As news of President Donald Trump’s decision to pull the U.S. out of the Paris Agreement on climate change spread, many states and cities immediately had a message for the president: even if you don’t believe in climate change, we see the reality, and if you won’t do something about it, we will.

Shortly after Trump’s announcement, a group of 86 mayors of U.S. cities—a group known as the Climate Mayors—issued a statement saying that their cities would continue to uphold Paris Agreement goals.

“We will intensify efforts to meet each of our cities’ current climate goals, push for new action to meet the 1.5 degrees Celsius target, and work together to create a 21st Century clean energy economy,” the statement read. “And if the president wants to break the promises made to our allies enshrined in the historic Paris Agreement, we’ll build and strengthen relationships around the world to protect the planet from devastating climate risks.”

The statement was signed by Democratic and Republican mayors of cities in both blue and red states, indicating that climate change really is a bipartisan issue.

Following on the heels of the mayors’ announcement, the governors of three states also took action. Governor Jay Inslee of Washington, Governor Jerry Brown of California, and Governor Andrew Cuomo of New York, announced the formation of the United States Climate Alliance.

“Today’s announcement by the president leaves the full responsibility of climate action on states and cities throughout the nation,” wrote Inslee. “While the president’s actions are a shameful rebuke to the work needed to protect the planet for our children and grandchildren, states have been and will continue to step up.”

“New York State is committed to meeting the standards set forth in the Paris Accord regardless of Washington’s irresponsible actions,” Cuomo wrote. “We will not ignore the science and reality of climate change.”

Brown wrote, “The president has already said climate change is a hoax, which is the exact opposite of virtually all scientific and worldwide opinion. I don’t believe fighting reality is a good strategy—not for America, not for anybody. If the president is going to be AWOL in this profoundly important human endeavor, then California and the other states will step up.”

New York, California, and Washington represent more than one fifth of the U.S.’s gross domestic product, and represent approximately 68 million people—about 20 percent of the United States’ population.

“With input from all participants, the U.S. Climate Alliance will also act as a forum to sustain and strengthen existing climate programs, promoting the sharing of information and best practices, and implement new programs to reduce carbon emissions from all sectors of the economy,” the governors’ statement read.

Connecticut Governor Dan Malloy and Virginia Governor Terry McAuliffe also expressed interest in joining the U.S. Climate Alliance.

Brown is about to visit China to discuss emissions-reduction policies with other leaders. He is also working to reauthorize a cap-and-trade program that expires in three years. Washington state is also capping carbon emissions and requiring power plants and oil refineries to reduce emissions over time. Governor Cuomo said in the statement from the U.S. Climate Alliance that he would use executive orders to ensure that New York will continue to abide by the Paris Agreement.