2016 was supposed to be the year when politicians finally addressed climate change. In an election where pretty much nothing went according to plan, it’s not surprising that other topics upstaged clean energy and ended up dominating our national discussion. Climate change only warranted a brief (yet infamous) mention during the televised debates, despite record-setting fall temperatures underlining its importance.

Despite the treaties, executive orders, and regulatory achievements of the Obama administration, environmentalists rightfully feel the government’s response is grossly inadequate to the challenges of climate change. It’s hard not to despair when most of the members of one major party deny the problem exists, a formula for gridlock and bipartisan inaction.

But while it’s easy to feel despair over the scant federal response to environmental issues, it misses a true bright spot in environmental action: our cities.

Cities? Those congested, smog-filled, overcrowded seas of asphalt—that’s what will save our climate? Yes, according to numerous initiatives, international actions, and local plans that view urban areas as opportunities, not problems. Cities have their share of challenges—they’re home to half the world’s population and produce around 75 percent of the world’s GDP and greenhouse gas emissions—but they also have the population density and sustainable transportation networks that make green solutions that much more impactful. In the U.S. alone, more than a dozen cities have committed to 100 percent clean energy futures, part of a nationwide Sierra Club campaign, and mayors are leading the charge towards better transportation systems, sustainable power, and resilient, walkable design.

Most importantly for the United States, the increasingly aggressive tone cities are taking when it comes to climate change offers a fantastic example of the maxim that all politics are local. As federal agencies and national politicians bicker, cities can’t turn a blind eye. They’re on the front lines of increasingly serious issues such as coastal flooding, rising temperatures and the heat island effect, as well as pollution and carbon emissions. Mayors around the world are pushing for green development—when energy is expected to account for 28 percent of worldwide infrastructure investment over the next 15 years, cities have to get serious about energy efficiency and cost savings.

But cities are seeing climate issues as not just as an intimidating challenge, but as a once-in-a-century opportunity for economic growth.

“Clean energy was something we had to do,” says Mike Bonin, a city councilperson in Los Angeles who has helped push municipal plans for clean energy. “Now it’s something we get to do. It’s an enormous chance to benefit the LA economy that’ll unleash tens of thousands of jobs, and more broadly, shared prosperity and a steep reduction in pollution.”

The nation’s second-largest city hasn’t made any binding resolutions or big plans just yet, like fellow California metropolises such as San Diego or San Francisco. LA has only begun to study how to implement such a solution. But like the city’s bold plans for transportation, this tentative step towards sustainability shows just why urban areas hold so much promise for green initiatives.

Bonin points to some of the work that’s already been done, such as reducing the reliance on coal-fired plants, with the goal of uniting voters behind a localized, clean energy future. Especially after a catastrophic natural gas leak, citizens are more aware of energy generation in their own backyards, and in a city once notorious for smog, pushing for local clean energy initiatives becomes an easier debate. This is happening elsewhere, too: St. Petersburg, Florida’s city council is about to pass a measure that will use resources from the BP oil spill settlement to speed up the transition towards clean energy and invest in local solar power.

“All transformative processes start with a visionary goal,” he says. “We’re pretty clear the fight on climate change won’t be won with white papers or studies. Implementation is key.”

One of the main drivers for city-level experimentation in clean energy is its rapidly dwindling cost. The Sierra Club’s report on cities that have taken the clean energy challenge and committed to cutting carbon emissions are motivated by fiscal prudence as much as environmental awareness. Saving money is a goal that crosses party lines, even in the deepest of red states.

"We didn’t do this to save the world—we did this to get a competitive rate and reduce the risk for our consumers," says Jim Briggs, Interim City Manager for Georgetown, Texas, which announced plans to buy 100 percent renewable power by next year. "I’m probably the furthest thing from an Al Gore clone you could find.”

San Diego, the nation’s eighth-largest city, embarked on a far-reaching Climate Action Plan last December with the support of a Republican mayor. The fact that a city known as a poster child for suburban development is pushing forward on a set of ambitious goals, such as lashing carbon emissions in half by 2035, suggests these actions aren’t just for outliers or tiny liberal college towns.

In the wake of the Paris Climate Treaty, the green actions being taken by U.S. cities show the country (finally) starting to catch up with the rest of the world. At the recent Habitat III Conference in Quito, Ecuador, a huge United Nations event bringing together civic leaders and planners from around the globe, the focus was on sustainable urban development and innovative solutions to city issues. A group of 160 mayors backed the C40 Cities Call for Action on Municipal Infrastructure Finance, a somewhat bland title that obscures the call for national and international funding of low-carbon and sustainable development projects.

City leaders understand that in a world that increasingly urban, they hold the key to any hope for a more sustainable future. As New York Times architecture critic Michael Kimmelman said in his report on the historic meeting, “Cities are being recognized increasingly as opportunities for economic and social progress, density as a response to environmental threats.” Internationally, smart, localized urbanism has become the driver of positive change.

“Cities have been leading the way in tackling climate change for many years, and mayors are determined to implement the Paris Agreement,” said Mayor of Paris and C40 Chair-elect, Anne Hidalgo. “Now national and regional governments, along with financial institutions must also act to give cities the power they need to create a sustainable future.”

The main goals of the campaign show just how inverted the power balance has become: mayors are asking for the power to access international climate funds, power to control spending them, and more responsive development banks. National governments are somewhat scolded, told to “create a stable policy and regulatory environment,” suggesting cities just want regulatory certainty, and to be left to their own devices.

These visions and bold plans sound great, one might say, but how can American cities pay for these kinds of changes? That skepticism has often been met with plans that have economic benefits at their core.

“We’ve had our eyes on the prize of clean energy in Los Angeles for more than a decade,” says Bonin. “There’s been a revolution with solar, it’s 80 percent cheaper than it was a few decades ago. Switching from fossil fuels to clean energy will save taxpayers money—it’s like a tax boost—and local energy storage and generation suddenly become a great source of good, local jobs.”

Cities across the country and globe have come to the same conclusion, that carbon reduction can actually mean economic expansion. European cities, such as Stockholm and Copenhagen, have seen healthy growth over the last few decades despite significant decarbonization efforts: since 1990, Copenhagen has slashed its carbon emissions by more than 40 percent, while experiencing economic growth of around 50 percent. Cities from Barcelona to Singapore have renewed their focus on clean energy and sustainable urbanism, and more and more U.S. cities are following suit.

While it’s true a more robust response from the U.S. government could make a big dent, it might be best to start small. Cities around the world are showing that it is possible to create plans for growth that are economically and environmentally sustainable.

"I would tell other cities to go for it," says Cody Hooven, the chief sustainability officer in San Diego. "What holds a lot of government back is being afraid of the naysayers. A plan like this is going to be hard to implement, but it’s important to be a trailblazer."