How Western Sydney is tackling the mysterious ‘heat island’ effect behind rising temperatures

WHAT if the actual design of your city is causing the thermometer to spike?

-higher density perhaps? With trees chopped for more housing

The biggest cause of the ‘heat island effect’ hard surfaces of buildings, roads, footpaths, roofs

-some residents call for trees to be removed

But people are getting there — it’s about generational change.

Councils are spacing out streets; using reflective colours, planting trees, using heat sensors; installing water features

THE science is unequivocal heat is a problem.

-we live in an urbanising world; more people live in cities, the cities are getting bigger and cities are getting hotter

-the urban heat island effect has been called inadvertent climate change


HEATWAVES … add Thermal Mass from Overdevelopment … Heat Island Effect and Mortality … e.g. Penrith …

Climate Statistics for Australian Locations … Sydney Observatory

Photo: Heat Island from Parramatta Council

How Western Sydney is tackling the mysterious ‘heat island’ effect behind rising temperatures

The Signal By Yasmin Parry

Updated 1 Mar 2018

Orange clouds over the Sydney skyline

PHOTO: Climate change is one thing, but what if it’s your city’s design that is causing temperatures to rise? (ABC News: Mary Lloyd)

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On a hot summer’s day in Sydney, you only need to drive half an hour west before the mercury starts to noticeably jump.

Penrith was the hottest place on the planet at 47.3 degrees on January 7 this year. In Sydney, the temperature reached a comparatively meagre 44 degrees.

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It’s a pretty standard story — the further you are from the ocean, the higher the temperature.

Rising global temperatures are one thing, but what if the actual design of your city is causing the thermometer to spike?

And while anyone close to the ocean can easily flock to the beaches on those hot sweaty days, people living out west have to find other ways to stay cool — which can often be expensive.

Western Sydney councils are banding together to tackle the growing heat problem, but it’s not as straightforward as you’d think.

How do you make a city cooler?

The Western Sydney Organisation of Councils (WSROC) represents eight councils trying to tackle climate change and the urban heat problem.

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Heatwaves kill far more people than other natural disasters. ABC Emergency has a checklist of things you can do to be ready.

*It’s particularly pertinent because the State Government’s policy is to move another million residents to Western Sydney in the next 20 years.

*They want to build a new airport and the world’s largest incinerator — all of which that means more roads and more roofs.

Stephen Bali, mayor of Blacktown and president of WSROC, worries it will only get worse.

“There is a change in the climate between eastern seaboard versus Western Sydney,” he said.

“There’s also pollution effects, because we don’t get those winds that often clear the air.

“And we live in a basin so pollution is higher and hence the actual impact on people is higher.

Cardiovascular disease, higher respiratory illnesses, every cancer rate that you can look at is higher in Western Sydney than on the eastern seaboard.

A tree lined street in Parramatta

PHOTO: Western Sydney councils, including in Parramatta, are banding together to tackle the growing heat problem. (ABC News: Laura Brierley Newton)

One simple idea is to just plant a lot of trees. Trees make an area cooler. But there’s a problem.

“Generally if you go to someone and say you want a medium to tall tree, people will say no,” Mr Bali said.

“Because they’re scared about — and quite rightly — the impact on the footpath and the road and amenities.”

Even that plan would take time, with a tree taking about 20 years to have any significant effect on an area.

“We have the issue right here and right now that we have to deal with,” Mr Bali said.

He said people generally did not want trees either in their front yards or around their house.

A young child in blue boardshorts cooling off under the water of a fountain in Parramatta.

PHOTO: What if a city’s very design is causing the thermometer to spike on sweltering summer days? (ABC News: Kathleen Calderwood)

“You look at the number of complaints that councils get [which] are people actually asking for trees to be cut down,” he said.

So even trees are not as simple a solution as you would think.

Thinking about the future

But people are getting there — it’s about generational change.

Councils are spacing out streets, they’re using reflective colours, planting trees, using heat sensors, holding design competitions, installing water features — these are just some of the things the west are doing to fix the city.

Western Sydney programs to combat urban heat:

  • Cool Parramatta
  • Turn Down the Heat
  • Blacktown’s Cool Streets program
  • Penrith’s Cooling the City Strategy

“You don’t have to have to have an argument about global climate change or anything,” Mr Bali said.

