Australia: Cyclones and Climate Change - Lethal Heating Editor BDA

There is strong evidence linking climate change to changes in cyclone behaviour affecting Australia, particularly demonstrated by recent events like Cyclone Alfred (March 2025). 

Here's the breakdown:

Climate Change Connection to Cyclone Intensity

1. Warmer oceans fuel stronger cyclones
   Sea surface temperatures off Australia's east coast reached record highs between October 2024 and February 2025, providing energy for Cyclone Alfred to intensify rapidly.
   Warmer waters increase wind speeds and rainfall capacity, with global studies showing cyclones now retain strength longer and move more slowly.
   
   
2. Increased rainfall intensity
   Alfred delivered up to 40% of Brisbane’s annual rainfall in 24 hours, a trend tied to climate-driven evaporation rates.
   For every 1°C of warming, rainfall intensity increases by at least 7%—a factor amplified in slow-moving cyclones like Alfred.

3. Higher storm surges
   Sea levels have risen 20 cm since 1900 due to fossil fuel emissions, exacerbating Alfred’s storm surge.
   This allowed floodwaters to penetrate further inland, threatening 20,000 homes in Brisbane alone.

Southward Shift in Cyclone Tracks

• Cyclone Alfred’s path toward Brisbane and northern NSW marks an unusual southward shift, attributed to expanding warm ocean zones.
  Research indicates cyclones are increasingly forming in subtropical regions due to:
  

  • Poleward expansion of warm ocean currents.
  • A 30 km per decade coastal creep in cyclone intensity zones since 1982.

• Southern cities like Brisbane lack cyclone-resistant infrastructure, heightening disaster risks.

Slower Cyclones = Prolonged Damage

Alfred’s slowed movement over southeast Queensland resulted from weakened steering winds—a phenomenon linked to climate-driven circulation changes. This caused:

• Extended heavy rainfall and flooding.

• Sustained wave heights exceeding 8 meters, worsening coastal erosion.

• Power outages and infrastructure strain affecting millions.

Scientific Consensus and Uncertainties

While the CSIRO notes that specific cyclone paths remain hard to attribute directly to climate change, key trends are clear:

• Fewer cyclones overall, but a higher proportion are severe (Category 3+).

• Slower decay over land, increasing inland flooding risks.

• The IPCC and Australian Academy of Science warn of more intense cyclones and southward expansion.

Policy Implications

Prime Minister Anthony Albanese’s assertion that climate change intensifies disasters aligns with Climate Council and ClimaMeter analyses, though CSIRO emphasizes nuanced attribution timelines. Regardless, Alfred’s impacts underscore the urgency of emissions reduction and adaptive infrastructure in southern regions.
Cyclone Alfred exemplifies how climate change is reshaping Australia’s disaster profile, demanding updated preparedness strategies for unprecedented weather extremes.

Links

• Cyclone Alfred More Intense and Destructive due to Climate Change
• Tropical Cyclone Alfred’s destruction driven by climate change
• Yes, Climate Change is pushing Australia’s cyclones southward
• Tropical Cyclone Alfred is slowing down – here’s why that makes it more dangerous
• Cyclone Alfred is slowing – and that could make it more destructive. Here’s how climate change might have influenced it
• Prime Minister Anthony Albanese’s statements on cyclone, climate change contradicted by CSIRO
• Fact Sheet: Tropical Cyclones and Climate Change
• Australia's changing climate
• Warm oceans, shifting winds: What is the science behind Cyclone Alfred’s strength?
• Tropical Cyclone Alfred – what the research says
• Here are seven things to know about tropical cyclones
• Tropical cyclone climatology