Former New York City Mayor Michael Bloomberg’s charitable organization has offered to make up the $15 million that the United Nations will lose after President Donald Trump announced that the United States will withdraw from the Paris Climate Accord.

Bloomberg is rallying representatives from cities, states, and companies to help meet America’s greenhouse gas emissions requirements despite Trump’s decision, according to various media reports.

The group—which currently includes 30 mayors, three governors, more than 100 businesses, and 80 university presidents—is negotiating with the U.N. to have its submission accepted among other nations as part of the climate deal, according to the New York Times.

“Americans will honor and fulfill the Paris Agreement by leading from the bottom up—and there isn’t anything Washington can do to stop us,” Bloomberg said, according to the Washington Examiner.

In a letter to the U.N. secretary-general, Bloomberg said “non-national actors” could achieve the 2025 emissions goal without the federal government’s help.

“While the executive branch of the U.S. government speaks on behalf of our nation in matters of foreign affairs, it does not determine many aspects of whether and how the United States takes action on climate change,” Bloomberg wrote, according to the Times.

Governors from New York, California, and Washington have signed onto the effort, according to media reports.

Trump’s decision to back out of the climate deal was lambasted by foreign leaders and climate scientists.