Western Sydney’s urban heat is getting worse. In fact, it’s unsustainable

In January 2020, Penrith recorded a temperature of 48.9 degrees. It was the hottest place on the planet that day. As temperatures again soar across NSW this week, western Sydney residents will face acute heat and water challenges from which other parts of the city are spared.

The so-called “latte line” separates the wealthier north-eastern suburbs from the less affluent south-western areas. This division is also visible in the physical environment, with the greener, more developed north-east contrasting with the crumbled, less developed south-west.

With western Sydney set to accommodate two-thirds of the city’s future population growth, measures to alleviate the Urban Heat Island (UHI) effect cannot come soon enough. The signs are not good.

Infrared images show the high temperatures generated by dark roofs in density housing.

In summer, temperatures in the eastern and western suburbs can differ by as much as 10 degrees, and the heat is so extreme that public spaces feel like “untouchable playgrounds”, with surfaces too hot to touch.

Rapid urbanisation in areas such as Parramatta and Blacktown has also disrupted critical water recharge zones, replacing them with impermeable surfaces. These zones, essential for maintaining groundwater levels and managing surface water flows, are increasingly being replaced by impermeable surfaces such as roads, pavements and dense urban developments. The shift exacerbates surface water run-off, flooding and urban heat.

Blacktown ranks second among council areas in terms of the number of housing approvals. A sole focus on immediate housing needs compromises green space, which is vital for ecological balance, recreation and sustainability, and potentially leads to long-term environmental and societal challenges.

Parramatta experiences frequent flooding because the ground can no longer absorb water effectively, which affects residents and infrastructure. This problem increases the risk of floods and raises temperature of the land, especially in summer. Concrete surfaces block water from replenishing underground reserves, leading to a decrease in soil moisture levels. As more housing is built and green spaces are lost, the temperature rises, causing more water to evaporate and creating a very challenging living environment.

A slight shift in planning decisions can significantly affect long-term sustainability. Regions are connected to each other, so it’s important to have frameworks that consider the specific context of each area. Models that focus only on urban areas often overlook the complexities of entire regions, which can result in unsustainable outcomes.

Parramatta aspires to become Australia’s first city aligned with the United Nations Sustainable Development Goals by 2050, aiming to attract multinational corporations and celebrate multiculturalism. But the plan for urban development in Parramatta City has been criticised for failing to consider overcrowding and for a lack of adequate infrastructure. Without substantial investment in transport, traffic congestion may worsen, with average speeds falling below 20km/h by 2061.

A lack of meaningful community consultation has left residents feeling excluded from decisions about the city’s future too.

Addressing these challenges is crucial for Parramatta to achieve its ambitious goals and balance local and global priorities.

Western Sydney’s urban planning comes with challenges that affect its sustainability. There is a lack of strong focus on water-sensitive urban design, making stormwater management less effective. Limited green space also means less cooling of urban areas and a lack of clean air and biodiversity. These issues make it harder for the city to handle climate change and improve quality of life.

Cities such as Singapore and Barcelona offer integrated solutions. Singapore’s ABC Waters Program combines stormwater management with attractive public spaces, while Barcelona’s plan shows how green spaces can improve air quality and make cities more resilient.

To advance sustainability, western Sydney should adopt water-sensitive urban design. This includes using features such as rain gardens, permeable surfaces and stormwater systems to reduce flooding. Adding more greenery through rooftop gardens and urban forests would strengthen the city’s ability to handle environmental challenges.

Local communities and all levels of government working together is key to creating a co-ordinated and comprehensive approach. It would ensure inclusive implementation, make western Sydney greener and more resilient, and turn it into a better – and more comfortable – place to live.

Dr Ehsan Noroozinejad is a senior research fellow at Western Sydney University’s Urban Transformations Research Centre. Omi Kumari is a geographer at Western Sydney University.