October 20, 2025
This study looks at how spring rainfall in Australia (from September to November) might change in the future due to shifts in major climate patterns. The researchers used 33 climate models to see how these patterns (El Niño–Southern Oscillation (ENSO), Indian Ocean Dipole (IOD), and Southern Annular Mode (SAM)) might behave as the climate changes.
They grouped the models based on the most common changes they showed:
• 19 models suggest ENSO will become stronger.
• 15 models suggest IOD will become weaker.
• 22 models suggest SAM will become stronger.
They found that changes in SAM don’t depend on changes in ENSO or IOD, but changes in IOD are slightly linked to changes in ENSO.
When they looked at how rainfall might change based on these groupings, they found:
• Rainfall patterns linked to ENSO and SAM are likely to become more pronounced.
• Rainfall changes linked to IOD are more mixed and less clear.
• The effects vary depending on the region and which climate pattern is changing.
Importantly, the models consistently show that parts of south-west Western Australia and southern Victoria are likely to get drier, no matter how these climate patterns change. The study also looks at how rainfall might be affected when ENSO and IOD events happen together or back-to-back.
