US billionaire Michael Bloomberg has offered $15 million to UN efforts to tackle climate change after President Donald Trump announced he is pulling the United States out of the Paris Climate Accord.

The money would support the operations of the UN Framework Convention on Climate Change Executive Secretariat, "including its work to help countries implement their commitments under the 2015 Paris Agreement on climate change," Bloomberg Philanthropies said in a statement late Thursday.

"Americans are not walking away from the Paris Climate Agreement," Michael Bloomberg said. "Just the opposite - we are forging ahead."

Bloomberg Philanthropies, in partnership with others, "will make up the approximately $15 million in funding that the UN's Climate Secretariat stands to lose from Washington.