The Trump administration has canceled $4 billion in U.S. pledges to the world’s largest climate fund — gutting a U.N. initiative helping over 100 countries adapt to the rapidly changing world.

“The government of the United States rescinds any outstanding pledges to the Green Climate Fund,” U.S. Secretary of State Marco Rubio wrote to U.N. Secretary-General António Guterres in a note dated Jan. 27, parts of which were seen by POLITICO.

The climate fund confirmed the decision. 

“We have been made aware that the United States of America has notified the United Nations of its decision to rescind outstanding pledges to the Green Climate Fund,” it said in a statement to POLITICO.

The move goes further than the first Trump Administration, which allowed pledges made by prior administrations to remain on the fund’s books. No other country has previously rescinded committed funds.

The U.S. State Department did not respond to a request for comment. A U.N. official declined to comment.

The Green Climate Fund was established in 2010 to channel funding to clean energy and climate adaptation programs across the developing world. It has since approved $16 billion worth of projects. 

In 2023, the Biden administration committed $3 billion to the fund. That matched an Obama administration pledge and made the U.S. the fund’s largest single contributor at $6 billion. 

However, the U.S. has delivered only $2 billion of that promised money, leaving $4 billion in outstanding funds. Other nations, including Germany, France, Japan and the United Kingdom, have actually delivered more money to the fund.

The U.S. withdrawal follows President Donald Trump’s order revoking and rescinding the country’s federal climate finance program, signed on his first day in office.

While the decision does not immediately change the Green Climate Fund’s balance sheet, the fund said its future ambitions will inevitably shrink.

“Looking ahead, the Fund aims to grow its total portfolio to at least $50 billion by 2030,” the fund said. “If pledges are not fully realized, our ability to support the climate ambitions of developing countries will be constrained.”