Climate Crisis Endangers Ice Archives, Imperils Global Heritage

When Margit Schwikowski helicoptered up to Switzerland’s Corbassière glacier in 2020, it was clear that things weren’t right. “It was very warm. I mean, we were at 4,100 meters and it should be sub-zero temperatures,” she says. Instead, the team started to sweat as they lugged their ice core drill around, and the snow was sticky. “I thought, ‘This has never happened before.’” What Schwikowski couldn’t see yet, but would find later in the lab, is that it wasn’t just the surface that was affected: Climate change had penetrated the ice and trashed its utility as an environmental record. Warming weather had created meltwater that trickled down, washing away trapped aerosols that researchers like her use as a historical record of forest fires and other environmental events. Because of the melt, she says, “we really lose this information.”

Schwikowski, an environmental chemist at the Paul Scherrer Institut near Zurich, is the scientific lead for the Ice Memory Foundation, a collaborative group that aims to preserve glacial ice records before climate change wrecks them. Their goal is to get cores from 20 glaciers around the world in 20 years, and, starting in 2025, lock them away for long-term storage in an ice cave in the Antarctic — a natural freezer that will hold them at close to minus 60 degrees Fahrenheit (minus 50 degrees Celsius). Since the program’s start in 2015, they have taken cores from eight sites, in France, Bolivia, Switzerland, Russia, Norway, and Italy. But the core attempted from Corbassière was a failure — and has the team wondering if they are already too late. Studies show the pace of glacial ice loss has accelerated from a few inches per year in the 1980s to nearly 3 feet per year in the 2010s. The team, watching in despair as ice cores melt and muddle, is not alone in seeing climate change wreaking havoc with scientific records — often in unexpected ways. Geologists who hunt for meteorites on the ice in Antarctica are finding their mission thwarted by warming temperatures. And while archaeologists who study the artifacts spat out by ice patches are seeing a bonanza of new finds, they are also racing to get to those objects before they rot. Other heritage sites are slumping into thawing permafrost.

What all these researchers have in common is a race to preserve what they can, while they can. When you are standing on a glacier that’s literally melting under your feet, says Schwikowski, “you really feel the urgency.” Due to climate change, high mountain glaciers are now endangered, losing ice faster than they are gaining it. Studies of a few dozen well-monitored glaciers in the World Glacier Inventory have shown that the pace of glacial ice loss has accelerated from a few inches per year in the 1980s to nearly 3 feet per year in the 2010s. A 2023 model of some 215,000 mountain glaciers showed that nearly half of them could disappear entirely by 2100 if the world warms by just 1.5 degrees Celsius, the ambitious maximum warming target of the Paris Agreement.

Glaciers have annual layers, just like tree rings. At the top, a single year might see a few feet of snow added to the surface. Hundreds of feet down, weight compresses ice that is thousands of years old into thin, flowing layers, where less than an inch may contain a century of snowfall. This ice preserves all kinds of information from the time when it was deposited. A spike in lead pollution comes at the height of the Roman Empire. A drop in pollen reveals the collapse of farming during the Black Death. The Chernobyl accident left a layer of radioactive cesium. Black carbon and the sugars from burned cellulose map out changes in forest fire activity across the globe. The ratio of different oxygen and hydrogen isotopes in the water also reveals the air temperature of the time.

Many mountain glaciers have been cored and studied over the past decades. Since scientific methods and research questions change over time, researchers preserve some cores or sections intact for future reference — to study, say, the genetics of ancient DNA. The National Science Foundation Ice Core Facility in Colorado, for example, holds 82,000 feet of collected ice cores — mostly from Greenland and the Antarctic, but also from North American mountaintop glaciers. The problem of glacial ice melting has been apparent for many years. “Everyone in our community is worried,” says a scientist.

The problem of glacial ice melting has been apparent for many years, says paleoclimatologist Ellen Mosley-Thompson of Ohio State University. In 2000, when she and her colleagues drilled to bedrock on Mount Kilimanjaro, they found the surface dated to the 1950s. The top

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