Living infrastructure like green roofs, walls and facades can deliver a range of benefits to cities, building owners and tenants. Which ones are going to get you, your local government and big business to part with some cash?
Here is the first of two blogs I’m writing on the business case for living infrastructure. This one focuses on the societal benefits developers, local, state and federal governments can look forward to.
‘We should think of the built environment as a potential ‘treatment’ for chronic disease, as well as a place for ‘prevention’ of disease.’[ref]Capon, A. ‘The view from the city’, World Health Design, July 2011, p.8[/ref]
In 2008, chronic disease surpassed infectious disease as the leading cause of death around the world.[ref]Fleck, Fiona, ‘Noncommunicable diseases now biggest killers’, World Health Organization, 2008. Viewed 11 March, 2016[/ref] Chronic disease is currently the largest burden on the Australian healthcare system and is the leading cause of illness, disability and death in Australia, accounting for 90% of all deaths in 2011. [ref]Australian Institute of Health and Welfare, Australia’s health 2014, Cat. no. AUS 178, Canberra, 2014[/ref]
Like infectious disease, chronic disease is ‘often preventable and/or attributable to lifestyle or behavioural choices’ [ref]Department of Health, Victorian Public Health and Wellbeing Plan 2011–2015, Prevention and Population Health Branch, Victorian Government, Melbourne, 2011, p.17[/ref]. The introduction of living infrastructure can help turn these negative health outcomes around by cleaning the air, offsetting the urban heat island effect and increasing liveability (more on these below).
Research has shown there are ‘multiple positive physical, mental and social health benefits to living near green and open public areas. Conversely, health outcomes are generally poorer in communities that lack such spaces’. [ref]Legislative Council Environment and Planning References Committee, Inquiry into Environmental Design and Public Health in Victoria, Melbourne, May 2012, p.ix[/ref]
Cleaning the air
Good air quality is essential for good health. We know emissions from cars, buildings and industrial pollutants can result in poor air quality due to the increased level of carcinogens, particulates and contaminants in the air.
As I mentioned in a previous blog post, a recent study by Berkeley Earth found that air pollution kills 1.6 million people in China every year, approximately 17% of all deaths there. This is happening now. It is a very real consequence of urbanisation without appropriate living infrastructure. If we don’t plan our cities and build greenery into our urban spaces the concept of liveability goes out the window and city living becomes a matter of survival.
Plants are known to filter the air. They remove carbon dioxide and provide oxygen. ‘For asthma sufferers, for example, living in an area where there are trees has been shown to have positive effects by reducing the particulate matter in the air.’[ref]Department of Environment and Primary Industries for the State of Victoria, Growing Green Guide: A guide to green roofs, walls and facades in Melbourne and Victoria, Australia, Melbourne, 2014[/ref]. Plants and trees can improve air quality and overall health.[ref] Nowak, David J., Hirabayashi, Satoshi, Bodine, Allison, Hoehn, Robert, Modeled PM2.5 Removal by Trees in Ten U.S. Cities and Associated Health Effects, USDA Forest Service And Davey Institute, 2013[/ref]. It makes sense to integrate them into existing infrastructure as living filters.
Offsetting the urban heat island effect
The creation of cities and urban densification has created a decidedly modern problem – urban heat islands. An urban heat island is ‘a measurable increase in ambient urban air temperatures resulting primarily from the replacement of vegetation with buildings, roads, and other heat-absorbing infrastructure’[ref]United States Environmental Protection Agency, Heat Island Effect Glossary, Office of Air and Radiation, February 2009. Viewed 11 March 2016[/ref]. The result is an increase in peak energy demand, air conditioning costs, greenhouse gas emissions and heat-related illness and mortality.
