After decades of United Nations climate summits, the model of gathering world leaders to negotiate agreements under complex rules is starting to show its limits, said the president of the next such summit, Brazilian diplomat Andre Correa do Lago.

"The Paris Agreement is working, but there is much more to do," he wrote in a letter released on Monday outlining his presidency's vision for the COP30 summit in the Amazon city of Belem in November.

Climate negotiators, he said, should be self-critical and address the "outside perception of talks having lingered for over three decades with meagre results."

"We need a new era beyond negotiating talks: we must help put into practice what we have agreed," he wrote.

At a press conference, Correa do Lago said the summits held by the UNFCCC, the UN body monitoring compliance with the 2015 Paris Agreement, are the best existing venue for climate negotiations but there are limits to what they can achieve.

He said despite its recommendations, the body has no authority over the entities meant to carry them out.

Global setbacks have further hampered climate change action.

U.S. President Donald Trump has withdrawn from the Paris Agreement and blocked funds to aid Ukraine in its conflict against Russia, forcing Europe to boost defense spending with resources that might otherwise have been invested in climate solutions.

Correa do Lago said Brazil will encourage countries to use other gatherings of world leaders, such as the G20 and the International Monetary Fund meetings, to push for action on global warming.

Brazil also aims to give more voice to other actors, such as civil society groups and Indigenous communities, he said.

Correa do Lago told reporters he would call two international meetings with global leaders prior to COP30 to discuss countries' pledges to lower emissions of greenhouse gases. The deadline to file new pledges was in February, but only 13 countries presented their contributions.