New York City is trading its signature glass-dominated skyline for one replete with plants, solar panels, and wind turbines. The day before Earth Day, the New York City Council passed a historic act that will turn the city green, literally. On Monday, April 22, the city council approved the Climate Mobilization Act, a package of bills and resolutions designed to drastically improve the energy efficiency of New York City. Buildings are front and center to this "New Green Deal" for New York, with green roofs taking the spotlight. Following in the footsteps of Toronto, San Francisco, Denver, and Portland, Oregon, all new residential and commercial buildings in the city must top roofs with either plants, solar panels, mini wind turbines—or a combination of all three.

The Javits Center's impressive green roof is roughly the size of five football fields.

"Today, we are passing a bill that won’t just make our skyline prettier—it will also improve the quality of life for New Yorkers for generations to come," said Rafael Espinal, the NYC Council member who sponsored the bill. "We’ve already seen the revolutionary benefits of green roofs in action thanks to places around the city like Brooklyn Steel, the Barclays Center, the Javits Center, the USPS Morgan Processing and Distribution Center, and many others," he continued. "They cool down cities by mitigating the urban heat island effect, cut energy costs, absorb air pollution, reduce stormwater runoff, promote biodiversity, provide soundproofing, and make our cities more livable for all." The bill covers all new buildings, as well as those undergoing certain major renovations. An accompanying bill adjusts requirements for smaller buildings and looks at ways of phasing in the change to avoid negatively impacting homeowners and small business owners.

Changing the material on a roof may seem like a small step, but the impact can be impressive. Vegetated green roofs reduce the urban heat island effect, as the plants absorb light that would otherwise become heat energy. By mitigating heat gain, green roofs can help reduce demand on power plants and even reduce energy use inside buildings. Research published by the National Research Council of Canada found that an extensive green roof can cut a building's daily energy demand for air conditioning by 75 percent. Plus, they look lovely.

More efficient buildings are at the heart of the Climate Mobilization Act, which recognizes that NYC's buildings are the number one contributor of carbon emissions in the city. 50,000 buildings over 25,000 square feet—just two percent of the city's total buildings—contribute half of all building-related carbon emissions.

A closer look at the Javits Center's green roof.