Greening the city

Ranked the world’s most liveable city seven years running, Melbourne sits in an enviable position on the global spectrum. However, the Victorian capital is just 32nd out of the top 100 cities listed on the Arcadis Sustainable Cities Index 2016.

City of Melbourne Acting Lord Mayor Arron Wood says the disparity between the two rankings means it’s only a matter of time before Melbourne loses its crown. He says the need to improve Melbourne’s sustainability exceeds simply retaining its title as the world’s most liveable city.

“There are a lot of important sustainability drivers that determines the liveability, health and environment of our city, including social and cultural aspects. But, the look and feel of our city is absolutely critical to its liveability. To me, that’s one of the points where we can achieve the most innovation and improve sustainability for the long term.”

With significant environmental impacts, including climate change, and Melbourne’s rapidly increasing population and urban density, Cr. Wood says achieving sustainable outcomes is a time-based challenge, one that Melbourne needs to start addressing.

He explains that green infrastructure – the green elements of a city, including the trees, plants and open spaces that help cool the environment, reduce pollution, support biodiversity and improve social, health and public wellbeing – are critical considerations that help improve a city’s sustainability, and are important now more than ever.

The impact of climate change, population growth and increasing urban density on City of Melbourne’s ‘urban forest’, for instance, is well-documented by the City, and an area where green infrastructure can make a difference.

The urban forest comprises all of the trees and other vegetation – and the soil and water that supports it – within the municipality. It includes everything from parks, gardens, river and creek embankments, green walls and roofs and more. Not only is it aesthetic, but it serves as a critical part of the city’s ecosystem services, such as air and water filtration, shade, habitat, oxygen, carbon sequestration and nutrient cycling.

In 1988, with a population of 39,512, City of Melbourne’s area included 24.6 per cent green cover – or tree canopy cover. By 2009, the City’s population increased to 94,341 and its green cover reduced to 13.6 per cent. Cr. Wood says these green spaces started disappearing once the city’s population grew and privately owned land was developed to facilitate that growth.

“Sites that might have once had a single property on them are being developed into apartments. House sizes are shrinking and 80 per cent of people in City of Melbourne now live in apartments.”

This decline in green space and green cover isn’t slowing either, but it is something the City is deeply invested in confronting.

If action isn’t taken to address Melbourne’s decreasing urban forest, the City expects to lose 27 per cent of the trees within its district in the next 10 years. In 20 years, the City anticipates 44 per cent of its trees will disappear.

“Trees have a really important role to play in the livability and sustainability of the city, and the big issue we’re seeing at the moment certainly revolves around the fact there’s quite a lot of green space in private hands,” Cr. Wood says.

Likewise, he says, green spaces within the city have a significant role to play in reducing environmental impacts such as the urban heat island effect – the heat impact human activities have on an urban or metropolitan area.

To address the challenges, the City of Melbourne has implemented a number of strategies and programs to increase the quantity and quality of green space and infrastructure in the city.

One of these strategies – the Urban Forest Strategy – seeks to manage the change that comes with climate change, population growth and urban heating, and protect against future vulnerability by providing a robust strategic framework for the city’s urban forest.

The strategy has myriad aims, including to increase the city’s tree canopy cover from 22 per cent to 40 per cent by 2040, mitigate the urban heat island effect and bring inner-city temperatures down, green the city’s laneways and rooftops and improve urban ecology, to name a few.

“The urban heat island effect is one big area that we can try and contain, and a good example is through our laneways and building rooftops,” Cr. Wood explains.

City of Melbourne mapped the entire city’s urban heat island effect and identified the hot spots and priority planning areas that need more canopy cover and where there’s an opportunity to increase public green spaces and improve urban ecology. These spaces include Melbourne’s laneways and rooftops.

The City launched its Green Your Laneway Program, which aims to green Melbourne’s laneways. As part of the program, the city developed an interactive map that shows the laneways that could go green, based on the amount of sunlight they receive, exposure to wind and physical characteristics.

“Through our research we’ve mapped out the potential of these green spaces for the city’s laneways at 60 hectares with a further 150 hectares of vertical space available on building walls within the laneways,” Cr. Wood says.

Following an intensive design process, the City has selected four green laneways to fund in central Melbourne – Katherine Place, Meyers Place, Guildford Lane and Coromandel Place.

The environmental and economic benefits of greening Melbourne’s laneways – identified by the city – are numerous. This includes diverting storm water run-off from laneways into the soil, filtering dust and pollution from the air, reducing noise levels in the city, insulating buildings from heat and cold – in turn, reducing energy expenditure and carbon emissions, reducing the urban heat island effect, extending the life expectancy of impervious surfaces and increasing property values. Not to mention the myriad social perks of providing new public green spaces in the central city.

“We’ve also identified 880 hectares of potential green space – five times the size of Royal Park – on building roofs in the city,” Cr. Wood says. Like Melbourne’s laneways, greening the city’s rooftops boasts the same economic, environmental and social benefits, with added potential to be used for solar energy creation and urban farming. “The opportunity, if we get this right, is massive,” he says.

“The great thing about implementing green rooftops and other green infrastructure in the urban environment is that it’s really being backed by solid data,” Cr. Wood adds, citing the City’s map of urban heat island effect hotspots.

While the Green Your Laneway Program is progressing, Cr. Wood says the big problem for greening rooftops and, overall, shifting the city’s mentality towards green infrastructure is the amount of privately owned property in the central city.

The City owns just 1.3 per cent of the buildings in Melbourne’s municipality, with the remaining majority owned privately.

Cr. Wood says the only real way forward is for the City and private sector to work together and collaborate, which he admits still has a long way to go.

“We still need to validate with the private sector just how beneficial green infrastructure is – it’s still a struggle to explain how green infrastructure is not just beneficial for livability of the city, but it can actually reduce operating costs in buildings,” he says.

Reducing the temperature of the city through green walls and roofs, for instance, can help insulate buildings from heat and cold, and in turn help to reduce energy expenditure for the building owners.

He adds that implementing the idea at an early stage in the building’s construction or maintenance also helps reduce refurbishment costs at a later date.

To help address these issues and increase the uptake of green infrastructure, the City has introduced the Urban Forest Fund, which complements its wider Urban Forest Strategy.

“We launched the Urban Forest Fund a year ago and it’s opportunity to bring together the different stakeholders and that’s now beginning to break down the barriers.”

The fund provides financial support to new greening projects that otherwise would not have received funding – incentivising the implementation of green infrastructure such as green spaces, tree planting, vertical greening or green roofs.

The $10 million fund will be used to match private investments in urban greening initiatives, dollar-for-dollar, with the first round of projects – three in total – announced to receive support in 2017 and with $1.3 million already committed.

The City also released its Growing Green Guide, which is directed at the private sector and provides technical guidance on creating green infrastructure such as green walls and roofs.

While the City is making a number of small successes here, Cr. Wood says the biggest achievement so far was signing off the development of a business case for a future regulatory mechanism with regards to green infrastructure, last year – the first step in mandating green infrastructure in Melbourne’s buildings.

“Having a mandated concept at the planning stage is the one thing we’re missing and signing off the business case is the first step. It’s going to be done in partnership with industry and we want to create a streamlined approval process that incentivises green infrastructure for the developers and building owners,” he says. “What’s even more innovative is that this is one of the first policies for green infrastructure in Melbourne, which involves working with the private sector.

“The icing on the cake will be to get a lot of collaboration between government, industry and the private sector – a lot of good can come from this for Melbourne.”

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