*“Manmade climate change in the Sydney basin will have an effect, there is no question about that. *

“So essentially how do we accommodate our health systems to recognise that there are these issues and apart from just building hospitals, which is an end product … we want to avert the illness.”

What is the urban heat island effect?

The urban heat island effect is caused when a metropolitan area is significantly warmer than surrounding areas due to human activity.

The biggest cause of it is hard surfaces, like roads, footpaths, roofs, as well as buildings.

They absorb the sun’s heat to send it rippling throughout the surrounding areas.

Aerial view of Parramatta showing the heat signatures of different suburbs.

PHOTO: A metropolitan area significantly warmer than surrounding areas due to human activity is known as a “heat island”. (Supplied: Parramatta Council)

Jonathan Fox, a researcher at the UNSW in the faculty of built environment, looks at how to design buildings of the future.

He said the science is unequivocal heat is a problem.

“We live in an urbanising world so more people live in cities, the cities are getting bigger and cities are getting hotter,” he said.

“And then we have a consequence of urbanisation, which is commonly referred to as the urban heat island effect.”

If you’re in a city today and you’re feeling hot, look around and you’ll start to notice all the things that make the heat worse, which add to the urban heat island effect.

These are things like dark concrete, no trees for shade, houses with dark roofs, endless paved roads as far as the eye can see.

“[The urban heat island effect] has been called inadvertent climate change, and there’s no doubt that the way cities have been constructed in the past, without knowledge of the climate effects of design, have exacerbated the overheating problem in cities,” Mr Fox said.

Simple solutions, like lighter roofs

A man stands in a park

PHOTO: The manager of Parramatta Council’s city strategy team, Geoff King. (ABC News: Laura Brierley Newton)

One city concerned about the rising heat is Parramatta.

The manager of Parramatta’s city strategy team, Geoff King, said when it gets hot in the Western suburbs of Sydney, it’s “scorching”.

“The data tells us that nobody goes out in the street, so people stay in their buildings,” he said.

“Once it gets over 35 degrees you get a major drop in pedestrian traffic. So I’d describe it as they scuttle from air conditioning to air conditioning.”

And when it heats up people stop going outside, they stop exercising and they stop buying things, which is bad for the economy.

Major infrastructure can deteriorate, and worst of all, people can get sick and die.

More people have died from heat waves in the past 100 years than every other natural disaster combined.

So Parramatta Council has a few different projects underway aimed at dealing with heat.

Tree with temp tracker

PHOTO: Parramatta Council has installed 20 temperature sensors among different tree species in the area. (ABC News: Laura Brierley Newton)

One of them is pretty simple. Lodged in the branches of different tree species are 20 temperature sensors — tiny little pieces of plastic stuck to tree limbs hidden from view.

It’s called Smart City project and is being run in cooperation with Parramatta parks and reserves workers.

“So it’s a really low tech, really flexible and easy way for us to monitor the temperature in the park under each of the tree species,” Mr King said.

“It basically logs temperature regularly for three months until the battery runs out and then it just becomes a USB stick.”

The council also have two water parks in operation — basically playgrounds covered in giant sprinklers.

Along with simple projects such as those, Parramatta Council regularly run design competitions for architects, asking them to rethink the design of buildings — like including awnings, reorienting the building’s outlook, and changing the materials

A kid scooters through a water park

PHOTO: Parramatta Council has two water parks in operation for residents to cool down on hot days. (ABC News: Laura Brierley Newton)

One of the questions Mr King raises is the trend of having dark roofs on houses and buildings.

“It’s an interesting question — why do we like dark roofs?” he said.

“I think it’s aesthetics related to what we know, and I’m going to hazard a guess here, I think the original colonial buildings that had Welsh slate on them came out as ballast in the ships.

“They were the top class, they were the top houses, and so they had black roofs.

“And I think over time we’ve associated black roofs with a quality finish and a high-class building, but in an Australian climate.

“So we’ve done a lot of research into roofs being a really simple way, the colour of roofs being a really simple way of reducing the energy load on your building.”

Mr King said the corrugated iron roofs found on more and more western Sydney homes work well, with the light silver colouring capable of reflecting the sun, instead of soaking it up.