The COP29 summit has agreed to inject at least $US300 billion ($A462 billion) annually to help poorer countries deal with the impacts of climate change, with rich countries leading the payments.
The new goal is intended to replace developed countries' previous commitment to provide $US100 billion ($A154 billion) per year in climate finance for poorer nations by 2020. That goal was met two years late, in 2022, and expires in 2025.
The agreement was criticised by developing nations, who called it insufficient, but United Nations climate chief Simon Steill hailed it as an insurance policy for humanity.
"It has been a difficult journey, but we've delivered a deal," Steill said after the agreement was adopted on Sunday.
"This deal will keep the clean energy boom growing and protect billions of lives. It will help all countries to share in the huge benefits of bold climate action: more jobs, stronger growth, cheaper and cleaner energy for all."
"But like any insurance policy – it only works – if the premiums are paid in full, and on time."
The COP29 climate conference in the Azerbaijan capital of Baku had been due to finish on Friday, but ran into overtime as negotiators from nearly 200 countries struggled to reach consensus on the climate funding plan for the next decade.
At one point delegates from poor and small island nations walked out in frustration over what they called a lack of inclusion, worried that fossil fuel producing countries were seeking to water down aspects of the deal.
The summit cut to the heart of the debate over financial responsibility of industrialised countries - whose historic use of fossil fuels have caused the bulk of greenhouse gas emissions - to compensate others for worsening damage wrought by climate change.
It also laid bare divisions between wealthy governments constrained by tight domestic budgets and developing nations reeling from costs of storms, floods and droughts.
Countries also agreed on rules for a global market to buy and sell carbon credits that proponents say could mobilise billions more dollars into new projects to help fight global warming, from reforestation to deployment of clean energy technologies.
Countries are seeking financing to deliver on the Paris Agreement goal of limiting global temperature rise to 1.5 degrees Celsius above pre-industrial levels - beyond which catastrophic climate impacts could occur.
The world is on track for as much as 3.1C of warming by the end of this century, according to the 2024 UN Emissions Gap report, with global greenhouse gas emissions and fossil fuels use continuing to rise.
The roster of countries required to contribute - about two dozen industrialised countries, including the US, European nations and Canada - dates back to a list decided during UN climate talks in 1992.
European governments have demanded others join them in paying in, including China, the world's second-biggest economy, and oil-rich Gulf states. The deal encourages developing countries to make contributions, but does not require them.
The agreement also includes a broader goal of raising $US1.3 trillion ($A2 trillion) in climate finance annually by 2035 - which would include funding from all public and private sources and which economists say matches the sum needed to address global warming.
Securing the deal was a challenge from the start.
Donald Trump's US presidential election victory has raised doubts among some negotiators that the world's largest economy would pay into any climate finance goal agreed in Baku.
Trump has called climate change a hoax and promised to again remove the US from international climate co-operation.
Western governments have seen global warming slip down the list of national priorities amid surging geopolitical tensions, including Russia’s war in Ukraine and expanding conflict in the Middle East, and rising inflation.
The showdown over financing for developing countries comes in a year that scientists say is destined to be the hottest on record.
Climate woes are stacking up in the wake of such extreme heat, with widespread flooding killing thousands across Africa, deadly landslides burying villages in Asia, and drought in South America shrinking rivers.
with DPA and AP
