A new study analyzing Mount Everest expeditions spanning more than a century has found that death rates among climbers have declined significantly in recent decades – despite a dramatic increase in the number of people attempting the world’s highest.
The research, “ Updates to Mortality on Mount Everest: 1921–2024 ”, published in the Journal of Physiology , examined expedition outcomes for more than 30,000 mountaineers who climbed above base camp. Researchers found that overall mortality above base camp declined from 1.4 per cent for the period 1921 to 2006 to 0.7 per cent for the period 2007 to 2024.
“This represents a substantial improvement in safety on Everest,” said Professor Kent Moore of the University of Toronto Mississauga, one of the study’s authors. “Advances in equipment, logistics, weather forecasting, and expedition support appear to be reducing risk—but the mountain remains inherently dangerous.”
The findings come at a time of unprecedented growth in climbing activity on Everest. More than three-quarters of recorded summit ascents have occurred since 2007, reflecting the rise of commercial expeditions and improved access to the mountain.
Despite increased traffic, the number of deaths declined in the modern era. Using the Himalayan Database, a comprehensive compilation of records for expeditions covering Everest and other peaks in the region, the study recorded 192 deaths between 1921 and 2006, compared with 117 deaths from 2007 to 2024. It found that mortality during spring summit attempts on standard routes fell from 3.0 per cent in earlier decades to 0.8 per cent in 2007 and 2024.
While overall mortality has decreased, the study highlights that the most dangerous phase for climbers remains unchanged: summit day. More than three-quarters of climber deaths from 1921 onwards have occurred during descent from extreme altitude. During this phase, climbers operate in the “death zone” above 8,000 metres, where oxygen levels are critically low and even minor impairments can quickly become life-threatening.
For sherpas and porters, who provide support to climbers, the most dangerous phase remains route preparation, with over 80 per cent of these deaths occurring lower on the mountain due to objective hazards such as avalanches.
In recent years, climbers were eight times more likely than sherpas to die during summit descent (0.8 percent versus 0.1 percent), suggesting that additional safety improvements may still be possible.
During the earlier period, about 25 per cent of deaths above 7000m were related to deteriorating weather. In contrast, no weather-related deaths were recorded between 2007 and 2024.
The study found that the nature of fatalities above 8,000 metres has changed. Deaths from falls and disappearances have decreased, likely reflecting the widespread use of fixed ropes and increased oversight among climbing teams.
However, many deaths are still classified as non-traumatic and lack a single, clear cause. Researchers note that a combination of hypoxia, exhaustion, dehydration, hypothermia, and altitude illness often contributes to fatal outcomes.
The authors emphasize that although Everest is safer than in previous decades, it remains an extreme and unforgiving environment.
“Most deaths still occur when climbers are severely impaired and rescue is difficult or impossible,” Moore states. “Preventing exhaustion and identifying problems early during summit attempts may be key to further reducing fatalities.”
The Journal of Physiology
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Updates to mortality on Mount Everest: 1921–2024
22-Apr-2026