Rising temperatures could cancel most outdoor school sports in summer by 2060s

Japan Times

16-04-2025

School sports tournaments and club activities across Japan may need to be canceled for much of the summer by the 2060s as climate change pushes heat levels beyond safe limits, according to a joint study by the National Institute for Environmental Studies and Waseda University.
Millions of students across the country participate in school sports clubs, and thousands of heat-related illnesses have been reported almost every year since 2018.
Current Environment Ministry guidelines call for halting strenuous outdoor activities when the wet-bulb globe temperature (WBGT) remains below 28 degrees Celsius for less than two hours (referred to as Heat Level 1) and stopping all activities, indoors or outdoors, when it remains below 31 C for less than two hours (referred to as Heat Level 2). The WBGT is a measure that combines heat, humidity, wind and sunlight.
However, the study shows those thresholds could be reached much more frequently in the future, especially in regions that are already warm. The study warned that, in the coming decades, nearly three-quarters of the country could face conditions in which intense physical activities should be suspended for months at a time.
The study analyzed projected levels of the WBGT from 842 locations across Japan from the past 12 years. They split the country into eight regions and found that many would experience dangerous heat during peak school club activity hours, which are in the late afternoon.
In the worst-case scenario, with continued reliance on fossil fuels, six out of eight regions would experience Heat Level 2 requiring intense activities to be canceled at least once a week, and four zones would need to suspend all physical activities entirely.
Even under the most optimistic emissions scenario, five of eight climate zones would still require one to four months of restrictions on strenuous outdoor activities.
Common countermeasures, such as early morning practices or moving activities indoors, that are in place currently may reduce the risks, but the researchers found they would not be enough in the future. Even with these steps in place, up to four regions would still require monthslong restrictions under the worst-emissions scenario.
'If climate change progresses, continuing club activities in the same way as before will become difficult,' the researchers said.
They called for fundamental changes to how school sports are run, including shifting tournaments to cooler months and investing in indoor training spaces — steps that many regional schools may struggle to afford without government support.
Some national tournaments, such as the high-profile Koshien national high school baseball championship, have begun taking precautions by holding games in the morning and evening to avoid peak heat. However, local events often lack the resources to do the same.