The two options in the text released at COP29 in Azerbaijan recognise a need of a trillion dollars per year, but both left the exact amount blank, marked with an "X".

The main sticking points -- who should pay, how much and the type of funding -- remain unresolved with one day left in the negotiations.

"The new finance text presents two extreme ends of the aisle without much in between," said Li Shuo, director of the China climate hub at the Asia Society Policy Institute.