Countries represented at the COP-29 summit in Azerbaijan have agreed to a compromise deal on climate financing that will see more than $460 billion spent yearly to 2035 to help developing nations adapt to climate change.

The deal will mean that richer nations lead the payments, according to the details of the agreement forged in Baku.

The new goal is intended to replace developed countries' previous commitment to provide $100 billion per year in climate finance for poorer nations by 2020. 

That goal was met two years late, in 2022, and expires in 2025.

United Nations climate chief Simon Steill hailed the new agreement as an insurance policy for humanity.

"It has been a difficult journey, but we've delivered a deal," he said after the agreement was adopted.

"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."

Shortly after the agreement was reached, India's delegation representative, Chandni Raina, told the summit's closing plenary session that the nation strongly objected to the financing deal.

"I regret to say that this document is nothing more than an optical illusion. This, in our opinion, will not address the enormity of the challenge we all face. Therefore, we oppose the adoption of this document," Ms Raina said.

UN Secretary General Antonio Guterres said that he had hoped for a "more ambitious outcome" from the summit, but acknowledged the agreement "provides a base on which to build".

"It must be honoured in full and on time. Commitments must quickly become cash," Mr Guterres said.

Countries also agreed on Saturday 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.

Negotiators walk out of COP29 meetings

Earlier on Saturday, negotiators representing several island nations temporarily walked out of the COP29 summit , amid tense discussions over funding to combat climate change.

Prior to the financial financial agreement forged during the summit, developing countries had demanded around $US390 billion ($600 billion) in annual funding.

Representatives from the least developed countries and small island nations blocs walked out of a negotiating room in frustration at one point on Saturday afternoon, but said they remained committed to finding a deal.

"We want nothing more than to continue to engage, but the process must be inclusive," the Alliance of Small Island States said in a statement.

Fiji's Deputy Prime Minister Biman Prasad said he was optimistic common ground could be found.

"When it comes to money it's always controversial but we are expecting a deal tonight," he said.

Deal on carbon offsets struck, despite greenwashing concerns

Despite the impasse on annual climate funding, a deal was reached between negotiators to establish new rules for carbon trading. 

The deal would see a United Nations-backed framework for carbon credit trading established, supporters say.

Carbon credits are generated by activities that reduce or avoid planet-heating greenhouse gas emissions, like planting trees, protecting existing carbon sinks or replacing polluting coal with clean-energy alternatives. 

Until now, these credits have mainly been traded by companies on an unregulated market dogged by scandal.

The new system, agreed on Saturday, would see both a UN-run system for trading carbon credits, open to both states and companies, and a country-to-country trading scheme.

However, some experts expressed doubt that the quality of the carbon credits traded on the regulated market would be much better than those that came before.

Erika Lennon of the Center for International Environmental Law said it would be necessary to make sure these markets do not create "even more problems and more scandals than the voluntary carbon markets".

Reuters/AFP