UN climate talks in Dubai were set Tuesday to run past a host-imposed deadline for a deal as at-risk nations voiced fury over a proposed compromise that stops short of phasing out fossil fuels.

The Emirati president of the COP28 summit has repeatedly pressed the nearly 200 nations to reach an ambitious deal by the official end of talks at 11 am (0700 GMT), in an effort to force decisions.

But after another late night of haggling, there was no sign that the talks were anywhere near completion, with negotiators waiting for a fresh text after wide criticism of a draft released Monday.

"We have time and we are prepared to stay a little longer," German Foreign Minister Annalena Baerbock said.

The team from the Marshall Islands — which lies on average 2.1 metres (seven feet) above sea level and is threatened with submersion as ice melts — vowed to stay until the end.

The Pacific archipelago's negotiator, John Silk, said that his country "did not come here to sign our death warrant".

Campaigners had hoped the COP28 summit — set in a glitzy metropolis built on petrodollars — would take the historic step of calling for the first time for a global phase-out of fossil fuels, which account for three-quarters of greenhouse gas emissions blamed for the planetary crisis.

But climate decisions must be made by consensus and Saudi Arabia, the world's largest oil exporter, has led opposition to the threat to its financial lifeblood.

The draft put forward by COP28 president Sultan Al Jaber — himself head of the UAE's national oil company — only lists a series of options including reductions in fossil fuel production and consumption.

'Broken beyond repair'

Clive Hamilton, a professor at Australia's Charles Sturt University and veteran watcher of climate negotiations, said the "extraordinarily weak draft" showed the influence of the fossil fuel lobby, which showed up at COP28 in record numbers.

"If anything like the current text is adopted, it will show the COP process to be broken beyond repair," he said.

Scientists say the planet has already warmed by 1.2 degrees Celsius (2.2 Fahrenheit) from pre-industrial times and that 2023 — marked by lethal disasters including wildfires across the world — has likely been the warmest in 100,000 years.

The 2015 Paris summit endorsed an ambition of checking warming at 1.5 Celsius — a goal endorsed in the latest draft, but which critics say is virtually impossible without serious efforts to curb oil, gas and coal.

"I don't think anybody here wants to be associated with the failure to live up to this responsibility. Not a lot of people in public life are asked to make life and death choices historically," said US climate envoy John Kerry, who helped negotiate the Paris accord.

"This is a war for survival," he said in a closed-door session which ended at around 2:30 am.

Kerry has supported calls to phase out fossil fuels, even though the United States remains the world's largest oil producer and much of the rival Republican Party adamantly opposes action on climate.

Revisions expected

Former US vice president Al Gore, who won the Nobel Peace Prize for his climate advocacy, said that the "obsequious" draft looked as if it had been written by the OPEC oil cartel.

"In order to prevent COP28 from being the most embarrassing and dismal failure in 28 years of international climate negotiations, the final text must include clear language on phasing out fossil fuels," Gore wrote on X, formerly known as Twitter.

Jaber acknowledged Monday there was work to do, and a person familiar with the COP28 presidency's thinking called Monday's text "an opening gambit" that could be built upon.

The 21-page text does not go so far as to demand action on fossil fuels, only presenting measures that nations "could" take.

"This is not a menu in a restaurant. We have to do all of these things," Canada's Steven Guilbeault, part of a group of ministers tasked by Jaber to shepherd negotiations, told AFP.

The latest draft deal also includes calls to accelerate zero- and low-emission technologies — including renewables and nuclear power — in language similar to a joint statement reached last month by the United States and China, the world's two biggest emitters.