Australia could see decades-long ‘megadroughts’, scientists warn

Megadroughts are exceptionally severe, long-lasting, and widespread drought events, spanning multiple decades or even centuries

Australia could face “megadroughts” lasting for more than 20 years in the future, a new study has warned.

The latest study painted a worrying picture of future droughts in Australia that researchers say could be far worse than anything in recent experience.

Megadroughts are exceptionally severe, long-lasting, and widespread drought events, spanning multiple decades or even centuries.

Researchers from the Australian National University (ANU) and the Centre of Excellence for Climate Extremes say their findings are before factoring in human impact on the climate since the Industrial Revolution.

Co-lead author Dr Georgy Falster, from the ANU Research School of Earth Sciences, said that if a megadrought occurred in Australia today, the consequences would be made even worse because of the climate crisis, as any drought would occur against a backdrop of hotter weather.

“The combination of climate change on top of naturally occurring megadroughts that could last for 20 years means that in the future Australia could see droughts that are worse than anything in recent historical experience,” Dr Falster said.

“We must consider, and prepare for, the possibility that one of these multi-decade megadroughts could occur in the near future.

The study focused extensively on the Murray-Darling Basin, Australia’s largest agricultural region, to assess the potential severity of future droughts. It revealed that the basin, already vulnerable to water scarcity, could experience droughts lasting for centuries, occurring once every 150 to 1,000 years.

The researchers used multiple climate models to simulate droughts that occurred during the past millennium – from the year 850 to 2000 – to determine how they might change in the future.

This includes predicting how long Australian droughts could last for, and how dry they could be.

“One of the confronting findings of our work is that it is possible for droughts in Australia to be much longer than any of the droughts that we’ve experienced in recent times. Droughts that continue for 20 years or more are something that we should expect to happen,” Dr Falster said.

Researchers say megadroughts are part of the natural variations in Australia’s climate. But what’s worrying is that we are now also “adding human-caused climate change into the mix, and that is probably increasing the chances of the next megadrought here,” Dr Falster said.

Co-author of the study, professor Nerilie Abram also from ANU, said: “The only thing we can do to lessen the potential severity and length of future droughts is to rapidly reduce greenhouse gas emissions. For example, by rapidly transitioning to renewable energy sources.”