Will the new green roof bylaw actually help the environment, or are politicians just trying to get the green vote?

David Miller’s green keenness has indeed been a driving force behind our city’s soon-to-be-instated bylaw, which will require all new buildings with more than 2,000 square metres of floor space to have 20 to 60 per cent plant coverage on the roof. It’s also true that some previous green initiatives—Earth Hour, anyone?—have been more sizzle than steak. But in this case, real benefits abound. Urban vegetation acts like a set of lungs that filter out pollution, and with more than 50 million square feet of plant-friendly roof surface in Toronto, the initiative should serve as a major smog buster. Green roofs could also bring down temperatures by a few degrees (though this may seem less of a bonus after a June that felt more like October). Plus, there are the culinary perks—like growing rooftop radicchio. All in all, a pretty good package, unless you’re in the condo biz. Predictably, developers are balking at the extra costs, but when the bylaw takes effect next February, they’ll have to go green or cough up the green—even if they can muster a damn good reason for being granted an exemption, every square metre that stays plant free will cost them $200.

• Question from Vera Zuck, Lawrence Park