Urban overheating is a growing problem, and UNSW researchers have created a national index to measure and then mitigate heat vulnerability in Australia's towns and cities.
Between 1900 and 2010, extreme heat events have claimed more Australian lives than the total number of deaths from all other natural hazards combined.
Understanding heat vulnerability and selecting appropriate mitigation and adaptation strategies to reduce it has become increasingly important due to the impacts of climate change. It is now a policy and planning priority for all levels of government in Australia.
UNSW researcher Associate Professor Lan Ding is leading a project to create a National Heat Vulnerability Observatory Index (NaVHO) to provide a standardised approach to data collection and measurement of heat vulnerability in the built environment.
The index can identify areas where populations are more vulnerable to the adverse effects of urban heat and contribute to cooling interventions.
The data is then used to model the impact of different heat mitigation strategies and advise local authorities about which would be most effective in their locations.
“Addressing the impacts of urban heat vulnerability is critical for Australia to plan for resilient, sustainable communities to combat climate change,” Ding said.
“Concerningly, many of the places in Australia that are most vulnerable to extreme heat have been designed without enough of the features that mitigate heat, such as urban surface treatments, green spaces and trees with water irrigation, and water-cooling systems.
“This exacerbates the urban heat island (UHI) effect and thereby intensifies the health, economic and environmental impacts of extreme heat for these populations.”
The NaHVO is a partnership between the NSW Department of Climate Change, Energy, the Environment and Water and UNSW's High Performance Architecture team, and has an advisory committee with representatives from government, industry and academia.
It was set up in 2023 to develop national benchmark datasets and an innovative, robust and consistent methodology to measure heat vulnerability in Australian towns and cities.
“The NaHVO enables those responsible for communities, from the national government down to local government, to see and measure the effects of urban overheating. And, importantly, to receive advice on cooling strategies and location-specific data on the impact of implementation of these strategies,” Ding said.
The researchers have just completed phase 1 of the project, where they built town-specific datasets for areas of Dubbo Region and Maitland City measuring heat vulnerability. They then modelled the potential effects of heat mitigation strategies and other planning decisions on those locations.
In both cities the team were able to use the multi-disciplinary benchmark datasets to model how the use of cool materials (on roads, pavements and roofs) and increased urban greenery (through planting and irrigation) would reduce heat.
The project team also conducted ‘microscale’ cooling potential analysis as part of the pilot.
Modelling showed that the use of cool roofs, cool pavement, greenery with water irrigation, water-misting and outdoor shading could reduce air temperature by 1.6°C in the areas studied in Maitland and 2°C in the areas looked at in Dubbo and the surface temperature by over 10°C in each location.
Having successfully shown the impact of the NaHVO in Dubbo and Maitland the team is setting up to expand the project to a further 21 cities in Australia.
“The more cities we collect benchmark data from, the more robust the NaHVO will be,” Ding said.