Green Roof can reduce water runoff, easing the local sewers and water treatment systems. By improving insulation air conditioning energy compsumption lowers and so does power plants demand.
Europe buildings have being using green rooves for over a decade. New Tokyo construction regulations require that at least 20% of medium and large building´s roof has to be green.
In the States the leader is Chicago, on most of the new buildings the rooves are green!
