Modelling by the ARC Centre of Excellence for Climate Extremes has forecast a bleak and worrying outlook for the future droughts Australia that will endure.
The study, published on Tuesday, warns of “exceptionally severe, long-lasting and widespread” megadroughts spanning more than 20 years, and with exacerbated impact due to climate change.
According to co-lead author Dr Georgy Falster, this could mean droughts that are worse than anything compared to Australia’s recent historical experience.
The ANU post-doctoral fellow explained that a megadrought experienced during hotter weather caused by climate change would be prolonged, and therefore required government and policymakers to prepare for multi-decade events.
“One of the problems with understanding protracted droughts in Australia is that our climate observations since the 1900s give us only a handful of examples to work with,” Falster said.
“This isn’t representative of the worst-case scenarios that are possible just through natural climate variations.”
“Thinking about when we might expect to see a 20-year-long drought in the Murray-Darling Basin in southeastern Australia, this varies a lot. We could see a megadrought occur every 150 years or 1,000 years,” she said.
A research team, co-led by ANU and the University of Sydney in collaboration with the University of New South Wales (UNSW), the University of Wollongong and the University of Monash, set out to predict how long future droughts could last for, and how dry they may become.
Researchers analysed how droughts may change, and how human-caused climate change would alter their characteristics by using multiple climate models to simulate droughts that took place between the years 850 and 2000.
“In this study, we paid particular attention to the Murray-Darling Basin. As the largest agricultural region of Australia, it’s important to know how bad droughts in this region could be, Falster said.
“We [also] compared simulated droughts in the 20th century, from the year 1900 to 2000, with those from the pre-industrial period, before the year 1850, to see if human-caused climate change has impacted how Australians experience droughts today.”
ANU’s Professor Nerilie Abram said that longer droughts in the areas of southwestern and eastern Australia, including the Murray-Darling Basin, were connected to human-caused climate change. These areas could expect less rainfall over the coming decades, she said.
“One example of this is the 21st century ‘Tinderbox Drought’, which was only three-years long but was exceptionally intense and set the conditions for the Black Summer bushfires.
“The Tinderbox Drought was likely made more severe by climate change,” Professor Abram said.
Rapidly reducing greenhouse gas emissions was the only way to lessen the potential severity and length of future droughts, Professor Abram added, including with policies that supported the rapid transition to renewable energy sources.
“We can also reduce the impacts of future droughts by being prepared with water storage and management plans, and community support networks.”
Findings were published in a special edition of Hydrology and Earth System Sciences on Tuesday.
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