Climate Summit Opens with Urgent Calls for Action as US Absence Looms Large

World leaders gathered at the edge of Brazil’s Amazon rainforest Thursday for the annual United Nations climate summit, issuing stark warnings that time is running short to prevent catastrophic climate change while criticizing the United States for its retreat from global climate efforts.

UN Secretary-General António Guterres opened the meeting in Belem, Brazil with a blistering critique of world powers who “remain captive to fossil fuel interests, rather than protecting the public interest.” He warned that exceeding the Paris Agreement’s key benchmark of 1.5 degrees Celsius (2.7 Fahrenheit) of warming would constitute a “moral failure and deadly negligence.”

“Even a temporary overshoot will have dramatic consequences… every fraction of a degree higher means more hunger, displacement and loss,” Guterres told the assembly.

Brazilian President Luiz Inácio Lula da Silva, hosting the conference at the gateway to the Amazon, sought to rally support for increased funding to protect tropical rainforests while pushing for progress on climate commitments that remain unfulfilled from previous summits.

“The window of opportunity we have to act is rapidly closing,” Lula warned in a rousing address, adding that there was “no greater symbol of the environmental cause” than the Amazon rainforest.

The critical importance of the venue was not lost on attendees. Known as the “lungs of the world” for its capacity to absorb carbon dioxide, the Amazon has lost 17% of its forest cover over the past half-century, cleared primarily for cattle ranching, logging, and mining operations.

However, the reduced participation at this year’s Conference of Parties (COP30) cast a shadow over the proceedings. Attendance was down by half compared to last year’s summit, with the leaders of the world’s three biggest polluters—China, the United States, and India—completely absent from the preliminary gathering.

The absence of the U.S. delegation was particularly notable. President Donald Trump, who has dismissed climate change as a hoax and withdrew the U.S. from the Paris climate accords upon taking office, did not send any senior officials to Belem. American participation was further hampered by the government shutdown that led to hundreds of canceled flights.

Several Latin American leaders directly criticized Trump’s stance. Colombian President Gustavo Petro declared Trump’s absence “100% wrong” and accused him of being “against humankind.” Chile’s left-wing President Gabriel Boric similarly denounced Trump’s claim that “the climate crisis does not exist” as “a lie.”

Indigenous groups expressed concerns that Trump’s inaction could embolden other countries to ignore the crisis. “It pushes governments further toward denial and deregulation,” said Nadino Kalapucha, spokesperson for the Amazonian Kichwa Indigenous group in Ecuador. “That trickles down to us, to Ecuador, Peru, Argentina, where environmental protection is already under pressure.”

Argentina’s President Javier Milei, who previously threatened to quit the Paris Agreement and last year withdrew Argentine negotiators from the climate summit in Azerbaijan, also boycotted this week’s meeting.

The political vacuum left European leaders including UK Prime Minister Keir Starmer, German Chancellor Friedrich Merz, and French President Emmanuel Macron to confront not only the climate crisis but also the erosion of global consensus that emerged with the Paris Agreement a decade ago.

“Today, sadly, that consensus is gone, with some arguing that this isn’t the time to act and saying that tackling climate change can wait,” Starmer said in his address.

Some climate experts, however, found a silver lining in the U.S. absence, suggesting it might actually reduce the risk of America blocking an ambitious agreement that requires consensus.

“Even if the U.S. plays an outsized role, it is one country and there are over 190 nations coming to COP, many of which are willing to stand up to the destructive tactics of the fossil fuel industry,” said Rachel Cleetus, senior policy director with the Climate and Energy program at the Union of Concerned Scientists.

Brazil’s role encapsulates the central dilemma of the climate crisis. While Lula has positioned himself as a champion of climate diplomacy in the Global South and won praise for reducing Amazon deforestation, his commitment has faced economic pressures. He recently granted Brazil’s state oil firm Petrobras a license to explore oil near the Amazon River’s mouth, prompting accusations of hypocrisy.

The centerpiece of Brazil’s proposal is the Tropical Forests Forever Facility, a fund that would compensate 74 developing countries for preserving their forests, using loans from wealthier nations and commercial investors. On Thursday, the Brazilian government announced $5.5 billion in pledges from Norway, Indonesia and several other countries, though it remains unclear whether major world powers will contribute.

As the conference continues, the World Meteorological Organization reported that 2025 is on track to be the second or third warmest year ever recorded, with greenhouse gas concentrations, ocean heat, and sea levels all continuing to rise.