Flooding and Evacuations Continue in Australia
Tens of thousands of people are under evacuation orders in the southeast of Australia, including Sydney's suburbs, as heavy rains and flooding continue. The storm system is an east coast low: not a tropical cyclone, but a storm known to be damaging because it hangs over the coast for days at a time. As of yesterday, officials said they had conducted more than 1,000 rescues, 30,000 people remained without power, 13 people had died, and the cost of damages could top AUD 1 billion (USD 732 million).
Bureau of Meteorology: AskBOM - What is an East Coast Low?, June 20, 2016.
A Current Affair: Historic flooding swallows towns on Australia’s east coast, February 28, 2022.
Why This Matters
Climate change increases rainfall intensity and the chance of a downpour. So does the La Niña climate pattern, which brings milder temperatures to the Pacific near Australia and is a driver of the current, intensified storms. However, this week's rains are even more intense than expected from La Niña conditions alone. This tracks with this week's IPCC report predicting that Australia will experience increasing extreme rainfalls over the coming decades. In addition to the disruption and harm of flooded streets and homes, intense rains can increase erosion and overwhelm stormwater systems.
Guardian: Climate change is making floods worse - here's how, October 19, 2021.
A Watery Imbalance
As Australia has experienced, climate change doesn't just present the problem of too much or too little water. It creates a switch between drought extremes and intense, heavy rains. Warmer air speeds up evaporation and increases moisture, which leads to changes in precipitation patterns.
In the US, both heavy downpours and dry spells are becoming more frequent and extreme, according to a recent US Today investigation. For almost a week last June, storms along the Mississippi River broke at least 136 daily rainfall records, while eight states had at least three record-dry years. That increased intense rainfall leads to infrastructure damage and other costs. A study published last month found that flooding in the US will get 26% more costly by 2050, and that this financial burden will primarily fall on people of color.
"It's not a contradiction to have huge floods, unprecedented floods, and unprecedented heatwaves and droughts at the same time," Michael Mann, acclaimed author of The New Climate War and a climatologist at Penn State University, told USA Today.