Submitted: Apr 16, 2008 - An aerial view of most urban areas shows swathes of asphalt, black tar and gravel-ballasted rooftops. Heat radiates off of the dark roofs, and water rushes over the hard, hopefully impermeable surfaces. Yet, there is a new trend that breaks up the monotony of common roofs: green rooftops. Long popular in Europe, green rooftops have begun to appeal to homeowners, businesses and even cities as an…