The 30th United Nations Climate Change Conference (COP30) has officially opened in the Brazilian city of Belém, as world leaders and negotiators gather to push for stronger cooperation in tackling the climate crisis. Around 50,000 delegates from more than 190 countries are expected to attend the 12-day summit, being held at the edge of the Amazon rainforest.

Speaking at the opening ceremony, UN Climate Chief Simon Stiell urged delegates to put aside divisions and work collectively to address the escalating global threat. “In this arena of COP30, your job here is not to fight one another – your job here is to fight this climate crisis, together,” Stiell said on Monday.

His comments followed the release of a new UN report showing that current national pledges are still insufficient to limit global warming to 1.5°C above pre-industrial levels by 2035. Scientists have repeatedly warned that surpassing this threshold would trigger far more severe climate impacts, including extreme weather events, rising sea levels, and widespread loss of biodiversity.

Brazilian President Luiz Inácio Lula da Silva opened the conference with a stark message, calling for renewed global determination. The United States is not participating in this year’s talks, consistent with President Donald Trump’s position on climate policy. COP30 President Andre Corrêa do Lago noted that the absence of the US “has opened some space for the world to see what developing countries are doing.”

Pablo Inuma Flores, an Indigenous leader from Peru, called for greater accountability from global leaders, urging them to act 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 joint letter released on Monday, dozens of scientists warned of accelerating ice melt and glacier loss. “The cryosphere is destabilizing at an alarming pace,” the groups said in a letter to COP30 published on Monday. “Geopolitical tensions or short-term national interests must not overshadow COP30. Climate change is the defining security and stability challenge of our time.”

As discussions unfold in Belém, the summit’s focus will be on strengthening multilateral cooperation and advancing adaptation measures. This year’s event marks ten years since the 2015 Paris Agreement, a landmark pact signed by 195 nations to limit global temperature rise, from which the US later withdrew unilaterally.

Brazil, as host, has said its priority is to rebuild trust in international cooperation. Brazil has also launched the Tropical Forest Forever Facility (TFFF), an initiative that seeks to channel global finance into conserving tropical forests. The plan proposes annual payments to countries that maintain their standing forests, creating long-term incentives for preservation. India has confirmed that it will join the TFFF as an observer.

Progress is also expected on the Global Goal on Adaptation, aimed at strengthening collective action and measurable progress on climate resilience. Developing nations are expected to push for greater support on climate finance and technology transfer, areas where developed countries have long-standing obligations.

As the summit continues, delegates will be expected to demonstrate whether international cooperation can translate into concrete climate action.