green or white?

Environmentalists, urban planners and politicians all agree the city’s roofs need to change so that less heat is absorbed and less electricity used for cooling offices and apartments within. But unanimity on the best way of doing this is more elusive, with green roofs and white roofs being spruiked from different corners.

In September, Victorian Environment Minister Gavin Jennings declared himself “a fan” of green roofs – a concept well advanced in American cities such as Chicago and Portland – where beds of vegetation adorn building tops.

Citing overseas research, Jennings said a green roof was capable of reducing local temperatures by about four degrees. The State Government has helped fund a study into adapting green roof technology to local conditions, while the Wonthaggi desalination plant will boast one of the biggest green roofs in Australia.

Lord Mayor Robert Doyle, meanwhile, declared himself a fan of white roofs this month; another method for tackling the heat island effect by spraying rooftops with a white, rubbery layer that reflects the sun’s rays. New York mayor Michael Bloomberg is another fan of the concept.

Sydney Morning Herald, 16 Jan 2010