Level 1 — Absolute Beginner

Switzerland is a country with high mountains. The mountains have big rivers of ice. We call them glaciers. The glaciers are melting very fast.

In 2026 the Swiss glaciers lost 5.5 percent of their ice. In the last five years they lost almost 20 percent. That is one fifth of all the ice.

One small glacier is now gone. Its name was Plattalva. It disappeared in September. Scientists say it is dead. The Aletsch glacier is the biggest in the Alps. It melted more in 2026 than in any other year.

Why is this happening? The summer was very hot. There were many heatwaves from May to September. The winter before it had very little snow. Snow protects the ice from the sun. Without snow, the ice melts quickly.

glacier

A very large, slow moving mass of ice in the mountains.

melt

To change from ice into water because of heat.

percent

A part of one hundred, used to show an amount.

disappear

To stop being there.

extinct

No longer existing at all.

Alps

The large mountain range in central Europe.

heatwave

A long period of very hot weather.

protect

To keep something safe from harm.

Level 2 — Elementary

Swiss scientists have published their yearly check on the country's glaciers, and the numbers are bad. In 2026 the glaciers lost 5.5 percent of their total volume. Added together, the last five years have removed almost 20 percent of all Alpine ice in Switzerland. The Swiss Academy of Sciences called it a catastrophic year.

The measurements come from GLAMOS, the national glacier monitoring network, led by Matthias Huss. In some areas the average thickness of the ice dropped by between 2.5 and 4 metres in a single year. At the lowest measuring point on the tongue of the Aletsch glacier, the largest in the Alps, 13 metres of ice thickness were lost. Both the Aletsch and the Rhone glacier recorded their most intense melting ever measured.

One glacier did not survive at all. The Plattalva glacier in canton Glarus vanished in September and has been declared extinct. The loss has a special sadness for scientists, because in the 1950s Plattalva hosted what was probably the most detailed glacier monitoring programme in the world, and its measurements from 1947 to 1985 form an exceptional record.

Two things caused the damage. Winter snowfall was well below the long term average at every altitude, so the ice began summer with almost no protective cover. Then heatwaves arrived again and again between May and September, and the zero degree line in the atmosphere sat above 4,000 metres for 76 days, a record and more than double the usual figure. Between July and September alone, Swiss glaciers released about 2,200 billion litres of water, more than four times the amount all Swiss households drink in a year.

volume

The total amount of space that something occupies.

catastrophic

Extremely bad and causing great damage.

monitoring

Measuring and watching something regularly over time.

thickness

How deep or thick something is from one surface to the other.

tongue

The long lower end of a glacier where it flows downhill.

canton

One of the regional states that make up Switzerland.

altitude

Height above sea level.

household

A group of people living together in one home.

Level 3 — Intermediate

Every autumn the Swiss glacier monitoring network GLAMOS, working with the Swiss Academy of Sciences, publishes a figure that functions as a national thermometer. This year the figure is 5.5 percent: that much of the country's remaining glacier volume disappeared during 2026. Stack the last five annual losses together and nearly a fifth of Swiss Alpine ice has gone since 2021. The academy described the year as catastrophic, which is unusually blunt language for a scientific body.

The detail is more striking than the headline. Average ice thickness fell by 2.5 to 4 metres across some regions in twelve months. On the tongue of the Aletsch glacier, the largest ice body in the Alps, the lowest monitoring station recorded 13 metres of thinning. Aletsch and the Rhone glacier, two of the most photographed and most studied ice masses in Europe, both posted the most intense melt rates ever recorded for them; the Rhone lost four metres of thickness between the middle of June and the middle of July alone. Matthias Huss, who directs GLAMOS, now oversees a network measuring a system in visible retreat.

