President Trump’s withdrawal of the U.S. from the global fight against climate change has gone further than almost anyone expected.
During the first year of his second term in office, the president and his administration have cut foreign aid for climate resilience, pressured countries to delay crucial carbon tax agreements, and removed the U.S. from the Paris Agreement, the landmark 2015 accord that saw the world’s nations come together around a plan to limit global warming.
Some of this was anticipated, but on Wednesday Trump took arguably his most dramatic step yet against global climate action. In a brief memorandum, he announced that he would “effectuate the withdrawal” of the U.S. from the United Nations Framework Convention on Climate Change, or UNFCCC, the bedrock treaty that first brought countries together to discuss the climate crisis more than three decades ago.
In other words, Trump hasn’t just skipped out on the world’s plan for tackling climate change — he’s also decreeing that the U.S. will no longer take any part in international talks on the subject. And this latest move may prove far more durable than leaving the Paris accord. Because of ambiguity in U.S. law, future presidents may not be able to reverse withdrawal from the UNFCCC even if they want to.
If Paris was a contract to stop climate change, the UNFCCC was akin to the boardroom in which countries hashed out that contract. Trump’s withdrawal from the latter is an even more extreme measure because it means that the U.S. government will no longer be eligible to attend global climate talks, known as COPs, and will be the only country in the world that is unable to participate in multilateral debates about climate change.
“This is a short-sighted, embarrassing, and foolish decision,” said Gina McCarthy, who was the White House climate advisor to former President Joe Biden, in a statement. “The Trump administration is throwing away decades of U.S. climate leadership and global collaboration.”
The UNFCCC also has a stronger basis under domestic law than the Paris Agreement ever did. The U.S. Senate ratified the convention as a formal treaty in 1992 by a vote of 92 to 0, and it was signed into law by President George H.W. Bush. (By contrast, the Obama administration used executive action to join the Paris Agreement without needing congressional approval.) Trump did not attempt to leave the treaty during his first term, and indeed no nation has ever attempted to do so.
No one knows for sure how a future president could rejoin the UNFCCC. Some experts believe that a future president could rely on the 1992 Senate vote to justify rejoining, but others say that Trump’s withdrawal this week annuls that vote, requiring a new Senate vote with two-thirds support — a tall order in a far more polarized political environment.
Article II of the U.S. Constitution says that the president “shall have power, by and with the advice and consent of the Senate, to make treaties, provided two thirds of the senators present concur.” But the document is silent about who has the authority to leave and rejoin those treaties; some legal scholars have argued that the president has unilateral power to terminate treaties, but others have argued the opposite. Senator Sheldon Whitehouse, a Rhode Island Democrat and leading climate hawk, said in a statement Thursday that only the Senate can withdraw from Senate-ratified treaties and that Trump’s move was illegal. The question of who has the authority to rejoin a treaty is even murkier. The Supreme Court has never ruled on the issue. In 1979, after evaluating a legal challenge to then-president Jimmy Carter’s termination of a defense treaty with China, the court referred to the issue as a “political question” not subject to judicial authority.
In their initial reactions to Trump’s move, climate experts offered a range of different views on the question of rejoining the UNFCCC, reflecting the extreme uncertainty on the issue. Sue Biniaz, who served for decades as a lead U.S. negotiator in climate talks, said that she believes the country “could rather seamlessly rejoin.” Michael Gerrard, a climate law expert at Columbia University, said by email that there are competing theories about Senate consent for rejoining treaties — and that he didn’t know immediately which theory was correct.
“I want to try to pin this down,” he said.
Experts also said it’s not even certain if Trump did withdraw from the treaty in a legal sense. His memo says that it pulls the U.S. from more than 60 international agreements covering everything from cyber security to cotton. It declares that, “For United Nations entities, withdrawal means ceasing participation in or funding to those entities to the extent permitted by law.” It is unclear if this means the U.S. will submit a formal withdrawal notice to the U.N. governing body, which is what would make the move official, or will simply not participate in negotiations for the remainder of Trump’s tenure. (The State Department did not immediately respond to Grist’s request for comment and clarification on the withdrawal.)
If the withdrawal goes forward, it could take the U.S. out of the international climate fight for far longer than the remainder of Trump’s term. Trump has cemented opposition to any form of climate action as a core commitment of the Republican party. And given that Republicans hold a durable advantage in the Senate, where rural states hold disproportionate sway, a future vote to rejoin the agreement looks remote. If a future president tried to rejoin the UNFCCC without Senate consent, anti-climate groups would likely file a legal challenge to the move by citing the Senate’s treaty authority.
For now, the other 197 countries that are party to the UNFCCC will continue to negotiate global agreements on climate change, albeit with the world’s largest economy missing. This was already the case in Brazil last year during the COP30 conference, which the Trump administration skipped even though the United States was still technically a party to the Paris Agreement at the time.
John Kerry, the former U.S. secretary of state and the lead climate envoy under the Biden administration, has said the move would further isolate the U.S. on the world stage.
“This is par for the course,” he said in a statement. “But it doesn’t change the fact that it’s a gift to China and a get-out-of-jail-free card to countries and polluters who want to avoid responsibility. It’s another self-inflicted wound on the world stage.”
Some climate advocates echoed this view, saying that the absence of the U.S. could make it harder to achieve consensus at COPs. Under the Obama and Biden administrations, the United States played a crucial role in securing the Paris deal and a 2023 agreement to phase out fossil fuels, helping to overcome hesitation from countries including Saudi Arabia and China. A long-term withdrawal could empower large emitters to frustrate agreements on fossil fuels. This already happened at COP30, where a group of oil-producing countries tanked talks to produce a “road map” on transitioning away from oil and gas.
“It is sad to attend international meetings and see an empty space where the United States should be,” said Kaveh Guilanpour, the vice president for international strategies at the Center for Climate and Energy Solutions and a leading expert on climate talks. “This is harmful to the world, because the enormous energy, innovation, and authority of the United States is missed.”
Some negotiators from developing countries downplayed the significance of the U.S. exit, in part because they’ve seen administrations from both political parties obstruct important global climate action, whether or not those presidents endorsed the Paris Agreement. Over the past decade, developing countries have grown more vocal in demands for trillions of dollars in financial assistance from the rich countries that have emitted the most carbon dioxide. This money would help poor nations transition away from fossil fuels and adapt to climate disasters, but the U.S. and Europe have said that they can’t afford to pay up.
“The absence of the U.S. is unfortunate, but I don’t think it is going to reverse global progress,” said Ali Mohamed, the lead climate envoy for Kenya, in an interview with Grist. “You have seen how in many countries, from Europe to Southeast Asia to Africa, the revolution of renewables is overtaking fossil fuels, because it makes business sense. International policy will continue to evolve and be developed by the coalition of the willing.”
Other observers said the withdrawal announcement was just paperwork confirming what was already apparent in Trump’s actions.
“The Trump administration has de facto already halted cooperation and dialogue in this space,” said Allison Lombardo, the former State Department deputy assistant secretary for international organization affairs in the Biden administration. “This formalizes what has already become a reality.”
Zoya Teirstein contributed reporting to this story.
This story was originally published by Grist with the headline Trump just took his most dramatic step yet against global climate action on Jan 8, 2026.
