US president Donald Trump’s announcement that the US will pull out of the Paris Agreement was met almost exclusively with disagreement and worry.

By pulling out of the agreement, the US joins a small group of countries who did not ratify the agreement—the others being Syria, who was not allowed to join the negotiations because of sanctions, and Nicaragua, who thought the agreement wasn’t tough enough. Foreign leaders were quick to criticize his decision—notably French president Emmanuel Macron who, openly trolling Trump, started a “Make Our Planet Great Again” campaign to promote France as the hub for research on climate change.

But the opposition was just as strong within the US. Shortly after the president’s speech, which included the statement, “I was elected to represent the citizens of Pittsburgh, not Paris.” That brought a rebuke from Bill Peduto, the mayor of Pittsburgh, in Pennsylvania, who declared that Trump’s decision did not represent his city and vowed that Pittsburgh would stick to Paris accord guidelines, regardless of the official US government stance.

He is not alone.

As of June 2, 83 American mayors, including those leading the US six largest cities, have signed a declaration committing to “adopt, honor, and uphold Paris Climate Agreement goals.” The group of “climate mayors,” who together represent over 40 million Americans, had sent an open letter to Trump in March, in which they announced their refusal to implement the executive order that rolled back some of the measures against climate change put in place by his predecessor, Barack Obama, and urged Trump to maintain the US commitment to fighting climate change.

As their call went unheeded, they are now keeping up with the promise take independent action, committing to increase efforts to meet their cities’ climate goals and the Paris Agreement target to hold global temperatures within 1.5°C of what they were before the industrial revolution. “The world cannot wait — and neither will we,” said the climate mayors’ statement.

Last night, city halls across America where lit up in green in a display of support of the Paris agreement:

Cities around the world similarly showed their support for the agreement:

The resistance isn’t ending at the city level, either. A group of state governors, too, including leaders of New York and California, have formed a coalition to continue the work against climate change despite the federal position on it.