Building evidence that effective Heat Alert Systems save lives in southeast Australia

In the January 2009 heatwave, a prototype heatwave alert system had just been introduced, based on research identifying a threshold temperature above which excess mortality occurred in Melbourne, Australia. By the time of the January 2014 heat wave, the heat alert system had been considerably refined, based on further scientific work (2–4) and intense interactions between climate scientists and public health authorities. The excess mortality associated with the 2014 heat wave was substantially lower than in 2009, even though the 2014 heat wave lasted longer.

The heat alert system relies on predicted daily temperatures routinely provided by the Bureau of Meteorology. When the temperature at any time in the next seven days is predicted to exceed the threshold identified as triggering excess mortality, a heat wave alert is issued to local government authorities, emergency services, the health and aged care sectors, government departments and agencies, and major metropolitan service providers. Media briefings also alert the general community to the actions that could be taken to minimize health risks associated with high temperatures. The recently increased quality of the temperature forecasts issued by the Bureau of Meteorology in Australia means that these forecasts provide credible warning of heat waves. This increased forecast quality, and the introduction of heat wave alert systems, have come at an important time, as record heat waves become more frequent and severe. Without the improved weather forecasts and the scientific work to develop credible heat wave alert systems, continued global warming will lead to excess deaths.