New research led by Monash University sheds a new perspective on forecasts of future rainfall in Victoria, showing that recent dry conditions may not fully reflect long-term climate change signals.
The study, published in Theoretical and Applied Climatology, highlights the important role of natural climate variability in shaping recent rainfall patterns, and how this influences expectations for the future.
Research by Scott Power, Adjunct Professor at Monash University's School of Earth, Atmosphere and Environment and the University of Southern Queensland, shows that how we interpret future rainfall depends not only on climate model projections, but also on how unusual recent decades have actually been.
"While many aspects of climate change are clear and well-established, including rising temperatures, sea levels, and more frequent heatwaves, regional rainfall is different," Professor Power said.
"This difference arises because natural rainfall variability can be large relative to the impact of greenhouse gases on rainfall.
"To understand projected changes for Victoria, we therefore need to carefully consider how much of the recent drying reflects long-term climate change versus natural variability."
The study introduces a new analytical framework that combines observational data with climate model output to assess how past variability affects future projections.
Using observations and results from 38 global climate models, the analysis found that natural variability may have played a substantial role in early 21st century rainfall declines in south-east Australia.
"If recent conditions were driven in large part by natural variability, then rainfall in coming decades may be higher than what we've experienced recently, unless climate models are seriously underestimating the drying influence of increasing greenhouse gases," Professor Power said.
While uncertainty remains, and further research is needed, this new approach provides a clearer picture of how natural variability and climate change affect past and future rainfall change.
The findings have practical implications for policymakers, planners, and industries relying on climate projections, particularly in water resource management and agriculture.
Read the research paper: https://doi.org/10.1007/s00704-026-06227-6
