Penrith is known for its hot, dry summers and has quickly become ground zero for what is becoming known as the urban heat crisis in Australia.
The major moment of concern came on January 4, 2020, when Penrith recorded an unprecedented 48.9 degrees – making it the hottest place on Earth that day.
Western Sydney University Professor of Urban Planning and Management, Sebastian Pfautsch, found that the suburb of Penrith offers a unique window into the urban heat phenomenon that is continuing to intensify globally.
“Penrith is a very good case study; we always call it a playground where we can establish conditions and therefore also solutions for the future that other countries may experience in 20 years because it is so extreme already,” Pfautsch explained.
The urban heat effect occurs when built up suburbs absorb and trap heat often through dark and dense surfaces like asphalt, low vegetation and disrupted natural airflow, causing the trapped heat to increase temperatures, impact climate change and affect human health.
This phenomenon has been found to be occurring in Penrith as the previously untouched green pastures have been quickly developed into dense suburbs to meet the needs of Sydney’s growing west, including the development of the new international airport.
“That process replaces pervious green surfaces with grey impervious hard surfaces and that means you change how much moisture is in the system and also how energy is stored and then re-emitted,” Pfautsch said.
“That’s the problem where we see those so-called Urban Heat Island effects, where during the daytime you have a lot of heating of the hard infrastructure and because it’s thermal mass is high compared to pastures and grass, it stores the heat very well and releases that during the night, that warms the air and that gives you the urban heat island effect.”
In his report Suburban Microclimate and How to Improve It, released in August 2024, Pfautsch and his team outlined how rapid urbanisation is making cities hotter and more dangerous.
“Today it is impossible to build cities that will not generate additional heat,” the report said.
“This is due to the conversion of open to capped spaces and associated changes in thermal mass, surface reflectivity, evaporative cooling and changes in airflows.”
The report came up with a series of recommendations that would reduce the impacts of urban heat including avoiding dark coloured surface materials, retaining established tree canopies, and designing suburb layouts to improve cool airflows.
Managing urban heat is now more about adaptation instead of prevention, says Pfautsch.
“There is to me an issue around recognising how much we actually can do, where are our limits, where we can influence what we call urban heat and urban overheating and where we just have to adapt,” he said.
“There is this discussion around mitigation and adaptation.
“Mitigation would have been good 20 or 30 years ago, but adaptation is what we need to do now because a lot of things were we thought we can mitigate extreme heat, we don’t have the means anymore. It’s too extreme.”
Emily Chate
Emily Chate joined The Western Weekender in 2024, and covers local news - primarily courts and politics. A graduate of the University of Wollongong, Emily has contributed to The Daily Telegraph and worked as a freelance journalist.