next spring, there's going to be an alpine meadow and a thatch of berry bushes on the roof of Shaw House, a seniors' home on Ward's Island. I helped build the garden a few weeks back, along with about 10 other volunteers. One more greened rooftop in a city desperately in need of hundreds of them. It's not like our civic leaders don't know that the profits of bloom, not the prophets of doom, can carry the day when it comes to cleaning up our air act and honouring the Kyoto Agreement. The city's environmental task force and its food and hunger action committee have both endorsed the sky plots, and last year City Hall even offered up its own third-floor roof for a case study by a coalition of avant-garde roofing companies called Green Roofs for Healthy Cities.
Earlier this month, the National Research Council, Environment Canada, the Toronto Atmospheric Fund and others released a joint report on the City Hall gardens. For the first time, there's hard data and computer models to show rooftop flower power is a cool way to save lives, energy, water, money and space.
Unfortunately, while the city's been quick to note these benefits, it's falling behind in terms of bylaws and incentives. There are some wonderful private initiatives, like the rooftops at Mountain Equipment Co-op and York University. Or the Royal York Hotel, where the herbs used on some 6,000 meals a day come fresh-picked from the roof. But as far as public policy goes, little is being seeded.
In Germany, by contrast, 80 municipalities provide roof-garden incentives, and 13 million square metres of green roofs have been built in the last five years. In Tokyo, the city's eagerness to counter the "urban heat-island effect" led to laws requiring all large buildings to green at least 20 per cent of their roof area.
In Portland, Oregon, where green roofs are appreciated for their role in storing rainwater and keeping the local river salmon-safe, downtown builders are allowed to increase their density if they provide green roofs. Chicago, which had a traumatic encounter with a death-dealing heat wave during the 1990s, is also making green roofs the law.
Toronto has no such laws or deals to offer.
This may be because T.O. had to digest amalgamation at exactly the moment when the inner city should have pioneered these kinds of innovations. Then there's the fact that green roofs have few champions here. Every year almost 1,000 people die from high smog levels, and thousands of kids come down with asthma, but no one is organizing their families into pressure groups for legislation on air-filtering sky gardens. Ironically, it's roofing entrepreneurs who are really energizing this planting push.
But governments don't seem interested in the tools and inducements needed to help private businesses that generate public benefits like clean air, reduced storm-water runoff or butterfly hideaways. The business coalition behind Green Roofs for Healthy Cities is lobbying for incentives to help building owners cover the short-term costs of renovating roofs to bear the extra weight of soil. At stake is the implementation lead in a multi-billion-dollar roofing industry that could export Toronto tech and know-how around the world.
"It's no longer a question of if," says Steve Peck, a former leader of the Clean Up The Don campaign and now the director of the business coalition. "It's just a question of which city moves first to capture all the benefits of innovation. There are places that could snap this up in a New York minute."
The City Hall experiment displays the creativity of this new roofing science. Each of its eight garden plots tests a different style of construction and maintenance. Some beds are "extensive" (low-cost, light-weight and shallow), and only hardy alpine plants can thrive in them. Others are "intensive" (more costly, lots of soil), providing conditions for plants with deeper roots. Some plots are designed to attract birds and butterflies to an area of the city that rarely harbours wild creatures. Some are just pretty. Two of the plots test whether food and farming have any place overlooking the city of the next century.
Soil and plants add a layer of insulation at the top of a building, helping to keep heat in during the winter and out in the summer. Owners of a typical high-rise can expect to see energy savings of about 25 per cent during the cold months, and at least that amount on air conditioning.
More surprisingly, green roofs don't just act as passive insulation. They become living machines, breathing and sweating places that air condition the entire city. Standard city building materials like cement and asphalt store heat. That's why summer nights bring no relief. And it's the hot air hovering near roofs that has to be cooled by air conditioning units. Vegetation on building tops does what humans do -- sweat -- which cools them through the process of evaporation.
Plants also work as air filters, capturing some of the free-floating particles that otherwise go into the air soup known as smog, says Brad Bass, a researcher with Environment Canada. The higher up the plants are in the sky, the more likely they are to capture the particles that make up smog, Bass explains.
As well, by reducing demand for coal-fired electricity to run air conditioners, green roofs reduce the sulphur dioxide that creates acid rain. "Just on those grounds alone, green roofs pay for themselves,' says Bass.
With the hard data finally in hand, it's time for some solid city policy.