Guest Post: Like rivers in the sky: the weather system bringing floods to Queensland will become more likely under climate change

Kimberley Reid, The University of Melbourne and Andrew King, The University of Melbourne

The severe floods in southeast Queensland this week have forced hundreds of residents to flee the town of Gympie and have cut off major roads, after intense rain battered the state for several days. The rain is expected to continue today, and travel south into New South Wales.

We research a weather system called “atmospheric rivers”, which is causing this inundation. Indeed, atmospheric rivers triggered many of the world’s floods in 2021, including the devastating floods across eastern Australia in March which killed two people and saw 24,000 evacuate.

Our recently published research was the first to quantify the impacts these weather systems have in Australia, and another study we published in November looked closely at the floods in March last year

We found while atmospheric rivers bring much-needed rainfall to the agriculturally significant Murray-Darling Basin, their potential to bring devastating floods will become more likely in a warmer world under climate change.

Storms and flooding for Melbourne Cup day, but media dares not mention climate change

Melbourne Cup day dawned with rain falling. Storms escalated with torrential rain through the morning. Power outages, train disruptions, flashflooding of stations and many low lying roads across the city eventuated. But the mainstream media failed to add 2 + 2 with the influence of climate change in this extreme weather event.

The previous day racing officials had ordered more racetrack irrigation overnight to reduce the firmness of the track. Perhaps they should have checked the weather forecast.

Intense rain events are becoming more frequent, the science is clear not only from models but also observational data. Part of the reason for this is a Warmer atmosphere that can carry more moisture. For every 1 degrees Celsius of warming the extra atmospheric carrying capacity is increased by an extra 6-7 per cent. So heavier rain. That means more flash flooding.