Brisbane's future greenery could capture more than 100,000 tonnes of CO2 a year.

Brisbane, January 22, 2010:

Extensive adoption of built-environment greenery in a two million-person city, like greater Brisbane, could capture at least 100,000 tonnes of carbon dioxide a year.

This is a calculation derived from a two-year study from Michigan State University, reported in October, 2009. Prior to this study, there was no major analysis of the true carbon saving impact of urban green roofs or green walls.

janis Green Infrastructure Network Australia Inc member, architecture Professor Janis Birkeland of Queensland University of Technology, said the Michigan State University study was a significant wake-up call for key architecture people in Brisbane.Her words follow her significant 2008 authorship of the 432-page book titled Positive Development -- From vicious circles to virtuous cycles through built environment design We can have our carbon sequestration actually designed into greenery on buildings “ and well-paid for by a raft of other benefits, Professor Birkeland said.She said the significant Michigan study should alert Brisbanes 400 or so architecture firms to the importance foreseen for the Cities Alive Australia World Green Infrastructure Congress in Brisbane in October, 2012. This was being offered $100,000 support by Brisbane City Council, and $10,000 support from Brisbane Marketing. But significant reduction of Brisbane peoples carbon footprints was only one of the dozen or so benefits this congress will show for green roofs and green walls plus allied technologies, she said. Four conference themes proposed show this. They were:

Climate Change Action Planning.
Improved urban water harvesting and management.
Much-advanced solar power use.
Food from the roof, especially aquaponics.

Improved architecture design was the key link. Poor architecture and urban design kills more people every year than terrorism she said. Apart from exacerbating the effects of floods, droughts, storms, earthquakes and waterborne diseases, urban development often causes city temperatures to rise by two degrees Celsius or more. This urban heat island effect has killed thousands of people during heat waves in many cities around the world, the most recent of which was 3,000 one hot day in Paris in 2003, she said. Yet, one of the easiest urban cooling solutions was green roofs and walls designed into buildings, which could pay for themselves in a few years through energy savings, Professor Birkeland said. To be sustainable, a built environment would need to leave Brisbanes ecology, as well as its people, better off after construction than before. Restoration or remediation is not enough because we have already exceeded the Earths ecological carrying capacity, Professor Birkeland said. The only way we can support even existing bio-regions and populations sustainably is to retrofit urban areas to increase net ecological carrying capacity in cities. Buildings must not only produce clean energy, water, soil, air, and food, but must also reverse the impacts of previous development and expand ecosystems in absolute terms. The best way to start was with green roofs and green walls technology about to be specially developed for Brisbane by Queensland universities, she said.

Because our ecological footprint already exceeds the Earths ecological carrying capacity, the only way we can achieve sustainability is for urban areas to be retrofitted to generate natural, as well as social, capital.

This could an be done by providing good Brisbane infrastructure for ecosystem services and bio-productive functions, such as green roofs and living walls.

We cannot improve upon nature, but we can easily modify our urban environments to create the infrastructure, conditions and space for increasing the ecological base (ecosystem goods and services, natural capital, biodiversity and habitats, ecological health and resilience) and the public estate, or universal access to the means of survival and bio-security.

Green roofs and green walls for Australian conditions can contribute to both, she said.

Professor Birkeland said current means of assessing building quality is based on a meaningless standard, which is less harm than typical buildings of the same kind.

Today we have the capacity to determine the pre-settlement ecological conditions. A sustainability standard would measure improvements over the original extent and level of ecosystem health, productivity and services. At QUT, we are working on measuring the value of ecosystem services in the built environment, she said.

Professor Janis Birkeland worked consecutively as artist, advocacy planner, architect, urban designer, city planner and attorney in San Francisco before entering academia in Australia. She has authored about 100 publications on built environment and sustainability and wrote the highly-successful and widely-adopted Design for Sustainability (Earthscan, 2002). She is now Professor of Architecture at Queensland University of Technology, Australia.

Michigan State University research: Using sedums, a plant that has been used atop Minneapolis Target Center and the American Life and Insurance Co. headquarters in Kentucky, the Michigan State University research determined that every square meter of sedum sequestered 375 grams of CO2 per year. The research was led by MSU horticulture Professor Brad Rowe and doctoral research assistant Kristin Getter. MSU maintains a comprehensive repository of green roof research. Rowe said that 375 grams per square meter is not a large amount, but that if buildings were equipped with green roofs over a large area, it would amount to a significant carbon sink. Rowe has been testing green roof technology since 2000. At MSUs Plant and Soil Sciences Building he grows tomatoes and green peppers, as well as other plants. Municipalities across the United States, Canada and the world are beginning to mandate green roofs, which are roofs covered with any form of vegetation” trees, grass, and other plant species. A roof covered entirely with vegetation was at least 10% more expensive to construct than a traditional roof, but it could double roof lifespan.

Increased construction costs could now be recouped within two years. In the long run, a green roof benefits the tenant, a citys services and the environment “ and save great quantities of energy “ and carbon emissions.