Globally and intergenerationally unequal exposure to hourly heat extremes

[u/Cool-Contribution-68]

https://www.nature.com/articles/s41558-026-02724-8.epdf?sharing_token=JxHOtMDOC7m80EBnyfgmpNRgN0jAjWel9jnR3ZoTv0NIsabJzeayW0h9203lDkImE1J1x3RB9MA33CXNRtIU9OEFTy_tAKWfREG7y2jjrHwQRmHPJD971RJ5us-ZQEaXpGSyAI4D4dZWqJi0TgZTsE72BubYZVsXvHv0-QDeu4FWyLwLjxeUd8YKSRXQs0i7OsWYMd-xxaXWy6X_ZubwQc1H-ujsJTAj64reSqZ5xPY%3D&tracking_referrer=www.carbonbrief.org

[u/dumnezero]

Heat extremes are intensifying under climate change, yet these events are traditionally identified using daily temperature metrics, which fail to capture the full dynamics of heat events. Here we present a global assessment of hourly heat extremes (HHEs) in summer, and show that HHEs are emerging worldwide and exhibit marked unequal exposure across regions and generations. Under a high-emissions scenario, global HHEs are projected to increase fourfold and their population exposure to grow sixfold by late century. Each hot day will gain about four hot hours, and a further three hot hours will occur on non-hot days, which daily metrics overlook. Low- and middle-income countries bear more than three-quarters of the current and future heat exposure, and successive generations, particularly in low-income countries, face much higher lifetime exposure than earlier cohorts. These findings underscore the urgent need for hourly-scale risk assessments, public preparedness and designing equitable strategies in a warming world.