Scientists warn heatwaves will intensify for 1,000 years even after net zero

Published in Environmental Research: Climate, the work draws on climate modelling 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 1,000 years once global emissions finally reach net zero.

Long-Term Climate Projections Reveal Escalating Risks

To explore potential futures, researchers selected a range of net zero dates between 2030 and 2060. They then calculated how heatwave behavior changes for every five-year delay in achieving that goal.

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

"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," Dr. King said.

Worsening Heatwaves for Centuries After Net Zero

The analysis shows that delayed emissions cuts lead to heatwaves that grow hotter, last longer, and strike more frequently. The 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 1,000-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.

Net Zero Will Not Guarantee Cooler Conditions

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

"While our results are alarming, they provide a vital glimpse of the future, allowing effective and permanent adaptation measures to be planned and implemented," Professor Perkins-Kirkpatrick said.

"It is still vitally important we make rapid progress to permanent net zero, and reaching global net zero by 2040 at the latest will be important to minimize the heatwaves severity."

Urgent Need for Adaptation and Faster Emissions Cuts

Dr. King said the research highlights how crucial it is to reduce emissions quickly while preparing for a world where extreme heat becomes increasingly difficult to manage.

"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 stabilization. This adaptation process is going to be the work of centuries, not decades," Dr. King said.