Science Insight: Trump pulls US out of another major UN climate treaty – Explained

The Donald J. Trump administration on Wednesday announced plans to withdraw the US from the United Nations Framework Convention on Climate Change (UNFCCC), which would make the US the only nation in the world not part of the main international agreement to slow the effects of climate change.

The administration also aims to leave the Intergovernmental Panel on Climate Change (IPCC) and over 60 other UN and international organizations, saying that continuing to support them doesn’t serve US interests. These include the Intergovernmental Forum on Mining, Minerals, Metals, and Sustainable Development; the International Renewable Energy Agency; and the International Energy Agency. The US will also withdraw from the Green Climate Fund (GCF), an international organization that finances climate mitigation in less-developed countries, and step down from the GCF board.

“We will not continue expending resources, diplomatic capital, and the legitimizing weight of our participation in institutions that are irrelevant to or in conflict with our interests,” Secretary of State Marco Rubio says in a statement on the withdrawals. Citing diversity, equity, and inclusion (DEI) mandates, gender-equity campaigns, and climate “orthodoxy,” Rubio says that the international science, aid, and peace organizations “actively seek to constrain American sovereignty.”

Simon Stiell, executive secretary of the UNFCCC, says in a statement that the US is essentially shooting itself in the foot with this decision, which will ultimately decrease the security and prosperity of the country. “While all other nations are stepping forward together, this latest step back from global leadership, climate cooperation, and science can only harm the US economy, jobs, and living standards, as wildfires, floods, mega-storms, and droughts get rapidly worse,” he says. 

The US ratified the UNFCCC treaty in 1992, agreeing to cooperate with a global effort to combat climate change. But the country did not sign the Kyoto Protocol, another UN effort, launched in 1995, that legally requires members to hit specific emission-reduction targets. The US is currently in the process of leaving the Paris Agreement, another international agreement under the UNFCCC, which aims to limit the global rise in temperature to less than 2 °C above preindustrial levels. This is the second time the US has left the Paris Agreement and becomes official 1 year after Trump signed the withdrawal notice on Jan. 20, 2025. 

Like the Paris Agreement, the UNFCCC requires 1 year of notice (PDF) before a country can officially withdraw from the treaty. But whether the president can unilaterally withdraw the US from a treaty that the Senate ratified is a legally unsettled question, says Maria Ivanova, director of the School of Public Policy and Urban Affairs at Northeastern University. “The Constitution requires two-thirds Senate consent to enter a treaty but is silent on how to exit them, and the Supreme Court has not ruled on it,” she says. Several presidents have made similar moves in the past, but the question hasn’t been resolved because they were not legally challenged successfully, Ivanova says. Trump pulling out of the UNFCCC is significant “because this could be the case that finally forces the courts to decide whether unilateral presidential withdrawal is constitutional or requires congressional involvement,” she says.

But there’s no question that the US can rejoin the UNFCCC in the future, says Rachel Cleetus, senior policy director of climate and energy at the Union of Concerned Scientists. “The Trump administration’s hostile, anti-science actions are utterly unhelpful to U.S. and global climate progress right now—and deeply against the interests of the American people,” she tells C&EN by email.

The American Chemistry Council did not provide a comment by publication time.

While he agrees it will be damaging to the US, the broader impacts of leaving the UNFCCC and IPCC are unclear, says Andy Miller, former senior science adviser for the US Environmental Protection Agency’s Office of Research and Development.

“Ironically, this may allow the UNFCCC and IPCC to take more stringent positions regarding climate action than would otherwise have been possible with US participation,” he says. Without US support, other fossil-fuel proponents won’t have as much sway over the IPCC, he says. In addition, other countries will likely take advantage of the absence of the US to maximize their advantages in clean energy and climate leadership among the remaining countries in the UNFCCC and IPCC, Miller says. “There will still be opportunities for nonfederal US scientists and organizations to participate, so there will be some US perspectives in the IPCC activities,” he says, “just not official government perspectives and priorities.”

The Trump administration’s action doesn’t change the reality of climate change, Cleetus says. “Forward-looking US states and the rest of the world recognize the scientific facts and will continue to move forward on climate action.”

The withdrawal from international organizations is a follow-up to Trump’s executive order from February 2025 that directed the US to withdraw from and cut funding to some UN organizations, including the UN Educational, Scientific, and Cultural Organization (UNESCO).