The Australian Actuaries Climate Index provides a strong signal that the underlying Australian climate has changed, consistent with a warming climate, Index Lead Collator Rade Musulin says. 

The latest index shows conditions are “ripening” for a return of destructive bushfire seasons in Australia, with a significant drop in recent extreme rainfall and a rise in extreme temperatures. 

More broadly, the index – which measures any exceedance of the 99th percentile of the 1981-2010 reference period to gauge changes in the extremes – shows a trend toward more volatile weather patterns. 

“It shows a longer-term trend of an increasing frequency of extremes,” Mr Musulin said. “We need to think about how these things develop over time.” 

He expects significant temperatures to be recorded in Australia this summer. 

“It would be premature to say Australia is heading into heatwaves like those we’re seeing in places like Athens and Texas but given what … the Australian Actuaries Climate Index is telling us, it’s certainly time to be vigilant.” 

The Bureau of Meteorology declared an El Nino “alert” in May. In the past, an El Nino event has then developed around 70% of the time. 

The autumn Index readings show the beginnings of conditions that could eventually be conducive to strong bushfires, the Actuaries Institute says, driven by high levels of fuel availability after several years of wet weather – and a return to a drier, hotter El Nino phase and a likely positive Indian Ocean Dipole.  

“Conditions are primed for potentially high bushfire risk in the summers ahead,” Mr Musulin said. “Whether that starts in early 2024 or 2025 is unknown but we are heading in that direction. All the ingredients are there.”