‘Like touching climate change': glaciers reveal records of the way the world was

The Guardian

31-05-2025

Howling wind relentlessly shakes the white tent, pitched among mounds of snow at a height of 4,100m (13,450ft) on the Corbassière, an Alpine glacier situated on the northern slopes of Switzerland's Grand Combin massif.
Inside are scientists from Venice's Ca' Foscari University and the institute of polar science at Italy's national research council (CNR).
They are camping here for 12 days, braving harsh conditions in freezing temperatures as low as -20C (-4F) as they work day and night to operate machinery that is drilling deep into the rapidly melting glacier.
Their mission is to salvage the Corbassière's remaining ice and unlock the precious trove of knowledge it holds about past climates before global heating completely wipes the glacier out.
The scientists do this by drilling a borehole and extracting long, cylinder-shaped ice cores. These are essentially centuries-old libraries containing records of preindustrial greenhouse gases, pollutants, pollen and bacteria that provide information about historic temperatures and the impact humans have had on the changing environment.
The deeper they manage to drill, the greater the potential for older ice and its rich archive to emerge. An expedition on the Grenz glacier on Monte Rosa in 2021 yielded ice cores containing climate information dating back over the last 10,000 years, including pollutants from the Roman era.
'A glacier is like a book made up of many pages,' said Jacopo Gabrieli, a glaciologist at CNR. 'The pages are layers of ice, with the first few already unreadable because of the melt. It's like throwing a glass of water on an old manuscript and watching the ink quickly disappear. We know the deepest layers are still readable because it is cold enough. But it is an absolute race against time.'
The Corbassière drilling expedition is the first of three planned by Follow the Ice, a scientific and educational project supported by Sea Beyond, an initiative led by the Prada Group. A week into the expedition, the team of 13, which includes mountain guides, a videographer and a nurse who doubles as a cook, welcomed a small group of journalists who were brought to base-camp by helicopter.
The team extracted two ice cores from the glacier, although they won't know the secrets they hold until analysis is done.
Along with greenhouse gases, previous glacier drills have enabled scientists to study cores for the DNA of ancient viruses that could resurface amid global heating, along with frozen insects and plants that could give insight into the history of forests and their ecosystems.
The mission on the Corbassière, backed by the Ice Memory, a nonprofit organisation aimed at preserving and analysing ice cores from the world's most at-risk glaciers, is incredibly daring.
For the first few days, the squad had to adapt to the altitude, many struggling to breathe or suffering headaches and nausea. Sleep has been scant, with hours spent clearing snow out of tents and away from pathways.
Unexpected changes in weather have stalled progress, as did the sudden breakage of a cable powering the drill. Victor Zagorodnov, a scientist who, at 75, is the oldest on the team, said: 'Constant signs of danger play with your mind, but you have to resist.'
Zagorodnov has been leading drilling expeditions on glaciers around the world since the 1980s. 'The first time was in Bolivia,' he said. 'The mind is telling you it's dangerous, and to leave. It causes nightmares. But you persevere.'
Zagorodnov, who is also a glacier-drilling technology specialist, compared the experience to 'learning to ride a bike'. 'You get used to it,' he said. 'Plus, when I first started the equipment was basic, today it is much more advanced.'
Gabrieli is more than used to witnessing the evidence of the climate crisis on glaciers. In 2020, during test drilling on the Corbassière, water was found at a 30m (98ft) depth. 'We put our hands in the water,' he said. 'It was like touching climate change.'
Another thing that dismayed him during that visit was rain. 'I didn't think it was possible to have precipitation at this altitude,' he added. 'It was only a small amount of rain but it was really depressing.'
The experience made the team realise even more that they needed to act quickly, and so returned to finish the work.
This time, the team came equipped with the more advanced electro-thermal drill, a device that penetrates glacier ice through melting. The thermal drill had reached about seven metres deep when a burning stench overwhelmed the scientists.
'We thought something was wrong with the drill but then realised it had hit a plastic bag,' said Carlo Barbante, a professor at Ca' Foscari who co-founded the Ice Memory Foundation. 'It must have been left there by climbers years ago, and really proved the impact of human activity on the climate. Plastic is everywhere, pollution is everywhere. It is very disappointing.'
After six days, the drill successfully reached a depth of 55m (180ft). But then the power cable breakage forced the team to revert to using an electromechanical drill.
Still, the device helped them to finish the job, and by day nine they were euphoric after making a major breakthrough: the drill hit 'bedrock' – the solid rock lying beneath the glacier – at a depth of 99.5m (326ft). The first of the two ice cores was extracted and transported down the mountain, and the second followed a week later.
The ice cores will be dated and the plan is for one to be analysed in Italy, while the other will be shipped to Antarctica, where a cave is being excavated to store ice extracted through glacier drills, providing a library of information for future climate scientists.
Apart from Europe, the Ice Memory foundation has so far drilled on glaciers in Bolivia, Russia and on Tanzania's Mount Kilimanjaro. The missions are costly and intense, but crucial, said Brabante.
'Glaciers, especially in non-polar regions, are very much at the forefront of global warming,' said Brabante. 'They are water reservoirs for millions of people, so if the ice completely disappears there will be huge problems. We are are witnessing what is happening and it must be documented so we can leave something for future scientists. This is our duty.'