Megadroughts are exceptionally severe, 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.
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.”