Property Lines is a column by Curbed senior reporter Patrick Sisson that spotlights real estate trends and hot housing markets across the country. Comments, tips, and suggestions on where Property Lines should head next are welcome at patrick@curbed.com .

The feasibility of a Green New Deal—a massive mobilization to decarbonize the economy—has gone from a progressive dream to one of the most commented-upon topics in American politics in a few months’ time.

There’s a hunger for action around the environment and, with federal policies frozen or in regression under the current presidential administration, much of the action in the U.S. around combating climate change has fallen to local and city leaders.

From pledging to stay in the Paris climate accords to adopting renewable power, U.S. cities have seen a flurry of activity and innovation, pushing new programs and initiatives. But as the need for emissions cuts and resiliency plans becomes clearer in the wake of increased billion-dollar disasters, flooding, and wildfires, the desire for big ideas only grows.

Luckily, there are plenty of examples of great policy around the globe. Curbed spoke with experts from the Natural Resources Defense Council, C40 Cities, Global 100%RE, Sierra Club, and the Rocky Mountain Institute to get their take on city climate policies that were progressive, practical, and, most importantly, working. Here are the ideas U.S. cities could copy.

London: An Ultra Low Emissions Zone to clean the air

Last Monday, London launched a plan to reduce emissions in the city center. Known as the Ultra Low Emission Zone, or ULEZ, the initiative charges a flat fee of 12.50 pounds (a little over $16) for vehicles coming into the city center that don’t meet specific emissions standards. Money generated from these fines gets funneled directly into bus, bike, and other mass transit improvements, part of Mayor Sadiq Khan’s plan to make 80 percent of London’s trips car-free by 2040. As C40 Cities reports, nearly 10,000 Londoners die prematurely each year as a direct consequence of air pollution; this may seem a small price to pay.

In the two years since ULEZ was announced and enacted, London has seen a 20 percent decline in carbon dioxide emissions, as drivers trade up to cleaner cars. Next, ULEZ will expand to cover a significantly larger section of London in October 2021.

The city also plans to use ULEZ money to fund transit projects that will serve Londoners living on the city’s outskirts, and who therefore have fewer transit options for reaching the center of the city. Researchers at the University of Oxford and the University of Bath found that if 1 in 4 city car trips became walking or cycling trips, England could save 1.1 billion pounds in health costs per year.

Vancouver, British Columbia: A building code that embraces change

Buildings account for nearly half of the energy usage in major cities, according to the Rocky Mountain Institute. But discussion about the minutiae of building codes often lacks excitement. Vancouver’s recent rewrite of its codes, which prioritize energy-efficient retrofits as part of an energy bylaw for large buildings, adds something that is missing in many such legal documents: speed.

Even the most environmentally progressive building codes don’t make a real difference for years after they are adopted, according to Jamie Mandel, managing director for RMI’s Building Program. After all, it’s very expensive, and often time-consuming, to apply new rules to old structures. Many energy-inefficient older buildings get grandfathered in. In New York, Mandel said, 70 to 90 percent of existing buildings don’t match the current codes.

Vancouver’s scheme solves the problem of getting older structures up to speed by adding more trigger points: When any number of different renovations gets done, for instance, owners are required to do energy efficient retrofits that meet the city’s new strict energy standard. While its a significant upfront cost, the added efficiency and lower energy bills saves money, and emissions, in the long run. It’s helping the city meet its goals to cut building-based emissions by 20 percent by 2020, and forcing the building trades, and suppliers, to up their game.

Singapore: Taming traffic with congestion pricing

The details of New York City’s long-awaited embrace of congestion pricing, which will charge drivers a fee to access a busy part of the city as a means to discourage the use of cars and raise money for transit improvements, are still being ironed out. But like any such program, the legislation’s original intent can be nullified with exemptions and carve-outs. The devil is in the details.

To create a system that’s both fair and effective, Rushad Nanavatty, Principal at RMI, says New Yorkers should look at the model created by Singapore. The dense island nation first adopted such a scheme in 1975, and has constantly updated it to create the most dynamic, detailed, flexible, and effective example on the planet.

“Congestion pricing done right is the most important single thing cities could do to cut emissions,“ says Nanavatty.

Via a system of electronic tolls, the city’s Electronic Road Pricing charges a fluctuating rate to every car entering the central business district on major roadways, based on traffic volume and time of day, reflecting real-time supply and demand and the presence of alternate transportation options. Authorities have even set a so-called “golden range” of ideal traffic speeds on major roads, and adjust tolls accordingly.

Amsterdam: Shutting off the gas permanently

With all the talk of electrification, especially in the transportation sector, it’s easy to miss how central natural gas is to many urban energy systems, especially for home heating. In California, residential clients heating their homes accounts for 40 percent of the natural gas burned in the state. In the northeastern U.S., gas and heating oil infrastructure is central to how major cities operate.

“This is becoming the number one new policy area we’ve been looking at in the building space,” says RMI’s Mandel. “We need to electrify end uses.”

