the year's end.
But others, notably the US, appear to think this is not politically feasible.
Some delegates are concerned that the whole process could collapse, given the divisions and lack of trust.
"There is the political will among developing countries. They are working for an agreement that includes further emissions reductions under the Kyoto Protocol," Martin Khor, executive director of the South Centre, an intergovernmental organisation of developing countries, told the BBC.
"Whether there is political will among the industrialised countries is another matter," he said.
Developing nations have been pressing to agree a series of preparatory meetings this year - as many as five - in order that outstanding differences on the text of a new agreement can be worked out in time for the next major summit in Mexico, in November and December.
But delegates here said that richer countries were resisting this, holding out for just one more meeting before November, which would leave no chance of agreeing a new global treaty or even agreeing a framework.
Analyses released since the end of the Copenhagen summit suggest that without further constraints soon, it will be very difficult to keep the rise in average global temperatures since pre-industrial times below 2C, a threshold commonly cited as indicating dangerous climate change.
The US, in particular, is in a sticky situation regarding domestic legislation.
An initial bill, introduced to the Senate last September, is widely seen as having no chance of passing.
A cross-party group of senators has been drawing up a new one, containing concessions to some states and industries.
But this version, if enacted, may reduce US emissions by considerably less than the 17% figure (from 2005 levels by 2020) that President Barack Obama pledged when he addressed Copenhagen.
"There's considerable uncertainty about whether there is going to be a US domestic bill that follows through on the president's 17% commitment," said Alden Meyer, director of strategy and policy at the Union of Concerned Scientists (UCS).
"[The administration is] very sceptical about the ability to get a full-blown legal deal that replaces the Kyoto Protocol or builds on it, given the state of play back home."
As to whether growing scepticism about the science of climate change - evidenced in some US opinion polls - was slowing the legislative process, Mr Meyer suggested it was not.
"The manufactured debate over the science is in our view just an excuse for [opposing senators] not to do what they weren't going to do anyway," he said.
"The attempts to swing votes behind the new bill aren't anything to do with climate science, they're to do with alleviating concerns from industries the senators are close to."
Immediately after the Copenhagen summit, the US appeared to have formed a powerful new alliance with the BASIC group of countries - Brazil, China, India and South Africa - that steered through the controversial and weak Copenhagen Accord on the summit's final day.
There were signs that this group saw the accord, with its voluntary nature, as more attractive than the traditional negotiations and supposedly binding commitments of the UN process.
However, the BASIC countries have now affirmed that the UN climate convention (UNFCCC) should be the sovereign body for international climate talks.
More than 120 countries have sent letters to the UNFCCC secretariat saying whether or not they endorse the accord.
A majority do endorse it, but many with the rider that they see it as just a political declaration leading to a full-blown treaty at some stage, and certainly not be a replacement for such a treaty.
Sources said the US was "bullying" small developing countries into endorsing the accord, claiming they would not be eligible for financial help from rich nations unless they did so.
Whereas this accusation appears to be straining relations that were already stretched, there are signs that the EU is preparing to give ground on one of the major demands of developing countries - that further emissions cuts for rich countries are made under the Kyoto Protocol.
In a strategy document released last week, the UK said it was prepared to consider the idea; and other EU leaders are also reportedly sympathetic.
"This is a pretty good first step," said Mr Khor. "It's not enough, but if more countries in the EU take this position, that could be the foundation of something that could be a salvation to this situation."
However, if the EU did formally move in this direction, it would put the bloc at odds with traditional allies such as the US, Canada and Japan.
The meeting here runs until Sunday evening.