April 15, 2026
South-eastern Australia experienced its wettest spring on record in 2022, leading to widespread and prolonged flooding. Previous research from our Hub has shown that large scale climate drivers can promote persistently wet conditions across eastern Australia in winter and spring.
Building on this, our latest CS Hub 5.4 Project Verification study asks a more detailed question: can the extreme rainfall in spring 2022 be fully explained by known climate drivers and human-caused climate change? How predictable was the extremity?
Using both statistical analysis and a state-of-the-art seasonal forecast system (ACCESS-S2), we find that the combined effects of La Niña, a negative Indian Ocean Dipole, a positive Southern Annular Mode, and long-term greenhouse gas warming explain a substantial portion of the unusually wet conditions, but not all of it.
Importantly, even with favourable ocean conditions already in place, the unusual atmospheric conditions further enhanced the potential for heavy rainfall, with a large-scale pressure pattern that enhanced moisture transport, record-strong winds aloft over Australia, and more rainfall associated with weather systems.
Together, these findings extend previous work by showing that while multi-year La Niña conditions set the stage for high rainfall, the extremity of the 2022 spring event depended strongly on atmospheric dynamics, highlighting the need to consider both oceanic drivers and atmospheric variability when assessing future climate risk in a warming climate.
Read the full paper > Zhou, Lim, Hope, Young, Pepler and Simmonds (2026) DOI https://doi.org/10.1007/s00382-026-08122-2
