Green Roofs, Seen from a Plane

The roof of the Vancouver Convention Centre, which I nominated as "Most Unique."

This week, American Way magazine, the in-flight rag of American Airlines, published “Rooftop Wonders,” a story I wrote about the best green roofs in North America.

I composed this story, strangely enough, while aboard an American Airlines flight from Baltimore to Dallas back in March. As I typed I glanced out the window occasionally to inspire myself; after all, that’s exactly what I encouraged the magazine’s readers to do.

Green roofs are starting to catch on across America. Like so many environmental trends that started on the fringe, this one is gaining respectability because it makes better dollar sense than what we’re doing now. Traditional roofing materials like tar paper may be cheap, but blanketing the roof with dark material makes the building permanently more expensive to operate. It heats the building underneath and causes the dwellers to crank up the A/C in summer. Rooftop plants do the reverse, cooling the building in summer and also acting as a layer of insulation in the winter.

The green-roof industry is maturing and gaining expertise, and the costs for materials and installation are dropping. Furthermore, cities like New York are beginning to change their building codes to make it easier for developers (or redevelopers) to do the right thing. Witness the sprawling green roof being installed on the Javits convention center in Manhattan.

The benefits bestowed by a green roof don’t stop at the four corners of a building. Green roofs counter the heat island effect, in which cities become several degrees hotter than the open lands that surround them as the sun’s heat soaks into all that asphalt and concrete.

Also, when a rainstorm hits, a green roof clings to water that a regular roof would shed. That’s important because all those hard, impermeable surfaces of the city give water nowhere to go. A downpour floods into the sewer, where it can overwhelm water-treatment plants and send sewage into waterways.

Though green roofs are starting to grow in cities everywhere, they are usually invisible from the street. Even residents of those buildings that have green roofs are often not permitted to enjoy them — some of the plants best suited to rooftops are fragile and can’t handle much foot traffic. That’s why I’m happy to publish this story in an airline magazine. Oftentimes the air is the only vantage point.

So next time you fly into a city, keep your peepers peeled for the green roofs. Also, I invite you to watch the video tour I recently did of New York’s green roofs.