Swiss glaciers have lost 50% of their volume since 1931. Exhibition released today by the scientists who first imagined the retreat of glaciers during the 20th century.

Melting glaciers in Alps – which experts refer to climate warming— this has been closely monitored since the beginning of the new millennium. But researchers know little about their evolution over the past decades because only a few glaciers were closely observed at the time.

To better understand their evolution, researchers from the Federal University of Technology Zurich (EPFZ) and the Federal Research Institute for Forests, Snow and Landscape (WSL) set about reconstructing the topography of all Swiss glaciers that existed in 1931.

“Based on these reconstructions and a comparison with data from 2000, the researchers conclude that glacier volume has halved from 1931 to 2016,” EPEZ and WSL said in a statement.

“Glacier retreat is accelerating”

A report published in the scientific journal The Cryosphere states that scientists have resorted to archival imaging (21,700 photographs taken between 1916 and 1947) covering 86% of the surface of Swiss glaciers, and to stereophotogrammetry, a technique to determine the nature, shape and the position of the object with the help of images.

“If we know the surface morphology of a glacier in two different time periods, we can calculate the difference in glacier volume,” lead author of the report, Eric Sitt Mannerfeld, said in a statement.

The result is amazing.

Thus, the Fisher Glacier, from which only a few tiny white spots remained in 2021, looked like a huge sea of ​​ice in 1928.

According to scientists, the glaciers have not retreated continuously over the past century. There were even periods when their mass increased in the 1920s and 1980s.

Despite this increase in the short term, “our comparison between 1931 and 2016 clearly shows that significant glacier retreat occurred during this period,” said Daniel Farinotti, one of the report’s authors, professor of glaciology at EPFZ and WSL.

And since then, the glaciers have been melting faster and faster.

So while they lost 50% of their volume between 1931 and 2016, they lost 12% in just six years from 2016 to 2022, according to the Swiss network of registries GLAMOS.

For Farinotti, the evidence is irrefutable: “The retreat of the glaciers is accelerating.”

^{Source: APE-MEB, AFP.}