Grist: Dont freak out, but theres a problem with green roofs: Theyre not necessarily greener than ordinary roofs. Soooooo kind of a major problem. With a little extra effort, though, green roofs can be efficient AND locally sourced you just cant take the easy way out. Scientific American reports: [R]ooftop vegetation has to be able to survive the high winds, prolonged UV radiation and unpredictable fluctuations in water availability. To resist these harsh environments, a majority of green roofs...