Last week, France passed legislation that requires all new commercial buildings be built with green roofs. The law requires partial roof coverage with either solar panels or rooftop gardens. The plan comes at a particularly green time for France—Paris is hosting the United Nations conference on climate change this year and is working towards its 2020 goal reducing its emissions and energy usage by a quarter. Even the Eiffel Tower has some spiffy new wind turbines.
While this might seem like a big step in the environmentally-friendly direction, it was actually a let-down for activists who were pushing for coverage of the entire roof, as opposed to just partial coverage. Rooftop gardens have several advantages—they insulate the building due to their thermal mass, reducing the amount of energy needed to heat or cool a building and they retain rainwater, preventing excess runoff. Rooftop plants also help prevent the "head island" effect, where cities become notably hotter than surrounding rural areas.
Toronto, Canada adopted a similar law in 2009, although theirs was a bit harsher, requiring both commercial and residential buildings to have green roofs. And in Switzerland, all buildings with a "suitable pitch" are required to have a green roof. Good thing there are tons of options when it comes to green roof designs. The California Academy of Sciences, for one, kept it interesting (photos below).
· France's New Green Roof Law and the Future of Urban Design [Architizer]
· The Eiffel Tower Goes Green with Spiffy New Wind Turbines [Curbed National]
· Should Paris in 2050 Be Full of Leafy, Food-Producing Towers? [Curbed National]