Anthropogenic climate change amplifies autumn heatwave risks for children during school reopening

School reopening typically occurs in early autumn in many Northern Hemisphere countries, with dates varying by region, yet emerging autumn heatwaves have increasingly disrupted school activities and heightened children's heat exposure risks in recent years. However, human influences on children’s exposure risk to such autumn heatwaves remain unclear. Here, we take an exceptional autumn heatwave in 2024 in China as an exemplary case and carry out an attribution and projection study based on a refined storyline-probability combined framework. We revealed that internal climate variability (atmospheric circulation and soil moisture) and the thermodynamic effect of anthropogenic climate change contribute 70.9% (48% and 23%) and 24.6% to the intensity of this heatwave, respectively. Model simulations suggested that anthropogenic climate change has increased such heatwaves by 514 times in frequency and 2.1°C in intensity under the 2024 climate. Even under the scenario of the 2°C target of the Paris Agreement, the frequency and intensity of such heatwaves near the end of this century are projected to further increase by 5.2 times and 0.9°C, respectively, than present. Both thermodynamic effects of anthropogenic climate change and anthropogenically induced changes in atmospheric circulation are likely responsible for these increases. Anthropogenic climate change increased the children’s exposure risk to 2024-like heatwaves by approximately 55% under the 2024 climate and population. Under a high emission scenario, future heatwave exposure risk will decrease first due to the rapidly declining children population; but will turn to increase in the end of the century due to the strongly increasing intensity of 2024-like heatwaves. These findings highlight the urgent need for emission reduction and child-focused adaptation.