President Joe Biden offered a public apology to a U.N. climate conference over his predecessor Donald Trump’s move to pull the U.S. from the Paris accord.

Biden was speaking in Glasgow, Scotland on Monday where world leaders were gathering to discuss implementing the agreement to contain global warming by mid-century.

He said: “I shouldn’t apologize, but I do apologize for the fact the United States, the last administration, pulled out of the Paris Accords and put us sort of behind the eight ball a little bit.”

Biden has frequently criticized the past administration’s approach to climate, but had not previously delivered a public apology to the world.

Biden reentered the agreement in one of his first official acts in office on Jan. 20.