Nations around the world are upping their game in the fight against climate change, even as President Trump recently announced the U.S.’s withdrawal from the Paris Agreement. And despite this reckless move, American mayors, state leaders, county officials, governors, major companies, and millions of citizens across our country have pledged that they’re “still in” when it comes to the agreement, and supporting the goal of limiting future warming to well below 2 degrees Celsius.

Even better, a new initiative by former New York City mayor Michael Bloomberg gives the urban layer of this movement a boost. He’s asked mayors from the 100 most populous cities in the country to share their plans for making their buildings and transportation systems run cleaner and more efficiently. The 20 that show the greatest potential for cutting the dangerous carbon pollution that’s driving climate change will share a total of $70 million in technical assistance funding provided by Bloomberg Philanthropies and partners.

It’s important to remember the equally vital contributions that can be made by private citizens—which is to say, by you. “Change only happens when individuals take action,” Aliya Haq, deputy director of NRDC’s Clean Power Plan initiative, says. “There’s no other way, if it doesn’t start with people.”

The goal is simple. Carbon dioxide is the climate’s worst enemy. It’s released when oil, coal, and other fossil fuels are burned for energy—the energy we use to power our homes, cars, and smartphones. By using less of it, we can curb our own contribution to climate change while also saving money. Here are a dozen easy, effective ways each one of us can make a difference: