With the clock running out on his administration, President Barack Obama pledged another $500 million to an international fund for combating climate change, increasing the country's financial commitment before his successor takes office on Friday.
President-elect Donald Trump has called for halting contributions to the fund, which was created under the global warming agreement reached in Paris in December 2015.
John Kirby, a spokesman for the U.S. Department of State, called the money a "critical tool that helps catalyze billions of dollars in public and private investment."
The latest contribution, announced on Tuesday, brings the total U.S. investment to $1 billion, still far short of the total $3 billion Obama had pledged.
"It's not being done to try to provoke a reaction from the incoming administration or to try to dictate to them, one way or the other, how they are going to deal with climate issues," Kirby said.
