Delegates at the United Nations climate talks have little time left to decide how the world plans to cap planet-warming emissions and keep the worst of warming at bay.

Simon Stiell, the executive secretary of the UN Framework Convention on Climate Change, told journalists on Monday that the “climate wolves” remained at the world’s doors as negotiations reach their climax at the summit.

“We do not have a minute to lose in this crucial final stretch and none of us have had much sleep,” Stiell said.

He added that “the areas where options need to be negotiated have narrowed significantly,” in particular how to reduce planet-warming emissions and the “transition with the proper means of support to deliver it”.

When asked directly if it was a possibility that negotiators could leave Dubai without a deal, Stiell did not deny that could happen.

“One thing is for certain: I win, you lose is a recipe for collective failure,” he said.

UN Secretary-General Antonio Guterres is expected back at the talks on Monday to repeat calls for countries to commit to slashing fossil fuels and limiting warming.

“We are on the brink of climate disaster and this conference must mark a turning point,” Guterres said on X, formerly known as Twitter, late on Sunday.

COP28 president Sultan al-Jaber on Sunday repeated calls for an ambitious outcome at the talks that’s in line with the Paris agreement to limit warming to 1.5 degrees Celsius.

“Failure or lack of progress or watering down my ambition is not an option,” he said.

Sticking points for the Global Stocktake – the part of talks that assesses where the world is at with its climate goals and how it can reach them – are along familiar lines.

Many countries, including small island states, European states and Latin American nations, are calling for a phase-out of fossil fuels, responsible for most of the warming on Earth.

But other nations want weaker language that will allow oil, gas and coal to keep burning in some way.

Lisa Fischer, program lead at E3G, said there is likely to be loophole language – the world “unabated” before fossil fuels for example – that leaves options for burning of oil and gas but somehow capturing the pollution, something that is tricky and expensive.

Key will be how “unabated” will be defined, she said.

-AP