Vanishing Alpine glaciers could weaken late-summer water supplies

As Alpine glaciers retreat, some communities could lose an important source of late-summer river flow and drinking water, BR24 reports. The effects are likely to be greatest in dry areas within the Alps, while lower-elevation regions generally rely on other sources.

Hot summers and a dry winter have accelerated the melt. Since 2022, almost one-fifth of glacier ice in the Swiss Alps has disappeared, and the Schwarzmilzferner, the last glacier in the Allgäu Alps, had almost completely melted by 2026.

Jörg Drewes, who heads the chair for urban water systems at the Technical University of Munich, said the European Alps are warming about twice as fast as the global average. As glaciers shrink, more exposed land warms, contributing to the loss of glaciers and permafrost.

Glaciers help maintain minimum flows in rivers in late summer, after snow reserves have melted, Drewes said. If they disappear, that flow will be lost. In higher Alpine areas, glacier runoff can also supply local drinking water, so communities may need to prepare for its decline.

Christoph Mayer of the Bavarian Academy of Sciences said inner-Alpine dry zones depend more heavily on glacier meltwater than wetter regions. The water is used for irrigation and can also enter drinking-water supplies through bank filtration. Most glaciers in the Eastern Alps are expected to disappear by 2050, he said; those in the Western Alps could last about 50 years longer because the mountains are higher.

In the Traunstein water management office’s district, the Watzmann and Blaueis glaciers each cover about two and a half hectares. Bernhard Lederer, the office’s head, said they have little significance for the water balance and are expected to disappear by 2030 at the latest. The region gets most of its drinking water from wells that draw on groundwater.

Rivers including the Salzach, Inn and Rhine also benefit from glacier runoff, particularly during hot, dry summers, Lederer said. Direct glacier water is not generally used for drinking water at lower elevations; it flows into rivers, seeps into the ground or replenishes groundwater.