A group of former leaders and climate experts say the annual UN COP climate talks are no longer fit for purpose and need to be reformed, publishing a critical open letter mid-way through what has so far been a fractious summit.

Nearly 200 countries are gathered in Baku, Azerbaijan, with a primary goal of agreeing on a new target for how much money needs to be provided to help developing countries adapt to climate change and recover from destructive weather.

So far, those talks have made little progress.

Delegates struggled for hours on the opening day to agree on an agenda and the mood has been soured by doubts about the future role of the United States under a Donald Trump presidency, diplomatic spats involving the host country and the withdrawal of the Argentinian delegation.

Friday's letter was signed by more than 20 experts, including former UN secretary general Ban Ki-moon, former Irish president Mary Robinson and the former head of the UN climate body that runs the annual COP summits, Christiana Figueres. The letter said the COP process had achieved much, but now needs an overhaul.

"It is now clear that the COP is no longer fit for purpose. Its current structure simply cannot deliver the change at exponential speed and scale, which is essential to ensure a safe climate landing for humanity," the letter said.

"This is what compels our call for a fundamental overhaul of the COP. We need a shift from negotiation to implementation, enabling the COP to deliver on agreed commitments and ensure the urgent energy transition and phaseout of fossil energy."

Figueres later said some of the ideas in the letter had been misinterpreted.

"The COP process is an essential and irreplaceable vehicle for supporting the multilateral, multisectoral, systemic change we urgently need. Now more than ever," she said in a post on LinkedIn.

Other leaders defended the COP process as essential after the publication of the letter. 

Michai Robertson, lead negotiator for the Alliance of Small Island States, said COP was the only platform where their countries were able to participate in climate negotiations and have a voice.

WATCH | Leaders speak of the importance of the COP process amid criticism: 

Some leaders defend the COP process as essential in wake of open letter

Alliance of Small Island States (AOSIS) lead negotiator Michai Robertson weighs in to point out that small nations aren’t able to have a voice in climate negotiations outside of COP, while Cat Abreu, director of International Climate Politics Hub, defends the COP process while adding that there is 'room for constructive feedback.'

Separately, Cat Abreu, director of International Climate Politics Hub, said the COP process, while "imperfect," is the best option available.

"It's clear that change is possible in this process, and there is room for constructive feedback to offer ideas for that change. And I think that that was what was intended by this letter," she told reporters.

Recommendations call for overhaul

The letter laid out several recommendations for how to refocus the talks and ensure that future meetings are actually tackling the existential threat of climate change. 

These include streamlining negotiations to get to concrete action faster, implementing mechanisms to actually hold countries accountable for the climate targets they commit to and amplifying the voice of science. 

It also suggested improving the selection process for COP presidencies to exclude countries that do not support the phaseout of fossil energy — a recommendation that comes just days after the president of this year's host country told the climate conference that oil and gas are a "gift of God."

The open letter noted that in 2023, a record number of 2,456 fossil fuel lobbyists were granted access to COP28, almost four times more than were at COP27. 

According to a new report released Friday by coalition Kick Big Polluters Out, at least 1,773 fossil fuel lobbyists have been granted access to the COP29 summit, outnumbering the delegations from almost every country attending. 

"The fact that the scientists who predicted all of this decades ago have been proven dead right should cause the rest of us to pay more attention to what they're telling us now," former U.S. vice-president Al Gore said at COP29 on Friday. 

"Do we listen to the polluters who don't want to do anything meaningful that might reduce fossil fuels? Or do we listen to the scientists who have been telling us what we need to do?"

He railed against inaction, highlighting the increase in extreme weather and the loss of sea ice. 

"It's getting a lot worse quickly and will continue to get worse until we as humanity decide to organize ourselves well enough to take action. That's what we're supposed to be doing here at this COP."

WATCH | Al Gore criticizes world powers, saying they bowed to fossil fuel interests: 

Former U.S. vice-president Al Gore gives fiery speech at COP29

Former U.S. vice-president Al Gore slams the fossil fuel industry, saying it’s time for world leaders to listen to scientists instead of lobbyists.

Criticism has been levied at the COP process in Baku multiple times over the past week. 

Barbados Prime Minister Mia Mottley called for urgent reform and Albanian Prime Minister Edi Rama spoke of leaders sitting on sofas and taking photographs while speeches at the summit played out on muted television screens.

Asked about the letter and the overall process, the COP29 presidency's lead negotiator, Yalchin Rafiyev, said: "The process has already delivered ... so far by reducing the projected warming, delivering finance to those in need — and it's better than any alternative."

However, he said the multilateral process was under pressure and that COP29 would be "a litmus test for the global climate architecture."

WATCH | Greta Thunberg says COP process doesn't lead to meaningful change: 

Climate activist Greta Thunberg says COP is 'failing us'

Swedish activist Greta Thunberg said on Friday that we have to 'stop pretending' that the COP process is going to lead to meaningful action on the climate crisis.