Deadly climate change-fueled floods inundate Australia's east coast

For more than two weeks, Australia’s east coast has been inundated by a series of rainstorms so severe they’ve earned a foreboding moniker fit for today’s supercharged weather, “rain bombs.”

Threat level: So far, at least 22 people have perished in the floods, and tens of thousands have been forced to evacuate their homes.

Driving the news: Scenes of flash flooding turning city streets and country streams into raging rivers have played out from Queensland, including Australia’s third-largest city of Brisbane, south to New South Wales, including Sydney.

• The floods have been so severe they prompted Prime Minister Scott Morrison to declare a national emergency.

The big picture: Australia is perhaps the best example of a region that is now, thanks to a combination of natural factors and human-caused climate change, alternating between heat, drought and wildfires on the one hand, and heavy rains with flooding on the other.

• It’s exhibit A for the Anthropocene.
• "New South Wales was hit hard by the 2019-20 Black Summer bushfires, and now it is in the grips of another climate-driven disaster. The recovery time for communities and emergency services between events is shrinking," Simon Bradshaw, a researcher at the Australian Climate Council, told Axios via email.

Between the lines: Climate change worsens the downpours and associated floods, climate scientists tell Axios, with La Niña conditions in the Pacific also playing a significant role.

• Above average rainfall is common in eastern and northern parts of Australia during La Niña events. November 2021 was the country’s rainiest on record, soaking soils and helping set the stage for the flooding to follow.
• Atmospheric rivers are also playing a role. These narrow corridors of extremely moist air can fuel intense precipitation over land, especially if they stall over one area.

By the numbers: The rainfall amounts in Australia have been off the charts.

• The town of Doon Doon, New South Wales, received 1 meter of rainfall in 48 hours, for a total of about 42 inches. That’s the same as the annual average precipitation in Washington, D.C.
• Brisbane had three days, Feb. 26-28, with more than 7.9 inches each day, for a record three-day total of 26.6 inches.

• Flood levels in the town of Lismore in northern New South Wales reached 47.1 feet, about 6.6 feet higher than the previous record.

Context: A firm conclusion of climate change research is that intense precipitation events are becoming more common as the climate warms. This is partly because the atmosphere holds more water vapor with each degree of warming.

What they’re saying: “The amount of rainfall has been record-breaking,” said Kimberley Reid, a climate researcher at the University of Melbourne. Flooding in 2010-2011 had a similar geographical scope, Reid said.

• "Climate change is firmly embedded in the 2022 flooding emergency," Bradshaw said.
• Climate scientist David Karoly of the University of Melbourne was more nuanced in his take. “Both climate change and the occurrence of La Niña are likely to have contributed to the increased risk of heavy rainfall in southeastern Queensland in the current event," Karoly told Axios via email.
• "The difficult part is to precisely quantify the increase in risk or the contribution to the amount of rainfall.”

What’s next: ​​Flooding is continuing, with a long recovery ahead for the thousands with damaged or destroyed homes. In the coming decades, such events are likely to be more common and impactful.