A team of researchers at the University of Technology Sydney have spent the past twelve months analysing the business case for more green roofs and walls in Australia.
A literature review as part of the project included a US Cost Benefit Analysis (CBA) which found a viable case for boosting urban greenspace. It showed increases in residential property values with good amounts of green infrastructure was between 6 and 15 per cent.
The review also found that the widescale adoption of green roofs in Toronto, Canada could reduce temperatures in urban areas by up to 5 degrees Celsius.
The Australian research was funded by Hort Innovation under the Green Cities Fund, with co-investment from the University of Technology Sydney, Elmich Australia, Junglefy, Aspect Studios, Flytogreen and contributions from the Australian Government.
‘Expanding the Living Architecture in Australia’ explores whether a mandatory or voluntary approach to green roofs and walls would work best in Australia, and draws on scientific literature and international case studies to illustrate how it could work in a localised setting.
It found green roofs and walls (otherwise known as GRGW) offer great potential to expand the living architecture in Australia and could deliver a suite of benefits from improved air quality and reduced storm water impacts, in addition to boosting community interaction and urban aesthetics.
UTS Associate Professor Sara Wilkinson said that building-related greenhouse emissions make up 40–50 per cent of total emissions, which is prompting policy makers and town planners to examine alternative methods of mitigation such as GRGW.
“With predicted temperature increases, urban centres will become hotter and less comfortable. Our project outlines the opportunity to mitigate these increases through a wide-scale GRGW effort,” she said.
“Currently, Australia has no consistent policy approach to GRGW except for the City of Sydney, NSW and the City of Melbourne, VIC, which have policies that align with their respective 2030 and 2040 sustainability targets.
“Barriers to adoption here in Australia include installation and maintenance costs, and a lack of awareness, professional guidance and experience when it comes to working on projects involving this kind of green infrastructure.
“Research suggests that these barriers will diminish over time as living infrastructure is considered earlier in the building timeline and that more offices and large residential blocks are retrofitted with GRGWs economies of scale will be realised.”
An integral part of the project was identifying international case studies of cities from around the world that are embracing GRGWs and to review a number of existing policy frameworks overseas, which could be adopted in Australia.
Associate Professor Wilkinson said that the research unearthed various incentives for those succeeding in GRGWs such as the introduction of subsidies, grants and guidance, which are all helping to boost green space in urban areas.
“Our research looked at Singapore, which leads adoption of GRGW under its voluntary-heavy approach. It proactively markets itself as a green ‘garden city’ to help attract investment, visitors and commerce,” she said.
“Greenery is ingrained in Singapore’s development sector, and is boosted by incentives, grants, awards, certification schemes and government led development, which has resulted in an 805% increase of GRGW and a thriving green life economy.
“In Europe, Rotterdam has a ‘voluntary-medium’ approach to increasing its installation of GRGWs through incentives, grants, tax benefits and demonstration projects, which achieved an increase of 120 per cent of green roof area from 2012 to 2017.
“London adopted ‘voluntary-light’ measures and achieved an increase of 360% of total green roof space over an 11-year period from 2005 to 2016, which has been encouraged by various policy instruments including the city’s Biodiversity Action Plan.
“In Canada, Toronto has the second biggest area of green roofs which, in large, has been spurred on by a 2010 policy that made it mandatory for all new developments with roofs over 2000m2 to be built with green roofs.”
The project modelled all four scenarios – from ‘voluntary-heavy’ right through to ‘mandatory’ – in Sydney and Melbourne, based on actual projects, to determine what could be delivered here in Australia.
“The research suggests that a policy package that enhances education and builds the business case of why GRGWs can perform equally or better than traditional infrastructure could be effective, as well as offering financial incentives such as grants right through to energy cost savings,” she said.
“A large proportion of our built environment could be retrofitted, so in this case we recommend a voluntary approach which includes a mix of initiative s for building owners such as tax benefits and avenues for accreditation.
The full report Expanding the Living Architecture in Australia (GC15001) is available upon request at Hort Innovation’s website. GC15001 is a Green Cities Fund project, which has been developed by Hort Innovation as part of its recently developed Hort Frontiers strategic partnership initiative.