Intensifying Heatwaves Projected for Next 1,000 Years

New research warns that dangerously hot and prolonged heatwaves will increasingly become the norm if progress toward net zero carbon emissions continues to stall. The study, published in Environmental Research: Climate, draws on climate modeling conducted by scientists at the ARC Centre of Excellence for 21st Century Weather and CSIRO.

Using large-scale simulations on supercomputers, the team examined how heatwaves could evolve over the next one thousand years once global emissions finally reach net zero. Researchers selected a range of net zero dates between 2030 and 2060 and calculated how heatwave behavior changes for every five-year delay in achieving that goal.

According to University of Melbourne researcher Dr. Andrew King, the results were consistent across all scenarios. The later net zero occurs, the more often extreme and historically rare heatwaves appear.

Dr. King emphasized that this is particularly problematic for countries nearer the equator, which are generally more vulnerable. He noted that 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 analysis shows that delayed emissions cuts lead to heatwaves that grow hotter, last longer, and strike more frequently. Researchers also found that warming in the Southern Ocean could continue to intensify heatwaves for centuries, even after net zero is reached.

Across the full one thousand-year simulations, most regions showed no sign of returning toward pre-industrial heatwave conditions. Instead, heatwaves remained elevated for at least a millennium. In some cases, when net zero occurred in 2050 or later, heatwaves became even more severe over time.

Lead author Professor Sarah Perkins-Kirkpatrick from the Australian National University noted that the findings challenge a common assumption that climate conditions will gradually improve once emissions reach net zero.

She stated, while our results are alarming, they provide a vital glimpse of the future, allowing effective and permanent adaptation measures to be planned and implemented. It is still vitally important to make rapid progress to permanent net zero, and reaching global net zero by 2040 at the latest will be important to minimize heatwave severity.

Dr. King highlighted the urgent need for adaptation and faster emissions cuts, stating that investment in public infrastructure, housing, and health services to keep people cool and healthy during extreme heat will differ significantly based on when net zero stabilization is achieved.

This adaptation process is going to be the work of centuries, not decades.