With time running down, negotiators at the United Nations’ annual climate talks have returned to the puzzle of finding an agreement to bring far more money for developing countries to adapt than wealthier countries have shown they are willing to pay.

Vulnerable nations are seeking $1.3 trillion to deal with damage from climate change and to adapt to that change, including building out their own clean-energy systems. Experts agree that at least $1 trillion is called for, but both figures are far more than the developed world has so far offered.

With two days left to break the impasse at the UN talks in Azerbaijan, rich nations have still not revealed how much they are ready to provide the developing world to fight climate change.

“We need a figure,” said Adonia Ayebare, chair of the G77+China group of developing nations.

“Then the rest will follow. But we need a headline,” the Ugandan negotiator told reporters on Wednesday.

Negotiators are debating three key components of the issue: how big the numbers are, how much grants or loans should total, and who contributes.

At a session where negotiators relayed their progress on Wednesday, Australia’s Minister for Climate Change and Energy Chris Bowen, one of the ministers leading talks on the money goal, said he has heard different proposals on how much cash should be in the pot.

As well as the $1.3 trillion proposed by developing countries, nations proposed figures of $900bn, $600bn and $440bn, he said.

Diego Pacheco Balanza, the chair of the Like-Minded Group negotiating bloc, said the group was also hearing a figure of $200bn in negotiating corridors. “That’s not enough,” he said.

“Developed countries whose legal obligations it is to provide finance continue to shift their responsibility to developing countries,” Pacheco Balanza added.

Developing nations say rich historic polluters have a duty to help and also want public grants from governments – not loans or private capital – to make up the majority of the new finance goal under negotiation.

Some of those on the hook for climate finance, including the European Union and United States, say they cannot show their hand until they know what they are agreeing to.

There is also a demand for emerging economies such as China and Saudi Arabia, which have grown wealthy yet remain classified as developing nations, to chip in.

While talks have gone around in circles for over a week, a slimmed-down draft is expected to land in the early hours of Thursday, ensuring a sleepless night for negotiators.

“I’m sure we will have some long days and hours ahead of us … This will be a very steep climb,” European climate envoy Wopke Hoekstra told reporters. He added “It is important to determine the elements first, so that you can have an informed conversation about what an ambitious and also realistic number could be.”

However, the lead negotiator of COP29 hosts Azerbaijan, Yalchin Rafiyev, urged countries to “pick up the pace”.

“Let us embrace the spirit of collaboration, compromise and determination to ensure that we leave this conference with outcomes that make a real difference,” Rafiyev said.