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ANZJPH study shows the benefits of heatwave warnings for our most vulnerable

ANZJPH study shows the benefits of heatwave warnings for our most vulnerable

Jeremy Lasek – PHAA

As Australia swelters through another scorching summer, a new report published in the Australian and New Zealand Journal of Public Health (ANZJPH) reveals the economic and health benefits of heatwave warning systems.

Already this summer, as of 25 January, Perth has broken heatwave records, with six consecutive days in the last month, and 11 total summer days reaching at least 40 degrees.

It’s resulted in catastrophic fire conditions and significant property damage for south-western WA.


To the east, Adelaide has been recognised as Australia’s hottest capital city, reaching 46.6 degrees in late January 2019. This eclipsed Melbourne’s 2009 recording of 46.4 degrees.

Warning those most at risk

A recent ANZJPH article, titled ‘Evaluating cost benefits from a heat health warning system in Adelaide, South Australia’ captures a one-week public health heatwave awareness campaign in 2019-20, targeted at vulnerable people (identified as the elderly, ill, homeless and outdoor workers) in the Adelaide community. The heatwave warning system requires personal contact with these people, where possible.

Providing context, the researchers note that, “the past five years have been the warmest in recorded history and the rise in global temperatures is exposing populations to record-breaking temperatures and more frequent heatwaves. In Australia, the frequency of extreme heat events has increased approximately fivefold since the 1950s.

“This heat exposure can have severe health consequences, particularly among vulnerable groups such as the elderly, outdoor workers and those with pre-existing illness or socioeconomic disadvantage. Over the past decade, state-based heat health warning systems (HHWSs) have been developed to integrate health system preparedness and emergency responses, and to provide early public warnings, timely advice and targeted support for vulnerable groups.”

Adelaide’s HHWS was devised after South Australia’s most deadly heatwaves in 2008 and 2009 when temperatures reached up to 45.7 degrees, resulting in a 16 per cent increase in ambulance call-outs, a three-fold rise in hospital admissions and 10 per cent increase in deaths. The evaluation was carried out by researchers from South Australia Health (SA Health) and the University of Adelaide, and is the first to assess the cost-benefit of an Australian heatwave warning system.

Benefits of HHWS activation

Adelaide’s HHWS is activated by the SA State Emergency Service (SA SES), “based on the BoM [Bureau of Meteorology] prospective three-day heatwave forecast”, and enacted by SA Health, the Red Cross, and local health networks.

The report found that, “The estimated cost for a one-week activation of the HHWS was A$593,000,” based on media advertising and staff costs. The campaign used various mediums for public health messaging, including:

  • Leaflets
  • Government agency websites
  • Television, Radio and Print media
  • Social media

Here’s a social media messaging example, by SA Health:

The research found a net benefit of up to $3.30 for every dollar spent, or $2 million, due to the following estimated reductions in health system burden:

  • 297 fewer ambulance call-outs
  • 119 fewer renal-related hospital admissions
  • 141 fewer heat stress hospital admissions
  • 279 fewer renal and/or heat related emergency department cases

The authors noted that, “the heat-related category incorporated admissions/presentations for dehydration, heat/sunstroke, and exposure to excessive heat.”

The biggest savings were for cuts to heat stress admissions ($750,000) and renal admissions ($643,000).


The ANZJPH article concludes: “Although heat warning systems have been implemented widely there is limited evidence about their health benefits and costs. This paper presents a descriptive assessment of the cost benefits of the South Australian HHWS intervention.

“Building on our previous evaluation of health benefits, we estimated potential cost savings from reduced morbidity that offset the estimated HHWS implementation costs by at least two-fold. On this basis, the SA HHWS represents a ‘no regret’ heatwave adaptation strategy.

“As temperatures rise, a dynamic system will be needed to respond to changing exposures and vulnerabilities, to drive heat adaptation, and to ensure that support is effective and appropriately targeted.”

Footnote: The ANZJPH study/article was jointly authored by Susan Williams, Monika Nitschke, Berhanu Yazew Wondmagegn, Michael Tong, Jianjun Xiang, Alana Hansen, John Nairn, Jonathan Karnon, and Peng Bi

Image: Pixabay/Pexels

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