The world must defeat climate denialism and fight fake news, Brazil's President Luiz Inácio Lula da Silva has told the opening meeting of the UN climate talks. In a rallying cry to COP30, President Lula again made thinly veiled references to President Donald Trump who branded climate change a con job in September.

The two weeks of talks kicked off on Monday in the lush Brazilian city of Belém on the edge of the Amazon rainforest. They take place against a fraught political backdrop and the US has sent no senior officials.

On Monday thousands of delegates poured into the COP venue in a heavily air-conditioned former aerodrome, some coming from accommodation in shipping containers and cruise ships moored on the riverside. Members of the Guajajara indigenous group, in traditional dress, performed a welcome song and dance for assembled diplomats.

Addressing the conference, President Lula said COP30 will be the COP of truth in an era of fake news and misrepresentation and rejection of scientific evidence. Without naming President Trump, President Lula continued, they control the algorithms, sow hatred and spread fear. It's time to inflict a new defeat on the deniers, he said.

Since President Trump took office, he has promised to invest heavily in fossil fuels, canceling over $13bn of funding aimed at renewable energy and opening more areas of the US to oil and gas exploration, which contrasts with the commitments of most nations to reduce greenhouse gas emissions.

This backdrop has put the COP talks in a tricky spot. There are fears the US may attempt to undermine discussions given its absence.UN climate chief Simon Stiell acknowledged progress had been made to reduce emissions but highlighted the need for nations to stop squabbling, stating, Not one single nation among you can afford this, as climate disasters rip double-digits off GDP.

Brazil aims to leverage its presidency of the talks to advance previous commitments including a push to shift away from fossil fuels, secure finance for vulnerable nations, and protect natural environments. Lula's key focus includes the Tropical Forest Forever Facility, intended to raise $125bn for global forest protection efforts. While fundraising has started slow, UK officials recently expressed commitment to the initiative.

The conference agenda outlines discussions to keep global temperature rises below 1.5C above pre-industrial levels, a goal clung to by many, despite recent statements acknowledging overshooting this target may be unavoidable. UN Secretary General António Guterres called the failure to limit global warming a moral failure and deadly negligence.\