Human-Induced Climate Change Made Australia's January Heatwave Five Times More Likely
New scientific analysis has revealed that human-caused global heating made the intense heatwave that affected much of Australia in early January five times more likely to occur. The research from World Weather Attribution (WWA) suggests that in the current climate, Australians should expect heatwaves similar to the January event approximately once every five years.
Unprecedented Heat Across Multiple States
The heatwave earlier this month represented the most severe temperature event since the devastating 2019-20 black summer, with temperatures soaring above 40°C in major cities including Melbourne and Sydney. Regional areas of Victoria and New South Wales experienced even hotter conditions, while extreme heat also affected Western Australia, South Australia, and Tasmania.
In Victoria, the extreme temperatures preceded bushfires that ultimately burned through 400,000 hectares of land and destroyed nearly 900 buildings. The temperature profile and driving weather system for January's extreme heat showed similarities to the 2009 south-east Australian heatwave, which significantly exacerbated bushfire conditions during that period.
Climate Crisis Outweighs Natural Weather Patterns
The WWA report indicates that the effect of greenhouse gas emissions outweighed the cooling influence of a weak La Niña weather pattern, which typically brings milder temperatures across most of mainland Australia. According to the analysis, the climate crisis made the extreme heat approximately 1.6°C hotter, while the La Niña likely lowered maximum temperatures by between 0.3 and 0.5°C.
"There was definitely a signal of human-induced climate change behind this event," stated report co-author Professor Sarah Perkins-Kirkpatrick, a climate scientist at the Australian National University. "The mentality here of 'suck it up, she'll be right' does not fly any more. The heat is getting worse and whether we like it or not... there's ultimately a limit to what we can actually physically cope with."
Deadly Consequences and Future Projections
Heatwaves—defined as three consecutive days where maximum temperatures exceed average levels—cause more deaths in Australia than all other natural hazards combined. Professor Perkins-Kirkpatrick explained that heat-related health impacts are often insidious, with effects becoming apparent days after the event and frequently exacerbating underlying medical conditions.
The report's authors warn that if global temperatures rise to 2.6°C above pre-industrial averages—a level predicted to be reached by century's end based on current emissions—similar heat events could occur every second year. Friederike Otto, WWA co-founder and professor of climate science at Imperial College London, emphasized that "as extreme heat is one of the deadliest extreme weather events that is changing very fast with global warming... it is important to highlight these rapid changes."
Scientific Methodology and Immediate Analysis
World Weather Attribution, an international collaboration of scientists, employs established techniques using weather observations and climate models to analyse the role of human-caused global heating in extreme weather events. While the methods are well-established, Professor Otto noted that the specific heatwave study has not yet undergone peer review, as the group makes results available within days and weeks following extreme weather events to provide timely information.
This analysis underscores the accelerating impact of climate change on weather extremes and highlights the urgent need for climate adaptation strategies to protect vulnerable populations from increasingly frequent and severe heat events.