The Plattalva glacier in canton Glarus did not make it to October. It vanished during September and has been formally declared extinct. Its disappearance carries archival as well as physical weight: in the 1950s Plattalva was the site of what was probably the most detailed glacier monitoring programme anywhere in the world, and the continuous series it produced between 1947 and 1985 remains an exceptional dataset. Perhaps 30 small glaciers may have been lost across Switzerland in the summer of 2026 alone, and 160 disappeared between 2016 and 2023.

Two mechanisms drove the melt and one unexpectedly restrained it. Winter snowfall came in well below the long term average at all elevations, leaving too thin a protective layer to reflect the summer sun off the ice beneath. Then heat arrived repeatedly from May through September, holding the zero degree isotherm above 4,000 metres for 76 days, a record and more than twice the average. Working the other way, less Saharan dust settled on the snowpack than usual, so more sunlight was bounced back into the atmosphere, which moderated the melting slightly. That, plus marginally better snow cover, is why 2026 ranks second rather than first in the record books, behind 2022. The hydrological consequence is immediate: between July and September the glaciers discharged roughly 2,200 billion litres of water, more than four times the annual drinking water consumption of every Swiss household combined.

retreat

The gradual shrinking and withdrawal of a glacier up its valley.

blunt

Direct and without softening language.

thinning

A reduction in thickness, measured vertically.

archival

Relating to stored historical records.

dataset

An organised collection of measurements used for research.

Level 4 — Advanced

The annual assessment compiled by GLAMOS, the Swiss glacier monitoring network, in conjunction with the Swiss Academy of Sciences has acquired the character of a national audit, and the 2026 edition reads as a write down. Switzerland's glaciers surrendered 5.5 percent of their residual volume over the hydrological year, consolidating a five year contraction of close to 20 percent. The academy's choice of the word catastrophic is notable chiefly because scientific institutions are ordinarily so careful to avoid it.

Granular measurements carry more weight than the aggregate. Mean ice thickness declined by between 2.5 and 4 metres across certain regions in a single season. At the lowest monitoring point on the tongue of the Aletsch, the largest glacier in the Alps and the reference body for the entire range, 13 metres of thickness were lost. Both the Aletsch and the Rhone registered their most intense ablation on record, the latter thinning four metres between mid June and mid July, and the hydrological signature is correspondingly extreme: between July and September Swiss ice discharged on the order of 2,200 billion litres, exceeding the annual potable consumption of the entire Swiss domestic sector by a factor of more than four. Matthias Huss, who directs the network, is measuring a system whose retreat is now legible without instruments. Giovanni De Cesare, who heads the Hydraulic Constructions Platform at EPFL, has examined the downstream implications for a country whose hydropower and summer river flows are partly glacier fed.

One entry has been removed from the register entirely. The Plattalva glacier in canton Glarus vanished during September and was formally declared extinct, a loss with a peculiar historiographical sting: in the 1950s Plattalva supported what was in all probability the most intensively instrumented glacier monitoring programme on earth, and the continuous series it yielded from 1947 to 1985 remains among the finest records in glaciology. Roughly 30 small glaciers may have been extinguished nationally in the summer of 2026 alone, against 160 lost between 2016 and 2023, and more than a thousand, some 40 percent of the national inventory, over the past half century.

The attribution is unambiguous and only slightly complicated. Winter accumulation fell well short of the long term mean at every elevation band, depriving the ice of the high albedo mantle that normally shields it through the ablation season, after which repeated heatwaves from May to September held the zero degree isotherm above 4,000 metres for 76 days, more than double the climatological average and a record in its own right. The one mitigating factor was counterintuitive: reduced Saharan dust deposition left the snowpack brighter than usual, raising reflectivity and trimming melt at the margin. Combined with slightly better residual snow cover, that is why 2026 finishes second to 2022 rather than first, its glacier loss day falling on 29 June against 26 June four years earlier. A 2025 study concluded that absent drastic emissions reductions, half of all Alpine glaciers could be gone within two decades. The Plattalva entry suggests the timetable is not theoretical.