William McDonough (TED04, 05) regularly drops jaws with imagery from the world’s largest “living roof,” which he designed for the Ford Motor Company plant in Dearborn, MI. Green roofs also feature strongly in the cities he’s designing for China. Their benefits are obvious: They improve air quality, restore migratory patterns for birds, and look a lot better than black tar. So when will your roof go green? WorldChanging this week assesses the state of the art in eco-roof technology, explaining the barriers to entry (cost, bureaucratic red tape) and pointing out the visionaries (including the city of Chicago, which offers $5K grants for green roof projects). Stay tuned for: Majora Carter at TED2006. She’s bringing green roofs and more to the South Bronx.