About 50,000 people are expected to attend the 12-day climate summit in the Brazilian city of Belem.
The 30th annual United Nations climate change conference (COP30) has opened in Belem, with leaders urging countries to unite against global warming.
“In this arena of COP30, your job here is not to fight one another – your job here is to fight this climate crisis, together,” UN climate chief Simon Stiell told delegates on Monday.
Some 50,000 people from more than 190 countries are expected at the event, held on the edge of the Brazilian Amazon.
Stiell said past talks had made a difference but warned there was “much more work to do” and that nations must move “much, much faster” to cut greenhouse gas emissions. “Lamenting is not a strategy. We need solutions,” he said.
A new UN analysis of countries’ climate plans found pledged cuts fall far short of what is required by 2035 to keep warming to 1.5C (2.7F) above pre-industrial levels. Experts say breaching that threshold will bring far more severe impacts.
“Climate change is no longer a threat of the future. It is a tragedy of the present,” Brazilian President Luiz Inacio Lula da Silva said, condemning efforts to undermine climate action. “They attack institutions, they attack science and universities. It’s time to inflict a new defeat on the deniers.”
The United States is not sending delegates to COP30, consistent with President Donald Trump’s anti-climate change stance. “It’s a good thing that they are not sending anyone. It wasn’t going to be constructive if they did,” former US climate envoy Todd Stern said of the decision.
COP30 President Andre Correa do Lago said the US absence “has opened some space for the world to see what developing countries are doing”.
Pablo Inuma Flores, an Indigenous leader from Peru, urged leaders to move beyond promises. “We want to make sure that they don’t keep promising, that they will start protecting, because we as Indigenous people are the ones who suffer from these impacts of climate change,” he said.
In a letter to COP30, dozens of scientists warned about rapid melting of glaciers, ice sheets and other frozen regions. “The cryosphere is destabilising at an alarming pace,” they wrote, adding that geopolitical tensions or short-term national interests must not overshadow the talks. “Climate change is the defining security and stability challenge of our time.”