11 September 2025
Australia’s changing climate is shaking things up, literally. New research from the University of South Australia (UniSA) warns that increasingly intense La Niña weather cycles are posing fresh challenges for homeowners, builders, and infrastructure planners.
In a paper published in the Journal of Environmental Management, researchers reveal that prolonged rainfall linked to La Niña events is magnifying shrink-swell movements in expansive clay soils, which can destabilise house foundations, crack pipelines, and damage road pavements.
These soils expand when wet and contract during dry spells, creating a cycle of ground movement that’s becoming more severe and widespread.
UniSA researchers analysed more than 100 years of rainfall and climate data to track the impact of La Niña across Australia’s major regions. Their findings highlight a growing need to rethink how we build and maintain structures in a climate that’s becoming increasingly unpredictable.
The research, led by UniSA candidate Bikash Devkota, shows that:
- La Niña events have varied significantly, with prolonged periods of high frequency in the late 20th century, followed by a relative lull and a recent resurgence in the last 25 years.
- Expansive clay soils in particular are highly sensitive to rainfall fluctuations, making them vulnerable to swelling and shrinking during both La Niña and El Niño cycles, respectively.
- Homeowners, insurers and regulators need to consider long-term climate variability, not just short-term cycles, when assessing soil risks to building foundations.
Senior author, UniSA Professor Simon Beecham says that climate variability must be factored more directly into building standards and long-term planning.
“Even small shifts in climate cycles can lead to cracking, subsidence or costly repairs,” Prof Beecham says.
With more intense rainfall events and prolonged droughts predicted in future, researchers say it is imperative to prepare for greater extremes, ensuring that building codes and planning frameworks can adapt to uncertain weather conditions.
Changes in climate patterns have already significantly influenced geostructures around the world, including in Australia.
The La Niña event that occurred at the break of the Millenium Drought (1997-2009) caused damage to thousands of houses constructed during the drought, as soils expanded after a prolonged dry period.
“Climate change could significantly impact many homes across Australia but, to date, it hasn’t been considered in development strategies,” Prof Beecham says. “It’s time to think about it more seriously.”
‘The changing frequency of La Niña cycles and their effect on footing design in expansive soils’ is authored by Bikash Devkota, Md Rajibul Karim, Mizanur Rahman, Hoang Bao Khoi Nguyen and Simon Beecham. DOI: 10.1016/j.jenvman.2025.127124
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Contacts for interview:
Researcher contact: Professor Simon Beecham E: Simon.Beecham@unisa.edu.au
Media contact: Candy Gibson M: +61 434 605 142 E: candy.gibson@unisa.edu.au
