Urban heat

Average temperatures in large cities are 1 °C to 3 °C higher than in rural areas, as urban areas tend to trap more heat than natural environments. These higher temperatures can affect human health and wellbeing, economic productivity, the environment, critical infrastructure and services.

In Australia, major heatwaves have caused more deaths since 1890 than bushfires, cyclones, earthquakes, floods and severe storms combined.

Some urban communities are more vulnerable to higher temperatures because of the ‘urban heat island’ effect, which occurs in urban areas where paved, dark coloured surfaces such as roads, roofs, and car parks lead to heat being trapped.

Urban heat islands develop in areas with hard, sealed surfaces and a lack of vegetation or ‘green infrastructure’ such as tree canopies, vegetated roofs and walls and waterways. This is because hard surfaces absorb, store and radiate heat, while green infrastructure reflects heat, provides shade and releases water into the atmosphere.

Urban heat islands are increasing the effects of climate change, making higher temperatures and extreme hot weather events more severe and difficult to manage, placing more people at risk of exposure. During a heatwave, for instance, temperatures in western Sydney, which has less green cover, are sometimes 10 °C higher than in eastern Sydney.

Planning how we use land plays an important role in reducing vulnerability to urban heat. It helps create places and communities that are more sustainable and resilient to a changing climate. We are delivering several planning initiatives to reduce urban heat.

• AdaptNSW – information on urban heat and the heat island effect, including strategies for mitigation and case studies
• Pulse of Greater Sydney 2020 – the Greater Cities Commission’s report has information on urban heat and the value of green infrastructure
• Climate Kids – NASA’s website has resources on urban heat for children
• ArchitectureAU – outlines what we are doing to achieve cooler and more liveable cities
• HeatWatch – the Australia Institute’s report covers extreme heat in western Sydney
• Cooling Western Sydney – Sydney Water has studied the role of water in mitigating urban heat in Western Sydney
• The SEED portal provides access the latest urban heat vulnerability, urban heat island effect and vegetation data.
• Western Sydney Regional Organisation of Councils have undertaken a number of urban heat-related initiatives, targeting exposure in Western Sydney, including:
  • Turn down the heat
  • Urban Heat Planning Toolkit
  • Cool Suburbs tool
  • Heat Smart Western Sydney
• NSW Health’s Beat the Heat
• The Government Architect NSW’s Greener Places framework