Yes, Climate Change is pushing Australia’s cyclones southward
The science is clear, climate change is pushing Australian cyclones further south. Events like Cyclone Alfred, currently bearing down on vulnerable cities like Brisbane and the Gold Coast.
Recent years have unleashed a flurry of “unprecedented” climate change fuelled disasters on Australian cities and communities. Bushfires, floods, heatwaves and drought.
Cyclone Alfred is presently bearing down on the communities of Brisbane, the Gold Coast, Byron Bay, Lismore and Coffs Harbour, and others. The impacts of climate disasters are certainly not foreign to these communities, but cyclones are a much rarer occurrence. Is the presence of Alfred this far south also attributable to climate change? Science suggests the answer is Yes.
What does the science say?
The scientific evidence is unequivocal. Recent years have set consecutive records for global temperatures. The ten warmest years on record all occurred in the last ten years. Last year, 2024, ranks as the warmest year on record, with the average global temperature increase exceeding 1.5 degrees for the first time.
I recently wrote about the advances being achieved in climate attribution science – the ability to establish the causal links between sources of greenhouse gas emissions, the warming of the planet and the devastating impacts caused by disrupted climate and weather systems.
While Alfred is far from the strongest cyclone to ever reach the Australian mainland, it is notable – and a cause of significant concern for the communities in its path – due to how far southward it has travelled. It is not unprecedented, but it is extremely rare for a cyclone to have Brisbane in its potential trajectory.
Science has long understood the link between climate change and the increased likelihood of Australian cyclones travelling further south. There are copious research papers that describe the changing climate dynamics and the expansion of the zone of potential cyclone vulnerability caused by global warming. A recently published special report by the Intergovernmental Panel on Climate Change (IPCC) warns of the “poleward” shift of cyclone intensity and the overall increase in cyclone severity.
Global warming is causing tropical weather conditions to stretch out increasingly further from the equator and with it, the warm ocean conditions that support the formation of cyclones, hurricanes and typhoons are encroaching on new population centres and putting an increasing number of people at risk.
A landmark report published by the Australian Academy of Science in 2021, outlines the scientific understanding of the risks posed to Australia under 3 degrees of global warming. The report concludes Australia faces more intense cyclones, and an expectation that the occurrence of cyclones will become more likely in southern parts of Australia’s east coast.
“Cyclones in the Australian region have increased in intensity but decreased in frequency over the past 30 years. Slow-moving and larger cyclones are projected in the future, leading to more extreme rainfall events and flooding. The height of storm surges and resulting coastal damage will continue to be exacerbated by sea level rise,” the Academy’s report says.
“Cyclone activity is increasing in south-east Queensland, northern New South Wales, and some West Australian sites (e.g. Shark Bay), demonstrating a southward shift.”
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The shift in cyclone behaviour could be devastating
Cyclone Alfred is an example of the vulnerabilities that become exposed as climate change pushes our climate and weather systems to new extremes. Global warming is pushing the path of extreme weather events towards new population centres that have rarely – and sometimes never – previously experienced such events.
As I type, Cyclone Alfred is expected to make landfall between Maroochydore and Brisbane after being downgraded to an ex-cyclone. Despite the downgrade, more than 250,000 properties have already lost power across Queensland and New South Wales, and communities throughout both States are being ordered to evacuate. Towns across the Northern Rivers region, including Lismore, are facing their third major flooding event in the last four years.
The potential for catastrophic damage in these increasingly cyclone vulnerable regions is considerable, with even comparatively “small” cyclone events able to inflict substantial damage on cities and regions that have never before been compelled to incorporate cyclone-proofing in city planning or disaster preparedness.
Some of the impacts of cyclones are obvious: they bring extreme rainfall, sea surges, flooding and damaging winds. But some impacts are less obvious and longer lasting: flood waters can foster disease, disrupt sewage systems and contribute to failures of electricity, telecommunications and drinking water supplies.
Crucially, for cities without a history of cyclones, the potential for damage is much higher. As infrastructure and critical services have never, or only rarely, had to deal with the disruption caused by cyclones, they are generally less prepared and less resilient to that disruption.
Earlier this week, Adjunct Fellow in the Climate Change Research Centre at UNSW, Dr Tom Mortlock, warned much of the future risk of cyclone impacts resides in the increasingly vulnerable southern regions.
“Tropical Cyclone Alfred is a reminder that tropical cyclones, while normally contained to north of the 25 degree parallel, can still track further south. Most tropical cyclones near Brisbane have been minor – the most damaging were Dinah in 1967 and Wanda in 1974. The 'Great Flood of 1954' – which resulted in large flooding for northern NSW and SE Queensland – was also caused by a tropical cyclone that made landfall just inside the Queensland border,” Mortlock said this week.
“While uncommon, most tropical cyclone risk actually resides in South-East Queensland. This is because there is significantly more exposure (people and assets) than there is further north, and so while the probability is lower, the risk (which is probability multiplied by consequence) is much greater.”
Insurance companies understand future cyclone risks, and it could cost you
While governments have been slow to respond to the climate crisis, corporations with money at risk have been under no illusions about the potential damage that a changing climate could cause.
As one example, Australia’s largest insurance company - Insurance Australia Group (IAG) – recognised the emerging risks inherent in predictions of more severe cyclones and an increased likelihood of cyclones travelling further south.
In its 2019 climate-related risk disclosures, IAG predicted that it would need to increase insurance premiums on properties due to the increased variability in weather and climate systems being driven by global warming.
“An illustration of this variability is the potential worsening risk of tropical cyclones impacting South East Queensland which could double at 2°C warming by as early as 2035 and triple at 3°C warming by as early as 2050. Further still, impacts at property level can vary significantly due to additional compounding effects of changes to flood risk, storm surge risk and sea level rise,” IAG’s report says.
“A temperature increase above 2°C could result in significant access and affordability issues. The increasing frequency and or severity of weather events, coupled with compounding effects of perils, may push some areas beyond affordability or indeed habitability.”
Recent analysis from climate risk firm Climate Valuation warned that as many as 1-in-10 Australian homes could become uninsurable, due to the combined effects of worsening fire, floods and cyclones.
The new normal
Unfortunately for all of us, events like Cyclone Alfred cannot be categorised as a ‘freak event’. The term is clichéd, but the scientific evidence makes clear how the risks posed by climate change are becoming very real and reflect a “new normal” – this includes cyclones reaching new parts of Australia.
It underscores the urgency of action to both limit a further worsening of the climate crisis and for measures to rapidly build protections and resilience to the climate impacts that are already locked in.
Please stay safe
If you are in a region impacted by Cyclone Alfred, please stay safe. The situation can evolve rapidly, and it is best to follow the instructions of emergency services.
Local ABC Radio stations are broadcasting emergency information. For emergency assistance call the Queensland State Emergency Service or New South Wales State Emergency Service on 132 500. The NSW SES website has further advice about how to prepare and what to do in an emergency.