The Obama administration wrote a second check for $500 million on Tuesday to the Green Climate Fund, an international organization designed to help the developing world adapt to global warming and deploy more clean energy technologies.

The announcement from the State Department comes less than three days before President-elect Donald Trump takes office. During the campaign, Trump vowed to choke off all U.S. funding for international global warming programs.

The most recent check from the Obama administration now brings total U.S. contributions to the Green Climate Fund (GCF) so far to $1 billion.

The funding for the GCF fulfills a pledge the U.S. first made as part of the U.N. climate talks beginning in 2009, when developed nations committed to spending $100 billion to assist the developing world, which is already reeling from the effects of climate change, like rising sea levels, scorching droughts and deadly floods.

This funding commitment helped make the Paris Climate Agreement — which went into effect in November of last year — possible since the industrialized world is responsible for the majority of human-caused climate change-to-date.

In 2014, the U.S. committed $3 billion toward the fund, but Congress refused to appropriate the money.

However, Congress didn't prevent funds from simply going toward the program, either. So, in a bureaucratic end run, the Obama administration directed money that had been appropriated through other legislation to be used for the Green Climate Fund.

Republicans on Capitol Hill have denounced such spending, alleging the administration is flouting congressional authority.

They will soon have an ally in a Trump administration, which has put forward a nominee for secretary of state, former ExxonMobil CEO Rex Tillerson, who says climate change is not a top national security threat to the U.S. and repeatedly refused to commit to keeping the U.S. within the Paris Climate Agreement during his confirmation hearing.