A “shocking” warning that heatwave deaths in Sydney could skyrocket by more than 400 per cent has brought the issue of urban heat back into sharp focus, particularly in the city’s west.
The dire prediction comes from the Australian government’s first-ever National Climate Risk Assessment, released on Monday, which modelled the impact of climate change under three different warming scenarios.
Heatwaves already cause more deaths in Australia than all other extreme events combined.
Sydneysiders have been warned that heatwave deaths could skyrocket by more than 400 per cent. (ABC News)
Even under the best-case scenario — 1.5 degrees Celsius of global warming — the assessment warns heat-related deaths in Sydney would double.
Under 3C of warming, it predicts heat-related deaths in Sydney could rise by 444 per cent.
The Climate Change Authority said the world is on track to see 2.9C of warming this century, based on current global commitments.
In Western Sydney, where the impacts of extreme heat are already being felt, communities and experts are working on ways to better adapt.
But they warn much more ambitious efforts are needed.
Reducing the ‘heat island’ effect
Many suburbs in Sydney’s west have less than 20 per cent tree canopy coverage. (AAP: Dean Lewins)
Improving the number of trees and vegetation is one of the solutions receiving the most attention across Sydney.
According to a Macquarie University study from 2020, trees and vegetation can lower temperatures by up to 6C on days of extreme heat.
But many suburbs in Sydney’s west have less than 20 per cent tree canopy coverage, fuelling what’s known as the ‘heat island’ effect.
Libby Gallagher, a landscape architect who has led urban cooling projects across Western Sydney, said this week’s report on heat risks was “obviously shocking” but not surprising.
She said there has been a “big push” by councils to mitigate the effects of urban heat by improving tree cover.
“That really is important to address the temperature changes that we’re going to be seeing, because trees are nature’s air conditioners,” Ms Gallagher said.
Blacktown City Council has planted more than 12,000 new trees in the past four years. (Supplied: Blacktown City Council)
In Blacktown alone, where temperatures have reached 47 degrees, the council has planted more than 12,000 new trees in the past four years.
Its mayor Brad Bunting said temperatures varied considerably even within the local government area, depending on the level of tree cover.
“You can see a new suburb like Marsden Park, will be quite a few degrees hotter than a suburb just next door that has a lot of green space,” Cr Bunting said.
Some councils, including the City of Parramatta, have developed heat maps to identify areas that are most vulnerable to urban heat, to be prioritised for additional trees.
The NSW government also has an online resource called Cooler Places to help town planners, urban designers and councils to reduce urban heat.
Parramatta council has heat maps to identify areas more susceptible to urban heat. (Supplied: City of Parramatta)
Cooling down notoriously hot spaces
One of the biggest contributors to urban heat is outdoor car parks, and a recent project to improve green shading has shown positive results.
The use of vine-covered structures at a car park in Merrylands has been shown to halve surface temperatures from 70C to 35C on summer days.
The initiative, described as Australia’s first ‘cool car park’, was funded by a NSW government grant program for urban greening projects.
Merrylands’ cool park has been described as a first for Australia. (ABC News: Declan Bowring)
Another solution being explored is the use of lighter-coloured asphalt for roads, with a trial by Blacktown Council finding it reduced temperatures by up to 11 per cent.
Bus stops are also a major concern, with hundreds identified across Western Sydney that do not have shelter or shade.
Sanaa Shah is with the advocacy group Sweltering Cities, which has been documenting the area’s “worst bus stops”.
Many submissions included bus stops that were completely exposed to the sun.
“Catching a bus on a hot day really should not be a health hazard,” Ms Shah said.
“Imagine on a 30C day or a 40C day, how dangerous it is to be catching a bus at one of those locations?”
Sanaa Shah says it could be dangerous waiting at a bus stop with no shelter from the heat. (Supplied: Sweltering Cities)
Rethinking artificial lawns and parks
The use of artificial turf has exploded in popularity, with sporting clubs increasingly turning to synthetic surfaces to make facilities more resilient to wet weather.
But its role in the urban heat effect has come under growing scrutiny, with one expert calling it “horrific”.
Sebastian Pfautsch, a professor of urban management and planning at Western Sydney University, has recorded surface temperatures of more than 100C on a summer’s day at sites with artificial grass.
“Plastic grass comes up as the hottest material of them all, even hotter than the soft fall rubber that is used in playgrounds,” Dr Pfautsch said.
Sebastian Pfautsch has recorded surface temperatures of more than 100C at sites with artificial grass. (Supplied)
Dr Pfautsch has been advising schools to get rid of plastic grass and other synthetic surfaces in playgrounds.
“Because it adds to heating up the local microclimate across the school, and it can be an absolute burn hazard for the kids if they fall on this stuff,” he said.
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With the health impacts of sweltering temperatures already playing out across Western Sydney, community spaces are being converted into ‘heat refuges’.
A heat refuge is a cool zone with good air-conditioning and facilities where residents can go on an extreme heat day.
In Blacktown, libraries, churches and community centres have been designated such refuges.
Ms Shah, who lives in Blacktown, said such refuges provided a “really important” role.
A community centre in Blacktown acts as a ‘cool centre’ during a heatwave. (Supplied: Blacktown City Council)
But she said more action was needed to ensure people’s homes were safe in extreme heat.
“When we’re building new suburbs we need to make sure that those suburbs are built to withstand the climate future.”
Ms Shah added that it was “baffling” that homes continued to be built with black roofs, which add to the urban heating effect.
“We are advocating to reform our construction code, to ensure that there’s less occasions of those hot boxes being planted across our suburbs,” she said.
In a statement, NSW Planning and Public Spaces Minister Paul Scully said the government has a target of 40 per cent tree canopy across Sydney by 2036, and has already funded 131 urban greening projects.
Mr Scully added that new design standards — known as the Building Sustainability Index, or BASIX, which came into effect last year — has made it “almost impossible” to install a dark roof.
“Better design is one of our best defences against rising temperatures,” he said.