Global warming raises triple threat
An “extreme of extremes” combination of three potentially devastating weather phenomena is tipped to occur more often as climate change takes hold – and Australia may be one of the worst-hit countries.
Researchers say the frequency of an extreme positive Indian Ocean Dipole (IOD) being followed by an extreme El Nino and an extreme La Nina, will rise from one in 187 years to one in 48.
Under such conditions, Australia could expect to suffer severe drought and heatwaves, then a rapid switch to heavy rainfall and destructive flooding.
Wenju Cai, lead author of a paper published in Nature Climate Change, told insuranceNEWS.com.au there is only one recent example of the three conditions combining – 1997-99.
“Australia got very lucky that time but the global impact was huge,” he said. “More than 250 million people were displaced in China and half of Bangladesh was flooded.”
Dr Cai says Australia had a taste of potential impacts in 1982/83/84, which fell slightly short because the positive IOD was not extreme.
“We had the Ash Wednesday bushfires in 1983 and floods in 1984,” he said. “We do not want this combination to happen.
“Our predictions are based on business-as-usual emissions, and we would be only too happy to be proved wrong.”
The Bureau of Meteorology says the current El Nino has continued to strengthen and is now mature. It will almost certainly last into next year.
The IOD is currently neutral, with three out of five international models indicating a switch to positive in spring.