Switzerland’s glaciers lost 5.5% of their ice volume in the 2025–26 monitoring year, the second-largest percentage decline on record, according to figures released on October 1 by Glacier Monitoring Switzerland, known as GLAMOS, and the Swiss Academy of Sciences. Researchers linked the loss to a winter with little snow followed by unusually hot, dry weather across the Alps.
The new figures show that almost one-fifth of Swiss glacier ice has disappeared since 2021. The 2026 decline was smaller than the record loss in 2022, but the monitoring bodies said the pace of retreat over the past five years is more than twice that of any earlier measured five-year period. The figures describe the monitoring year ending on September 30, rather than a calendar-year total.
According to the research summary provided by ETH Zurich, the 2025–26 winter was among Switzerland’s ten least snowy on record. Heat and dryness from May through September left glaciers exposed: the freezing level rose above 4,000 meters on 76 days, more than twice the usual number, and snow was absent even at 3,500 meters by September. Winter snow normally shields old ice from summer heat and supplies material for new ice.
GLAMOS reported average ice-thickness losses of about 2.5 to 4 meters on measured glaciers, while some lower glacier tongues lost as much as 10 meters. The Rhône, Aletsch and Clariden glaciers recorded their greatest measured melt, and small glaciers including Bella Tola and Griessfirn disappeared completely, according to the ETH Zurich account of the findings.
From July through September, the glaciers released about 2.2 trillion liters of water, more than four times Swiss households’ annual drinking-water use, the researchers estimated. That melt can ease shortages during dry summers, but GLAMOS director Matthias Huss told Reuters that the benefit diminishes as the glaciers shrink. Swiss ice also helps feed major European river systems, making the retreat relevant beyond the country’s borders.
The monitoring group said continued warming threatens the long-term survival of Alpine glaciers. Its measurements provide a new benchmark for assessing future losses, water availability and changes to mountain terrain. Researchers will continue to survey the remaining ice as the next winter’s snowfall and subsequent summer temperatures determine how much further the glaciers retreat.
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