Terraforming Australia: a new response to climate change

by GEOFF WILSON

Australian cities now need terraforming – so that they become part of a climate-change response, rather then being one cause of it.

Terraforming is “Earth-shaping” of a planet, moon, or other body. It is the hypothetical process of deliberately modifying atmosphere, temperature, or ecology to be similar to those of Earth in order to make it habitable by humans.

I use the term to describe transformation of a city’s built environment so that it more closely resembles a rural countryside in terms of environmental advantages.

Terraforming is a convenient term for a most convenient truth.

It is demonstrably good for our fiscal economy. Australian built-environment professionals can team with Australian primary producers for new business opportunities.

Both can specialise in the nascent urban greenery market.

North America and Europe now have 15 green roof infrastructure national associations. They represent urban planners, built-environment educators, engineers, architects, horticulturalists, developers, specialist builders and municipal government.

Their international organization is the World Green Roof Infrastructure Network (WGRIN), which next meets early in May, 2007 in Minneapolis, United States, to begin a global campaign that is expected to eventually terraform much of the world’s built environment. Australia has formed a member organisation of WGRIN — Green Roofs for Healthy Australian Cities.

WGRIN plans to include many Asian, African and South American countries in its work – especially the populous China and India. This has great significance for Australia’s credibility as a player in the new terraforming world economy that can be developed to help cope with climate change problems.

Whether those problems are caused by a hotter sun, vulcanism or out-of-control human expansion does not matter. What does matter is a response that has strong economic advantages that try to balance the economic losses from a voluntary or forced decline in the world’s unsustainable carbon economy.

Green roofs and walls of terraforming can be retrofitted or designed in new construction. Design varies according to roof load and slope, solar aspect and budget. Two types of green roofs are favoured — extensive (low profile) and intensive (high profile). A combination of both is also possible.

Australia has just began a serious start on green roof development In February 2007 group action coalesced on development of Australian guidelines and regulations for green roof and green wall structures. These have four important factors:

1. Buildings for green roof and wall “terraforming” must be made water-tight, with no root penetration.
2. Appropriate species of hardy plants must be chosen and established on well-designed substrates.
3. Each green roof and green wall plan must have a sound integration of professional expertise in both the “black arts” (water-proofing) and the “green arts” (plant selection, substrate choice, plant establishment and plant maintenance).
4. Each building approval for green roofs and walls must have a long-term maintenance plan of both the waterproofing and the greenery.

To achieve this up to a dozen university or TAFE-trained professionals with different expertise must team up with owners or developers of buildings.

Many Australian plants from coastlines and inland areas are suited to green roofs and green walls that require low maintenance urban vegetation tolerant of heat and cold, and drought and wind.

These native plants represent a big new regional business opportunity in Australia as green roof retrofits and new designs expand. A global export market is expected to develop.

A new horticultural industry in prospect for Australia now well deserves government analysis and support – as an important economic offset to whatever business advantage may be lost in reduced coal use.

A similar economic offset is possible in new careers and new business for urban planners, architects, landscape architects, horticultural and landscape contractors, builders, roofers, developers, and building owners. New careers will also develop in built-environment regulation, research and academia.

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

Advantages of green roof and wall terraforming

Three most important green roof and green wall benefits to help counter climate change are:

1. 1. Thermal insulation – reducing 7% to 8% fossil fuel energy use in heating and cooling of buildings.
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   2. Storm-water management — lower runoff of rainfall at peak times enables drainage infrastructure to cope without massive and costly upgrades. Climate change may bring many more rainfall peak loads which challenge existing drainage works.
2. 3. Reduction of ambient temperatures in cities — caused by the “heat island effect” of buildings and roads. Sometimes this effect can be five to 10 degrees Celsius above rural temperatures close by. The City of Toronto estimates that a mere 8% of green roofed buildings can reduce its heat island effect by up to 2 degrees Celsius. Lower rooftop temperatures from green roofs and walls mean that air entering air conditioners is often 5 degrees C lower in temperature than air from a traditional roof – to provide further fossil energy savings.
3. Other benefits of green roof and wall terraforming include:
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   • Air cleaning effects. Green roofs trap and ameliorate harmful particulates and dusts. Microbial action within the green roof may be enhanced with probiotics that reduce air-borne carcinogens on particulates or dusts to harmless products. Air cleaning can also reduce lightning strikes in cities.
4. • Water cleaning effects. When micro-organisms in a green roof chew up harmful airborne particles the water then harvested from the green roof is much purer than street or rooftop runoff. A green roof can also be used to renovate “grey water” from homes and businesses.
5. • Longer roof life and lower roof maintenance costs. A green roof can protect the underlying structure so that it will last around 40 years instead of 10 to 20 years. So, while a green roof may cost more in the first instance, its long-term benefits to building owners can be huge.
6. • Noise insulation against transport noises – especially trains, trams, buses, trucks and aircraft. A 12cm deep green roof pad will reduce noise by 40 decibels. The Netherlands’ Schiphol Airport (pictured) has been built with green roof technology for this purpose.
7. • Visual beauty. A green roof has a calming effect that reduces urban stresses on people and enables hospitals to release patients from half a day to two days earlier in some cases. Green roofs also provide urban workers with more pleasant, restful surroundings that increases productivity and reduces absenteeism.
8. • Habitat creation for small song-birds, butterflies and bees. This has been found to be significant in some overseas suburban green roof developments. Ford has a bee farm on its 10-acre green roof. Other green roof projects are aimed at providing habitat for migratory birds.
9. • Fire resistance. A study in Berlin found this was particularly the case with succulents. It is also relevant to ‘earth roofs” for Australian farmers in fire-prone areas. In many parts of Australia, South Africa, the French Riviera and California, green roofs in urban and rural areas .can save lives and property losses from fire.
10. • Electromagnetic insulation. Electromagnetic radiation can be reduced by 99.4% with a 10cm substrate depth.
11. • Food from the roof. This is a business opportunity for many, as technologies such as hydroponics, aquaculture, aquaponics, vermiculture and insect culture are set on commercial rooftops close to where produce is consumed. Importantly, they will recycle food nutrients within cities and reduce methane emissions from landfill.
12. • Extra revenues for building owners renting for food from the roof, or providing an improved office or work environment for tenants, who are willing to pay more for superior office environments. Owners of green roofed building find their rental properties easier to market, and productive of higher rentals, plus better tenants.
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    • More valuable buildings. Real estate valuers are predicting that retrofit green roofed buildings will improve in capital value by at least 5% to 10%. In many municipalities green roofs allow extra ground floor car park spaces to be approved. Some municipal authorities now offer “fast tracking” of building designs that have green roofs – thus reducing the original cost of the building and adding to its value.
13. • Savings for governments. With rapid urbanisation around the world, and rapid onset of cimate change problems, government leadership on green roofs is vital. The Ciity of Toronto estimates that 8% green roofs in Toronto made direct energy savings of C$12 million a year in buildings from reduced cooling demand in summer. Indirect savings included reduced peak load energy demand of C$80 million a year. Also, it meant reduction of storm-water flows by 12 million cubic metres a year, so that existing drainage infrastructure can cope, and sewage overflow events were less frequent. Toronto’s savings from 8% green roof cover were estimated to be C$79 million a year from reduced capital costs for storm-water management, erosion control and sewer overflows.