Daniel Kebede, general secretary of the National Education Union (NEU), said classroom temperatures exceeded 40°C during repeated heatwaves this summer, forcing hundreds of thousands of students to be sent home. He described the level of distress among members as comparable to the Covid-19 pandemic.
Kebede said schools were "built for a different climate" and required urgent adaptation ahead of what forecasters predict will be an El Niño-charged summer next year. He called on the government to launch a mass retrofitting programme to ensure buildings can stay cooler.
In an interview with the Guardian, Kebede proposed a series of structural changes that he said merited a "really serious discussion". These include moving the school year to give a longer summer holiday, as is common in hotter countries; adopting earlier start and finish times; and shifting examination periods away from the hottest part of the year.
"There needs to be a really serious discussion about how we make sure there is the continuity of education in this changed climate," he said.
Kebede said he was inundated with messages from teachers during the summer urging the union to act. "The last time I felt that level of panic in the profession was during the Covid pandemic," he added. "I was being routinely contacted by members in distress … they felt there was a real risk and danger to themselves and to their pupils."
The union's call comes as the UK faces increasingly severe heatwaves linked to climate change, with the Met Office warning of heightened temperatures driven by a strong El Niño event.