A sailboat puts out of bay amid rain in Sydney, Australia, on March 1, 2022. The torrential rainfall, which began in the nation's most populous city Sydney last week and has since moved north into southern Queensland, has already claimed eight lives and seen thousands stranded. (Xinhua/Bai Xuefei)
SYDNEY, March 1 (Xinhua) -- As Australia's east coast experiences some of its worst rainfall and flooding in recorded history, scientists have flagged the extreme weather may be the nation's new reality amid climate change.
The torrential rainfall, which began in the nation's most populous city Sydney last week and has since moved north into southern Queensland, has already claimed eight lives and seen thousands stranded.
Local resident from one of the worst hit towns, Lismore in northern New South Wales (NSW), Harvey Nelson told Xinhua that people across his town have been stranded on roofs and unable to contact emergency services due to a backlog of requests.
"Every year we get warned and told to evacuate and it's never been this bad," said Nelson. "Even people who have never had floods are now being caught."
The Bureau of Meteorology recorded that the Wilsons River, which runs through Lismore, rose to a historical high of 14.4 meters on Monday afternoon. The second worst flood event saw the river reach 12.3 meters in 1954.
A rain gauge near the town registered a staggering 775 mm of rain in the 24 hours to 9:00 a.m. on Monday morning.
Lismore Mayor Steve Krieg told local news outlet ABC on Monday that as many as 1,000 people could still be trapped and awaiting rescue in the town, with around 400 calls for help yet to be answered.
Kimberley Reid, PhD researcher from the University of Melbourne's School of Earth Sciences, told Xinhua that the catastrophic downpour is the result of a build-up of "atmospheric rivers".
"An 'atmospheric river' is just a region of really strong moisture transport. It's like a highway of moisture," said Reid.
When the "river" hits a low-pressure system, it is lifted into the air before dumping huge amounts of water in a short period of time; the longer the moisture has been building, the more water that is released.
Reid said another important factor when it comes to assessing flooding is the amount of moisture in the soil.
Australia's uncharacteristically wet summer due to a La Nina weather event in the Pacific Ocean has meant that soil has been unable to absorb any more rainfall, further exacerbating flash flooding.
"Since October last year, southeast Queensland has had above average soil moisture. So, when these heavy rains come in, all that rainfall just goes on to the surface," said Reid.
She added that these weather events may become up to 80 percent more likely by the end of the century if global warming is not curbed, citing the common approximation that the atmosphere can hold 7 percent more water vapor for every degree of temperature increase.
"Climate change is really affecting how much moisture the atmosphere can hold, and there is a lot more uncertainty regarding the setup of the weather system," said Reid.
Expert in urban design and planning, Professor Elizabeth Mossop from the University of Technology Sydney, told Xinhua that as climate change increases the frequency and severity of severe weather, Australia would need to treat the mitigation of floods as part of its "business as usual" and not just a one-off disaster.
"Where we are doing new development, we have to do that in such a way that we are not going to aggravate or make the flood conditions even worse," she noted.
She said this would likely mean building houses away from flood plains and using less concrete in areas where soil is needed to soak up flood waters. She added that the most important thing was controlling the flow of water, and redirecting it away from humans.
"We need more green space, more floodable space around these major drainage areas, so that the water can rise without causing damage," Mossop said.
She said that while it was important to provide immediate help to people impacted by the floods, it was also important to provide ongoing, direct support through existing community programs.
According to her, displacement amid floods is one of the most damaging things socially, because people lose their networks and they lose their social support.
"People are often worried about sandbags, and rebuilding houses and things like that, but the social and psychological impacts are often incredibly important," she added. ■
People walk past the Sydney Opera House amid rain in Sydney, Australia, on March 1, 2022. The torrential rainfall, which began in the nation's most populous city Sydney last week and has since moved north into southern Queensland, has already claimed eight lives and seen thousands stranded. (Xinhua/Bai Xuefei)
People walk amid rain in Sydney, Australia, on March 1, 2022. The torrential rainfall, which began in the nation's most populous city Sydney last week and has since moved north into southern Queensland, has already claimed eight lives and seen thousands stranded. (Xinhua/Bai Xuefei)
A woman walks amid rain in Sydney, Australia, on March 1, 2022. The torrential rainfall, which began in the nation's most populous city Sydney last week and has since moved north into southern Queensland, has already claimed eight lives and seen thousands stranded. (Photo by Hu Jingchen/Xinhua)
A man walks amid rain in Sydney, Australia, on March 1, 2022. The torrential rainfall, which began in the nation's most populous city Sydney last week and has since moved north into southern Queensland, has already claimed eight lives and seen thousands stranded. (Photo by Hu Jingchen/Xinhua)
The Sydney Opera House is seen amid rain in Sydney, Australia, on March 1, 2022. The torrential rainfall, which began in the nation's most populous city Sydney last week and has since moved north into southern Queensland, has already claimed eight lives and seen thousands stranded. (Xinhua/Bai Xuefei)