Exclusive data obtained by Guardian Australia reveals stark disparities in heat vulnerability across major Australian cities, with western Sydney and outer suburbs of Melbourne, Adelaide, and other cities at highest risk. The Heat Vulnerability Index, developed by RMIT researchers, combines satellite temperature readings with data on susceptible populations, built environment, green space, and socioeconomic factors.
Dr Melanie Davern, director of the Australian Urban Observatory, explained that vulnerability is not solely about land surface temperature. Factors such as age, pre-existing health conditions, income, and the built environment all contribute. For instance, older adults sweat less and struggle to cool down, while those with cardiovascular or respiratory diseases are more susceptible to heat.
A separate Monash University study found that heatwaves caused 1,009 deaths in Australia between 2016 and 2019, with higher mortality in communities with more elderly residents, those needing assistance, or lower income and education levels. The index also highlights unexpected hotspots like Carlton and Fitzroy in Melbourne, and Woolloomooloo and Rushcutters Bay in Sydney, which score highly due to heat sensitivity factors despite being relatively affluent.
Dr Qian (Chayn) Sun, who developed the indexes, noted that heat sensitivity measures community susceptibility, while adaptive capability reflects individual ability to mitigate heat, such as affording air conditioning. The maps show that vulnerability cuts across socioeconomic lines, though areas of greater advantage tend to have lower vulnerability overall.
Satellite data confirms that many vulnerable areas, such as Brimbank in Melbourne’s west, exhibit a clear urban heat island effect, with higher land surface temperatures exacerbating the risk.
