Developed nations have mobilised some US$80 (S$111.82)-US$90 billion per year to help the poorest survive a warmer world, delegates at Paris climate talks said, but emerging countries dispute the figures and say a goal of US$100 billion by 2020 is far from reach.
The issue is central to UN talks in Paris, where nearly 200 nations are trying to forge a new pact on climate change.
In October, the Organisation for Economic Co-operation and Development (OECD), which represents rich nations, calculated that financial pledges from the developed world totalled US$62 billion in 2014 towards an agreed UN goal to reach US$100 billion by 2020.
Since that report, new promises of funding have been made, including from Britain, France, Germany and Japan, the delegates said.
The OECD has yet to update its figures, but delegates at the UN talks said they had used the OECD methodology to analyse the new money.
One national finance expert, speaking on condition of anonymity, said the new total was some US$94 billion, while non-governmental organisation Oxfam said the figure was more like $82 billion.
Developing nations, such as India, have accused the West of a lack of transparency and say the OECD vastly over-estimated the size of contributions.
An Indian finance ministry report said "the only hard number" was US$2.2 billion that was clearly climate money.
The arguments are bitter as developing nations fight for help to deal with weather impacts they say hit the poorest hardest.
Richer nations, meanwhile, say the world has changed since the 1997 Kyoto Protocol and countries such as China no longer count as emerging nations.
The European Union is among those to reject criticism it has not been transparent.
Despite its own financial crisis, it says it has been the biggest contributor of climate finance, providing US$15.78 billion in public money in 2014.
The EU has also promised to increase funding, but says developing nations must also help with the cost of switching to lower carbon energy and dealing with extreme weather. "The European Union is fully prepared to play its part. We have heard some say we do not live up to our responsibilities and this could not be further from the truth," European Climate and Energy Commissioner Miguel Arias Canete said in Paris.
The OECD said it had sought to provide a robust methodology, but cautioned that projecting how much global climate money would be available by 2020 from a plethora of grants and loans, some public and some private, was complex.
Joe Thwaites, research analyst at the World Resources Institute (WRI), said many more details were needed on how donations were being counted, but the trend was positive.