Outgoing Secretary of State John Kerry gestures on the opening day of the World Economic Forum, on Jan. 17, 2017, in Davos. (Fabrice Coffrini/AFP/Getty Images)

This story has been updated.

With just three days until President-elect Donald Trump’s inauguration, the State Department on Tuesday announced a half-billion-dollar contribution to the United Nations’ Green Climate Fund, part of $3 billion the United States has promised to the fund under President Obama. That’s on top of another $500 million transferred last March, meaning the United States has now sent $1 billion to the fund, or a third of the president’s pledge.

“The Green Climate Fund is a critical tool that helps catalyze billions of dollars in public and private investment in countries dealing not only with the challenges of climate change, but the immense economic opportunities that are embedded in the transition to a lower carbon economy,” said Department spokesman John Kirby at a press briefing Tuesday.

Republicans have been heavily critical of this spending, and Trump pledged, while campaigning, that “we’re going to cancel the Paris Climate Agreement and stop all payments of U.S. tax dollars to U.N. global warming programs.” Coming so close to the inauguration, the new expenditure is likely to spark controversy for this reason.

Kirby said in a statement that the funds came from a 2016 appropriation for the agency’s Economic Support Fund. This $4.3 billion fund contains some dollars earmarked for specific programs and other dollars that are not officially allocated — the current monies came from the latter.

By the year 2020, under the 2009 Copenhagen accord, developed nations are supposed to be allocating $100 billion annually on climate-change aid to poorer, developing nations, money to be used for clean energy projects and climate change adaptation measures, among other expenditures. Much, but not all of this money is intended to be distributed through the Green Climate Fund, which has already raised $10 billion so far.

The broader idea of wealthier nations helping poorer ones adapt to a changing planet, and to transition their energy systems, was a fundamental component of bringing all nations on board to the agreement, and environmental groups hailed the move Tuesday.

“The amount paid-in today, $500 million, constitutes only 0.012% of the federal budget each year, or $1.53 per American,” said Heather Coleman, climate change manager at Oxfam America, in a statement heralding the payment.

“This contribution shows that even as we face an incoming Administration that engages in dangerous climate denial, those of us in the United States who believe in taking action to save our planet, our economy, and our future will continue doing everything in our power to move forward,” added Sen. Jeff Merkley (D-Ore.) in a statement. “I am glad that other countries are continuing to take this challenge seriously and that we can continue to work together to fight climate change.”

At the State Department press briefing, when asked about the timing of the release of the funds, Kirby said that “this is an investment that had been long-planned. I don’t — I don’t believe there was any nefarious desire or intent to do it just two days before [the inauguration].” He said that the monies had already been transferred to the Green Climate Fund.

But of course, the Trump administration and a sympathetic Congress could block further payments. However, that would create awkwardness with other countries that are deeply committed to climate change, said John Coequyt, director of international climate policy at the Sierra Club. Coequyt pointed out that Trump’s nominee to head the State Department, Rex Tillerson, has signaled that he wants to keep a “seat at the table” when it comes to the Paris climate agreement.

“It’s a head of state issue, and you know, president-elect Trump is going to hear it when he goes to talk to other heads of state,” said Coequyt. “They can decide that they don’t want to move another penny, that is their decision to make, but it’s pretty clear that it is not in our national interest.”

Carol Morello contributed to this report.

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