Swiss glaciers have suffered a near-record loss of ice in 2026, with more than 5% of the country’s remaining glacier ice disappearing in the past 12 months as intense summer heatwaves take their toll on Alpine peaks.

Scientists described the 5.5% loss as “extraordinary” and warned that such rapid melting could threaten water supplies for farming, hydropower and transport in the decades ahead, reports BBC.

Glacier loss can also destabilise mountain slopes and increase the risk of landslides and, in extreme cases, flash flooding.

Scientists said long-term glacier thinning and thawing frozen ground likely contributed to the risks behind Nepal’s August flooding, although the event was triggered by the collapse of a large area of bedrock and glacier ice.

The latest report’s notable finding is not that Swiss glaciers are shrinking, which is expected in a warming climate driven primarily by fossil fuel emissions, but the pace of the loss. Until recently, Alpine glaciologists considered losing 2% of ice in a year “extreme”.

“It’s really just disastrous,” said Dr Matthias Huss, director of Glacier Monitoring Switzerland, which produced the report.

Swiss glaciers entered summer with less snow than usual following a mild winter. Much of that snow disappeared during intense heatwaves in May and June, exposing the darker glacier ice beneath, which absorbs more of the Sun’s energy and accelerates melting.

“Ten years ago, I wouldn’t have thought that it’s possible to lose glaciers so quickly,” said Dr Fabien Maussion, a glaciologist at the University of Bristol who was not involved in the report.

“What’s happened over the summer now is extremely distressing… but at the same time it was to be expected from a climate scientist’s perspective,” he added.

Meltwater from glaciers can provide an important source of water for irrigation, hydropower and shipping during hot, dry conditions. Scientists estimate Swiss glaciers released 2.2 trillion litres of meltwater between July and September.

While that helped ease water shortages this summer, it has rapidly depleted the frozen supply. Smaller glaciers may not be able to replenish water levels to the same extent, Huss warned.

“Every drop of water that runs off during these heatwaves is kind of old water that’s been stocked in the glacier ice centuries or decades ago,” he said. “It’s helping us [now] but it’s unsustainable, so we won’t have it at [our] disposal in the next heatwave.”

The River Rhine reached record lows in places this summer, affecting shipping routes and increasing transport costs.

Researchers also found no snow remaining at measurement sites as high as 3,500 metres above sea level, where temperatures are lower and glaciers are typically snow-covered.

“At some glaciers we’ve seen four metres of ice loss at the highest point, where they should be covered by several metres of winter snow at this time of the year,” Huss said.

Snow is essential to glacier growth as it eventually compacts into ice. If no snow survives the summer, it cannot replace ice lost through melting at lower elevations, causing glaciers to shrink and eventually disappear.

“Glaciers are complex because they gain mass at the top and they flow downstream, so there is a lot of physics,” Maussion said. “But in its simplest form, what we see right now is that we took an ice cube out of the fridge and it’s just melting in front of our eyes.”

Scientists say the climate is now too warm for many Alpine glaciers to survive. Some, including Plattalva in eastern Switzerland, have already disappeared.

However, researchers stress that sharp cuts to carbon emissions could still save much of the world’s glacier ice, particularly in the Himalayas and polar regions where most of the planet’s ice is found.

“There we still can make a big difference with protecting the climate,” Huss said. “If these ice masses can be saved or stabilised, we can limit the rise of global sea levels… which could affect billions of people living along the coast.”