Just imagine an aerial view of your favorite city – and instead of all that asphalt and concrete, lush, green landscapes dotted the rooftops. Green roofs could make that vision a reality. A green roof is a roof that has been covered with living vegetation. They can be added to existing roofs, and can cover all or part of the roof. Green roofs last longer than conventional roofs, reduce energy costs with natural insulation, create peaceful retreats for people and animals, and absorb storm water, potentially lessening the need for complex and expensive drainage systems. On a wider scale, green roofs improve air quality and help reduce the Urban Heat Island Effect, a condition in which city and suburban developments absorb and trap heat.