Olivia Henry
Australian Science Media Centre
As the east coast floods Australia faces a third consecutive La Niña year, the eastern states are bearing the brunt of the signature wet conditions with heavy rains and widespread flooding across northern Tasmania, central and northern Victoria, and southern inland New South Wales.
The extreme weather has destroyed hundreds of properties, and has also seen rescues and evacuations along the Maribyrnong River in Melbourne’s west.
Thousands are also under evacuation orders for flooding in NSW and Tasmania.
Although much of the eastern seaboard has faced the brunt of these La Niña events over the past three years, Dr Margaret Cook from the University of the Sunshine Coast says Victoria and Tasmania has faced relatively little flooding up until now.
“These heavy rains are unusual,” she says.
“Dense cloud bands have crossed the desert, carrying moisture evaporating from seas off north-west Australia. Rain has fallen across almost the entire continent in the last two weeks. Our rain events are usually regional – not national.”
These wetter-than-normal conditions are due to a combination of the ongoing La Niña event as well as a negative Indian Ocean Dipole (IOD) and positive Southern Annular Mode (SAM), all of which encourage rainfall, according to Dr Agus Santoso from the UNSW Climate Change Research Centre.
“A negative IOD tends to see higher than normal rainfall over southeastern Australia, such as Victoria”, he says.
“Extreme rainfall generating weather systems, which can occur at any times, can lead to flooding especially given the already wet conditions and saturated catchments.”
While Dr Santoso expects these conditions to weaken in the summer, many experts are concerned for the lives and homes already destroyed and at risk, particularly as many affected are underinsured or not insured at all.
East coast floods secondary impact
According to Professor Paula Jarzabkowski from the University of Queensland, “Australia [is] one of the most prone countries to secondary disasters from climate change, like flood and bushfire [and] is also one of the most under-insured of comparable economies.”
This is because, as climate change increases the likelihood of such cascading weather events, Australians also likely to see similar cascades in rising insurance costs and plummeting property value.
“Many Australians are uninsured or underinsured for flood because each time it floods, their premiums go up. At a certain level that becomes unaffordable so they take the risk of going without insurance. That’s not a risk that they as individuals can afford,” Professor Jarzabkowski says.
“Each time an uninsured property floods, society has to pay to help those people make good. At the same time, the wealth and viability of those owners to contribute economically to society is reduced.”
This spiral could lead to about one in 25 Aussie homes being uninsurable by 2030. Because of this, experts are pushing for new housing standards to future-proof Aussie homes and make them more resilient to climate change.
Until then, Dr Santoso urges Aussies to keep an eye on the alerts and predictions.
“The La Niña event is currently expected to weaken in summer. A negative IOD does not typically last beyond spring. The SAM has been in a positive phase and is expected to continue in the coming weeks. The SAM is not very predictable beyond weeks”, he says.
“Stay updated with the weather forecast, be alert and stay safe.”
You can read the full AusSMC Expert Reaction here.