Australia's Winter 2025-25 Heatwave Worst Since 2019-20's Black Summer, Made 5X More Likely By Global Warming

Human-caused global heating made the intense heatwave that affected much of Australia in early January five times more likely, new analysis suggests. The heatwave earlier this month was the most severe since the 2019-20 black summer, with temperatures over 40C in Melbourne and Sydney, even hotter conditions in regional Victoria and New South Wales and extreme heat also affecting Western Australia, South Australia and Tasmania.

In Victoria, the heat preceded bushfires that burned through 400,000 hectares and destroyed almost 900 buildings. A report by World Weather Attribution (WWA) suggests that the effect of greenhouse gas emissions outweighed the effects of a weak La Niña, which usually means milder temperatures across most of mainland Australia.

The report’s authors suggest that the climate crisis made the extreme heat about 1.6C hotter, while the La Niña likely lowered maximum temperatures by between 0.3 and 0.5C. “There was definitely a signal of human-induced climate change behind this event,” said Prof Sarah Perkins-Kirkpatrick, one of the report’s co-authors and a climate scientist at the Australian National University.

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In the current climate, Australians should expect heatwaves similar to the January event about once every five years, the analysis suggests. The report’s authors warn that similar heat events could be expected every second year if the world warms 2.6C above the preindustrial average, which is predicted to be reached by the end of the century based on current carbon emissions.

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https://www.theguardian.com/australia-news/2026/jan/23/australias-worst-heatwave-since-black-summer-made-five-times-more-likely-by-global-heating-analysis-finds