Glaciers in Switzerland lost around 5.5% of their ice volume during the 2025–2026 hydrological year, recording their second-largest annual loss after the record set in 2022, amid repeated heatwaves and declining snow cover in the Alps.
The Swiss Glacier Monitoring Network, GLAMOS, and the Swiss Academies of Arts and Sciences announced the findings on 1 October 2026. The data show that the retreat of the ice is accelerating, with nearly one-fifth of Switzerland’s glacier volume disappearing in just five years. The loss has affected the thickness of the ice masses, with the average thickness of some glaciers falling by between 2.5 and 4 metres.
Record melting on the Great Aletsch and Rhône glaciers
The retreat reached around 10 metres in some parts of glacier tongues during the summer. These are the lower extensions of glaciers into valleys. The Great Aletsch and Rhône glaciers, along with others, recorded their greatest melting since measurements began for each of them, although the overall loss across Switzerland remained slightly below the record level recorded in 2022.
Heatwaves contributed to higher melting rates, with every month from May to September 2026 experiencing at least one heatwave. By September, snow had disappeared even at an altitude of 3,500 metres, depriving the ice of a cover that helps protect it from sunlight and heat.
Human-induced warming worsens snow loss
The official scientific report ‘Switzerland’s Climate 2025’, issued by MeteoSwiss and the Swiss Federal Institute of Technology Zurich, attributes most of the warming observed in the country to greenhouse gas emissions from human activities, with other factors making smaller contributions.
The report forecasts that heatwaves, summer droughts and the decline in winter snow will continue to intensify as the planet warms. Pressure on glaciers increases when reduced snow accumulation in winter coincides with higher summer temperatures, because their survival depends on the balance between accumulation and melting seasons. The effects of shrinking ice extend to freshwater supplies.
A study published in the journal Nature Climate Change in 2018 found that rising temperatures initially cause larger quantities of ice to melt, increasing the flow of water into rivers. But continued melting gradually reduces the reserve itself, diminishing its ability to provide water in the future even as temperatures remain high.
That water helped ease the effects of the drought at the time, but at the expense of the reserve capable of feeding rivers in subsequent years. These changes affect agriculture, electricity generation and river navigation, sectors that experienced direct consequences during the 2022 drought.
That year, restrictions were imposed on domestic and agricultural water use, while hydropower generation declined and navigation on the River Rhine was disrupted because of low water levels. Glacier melt is not the only factor behind drought, as rainfall, snowfall and evaporation rates also play key roles, but it demonstrates the importance of glacier reserves in easing water shortages.
Meltwater lakes warn of flash floods
The retreat brings another risk: meltwater accumulating in lakes in front of retreating glaciers.
The water could surge suddenly if the natural barriers containing it collapse, exposing the area to flash floods before it faces increasing water shortages as the ice masses continue to shrink.
