This New Years we celebrated a historic climate agreement at COP21, a powerful message that world leaders are ready to commit to a sustainable future. Optimism oozed from Paris, but behind the smiles of all involved lurked the grim reality that the fate of the 2 degrees cap now lay in the hands of national governments. We’re now well into 2016 and with Washington gridlock as immobile as ever, it’s time to look local for action.

And that’s exactly what the Sierra Club is doing.

Last month, the Sierra Club launched its #ReadyFor100 campaign, urging 100 cities across America to commit to 100% renewable energy. The group is using its 2.4 million members and supporters to organize a grassroots campaign to demand climate action from local governments.

Following the bold agreement reached at COP21, the campaign hopes to capitalize on the inspiring goals set by world leaders in Paris and turn promises into reality around the globe. Green cities abroad that have committed to 100% renewable energy, including Paris, Sydney, and Vancouver, are lauded to inspire domestic action, urging mayors across the country to fully commit to renewable energy.

The campaign opened with a direct action event. The United States Conference of Mayors conveniently brought together nearly 300 city leaders from across America to Washington, DC last week, so Sierra Club organizersconvened outside the conference for the campaign launch. The group projected “Mayors, are you #ReadyFor100?” across the building entrance along with images of windmills stretching half the height of the building, challenging city leaders to act on climate.

Some mayors have already got the message. While 100% renewable may sound like a lofty goal, fifteen U.S. cities are committed, including San Francisco, CA, Grand Rapids, Michigan, and most recently San Diego, CA (the 8th largest city in the U.S.) became the largest U.S. city to commit to 100% renewable energy. What’s more, 4 cities — Aspen, CO, Burlington, VT, Greensburg, KS, and Kodiak Island, AK — have already achieved their goal of 100% renewable, and are eager to help other cities follow suit.

“Last year Aspen hit its goal of 100% renewable energy, demonstrating that it is 100% possible. We plan to work with the Sierra Club to inspire more cities to commit to this essential way forward for the health of our communities, our country and the planet,” said Aspen, CO Mayor Steve Skadron.

The public supports the transition too, regardless of political stance. “Poll after poll show huge, bipartisan majorities are ready for clean energy. Every market indicator shows our economy is ready. All over the country, clean, renewable energy is creating jobs, growing local economies and safeguarding the health of our families from dangerous pollution,” says Michael Brune, Executive Director of the Sierra Club.

The data supports Mr. Brune’s enthusiasm. Solar prices have fallen 80% in recent years, renewables are competitive with coal and gas in several regions of the country, and investment in clean energy is over 3 times more efficient at job creation than the fossil fuel industry. Stanford scientists say that the average American family will save $260 per year in energy costs on top of $1500 in health care costs from the complete transition to renewable energy. The rise of renewables cannot be denied, and it’s time for cities to take advantage of it.

Wondering how committed your home is to clean energy? Check out the Sierra Club Ready For 100 website to see how your city ranks and tell your mayor to commit to 100% renewable. Who takes first place? Our very own San Francisco Bay Area, of course.