level from the Colle Gnifetti glacier saddle in 2021 were well preserved. Two ice cores reached as far down as the bedrock to a depth of over 80 metres. Containing the oldest ice in the Alps, these twin samples are particularly impressive. They are a living record of our climate and atmosphere over the last 10,000 years. An ice core extracted from the nearby Lyskamm ridge in autumn 2023 went down to a depth of up to 100 metres. But this ice is estimated to be much younger, dating back 150 to 200 years. ing built for this purpose in Antarctica. Two ice cores will be extracted from every location and sent to this facility for storage. One of the two samples will then be used for current research. As new tools and technologies become available, the ice may give future generations of scientists the chance to gain new insight into past environmental events and the evolution of the Earth’s climate. Construction work on the Ice Memory Sanctuary in Antarctica will begin at the end of 2025, says Stocker. The Concordia international research station will be the location, where Swiss scientists recently helped to extract an ice core revealing a continuous record of the Earth’s climate and atmosphere stretching back over 1.2 million years (see box). Revealing past air pollution Whereas the Antarctic drillings offer a window into earlier ice ages, the ice cores extracted from glaciers are important for other reasons. “The information that we obtain from glaciers is unique because it originates from a populated part of the world where pollution is greater than in Antarctica,” Stocker explains. For example, it allows researchers to trace the impact of industrialisation on air quality and the Earth’s climate. The ice also reveals past events such as the nuclear tests of the 1960s. There is little time to spare in recovering this natural archive. “Temperatures in Switzerland and the Alps in particular have soared in the past ten years,” says Stocker. The change has been especially stark in the last four years. “Meltwater has penetrated the glaciers and distorted their data.” Researchers discovered this at first hand during an Ice Memory expedition on the high-altitude Corbassière glacier in the Grand Combin massif (canton of Valais) in 2020. The drilling results in 2018 had shown the situation was stable, but a similar drilling attempt two years later revealed significant glacial melt. Trace substances in the ice had essentially been washed away. In other words, global warming has made the Corbassière glacier more or less unusable as a climate archive. 10,000-year-old ice from the Monte Rosa massif A later expedition to the Monte Rosa massif on the Swiss-Italian border yielded better results. The ice cores extracted 4,500 metres above sea The fragment of a drilled ice core from Lyskamm mountain contains insights into the distant past. Picture right: the team in the protective drilling tent. Photos: Riccardo Selvatico, Ice Memory Foundation Right page: The Lyskamm research mission with its drilling equipment in the protective tent. Photo provided Thomas Stocker says drilling in the Alps is especially important, as clues to the development of civilisation are preserved in the glaciers. Photo: University of Bern “We must preserve this heritage for future generations.” Thomas Stocker – climate researcher and one of the masterminds of the Ice Memory programme Swiss Review / July 2025 / No.3 12 Nature and the environment
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