France has adopted a law that mandates covering rooftops of new buildings in its commercial zones with plants or solar panels, at least partially.
Greenery on roofs acts as insulation from heat and cold. It reduces the energy required to heat a building in winter and to cool it in summer.
Also, plants help retain rainwater and reduce runoff. Green cover improves biodiversity and gives birds a place to nest in urban environments, ecologists say.
French environmental activists had earlier sought that the law should mandate that entire rooftops of new buildings be covered by plants. But the incumbent socialist government convinced activists to limit the scope of the law to commercial buildings alone.
Further, the law was simplified for businesses by requiring only part of the roofs of buildings to be covered with plants. The law gives them the choice to instal solar panels to generate electricity in part of the roof.
Green roofs are common in Germany and Australia. In 2009, the Canadian city of Toronto adopted a by-law that mandates industrial and residential buildings to cover rooftops with greenery.
Ajith Kumar S