Poor nations are pressuring their wealthy counterparts to pay up for the mounting damage being caused by global warming, pointing to increasing powerful storms, cyclones, droughts and floods afflicting their people.
The campaign being waged at the COP26 UN climate summit in Glasgow, Scotland, seeks hundreds of billions of dollars per year more for climate-vulnerable economies even as they struggle to access $US100 billion ($A135 billion) pledged by world powers years ago.
Those previously promised funds, meant to help developing nations transition away from fossil fuels and adapt to the future realities of a warmer world, were offered in recognition that poorer countries are the least responsible for climate change.
"We've been too slow on mitigation and adaption, and so now we have this big and growing problem of loss and damage," said Harjeet Singh, an advisor with Climate Action Network, who is involved in the negotiations on behalf of developing countries.
He said talks so far were focused on including language about "loss and damage" in the official text of the summit agreement, a request he said was facing resistance from the United States, the European Union and other developed countries worried by the potential costs and legal implications.
EU climate policy chief Frans Timmermans told reporters the bloc supported efforts to "get money where it needs to be as quickly as possible" but that work still needed to be done to get the details right.
Climate-vulnerable countries have been raising the issue of who should pay for climate damage since the earliest international talks on global warming decades ago.
Economists now estimate the costs of damage from climate change-related weather events could be around $US400 billion ($A540 billion) per year by 2030.
Wealthy nations could acquire the funds, at least in part, by revoking subsidies and imposing fees on fossil fuel companies, the Climate Action Network's Singh said.
He added that without some financial assistance, the costs of damage from climate change could bankrupt fragile economies, hampering their ability to contribute to the fight against climate change.
"If your house is on fire, you first put out the fire. Not think about how to prevent fires 10 years from now," he said.