France is requiring that new buildings “green” their roofs

Green is France’s new favorite color.
Green is France’s new favorite color.
Image: AP/Remy de la Mauviniere
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French parliament approved a law last week that will force all rooftops of new buildings in commercial areas to be partially covered in either solar panels or plants.

Rooftop vegetation—otherwise known as green roofs—aren’t there to just look pretty. They reduce runoff by absorbing water, provide habitats for birds and other wildlife, and minimize the amount of energy buildings need to regulate temperatures. They also help to combat the “heat island” effect, in which cities become hotter than nearby rural areas, sometimes by as much as 22 degrees Fahrenheit (12 Celsius).

Despite the pleas of environmental lobbyists, the law won’t apply to rooftops outside commercial zones. It also won’t force existing buildings to be retrofitted with green technology.

But that doesn’t mean existing buildings can’t go green on their own. France’s most iconic structure—the Eiffel Tower—did so last month when it was installed with wind turbines. Paris wants to consume 25% less energy and emit 25% less emissions by 2020.

Paris is also the site of this year’s major United Nations conference on climate change. While France currently gets about 80% of its electricity from nuclear energy, and has lagged behind other European countries like Germany and Denmark in developing green technologies, it certainly seems to have some momentum headed into the important November conference.

In 2009, the city of Toronto required both residential and industrial buildings to have green rooftops. And last year, Sydney pushed an initiative (pdf) to install more green roofs, hoping to help make Australia’s largest city sustainable by 2030. The US is also installing more green roofs, but the ones in Manhattan, at least, are not working as well as was hoped.