If you were in Sydney in January, chances are (or rather, bad luck is) that you experienced the most severe heatwave since 2019. Sydney’s summers will produce scorching heat, not just warmth, more frequently from now on than they did just a few decades ago. So what really happened this year, and where to go from there?
When it comes to climate change, some numbers are easy to remember, for all the scary reasons. For example, globally, the last 11 years have been the hottest on record, and the last three years have been hotter than the previous eight.
In Sydney, the intense heat on 7-9 January brought temperatures of 42.2°C on Observatory Hill and 42.5°C in Penrith. Even the fact that the La Niña cycle was meant to bring naturally cooler weather did not matter.
The World Weather Attribution estimates that such intense heatwaves could now occur every five years in Australia’s southeast. It was also five times more likely to occur at all than if human activities had not unequivocally altered the planet’s climate since pre-industrial times.
Heatwaves impact our health. Vulnerable populations often fail to recognise the dangers of severe dehydration, exposure to poor-quality air and an overwhelmed cardiovascular system. In a telling fashion, the Royal Melbourne Hospital observed a 25% increase in the number of patients struggling with heat during the January episode.
Importantly, we have learnt from previous experiences. This summer, we employed early warning systems and avoided major power outages (even when using air conditioning heavily across the state by powering the grid with renewable energy sources.
Beyond the obvious need to reduce carbon emissions on a global scale, we know how to prepare even better, locally, for future heatwaves: green our cities, cool our roofs, provide thermally safe housing and working conditions everywhere, including in often-overlooked rural areas.
Decades ago, scientists warned humanity about the impacts of climate change. Today, we have the foresight and the technical means to implement change and adapt to what we know with certainty will happen again soon.
Let’s see how we fare in about half a decade.
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References
- World Meteorological Organization, press release 14 January 2026.
- Clarke et al. (2026) Climate change eclipses La Niña cooling in Australia to drive extreme heatwave and heightened fire risk (WWA scientific report No. 80) World Weather Attribution; doi: 10.25560/127151.
- IPCC, 2023: Summary for Policymakers. In: Climate Change 2023: Synthesis Report. Contribution of Working Groups I, II and III to the Sixth Assessment Report of the Intergovernmental Panel on Climate Change [Core Writing Team, H. Lee and J. Romero (eds.)]. IPCC, Geneva, Switzerland, pp. 1-34; doi: 10.59327/IPCC/AR6-9789291691647.001
- Yenetti et al (2020). Urban Overheating and Cooling Potential in Australia: An Evidence-Based Review. Climate (8, 126); doi:10.3390/cli8110126.
