'Cruel Heat' in Japan: Temperatures Above 40°C for Fifth Day Straight

Japan is grappling with an unprecedented heatwave, marking the longest period of extreme temperatures since comparable records began in 2010. For the fifth day in a row, temperatures have soared above 40°C (104°F) in several regions, prompting the Japan Meteorological Agency (JMA) to issue heatwave alerts. The country has introduced a new term, 'kokushobi' or 'cruel heat day,' to draw greater public attention to the dangers of the ongoing heat, although it does not trigger national-level official actions.

The intense heat has led to a significant increase in medical emergencies. Between July 13 and 19, nearly 11,000 people sought emergency medical care nationwide, with 14 individuals confirmed dead upon arrival at hospitals. The agency has urged the public to treat this heatwave as a "disaster."

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Scientists attribute the rising frequency and intensity of extreme heat events in Japan and globally to human-caused climate change. Last year, Japan endured its hottest summer on record, with a high of 41.8°C recorded in Isesaki on August 5, 2025. The nation aims to halve its annual heat-related deaths, which currently average around 1,300, by 2030.

Tokyo alone saw 453 hospitalizations due to heat on a single Thursday, a record for the past 16 years of data collection. The JMA's 'cruel heat day' designation, created in April, highlights the severity of the situation, underscoring the urgent need for adaptation and mitigation strategies in the face of escalating climate impacts.

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