2 From Hot Suburbs to Cool Towns: in conversation with Dr Cool

Sebastian is well known as Dr Cool for his impactful research, advocacy and strategies for keeping cities cool, including how to reduce heat emission from roads, which materials should be used in playgrounds to reduce the risk of skin burns, and what is needed to build homes that require less electricity for air conditioning. He is a Professor of Urban Planning and Management in the School of Social Sciences and co-leads the research stream of People-Centred Sustainable Precinct Design at the Urban Transformations Research Centre. In his interdisciplinary research he collaborates with colleagues across the University, government administrations and industry to climate proof our cities. Sebastian was invited to the NSW Government Greening our City expert panel, works as an independent advisor for the New South Wales (NSW) Chief Scientist and Engineer, contributed to the 2050 Masterplan of Sydney Olympic Park, co-developed Australia’s first Handbook for Urban Green Infrastructure (UGI) for Standards Australia and designed the microcredential Cool Green Cities. He is also Director of SIMPaCT, a large-scale research project that developed and operates an AI-based park irrigation system for optimal cooling during hot summers. Recent highlights are working with the BBC on the documentary Life at 50C – Heat hitting home in Australia and joining Costa Georgiadis on the ABC’s Gardening Australia program to explain the importance of urban trees for cooling. Just this month (August 2024) he became the Deputy President of the Australasian Green Infrastructure Network (AGIN) where he continues his advocacy work for more plants in our urban landscapes and skywards on our buildings. In this interview with Jen Dollin, Director Sustainability Education and Partnerships, Sebastian shares his work and his passion for impactful change.

Why is this work so important for Australia and Western Sydney?

Well, it is expected that by 2060 70% of the human population will live in cities where they will be increasingly exposed to climate change-induced stresses and shocks–heat being the most frequent and detrimental impact. In Australia, heat kills more people every year than all other natural disasters combined. We are one of the most urbanised countries in the world, where nearly 90% of the population lives in towns and metropolitan areas, a trend that is increasingly leading to larger and denser cities. These processes of expansion of cities at their fringe zones and densifying within, make cities hotter. This is counterproductive in a time where our summers are becoming hotter. We must do the opposite – develop urban spaces so they keep cool. This outcome is absolutely critical because rapid planetary warming and continued urbanisation leaves millions of people suffering from the impacts of heat. In 2018, Australia was the last of 64 countries with either a national or international climate policy and was ranked 172 out of 180 countries for average per capita greenhouse gas emissions.

And yet we are a very wealthy country with the knowledge and skills to do much better. Also, across Australia, there is an increasing community expectation that we take climate action and become serious in our efforts to mitigate where we still can and adapt where we must.

And there is a special urgency for Western Sydney. It is the fastest transforming space in Australia; new highways, metro and train lines, new towns, industrial areas, an entire city–Bradfield–next to the new international airport. The rate of development across Western Sydney is simply phenomenal. Yet, Western Sydney is naturally a hot place in summer. Heatwaves are a regular burden for those that live and work here. I already measured 52°C in the Local Government Area of Blacktown where the north-western priority growth area is located. With my work on urban cooling, I try to show those that are developing and living in Western Sydney how to do it heat-smart.

What causes cities to heat up?

The general thermal effect of the geometry and dominant elements of cities can lead either to warming or cooling of microclimates in cities. This includes how a city is laid out through building density, building height and size, heat from human activities such as domestic and industrial heating, the heat retaining properties from building and road materials, and the amount of access to water such as irrigation and vegetation cover. Antonio Guterres, Secretary-General of the United Nations, is spot on when he said last week: “Earth is becoming hotter and more dangerous for everyone, everywhere.” We must do things differently!

What are some examples of the possibilities available now to create heat-smart towns and cities for tomorrow?

There are many, from simple changes around residential homes to turning public parks into large air conditioners! Our Urban Heat Mitigation and Adaptation program fuses techniques traditionally used in urban planning with those from landscape design as well as material, environmental, plant, social and educational science to create practical solutions that make our settlements heat resilient and more liveable. We have developed solutions for schools, playgrounds, car parks, buildings, roads, and entire local government areas. Living Labs across Western Sydney actively demonstrate contemporary solutions to cool urban space such as: Cool Roads across Western Sydney councils, Green Track for Parramatta Light Rail, the AI-based irrigation system called SIMPaCT for Sydney Olympic Park Authority, the UV Smart-Cool Playground at Merrylands, the Cool Schools program, or our cool car park projects in Holroyd and Wentworthville. Given the extreme heat that the communities of Western Sydney face, I have now started to also work with colleagues in public health and develop cooling strategies for social and affordable housing and also how wheelchair users can navigate urban spaces better during hot days.

Tell us more about how some of these initiatives actually work?

