More green space alone won't beat urban heat

New Victoria University (VU) research reveals the solution to reducing the impact of extreme heat in urban areas cannot be solved by simply adding more green spaces - what’s needed is a different approach to urban planning.

As parts of Australia knows all too well, unlike other natural disasters, heatwaves often arrive silently, without dramatic visual clues and often persist for consecutive days, affecting health and potentially causing harm. 

For city dwellers, the local park is a refuge, but not all green spaces offer protection from the heat, and some designs, depending on where they are and how they are designed, might be adding to the problem.

Urban form and part cooling performance during extreme heat events: a case study in Melbourne, published in Elsevier journal looked at Central Gardens in Hawthorn and evaluated how surrounding urban structures influenced the cooling performance during an extreme heat (42 degrees) event in Melbourne.

Led by PhD candidate Ms Maryam Norouzi, and Associate Professor Elmira Jamei, the study confirmed urban parks provide substantial cooling benefits during extreme heat conditions; however, both the size and spatial extent of these benefits are strongly shaped by the surrounding urban structures and vary considerably between daytime and nighttime periods.

While daytime cooling reduces heat exposure during periods of intense solar radiation and high air temperatures, nighttime cooling is equally important because it allows heat accumulated within the urban environment during the day to dissipate, helping cities recover before the next day's heat.

“The message to urban planners is clear: you can't just say 'add more parks' as a blanket heat solution. A park in a dense city centre needs a completely different design strategy than a park in the suburbs. In cities, you want to protect daytime shading but improve nighttime airflow. In the suburbs, you want to keep the park connected to the street network so the cool air can flow out and help the whole neighbourhood, not just the park itself,” Associate Professor Jamei said.

In low-rise urban environments, the results show that park cooling benefits can extend further into surrounding neighbourhoods. Urban planning in these areas should prioritise maintain open ventilation pathways between parks and adjacent streets, avoiding excessive development immediately around park boundaries, and integrating parks with connected green networks such as street-tree corridors and vegetated residential gardens.

“The relationship between urban parks and the surrounding built environment strongly influences how effectively parks cool cities during extreme heat. This means that improving urban resilience is not simply about creating greener spaces but about designing parks and the surrounding neighbourhoods to work together as an integrated system,” Ms Norouzi said.

Ultimately the findings indicate that park design and placement should be tailored to surrounding urban structures to better support cooling impact of urban parks.
“Policymakers could be hugely influential in designing climate-adapted cities to promote outdoor thermal comfort and create healthier urban environments for future generations,” Associate Professor Jamei said.