Glaciers in Switzerland lost 5.5 per cent of their ice volume this year, the second-biggest percentage drop on record, according to the GLAMOS glacier monitoring service and the Swiss Academy of Sciences.

Heat waves and low winter snowfall drove the loss. Over the past five years alone, the volume of ice in Switzerland has declined by nearly a fifth.

"Alpine glaciers have no chance of surviving in the long term under such conditions," GLAMOS and the academy said in a statement released on Thursday.

"The warming that we are experiencing now can be attributed 100% to anthropogenic climate change," said Matthias Huss, who heads GLAMOS. "Without human emissions or fossil fuels we wouldn't have any warming at the moment."

The average thickness of individual glaciers decreased by 2.5 to 4 metres this year, with local losses of up to 10 metres on some glacier tongues. The record retreat came in 2022, when summer heat, low snowfall and Sahara dust darkened the glaciers.

The freezing level remained above 4,000 metres for a record 76 days. Several smaller glaciers disappeared completely, including Bella Tola in Valais and Griessfirn in Glarus.

Scientists estimate Swiss glaciers lost around 2.2 trillion litres of water between July and September, temporarily easing summer water shortages.