New Delhi: Heat waves are no longer limited to short spells of extreme temperatures. They are increasingly developing into massive weather events that
can last for months, affect large parts of the planet and cause widespread damage to human life, agriculture and ecosystems.
A Reuters special report published on October 20 has identified these events as ‘heat storms’, a term used to describe exceptionally large and prolonged heat waves. The investigation analysed hourly temperature data from more than one million grid squares across the world, covering the period since 1960, and consulted two dozen meteorologists and climate researchers.
The findings point to a dramatic rise in the frequency and scale of extreme heat events, with climate change and successive El Niño episodes contributing to their expansion.
What are heat storms and how have they grown?
Reuters defines a heat wave as five or more consecutive days of abnormally high temperatures. A heat wave that covers at least 1 per cent of the Earth’s surface at its peak is classified as a heat storm under the investigation’s methodology.
In the 1960s, the world experienced an average of around five heat storms a year. In the current decade, that figure has risen to approximately 102 annually.
The largest heat storm on record, named Vera, lasted 367 days during 2023-2024 and affected nearly 85 per cent of the planet over its lifetime. At its peak on January 5, 2024, it covered 31.3 per cent of Earth’s surface.
The consequences were visible across continents. Temperatures at Mecca’s Grand Mosque reached 51.8 degrees Celsius during the annual Hajj pilgrimage, with more than 1,300 pilgrims dying amid the extreme heat. In Europe, soaring temperatures contributed to devastating wildfires in Greece. In the Philippines, intense heat made conditions unbearable for students in schools with limited air conditioning.
Heat storms have also affected agriculture. In Ivory Coast, prolonged heat and drought damaged cocoa production, while drought linked to extreme heat events in Spain contributed to poor olive harvests and a surge in olive oil prices.
New heat storm surpasses previous record
The threat has continued into 2026. Another major heat storm, named Raimundo, began on February 28 and has affected nearly three-quarters of the planet during its lifetime. On August 28, it covered 33.8 per cent of Earth’s surface at its peak, surpassing Vera’s previous record for the largest area covered at a single point in time.
Raimundo also brought intense heat to parts of Europe, fuelling major wildfires in Spain and France. The investigation found that both Vera and Raimundo passed over a melting glacier in Nepal before its collapse on August 26, which was followed by catastrophic flooding. Early indications suggest that rising temperatures contributed to the collapse, although the precise causes require further assessment.
The findings also highlight a decline in extreme cold events. Reuters’ analysis found that the area of the planet experiencing cold snaps or cold storms on an average winter day has shrunk by nearly 80 per cent since the 1960s.