Key to the success of all these projects is our empirical assessment of their effectiveness. We measure how much cooler things like roads and playgrounds are once we have delivered our intervention. Also, the initiatives vary in their complexity. Take for example the Cool Roads Trial where we coated roads and car parks with a highly reflective paint. Super simple with immediate and measurable cooling benefits. At the other side of the complexity spectrum are initiatives like SIMPaCT (Smart Irrigation Management for Parks and Cool Towns).^[3] This initiative is also a great example of interdisciplinary impact! Disciplines like Computer Science, Environmental Modelling, Plant Sciences, Engineering, Remote Sensing and Urban Planning work together. This $6 million project combines smart sensing technology with machine learning to manage the irrigation of Bicentennial Park at Sydney Olympic Park for maximum cooling benefits in summer. The technology considers weather forecasts, soil moisture, and local environmental conditions to determine optimal irrigation commands that maximise the cooling capacity of plants growing on 200 individually controllable watering zones within the intricate park landscape. Whilst maximising air cooling, the technology also leads to the highest possible efficiency in the use of irrigation water, contributing to the usability of public green space and reducing the economic burden of ongoing maintenance. Live data from the park are streamed onto the project website, where park visitors can find the coolest location in the park for a picnic. The project itself is communicated via signs across the park, using the technology developed by the Digital Trust for Places and Routines (DTPR) – a first in the Southern Hemisphere, implemented at Sydney Olympic Park. SIMPaCT has won important national awards in the Internet of Things (IoT) industry (IoTAA Impact Awards for Best Research and IoT For Good categories, InnovationAUS Awards, Banksia Foundation Award and awards from Parks and Leisure Australia and the Australian Institute of Landscape Architects).

That’s just fantastic, congratulations! We also need to think about aligned government policy to support these innovations. What are some of the changes you have seen for this agenda?

Government policy is critical, and I’m pleased to say this research has and continues to shape NSW Government initiatives such as Greening Our City, Cool Suburbs, Heat-Smart Planning, and the Greater Sydney Heat Taskforce. Our project outputs are used by Adapt NSW to improve community resilience against heat and even by developers that integrate our findings in their master-planned suburbs.

Heat-mapping work undertaken for Penrith City Council (PCC) led to statutory changes in the Council’s Development Control and Local Environmental Plans in 2021. PCC introduced controls on building design and materials, landscaping, tree canopy, and cooling systems to mitigate urban heat. This was a first in Australia and subsequently the Council won the 2022 Climate Change Resilience Award from the Planning Institute of Australia.^[4] The award recognises projects and initiatives that provide outstanding leadership and/or innovation that makes a positive impact on addressing climate change. The change in PCC policy is evidence that the research has contributed heat-resilient city design, the beneficiaries of which will be the residents and future residents of the local area.

Research recognition  

The impact of this research has been confirmed through several award-wining urban cooling demonstration sites: the UV-smart Cool Playground (2021), Cool Roads (2021), Green Track for Parramatta Light Rail (2022, winning several state and national awards from the Planning Institute of Australia and the Australian Institute of Landscape Architects), Cool Green Parking (2023). Every year since 2020, this research has produced several hundred headlines in print and online media worldwide, including Bloomberg Green, the New York Times and the Washington Post, reaching an estimated annual readership of 1 billion people.

SDG Alignment

Our Urban Heat program highlights the importance of cross-sectoral collaborations, including connecting industry and policymakers with new and emerging technologies (SDG9) that support climate mitigation and adaptive capacities (SDG 13) for our cities and suburbs (SDG 11).

Additional Resources

ABC News. (2022). Why Australia’s suburbs are so hot. https://www.youtube.com/watch?v=ONaqsKxu-gU

ABC Radio National. (2025). Roundtable: Climate-proofing our homes and communities. https://www.abc.net.au/listen/programs/lifematters/roundtable-climate-proofing/102667724  

Australasian Green Infrastructure Network. (n.d.). Creating healthy, liveable, climate resilient communities through Green Infrastructure. https://www.agin.org.au/ 

Pfautsch, S., Rouillard, S., & Wujeska-Klause, A. (2024). Suburban microclimate and how to improve it. https://researchers.westernsydney.edu.au/en/publications/suburban-microclimate-and-how-to-improve-it  

Pfautsch, S., & Wujeska-Klause, A. (2021). Guide to climate-smart playgrounds: Research findings and application. https://researchers.westernsydney.edu.au/en/publications/guide-to-climate-smart-playgrounds-research-findings-and-applicat 

Pfautsch, S., Wujeska-Klause, A., Piracha, A., Paolini, R., van den Nouwelant, R., & Morrison, N. (2022). Despicable urban places: Hot car parks. https://researchers.westernsydney.edu.au/en/publications/despicable-urban-places-hot-car-parks 

United Nations. (2025). Press briefing: Antonio Guterres, Secretary-General… https://webtv.un.org/en/asset/k1v/k1vrvdjpbr