Dramatic shifts in fast-flowing air currents high above Australia are driving the country’s recent wave of severe droughts, heatwaves and catastrophic bushfires, according to new research published by academics writing in The Conversation.
The study, authored by Milton Speer and Lance M. Leslie, links major changes in upper-atmospheric jet streams to persistent rainfall deficits across southern Australia over the past decade. Researchers say the findings underscore how climate change is reshaping large-scale weather systems, with profound consequences for water security, agriculture and bushfire risk.
Jet Streams Shift South
About 8 to 10 kilometres above the Earth’s surface, narrow bands of powerful westerly winds known as jet streams steer rain-bearing systems across the continent. Historically, these systems delivered winter rainfall to southern Australia.
However, researchers found that since 2015, the subtropical jet stream has shifted roughly 10 degrees of latitude or about 1,000 kilometres further south toward Antarctica. As a result, winter cold fronts and low-pressure systems have tracked south of the mainland, bypassing key agricultural and population centres.
The shift has contributed to at least a 25% reduction in annual rainfall across southern Australia, leaving the region in the grip of prolonged drought.
“Our findings should be a wake-up call,” the authors wrote, warning that hotter and drier conditions are likely to persist as global warming continues to push atmospheric circulation patterns poleward.
Drought in the South, Flooding in the East
Southern Australia stretching roughly 4,000 kilometres from Perth to east of Melbourne and home to about 10 million people has experienced two major droughts in recent years: the 2017–2019 “Tinderbox Drought” and a second drought that began in 2023 and is ongoing into early 2026.
Six of the past ten years have been classified as dry in the region, with rainfall deficiencies lasting three months or longer and severely affecting agriculture, ecosystems and water supplies.
In stark contrast, eastern Australia including Sydney and Brisbane has experienced moderate to extreme wet conditions, with episodes of flash flooding. Researchers attribute this divergence to the repositioning of the jet streams, which has redirected rain-bearing systems away from the south and toward the east and north.
Mounting Pressure on Water Supplies
Major cities in southern Australia are already feeling the strain.
In Adelaide, three consecutive dry years have reduced inflows to reservoirs, prompting the city’s desalination plant to quadruple its output since early 2025. Perth, which has seen a long-term rainfall decline since 1970, operates two desalination plants and is constructing a third.
Melbourne’s water storages, which briefly recovered during the La Niña years from 2021 to 2023, have fallen to their lowest levels since the Tinderbox Drought. The city reactivated its desalination plant in April 2025, and a second facility is planned, though it may take nearly a decade to complete.
Despite brief rainfall relief in July 2025, extreme heat and record low precipitation between December 2025 and February 2026 have prolonged drought conditions across much of the south.
Low winter rainfall and parched vegetation have heightened bushfire risk across southern Australia. This summer’s extreme heatwaves, combined with dry westerly wind changes, have produced catastrophic fire conditions.
More than 430,000 hectares have burned in Victoria alone, according to the report, as drought-stressed landscapes became highly combustible.
The researchers warn that a potential El Niño event later in 2026 could intensify existing drought conditions. Melbourne’s water storage, currently at around 70% capacity, could fall significantly if dry conditions persist.
Climate Change Driving Atmospheric Change
The study builds on earlier research comparing atmospheric patterns between 1965–1992 and 1993–2020, which also showed a gradual poleward shift in jet streams. The latest findings suggest the most dramatic relocation has occurred in the past decade.
Scientists attribute the changes to rising greenhouse gas emissions, which are warming both the oceans and the atmosphere. As global temperatures continue to climb, the jet streams are expected to shift even further south.
The authors argue that policymakers, primary producers and communities must prepare for a future defined by more frequent and intense climate extremes.
“These conditions should be a jolting wake-up call,” they wrote, warning that southern Australia must brace for another hot, dry year ahead.