Terraforming the new economy

The major benefits of green roofs and green walls regarding climate change are:

• lower city temperatures and energy savings of at least 7-8 per cent; and
• storm-water management. Reduced runoff of rainfall at peak times enables drainage infrastructure to cope with extreme events without massive and costly upgrades.

Urban heat island effects can sometimes be 5-10C above nearby rural temperatures. The City of Toronto estimates that having 8 per cent of its buildings green-roofed would lower its heat island effect by up to 2C.

In Australia lower rooftop temperatures from vegetated roofs and walls mean that air entering air conditioners will be up to 5C colder than air from a traditional roof, saving large amounts of energy now used for cooling.

Other benefits of green roof and wall terraforming include air and water cleaning, longer roof life and lower maintenance costs, noise and electromagnetic insulation, visual beauty, habitat for songbirds, fire resistance, food production, new sources of income from the building and a more valuable building. The plants, being permanent, also contribute by locking up carbon dioxide.

Many Australian plants from coastlines and inland areas are well suited to planting on green roofs and green walls because they are tolerant of heat, cold, drought and wind. These native plants represent a new regional business opportunity as green roof retrofits and new designs expand. A global export market is expected to develop as terraforming catches on worldwide.

The prospect of an entirely new horticulture-based industry in Australia deserves consideration by all levels of government as an economic offset to the inevitable costs of countering climate change - as well as a way to cool and beautify the urban landscape.

This will generate new careers and new business for urban planners, architects, landscape architects, horticultural and landscape contractors, builders, roofers, developers, and building owners, as well built-environment regulators, researchers and academics.

Green roofs and walls are thus a wide-ranging convenient truth worth grasping in a federal election year.