Urban greening and cooling in response to increasing surface temperatures and water scarcity

The 2021 Report of the United Nations Intergovernmental Panel on Climate Change (IPCC AR6) found that climate hazards are posing an increased risk to the degradation of ecosystems, directly impacting human populations across the globe.

In particular, the report projected a rise in surface temperatures with increased interannual precipitation variability due to the general intensification of the hydrological cycle, causing more frequent flood and drought events. In turn, increased flooding and drought events affect water availability.

Heavily urbanised areas with reduced urban greenery and permeable surfaces are even more vulnerable to climate hazards such as flooding due to a higher speed of run-off from impermeable pavements and roads. Increases to surface temperatures can lead to extreme heat stress significantly impacting human and environmental health.

The Greening The West (GTW) initiative was established by the then City West Water, now Greater Western Water, who are supporting a proactive approach to a number of urban greening and cooling initiatives in partnership with the local government areas in Melbourne’s western suburbs.

This is an adaptive and equitable response to climate change to drive climate resilience in a region that has less than ten percent tree canopy, low rainfall and higher than the state average rates of preventable, chronic health issues.

The solution was to deliver quality, connected open spaces, increase tree canopy and urban greening, supplied with sustainable water (stormwater and treated wastewater), supporting local government areas and state government agencies to deliver greening and cooling benefits to these communities.

GTW was established in 2011 with the vision to, “enable sustainable and liveable communities through urban greening” and was initially set-up as a thinktank to work in collaboration in response to climate change across Melbourne’s west. It aimed to see an increase in quality, green spaces, parks and sports ovals, and to improve urban greening through innovative blue and green infrastructure initiatives.

Since its inception, GTW has leveraged both federal and state funding to deliver both blue and green infrastructure initiatives and have planted over one million trees across parks, open spaces and along waterways.

In 2018, GWW funded $12M to support their initiative “Water for a Greener, Cooler West” program, taking a 50-50 collaborative co-funding approach to support local governments to deliver innovative stormwater harvesting projects. Through the GWW collaboration it has delivered nine stormwater harvesting projects, supporting local governments to deliver Integrated Water Management outcomes, such as potable substitution, urban greening and cooling benefits, to ultimately support community health, wellbeing and liveability.

In 2021, the Victorian Department of Environment, Land, Water and Planning (DELWP) used the GTW platform and collaboration to provide $5m to GTW local governments and partners to deliver their “More Trees for a Cooler, Greener West” initiative.

“Green and blue infrastructure is a low-cost strategy to improve access to high quality, irrigated green space that can bring high impact results – environmentally, economically and for the health and wellbeing of the residents who live there.”

The IPCC AR6 reported with high confidence that, “3.3-3.6 billion people live in contexts that are highly vulnerable to climate change”, and that our, “unsustainable development patterns are increasing exposure of ecosystems and people to climate hazards”.

The urban greening and cooling activities are a response to climate-related threats in heavily urbanised areas, adapting to them by making Melbourne’s western suburbs more liveable and resource conscious. This will also contribute to addressing Greater Western Water’s challenge of providing climate-resilient infrastructure.

Trees are being planted and irrigated using alternative water sources, in an effort to increase alternative water use for green spaces 25% by 2030; increase green space 25% by 2030; and to double the tree canopy cover in Melbourne’s western suburbs by 2050. The scheme aims to increase resilience in response to climate change-induced water scarcity and is currently saving 110 megalitres of water annually. In addition, the cooling effect of additional green space reduces the effects of climate-related heat stress (up to 6 °C of cooling in summer).

The scheme also engages with the public as key stakeholders by promoting community participation in the greening process with an effective grass roots implementation strategy. The use of a relatively simple technology—planting trees and sourcing alternative water—stands to make its applications more implementable and effective.

Greening The West with Greater Western Water, alongside partners including local councils and universities, are building the adaptive capacity of communities in Melbourne’s western suburbs that can withstand the imminent changes to climatic conditions. Encouraging public participation is a key component of the project, promoting sustainability practices in schools and local communities.

This article was adapted from: Water Services Association of Australia. 2021. Towards resilience: Climate change and the urban water industry in Australia and New Zealand.
Images: Greening the West projects (Header: A Forest for Australia – Altona Treatment Plant; In-article: Exford Primary School Campus Greening.)
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