This temperature rise and the associated problems can be offset through city-wide implementation of living infrastructure like green walls, roofs and facades. By covering the building surface with a layer of vegetation you shade the building materials that would otherwise absorb heat and kick-start the evapotranspiration process, resulting in latent heat loss that lowers surrounding air temperatures.[ref]Department of Environment and Primary Industries for the State of Victoria, Growing Green Guide: A guide to green roofs, walls and facades in Melbourne and Victoria, Australia, Melbourne, 2014[/ref]
Here’s a few figures from a Canadian study to put things into perspective:
A 2005 study in Toronto, Canada modelled the effect of implementing green roofs on low-rise buildings with low slope and at roofs of areas greater than 350 m2, and concluded that green roofs, implemented as a city-wide strategy, could mitigate the heat island effect by reducing local ambient temperatures by 0.5 to 2°C. It was calculated that this could save Toronto homeowners and businesses CAN$21 million annually by reducing the energy demand for mechanical cooling.[ref]ibid. (Original source: Banting, D., Doshi, H., Li, J. & Missios, P. 2005, ‘Report on the environmental benefits and costs of green roof technology for the City of Toronto’, Prepared for City of Toronto and Ontario Centres of Excellence – Earth and Environmental Technologies, Ryerson University.)[/ref]
Make cities an attractive place to be and the flow on effect is huge. Research has shown that well-planned improvements to public spaces in town centres can increase trade by up to 40% as well as generating significant private sector investment.[ref]Cilliers, E.J., ‘Bridging the Green-Value-Gap: A South African Approach’. World Academy of Science, Engineering and Technology, International Science Index 30, International Journal of Environmental, Chemical, Ecological, Geological and Geophysical Engineering, 3(6), 2009, p.184[/ref]
‘Green infrastructure enhances the economic attractiveness of commercial precincts, increases residential property values, and creates improved opportunities for tourism and economic regeneration.’[ref]Ely, Martin and Pitman, Sheryn, Prepared for the Green Infrastructure Project, Botanic Gardens of South Australia, Department of Environment, Water and Natural Resources, Green Infrastructure: Life support for human habitats, June 2014, p.5[/ref]. The potential savings to health care expenditure due to improved physical, mental and social health as consequence of well-designed urban green space has also been noted in a number of studies.
‘Liveability is defined in terms of the interaction between a community and the environment. The value of green spaces is thus described as the region’s life support system which provides multiple social, economic and environmental benefits.’[ref]Ely, Martin and Pitman, Sheryn, Prepared for the Green Infrastructure Project, Botanic Gardens of South Australia, Department of Environment, Water and Natural Resources, Green Infrastructure: Life support for human habitats, June 2014, p.5[/ref]
What can increased liveability do for your city? When a city is aesthetically beautiful, green and easy to get around, residents get out more – they’re active, they spend more, and the economy and investment in the area is boosted.
A study of the living habits of Copenhagen residents saw a $12 million saving in healthcare costs as a result of 10% more cycling in the city. This lead to increased productivity of $31 million and an extra 61,000 years of life.[ref] Juniper, Tony, What has nature ever done for us? How money really does grow on trees, Profile Books, London, 2013[/ref]
If the place was hard to get around on a bike, devoid of greenery or physically unattractive I doubt the results would be the same.
Storm water management
Green roofs absorb and retain water and can be a great strategy in the management of storm water runoff in urban environments. When rain falls on a bare roof, the run-off flows into drains rapidly and enters the storm water system. In contrast, when rain falls on a green roof, the plants and growing substrate intercept the rainfall. Some of the water is evaporated from the plant foliage, while some is absorbed into the substrate and subsequent layers where it is either stored or slowed for eventual release into the storm water system.[ref]Department of Environment and Primary Industries for the State of Victoria, Growing Green Guide: A guide to green roofs, walls and facades in Melbourne and Victoria, Australia, Melbourne, 2014[/ref]
A slower storm water system means minimised overflow, flood risk and potential for contaminants (like sewage, pesticides, motor oil or animal droppings) to pollute our waterways. As the climate changes and weather patterns become more erratic, it is important to safeguard our society from these risks.
Waterborne illness or floods due to poor storm water management have the potential to increase government spending, insurance premiums, healthcare and overall living costs. Rather than spending money on a complete overhaul of the storm water management system, governments can mandate or provide incentives for the implementation of green roofs in their area and mitigate these risks. A similar plan has already been implemented in Washington DC with great results.[ref]Karimi, Hamid, ‘Protecting blue through green: How Washington, DC is managing stormwater through green infrastructure policy’, Living Architecture Monitor, Vol:7, Issue 2, Summer 2015, p.14-15[/ref]. Plants and living infrastructure certainly seem like a small investment for benefits like these.