Green roofs can help cool cities in the summer heat, but building them is only the first step – many don’t survive

The rooftop of the Javits Center in New York is still thriving, but others have struggled. Xinhua/Wang Lei via Getty Images As summer temperatures soar across the United States and Europe, cities are being forced to confront the difficult reality that they’re getting dangerously hot. Record-breaking heat waves strain power grids, send people to cooling shelters and can make the top floors of some apartment buildings unlivable. One way to help cool buildings is to install green roofs – living…