The annual UN climate talks are taking place for the first time in the Amazon rainforest as global temperatures smash heat records and political distrust grows over climate action.

As he took office on Monday, Trump announced the United States' withdrawal from the 2015 Paris accord adopted by 195 parties to curb greenhouse gas emissions driving climate change.

"We are all still analyzing President Trump's decisions, but there is no doubt that it will have a significant impact on the preparation of the COP," newly appointed COP30 president Andre Correa do Lago told journalists.

"The US is an essential player because it is not only the largest economy, but also one of the largest emitters, and also one of the countries that has provided solutions, with technology."

Under the accord's rules, the United States will formally exit in one year.

Brazilian President Luiz Inacio Lula da Silva on Tuesday named Correa do Lago to preside over the November meeting.

"We will hold a historic COP30 for a fairer and more sustainable future for our planet," Lula wrote on X.

- COP struggles -

Correa do Lago, climate secretary within the foreign ministry, is a former ambassador to Japan and India who served as Brazil's chief climate change negotiator between 2011 and 2013.

The appointment of the seasoned climate expert comes after two years in a row in which COP talks were headed by oil executives.

Lula's decision was welcomed by civil society groups.

This year's COP comes as average global temperatures in the past two years have exceeded the 1.5 degrees Celsius benchmark set under the Paris climate accord a decade ago.

"Andre is a skilled diplomat, well-regarded by the international community, who understands the subject and its dynamics. He's taking on not just a planet, but a hot potato," said Caetano Scannavino, coordinator of the Health and Happiness Project in the state of Para.

"It's the 10th anniversary of the Paris Agreement, amidst Trump's return, a rising far-right, declining multilateralism, and recent COPs that have made little progress. It's a tough mission that will require all our support."

Experts view the UN conference, set for November 10-21, as a crucial chance for humanity to reverse the warming trend with firm commitments to reduce global emissions.

- Amazon city -

Lula has positioned himself as a global flag-bearer for the environment, and since taking office, deforestation in the Amazon has fallen sharply.

But he also wants to expand Brazil's oil exploration, complicating its image as COP30 host.

The world's largest tropical rainforest is critical in the fight against climate change, but increasingly suffers its effects, with fires and droughts growing more severe each year.

Hosting the massive global event in the Amazon for the first time has presented Brazil with several challenges.

The city of Belem, where some 60,000 participants are expected, is scrambling to provide enough infrastructure and hotel rooms for guests.

Record public investment is restoring monuments, transforming the abandoned port warehouses into leisure zones, and dredging the river bay to anchor two cruise ships, which will expand lodging options alongside two new hotels.

At the negotiating table, Brazil is tasked with boosting climate aid to help developing countries reduce emissions and prepare for the dangerous impacts of a warming world -- a goal not met at the 2024 meeting in Azerbaijan.