Addressing a press conference, Secretary of State Hillary Clinton said her country will mobilise $100 billion yearly till 2020 if developing countries agree to transparency in national commitments.
"There have been occasions in this past year when all the major economies have committed to transparency," Clinton said.
She urged all sides to seek common ground in the final stretch of negotiations.
"I understand that the talks have been difficult," she said.
"And we will continue doing all that we can do. But the time is at hand for all countries to find common ground," she added.