Climate change research warns of increasing daily extreme heat hours

Research published in ‘Nature Climate Change’ and conducted by scientists from the UK, US, and China warns that global warming is significantly extending the duration of extreme heat episodes. Analyzing meteorological data from 1981 to 2023, researchers found that extreme heat hours—defined as temperatures exceeding 90 percent of historical records for that specific hour—have increased by 62 hours per decade.

Under a high-emissions scenario, hot days could see an additional four hours of extreme heat by the end of the century, potentially reaching 21 hours of intense heat per day. Even in moderate emission scenarios, these hours are expected to triple. This trend threatens to eliminate the natural thermal relief typically provided by nighttime temperature drops, increasing the risk of thermal collapse and cardiovascular complications.

Human impact is expected to rise sharply, with the number of people affected projected to increase by 369 percent in moderate scenarios and 481 percent in worst-case scenarios. Vulnerable regions include Southeast Asia, East Asia, Africa, and Western Europe. Experts emphasize the need for urban planning reforms and changes to outdoor labor schedules in sectors like construction and agriculture to prevent heat-related mortality.