A groundbreaking study conducted by researchers from the University of Queensland and Griffith University has revealed that urban residents in Australia face a significantly higher risk of death during heatwaves compared to their rural counterparts. The research, published in the Environmental Impact Assessment Review in March 2025, examined two decades of temperature and mortality data across Australia’s major cities, including Melbourne, Sydney, Adelaide, Brisbane, Hobart, Perth, and Darwin.
The study utilized the Heatwave Vulnerability Index (HVI) to identify regions most susceptible to heatwave-related fatalities. Even during mild heatwaves, there was a notable correlation between deaths and HVI scores in Australia’s capital cities. The far north and southern regions of Western Australia were highlighted as high-risk areas, alongside critical zones in the capital cities of Victoria, Queensland, and Tasmania.
The “heat island effect” in cities caused by the absorption and retention of heat in surfaces such as roads, buildings, and railway lines was identified as a significant factor in elevating urban mortality during extreme temperature events. This phenomenon mirrors trends observed in Greater London, where HVI data has been used to predict increased ambulance call-outs and mortality rates during heatwaves.
Lead author Patrick Amoatey emphasized that socioeconomic factors compound the risks for urban residents. “City dwellers with low income, low education, diabetes, and limited access to health services are at the highest risk of heatwave-related deaths,” Amoatey noted. This finding is especially concerning given that 70% of Australia’s population resides in urban areas.
The study’s alarming findings are underscored by a separate publication in Environmental Research Climate on January 27, 2025. That study examined the impact of human-induced climate change on heatwave-related mortality in Victoria during the 2009 southeast Australian heatwave. Over a five-day period, Victoria experienced approximately 374 excess deaths, with peak temperatures soaring 12-15 degrees above normal.
“Our results suggest that heatwaves with higher associated mortality rates will occur more frequently in the future,” warned Nicholas Osborne, one of the study’s authors.
Researchers hope their findings will serve as a wake-up call for health authorities and communities to prepare for the intensifying threat of extreme temperatures. By leveraging HVI data, officials can identify vulnerable populations and implement targeted interventions to reduce heatwave-related deaths.
As Australia grapples with the escalating impacts of climate change, this study underscores the urgent need for cities to adopt heatwave preparedness measures, including public education campaigns, improved access to healthcare, and urban planning strategies that mitigate the heat island effect.