This was published 10 months ago
Brisbane is getting hotter – some parts more than others
By Tony Moore
Experts say urban heat has become a major issue for many cities, including Brisbane, to tackle.Credit: Nordacious
Urban development is creating “heat islands” in subtropical Brisbane, affecting the quality of life of people who live, work and move in areas where there is more concrete and bitumen.
At Bowen Hills, for example, a convergence of roads and tunnels and overpasses – not far from a hospital, university campus and showgrounds – can sometimes push up temperatures by almost five degrees.
While the interchange is considered vital to keeping city traffic moving, its impact on the urban environment illustrates the need to consider heat when planning for growth.
Griffith University’s Dr Tony Matthews says Bowen Hills is a heat island.Credit: Tony Moore
Brisbane is set to have higher-density development in the inner city, particularly around major roads and public transport services. Houses on large blocks with a backyard have made way for townhouse complexes and apartment towers with smaller gardens.
In the outer suburbs, greenfield development sites have replaced bushland in areas where the car is the predominant mode of transport.
Griffith University’s Dr Tony Matthews said planners needed to prevent, and better manage, heat islands for the overall good of the city.
“In the simplest terms, a heat island is an area of land that is significantly and measurably hotter than the surrounding area,” Matthews said.
“At the largest scale, if you look at a city from a satellite in space, you can get a sense of its heat profile, and you can see that the surrounding countryside is much cooler because it is not built on.
“But then at the local level, you can find heat island effects on one part of the street and not on other parts of the street.
A heat map of Brisbane for January 19, 2024. Darker colours show hotter areas.Credit: Meteoblue
“Usually, it is caused by the built environment: houses and streets and buildings, which soak up the sun’s heat all day and release that heat back into the street during the day and into the night after the sun has gone down.”
How cities, and people, adapt to the weather is becoming increasingly important. The Bureau of Meteorology now reports an apparent or “feels like” temperature, and has frequently warned of heatwaves this summer.
Unions have campaigned for better protection for workers who spend time in the heat, while renters have pushed for better building-design standards.
Air-conditioning in schools, offices and homes is already testing the electricity network. Last month, Energex reported a new peak demand, and in Camp Hill there were outages when the system was unable to meet demand.
QUT’s School of Architecture and Built Environment is investigating factors affecting urban heat vulnerability in subtropical cities.
Professor Tan Yigitcanlar said Brisbane was not the only city feeling the heat.
“In recent years, with the rise in climate change impact, urban heat has become a major issue for many cities to tackle consequently,” he said.
“Extreme heat events are becoming more frequent and intense due to climate change, which has directly caused a substantial increase in heat-related morbidity and mortality. This indispensably puts an extra burden on medical systems and national finance.
“It is urgent for local governments to locate the harmful heat and identify the characteristics of vulnerable populations.”
The current South-East Queensland Regional Plan requires councils to undertake local-scale heat-hazard risk assessments to help guide their planning decisions and roll out “greening and cooling strategies”.
Matthews said such strategies should not be confined to housing design or broader town planning.
“We need to be very smart about planning for the negative impacts of heat on people where we find them,” Matthews said.
“You have vulnerable communities spending large periods of time in certain locations. So there is an incentive there and an obligation to identify and address those quickly and meaningfully.”
Five years ago, the Queensland government used climate change modelling to predict that Brisbane’s weather would be more like Bundaberg’s by 2030.
While this summer has been far wetter than the Bureau of Meteorology expected, the south-east has still felt the heat. Not only have there been days when Brisbane was hotter and more humid than Bundaberg, new benchmarks have also been set: a weather station at Beerburrum recorded its highest January mean daily minimum temperature, while stations at Amberley and Gatton recorded temperatures not experienced in decades.
Matthews said more heat mapping was required to understand the issue. He said Brisbane could learn from good development outcomes, such as South Bank, and from those that created the current heat islands.
“The whole area around the Royal Brisbane and Women’s Hospital is going to be artificially hot because there is very little tree cover, lots of concrete and lots of vehicles generating heat,” he said.
“Pretty much all of Woolloongabba currently, and also Main Street up to Kangaroo Point, is a desert-like type of place where lots of people are living.”
The future of Woolloongabba depends on an ongoing review of venues for the 2032 Olympic and Paralympic Games, and development of government land around the Cross River Rail station. It is bound to look different, and if those who live there are lucky, it might feel cooler too.
This article was produced in collaboration with the Australian Science Media Centre, with support from the Walkley Foundation-administered Meta Public Interest Journalism Fund.