In many countries across the Northern Hemisphere, school reopens in early autumn — a time that is supposed to offer a welcome break from the intense summer heat. After a long, hot summer vacation, children and families expect cooler, more comfortable weather for the return to school. However, in recent years, autumn heatwaves have increasingly disrupted this expectation, bringing dangerously high temperatures during the school reopening period and putting children’s health at risk.

A new study published in Weather and Climate Extremes investigates this growing threat. Led by Professor Qian Cheng’s group at the Institute of Atmospheric Physics, Chinese Academy of Sciences, in collaboration with researchers from China, the US, and the UK, the study focuses on the exceptional autumn heatwave that struck China from 1–10 September 2024. Using a refined storyline-probability combined framework, the team conducted an attribution and projection analysis.

“We found that human-caused climate change has already increased the frequency of such autumn heatwaves by more than 500 times and intensified them by more than 2°C under today’s climate,” said Professor Qian. “Even if we achieve the Paris Agreement’s 2°C target, children near the end of this century will still face heatwaves that are five times more frequent and nearly 1°C hotter than today — turning what should be a cool, comfortable return to school into a serious health hazard.”

The study also explains what “children’s exposure to heatwaves” means from a public health perspective. Children are more vulnerable than adults during extreme heat. Their bodies are less efficient at regulating temperature, they sweat less, and they often rely on adults to keep them cool and hydrated. When a heatwave strikes during school hours, children may be exposed to dangerous levels of heat in classrooms without air conditioning, on playgrounds, or during commutes. This exposure can lead to heat exhaustion, heatstroke, dehydration, and longer-term impacts on learning and development. In simple terms, exposure risk is the combination of how hot it gets and how many children are in harm’s way.

The study found that human-caused climate change has increased children’s exposure risk to 2024-like heatwaves by about 55% under current climate and population levels. Looking to the future, the trend becomes more complex. Under a high-emission scenario, children’s exposure risk will initially decline due to a rapidly decreasing child population — but toward the end of the century, the sharply increasing intensity of heatwaves will reverse this trend, causing exposure risk to rise again. Only under lower-emission scenarios (SSP1-2.6, aligned with the Paris Agreement) does exposure risk continue to fall.

These findings highlight the urgent need for both emission reductions and child-focused adaptation strategies — such as heat-resilient school buildings, flexible school calendars, and heat-health action plans.

Paper info:

Ye, Y., C. Qian*, A. Dai, S. Li, T. Li, X. Cui, J. S. Ji, and X. Zhang, 2026: Anthropogenic climate change amplifies autumn heatwave risks for children during school reopening. Weather Clim. Extrem., 52, 100892, https://doi.org/10.1016/j.wace.2026.100892