Researchers have warned that Australia could be facing 20-year “mega-droughts” and that future dry periods may be “far worse than we imagined”.
A research team from Australian National University and The University of Sydney examined computer simulations of Earth’s climate over the past 1150 years.
“Worryingly, we found that given enough time, natural variability in Australian rainfall can produce ‘mega-droughts’ lasting 20 years or more,” they said.
“If we add in human-caused climate change, it suggests future droughts will be far worse than we imagined.”
The study revealed Australia had experienced a 39-year drought around 800 years ago.
However, during the 20th century, droughts in southwestern and eastern Australia were longer on average compared with pre-industrial periods.
“This change is consistent with the rainfall trends expected in these regions in future due to human-caused climate change,” they said.
“It suggests that an emerging human influence on our climate has already made southern parts of Australia more drought-prone.”
Despite the longer average droughts in the 20th Century, the research did not find significant difference in the intensity or recurrence of droughts between the different periods.
“The devastating impacts of Australia’s last major drought from 2017 to 2019, known as the Tinderbox drought, are a stark reminder of what we might expect in future,” the researchers said.
“The drought was likely worsened by human-caused climate change, and preceded the catastrophic Black Summer fires.”
“Our work highlights the need to consider the unthinkable when it comes to preparing for future droughts. This has implications for industry, governments and communities as they adapt to a warmer future.”
The research was conducted by Georgina Falster, Postdoctoral Fellow (Australian National University), Nerilie Abram, Chief Investigator for the ARC Centre of Excellence for Climate Extremes, Deputy Director for the Australian Centre for Excellence in Antarctic Science, Deputy Director for the Centre of Excellence for 21st Century Weather (Australian National University), and Nicky Wright, Research Fellow (University of Sydney).
More detail can be found on the ANU website.
