Record-breaking heatwaves projected to last a millennium even after net zero target is reached

by Simon Mansfield
Sydney, Australia (SPX) Nov 27, 2025
Researchers from the ARC Centre of Excellence for 21st Century Weather and CSIRO, publishing in Environmental Research: Climate, forecast that hotter and longer heatwaves will become prevalent for at least the next 1,000 years, regardless of when net zero emissions is reached.

Using climate models and supercomputers, the team simulated how heatwaves would respond over a millennium after the global net zero milestone, analyzing scenarios where net zero is delayed between 2030 and 2060 in five-year increments.

Co-author Dr Andrew King of the University of Melbourne reported that heatwave events, once rare, will increase in occurrence and intensity the longer net zero is postponed. He stated, "This is particularly problematic for countries nearer the equator, which are generally more vulnerable, and where a heatwave event that breaks current historical records can be expected at least once every year or more often if net zero is delayed until 2050 or later."

The simulations revealed that heatwaves become systematically hotter, longer, and more frequent as global net zero is delayed. Extra warming from the Southern Ocean could worsen heatwaves even after net zero is reached.

Most simulation scenarios showed little or no reduction in heatwave severity over the entire 1,000-year window and, in some cases, regions exhibited continued increases in heatwave intensity if net zero occurs after 2050.

Lead author Professor Sarah Perkins-Kirkpatrick from the Australian National University commented, "While our results are alarming, they provide a vital glimpse of the future, allowing effective and permanent adaptation measures to be planned and implemented." She emphasized that rapid progress to permanent net zero, preferably by 2040, will be critical to limiting future heatwave severity.

Dr King noted, "Investment in public infrastructure, housing, and health services to keep people cool and healthy during extreme heat will very likely look quite different in terms of scale, cost and the resources required under earlier versus later net zero stabilisation. This adaptation process is going to be the work of centuries, not decades."

Research Report:Heatwaves in a net zero World

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