City Residents Face Higher Risk of Heatwave Deaths

New research from the University of Queensland has revealed that human-induced climate change has led to a 20% rise in heatwave-related deaths. And if you live in a city, you’re at an even higher risk.

The study, the largest of its kind in Australia, found that people in urban areas—especially those with lower incomes, less education, or existing health conditions—are more vulnerable to extreme heat compared to those in regional areas. That’s because of the urban heat island effect—where roads, buildings, and railway lines absorb and trap heat, making cities significantly hotter than surrounding rural areas.

PhD candidate Patrick Amoatey, who led the study, said even lower-intensity heatwaves were linked to an increase in deaths. He believes a Heatwave Vulnerability Index, already used in other countries, could help Australian authorities predict spikes in ambulance callouts and mortality rates during extreme heat events.

“We already have useful tools and state-based action plans, but a vulnerability index could help communities better plan and build resilience,” he said.

So, what exactly counts as a heatwave? According to experts, it's three consecutive days where the maximum temperature sits in the top five percent for that area. And these events are only going to become more common.

"Our results suggest heatwaves with higher mortality rates will happen more often in the future," said Associate Professor Nicholas Osborne. "From a public health perspective, our studies can help guide decisions on health infrastructure and the workforce needed to cope with rising demand during heatwaves."

A separate study by researchers from UQ and the Australian National University looked at Victoria’s extreme heatwave in January 2009. During that five-day event, temperatures soared 12–15°C above normal, leading to an estimated 374 excess deaths.

Dr. Osborne said climate change had increased the death toll of that event by 20%.

“These findings align with other research showing heat-related deaths are rising due to human-induced climate change,” he said.

With cities home to 70% of Australia’s population, the study highlights the urgent need for better planning, public health strategies, and infrastructure to help communities withstand future heatwaves.