An historic shift is beginning to look more likely at the United Nations climate talks in Qatar, with rich nations closer to agreeing that they should compensate poor nations for losses due to climate change.
The United States has fiercely opposed the measure - it says the cost could be unlimited.
But after angry tussles throughout the night, the BBC reports, the principle of "loss and damage" is now in the final negotiating text.
Small island states at risk of inundation say they will walk out if the US vetoes the proposed deal.
The BBC's correspondent says the political stakes are high. The European Union's position is not yet well defined, but soundings suggest that it can live with the text.
The US will be seeking support from other big polluters - like Canada - likely to face liability for climate damages.
If the US is left alone fighting against the chair's text, its negotiators face a dilemma - either to bow to the majority and accept that the nations that caused climate change bear a moral responsibility to other nations damaged by it, or to refuse to sign.
If it vetoes the text, President Barack Obama will be accused of hypocrisy and failure after re-committing himself to tackling climate change since his re-election.
Another $US60 billion sought
AAP reported earlier that the issue of funding for poor countries has hamstrung the negotiating by envoys from nearly 200 countries.
Developing countries say they need at least another $US60 billion between now and 2015 - to deal with a climate-change-induced rise in droughts, floods, sea levels and storms.
But the US and the EU have refused to put concrete figures on the table for 2013-2020, citing the tough financial times.