Photos show Swiss glaciers shrinking by half
Switzerland’s glaciers lost half of their volume between 1931 and 2016, according to analysis of historical national survey photographs. Researchers at the federal technology institute ETH Zurich and the Swiss Federal Institute for Forest, Snow and Landscape Research (WSL) compared photographs from the first half of last century to the current state of glaciers. Using a comparison technique, known as stereophotogrammetry, scientists say they can accurately calculate the changing topography of glaciers and the difference in ice volume. They looked at 21,700 photographs taken between 1916 and 1947 by the Swiss National Survey institute, now known as swisstopo. They found that Swiss glaciers lost half their volume between 1931 and 2016 - and a further 12% between 2016 and 2021. This amounts to a loss of 62 cubic kilometres of ice. "This is about 20% more than previously assumed," Daniel Farinotti, Professor of Glaciology at ETH Zurich and WSL, told Swiss public broadcaster SRF.