Switzerland’s 1,400 glaciers have lost more than half their total volume since the early 1930s, a new study has found, and researchers say the ice retreat is accelerating at a time of growing concerns about climate change.

ETH Zurich, a respected federal polytechnic university, and the Swiss Federal Institute on Forest, Snow and Landscape Research on Monday announced the findings from a first-ever reconstruction of ice loss in Switzerland in the 20th century, based in part on an analysis of changes to the topography of glaciers since 1931.

The researchers estimated that ice volumes on the glaciers had shrunk by half over the subsequent 85 years — until 2016. Since then, the glaciers have lost an additional 12%, over just six years.

“Glacier retreat is accelerating. Closely observing this phenomenon and quantifying its historical dimensions is important because it allows us to infer the glaciers’ responses to a changing climate,” said Daniel Farinotti, a co-​author of the study, which was published in scientific journal The Cryosphere.