New climate modeling indicates that heatwaves will become hotter, longer, and more frequent for centuries even after global net-zero emissions are achieved. Delays in reaching this goal exacerbate the risks, particularly for equatorial nations. The study emphasizes the need for rapid emissions reductions and long-term adaptation strategies.
Researchers from the ARC Centre of Excellence for 21st Century Weather and CSIRO have used supercomputer simulations to project heatwave trends over the next 1,000 years following net-zero emissions. Published in Environmental Research: Climate, the study examines scenarios where global net zero is reached between 2030 and 2060, assessing changes for every five-year delay.
The findings reveal that later achievement of net zero leads to more severe heat events. Heatwaves grow hotter, last longer, and occur more often, with no return to pre-industrial conditions in most regions for at least a millennium. Southern Ocean warming may continue to worsen heatwaves for centuries after net zero.
Dr. Andrew King from the University of Melbourne highlighted the disproportionate impact on equatorial countries, which face greater vulnerability. "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," he said.
Lead author Professor Sarah Perkins-Kirkpatrick of the Australian National University stressed the urgency of action. "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 noted. She advocated for net zero by 2040 at the latest to minimize severity.
Dr. King added that adaptation will require centuries of investment in infrastructure, housing, and health services, with costs varying by the timing of net zero. The research underscores that net zero alone will not immediately cool the climate, challenging assumptions of quick recovery.