Leaders of the world's biggest economies must send a clear signal on the need to tackle global warming, COP29 climate summit host Azerbaijan said on Monday.

The plea came as Group of 20 (G20) leaders met in Brazil with climate just one item on an agenda spanning war in Ukraine and the implications of Donald Trump's election victory.

In Baku, the main objective for the nearly 200 countries gathered for COP29 is to agree a deal on how to provide trillions of dollars in financing for climate projects, with talks on a new finance goal and cutting emissions bogged down.

"We cannot succeed without them, and the world is waiting to hear from them," said COP29 President Mukhtar Babayev, adding: "They account for 85% of global GDP and 80% of emissions".

"We urge them to use the G20 meeting to send a positive signal of their commitment to addressing the climate crisis. We want them to provide clear mandates to deliver at COP29," he told a press conference in Baku.

While the G20 looked to have agreed movement on climate finance, prior to the text being seen it was unclear to those in Baku what had been agreed and how it would impact talks, which entered their second week in Azerbaijan.

U.N. climate chief Simon Stiell warned leaders who are set to arrive to help drive forward a deal, not to waste time with "bluffing, brinksmanship and premeditated playbooks".

"We'll only get the job done if parties are prepared to step forward in parallel, bringing us closer to common ground," he said, adding: "So let's cut the theatrics and get down to real business."

FOSSIL FUELS

Another contentious area of discussion has been how to move forward a deal struck in Dubai last year on transitioning from climate-damaging fossil fuels.

A dispute over this delayed the start of negotiations last week and looks to have made little progress towards resolution.

European and small island countries have run up against the Arab group of nations on how prominent the future of fossil fuels should be on the agenda and how countries should be held accountable for the promises they made last year.

Australia's Sally Cox, speaking for the Umbrella Group, which includes Japan and the United States, said it was "deeply disappointed" some parties had "repeatedly blocked progress".

"Substantive outcomes on these matters will be critical at COP29," Cox added, without naming specific countries.

Groups including the 27-nation European Union said there was a need for Azerbaijan to follow in the footsteps of past COP presidencies and take a leadership role in guiding the talks towards a deal.

"That has been the case at every single COP and it certainly is the case at this COP," EU climate chief Wopke Hoekstra said.