Texas mayors are no stranger to dealing with climate change denial: for years, leaders at the state level have been unwilling to incorporate climate change into their future planning, forcing cities that were interested in addressing it to tackle the problem themselves. So when President Donald Trump announced his intention to withdraw from the Paris Agreement in June, it’s unsurprising that 6 Texas mayors were among the some 346 mayors across the country who pledged to pick up the slack to meet the country’s outlined emission reduction targets anyway. They vowed to “adopt, honor, and uphold the commitments to the goals enshrined in the Paris Agreement.” (For a detailed analysis of the impact cities could have on curbing carbon emissions, see this excellent Citylab piece by Laura Bliss.)

The six Texas mayors who are now members of Climate Mayors, an organization co-founded by former Houston Mayor Annise Parker in 2014, are Steve Adler of Austin, Mike Rawlings of Dallas, Sylvester Turner of Houston, Ron Nirenberg of San Antonio, John Thomaides of San Marcos, and Scott Saunders of Smithville. Together, these six mayors lead cities that are home to a collective 6.1 million Texans. (Turner is a current co-chair of the organization.) Don’t see your city on this list? Climate Mayors encourages concerned citizens to contact their mayor or local officials to gauge their interest in joining the network.

What can mayors do to help curb climate change? That depends on the specific city and government structure, but generally they can enact green policies, like purchasing electric or hybrid vehicles for government use, swapping out old light bulbs for LEDs in government buildings and on city streets, and even having a city-owned utility’s energy portfolio shift to include more renewables.

Just last week, Austin Mayor Steve Adler was in Illinois to attend the North American Climate Summit, where he was one of more than fifty mayors worldwide to sign on to the Chicago Climate Charter. Speaking at the summit, former president Barack Obama, who signed the Paris Agreement when he was president, lauded the work mayors are doing to address climate change. “Cities and states and businesses and universities and nonprofits have emerged as the new face of American leadership on climate change,” he said.

“Miami already floods on sunny days,” Obama said. “Western cities across North American are dealing with longer and harsher wildfire seasons. A conveyor belt of some of the strongest hurricanes on record this summer smashed into Houston and Florida and Puerto Rico, and more than two months later, they are still struggling to recover.”

“Obviously, we’re in an unusual time when the United States is now the only nation on Earth that does not belong to the Paris Agreement,” Obama said. “And that’s a difficult position to defend. But the good news is that the Paris Agreement was never going to solve the climate crisis on its own. It was going to be up to all of us.”

In that spirit, this Tuesday, Adler was one of seventy mayors to sign Environment America’s “Mayors for Solar Energy” statement, pledging to make solar power “a key element” of Austin’s energy portfolio. “Austin will not stop fighting climate change. Worldwide, cities will lead in achieving climate treaty goals because so much of what’s required happens at the local level. Regardless of what happens around us, we’re still Austin, Texas, and that means aggressively increasing the amount of power we get from renewable resources to 65% by 2027,” Adler said in a press release. (Austin Energy will get a full 51 percent of its power from renewable sources by 2020, the company announced on Thursday, up from 40 percent today.) Smithville’s Scott Saunders and Universal City’s John Williams also signed the solar pledge, along with former Buda mayor Todd Ruge.