Amsterdam’s To a City Without Natural Gas plan seeks to change this paradigm on a neighborhood-by-neighborhood basis, aiming to completely eliminate domestic natural gas use by 2050. It’s a central tenet of a bold plan to cut emissions from the built environment 80 percent. To accomplish this, authorities will swap gas heat, currently used by 90 percent of homes, with whatever works best, be it electric heat pumps, geothermal energy, even waste heat.

By working on the neighborhood level, the Dutch gain efficiency, and can design district-wide heating systems that decrease waste. New buildings and neighborhoods won’t even be connected to a gas grid going forward. It’s a pragmatic, and positive, step toward weaning the nation from fossil fuels.

Paris: Reclaiming the streets from cars

Paris mayor Anne Hidalgo has made it her personal crusade to cut car usage in the City of Lights. First, the city banned cars from the quayside of the River Seine in 2016. Then, it expanded the car-free zone and added bike lanes, and introduced an annual car-free day in the fall.

Based on Hidalgo’s future goals for changing transportation, those holidays seem more and more like a sign of things to come. Overall, Paris has cut car trips by 45 percent since 1990, with the number of cyclists in the city growing ten times over the same span. By 2024, diesel cars will be banned, and by 2030, all cars that run on gas won’t be able to operate in the city. Last November, Hidalgo announced plans to ban cars altogether in the city center, and introduce autonomous, electric shuttle to ferry tourists and locals between sites like the Louvre and Bastille.

Though Hidalgo has put the process in overdrive, Paris’s bold plan to pedestrianize has been decades in the making. It’s all possible because the city has prioritized other ways to get around, investing in pedestrian-friendly streetscapes and a vast expansion of transit and bike lanes. Like many global cities, Paris suffers from the effects of air pollution. But bold policy has helped the city chart a path away from car dependency.

Tokyo: Connecting with the countryside to create a clean energy partnership

The continued advances in green-energy technology—and the dropping costs of wind and solar energy—offer increasingly appealing ways for cities to plug into renewable power. But as much as mayors want to go green, fitting vast arrays of solar panels and wind turbines in a dense urban environment doesn’t usually work out. That’s why a new energy partnership between Tokyo and the nearby mountainous region of Nagano makes so much sense.

“Renewable energy is difficult to harvest in cities, for obvious reasons,” says Rian van Staden, a coordinator of the Global 100% Renewable Energy Platform. “This combination is helping generate power in areas that have been overlooked economically, and send money back to the rural economy.”

Nagano has great potential for solar, wind, and geothermal energy production—and Tokyo has a hungry energy market. By partnering up, Tokyo can buy down its CO2 footprint while Nagano can use the proceeds of energy generation to fund local development.

Van Staden sees these kind of partnerships as the future for decarbonization and good economic policy. While a city’s plans to cut energy usage can begin to make a difference, all the efficiency plans and electrification efforts won’t reach their potential unless they’re fueled by green power.

Freiburg, Germany: One man’s waste is a city’s power source

Known as one of the homes of the environmental movement, the German city of Freiburg, rebuilt after WWII to be a model of sustainability, boasts an integrated transport system, one of the lowest rates of car ownership in the country, a high concentration of energy-efficient passive homes, and a focus on recycling.

But what impresses van Staden most is the city’s commitment to a circular economy: In keeping with its focus on energy efficiency, Freiburg has created a system of power generation that’s incredibly sustainable, using what’s typically described as waste to power parts of the city in a carbon-neutral way. The city has set up a number of circular loop: The gas being produced from a nearby landfill has been turned into energy for a neighborhood in the area (soon, compostable biowaste will be substituted). And heat generated by an incinerator plant is being used to cure wooden pallets in an industrial park.

“This is a very specific type of magic,” says van Staden. “It’s only possible with substantive analysis of current emissions and energy flows. But if you can make the investment, you see significant payback.”

Shenzhen, China: Betting big on electric transportation

Shenzhen, a 12.5 million-person metropolis, made headlines in 2017 when it became the first city to operate an all-electric bus system. Considering the city has more than 16,000 buses—more than the combined number operating in New York City, LA, Toronto, New Jersey, and Chicago—that’s a big deal on its own.

But the city’s embrace of electric bus lines is just the beginning of wholesale change happening in its streets. Shenzhen built out infrastructure for charging thousands of buses and opened these charging stations for use by private drivers, making it easy for everyday commuters to plug in. The city is also near many of the country’s battery manufacturers, which means the newest innovations are inspired by the everyday experiences of Shenzhen commuters. Shenzhen officials have also pushed to electrify other parts of the city’s transit system, including freight delivery and taxis.

The true benefit of such a system comes down to how the electricity that powers these vehicles is generated, and Shenzhen is far from running on 100 percent renewable power. But by building out such an impressive fleet of electric vehicles, the city can begin to realize the benefits of investing in and adopting renewable power. And the roads have rarely been so quiet.