Late last year, German-born chemist Margit Schwikowski and a team of international scientists attempted to collect ice cores from the Grand Combin Glacier, located high on the Italian-Swiss border, for an effort to United Nations-supported climate monitoring. In 2018, they explored the site by helicopter and drilled a shallow test core. The core was in good condition, Schwikowski said: it contained well-preserved atmospheric gases and chemical evidence from past climates, and ground-penetrating radar showed a deep glacier. Not all glaciers in the Alps protect both summer and winter snowfall; If all had gone as planned, these carrots would have been the oldest to date, she said.
But in the two years it took scientists to come back with a full drilling setup, some of the information that had been trapped in the ice was gone. The freeze-thaw cycles had created layers of ice and pools of meltwater throughout the glacier, which another team member described as a water-laden sponge, rendering the core unusable for basic climate science.
We were just two years too late.– Margit Schwikowski, Paul Scherrer Institute
The sudden deterioration “tells us exactly how sensitive these glaciers are,” said Schwikowski, head of the analytical chemistry group at the Paul Scherrer Institute in Villigen, Switzerland. “We were just two years too late. “
The mission to Grand Combin highlights the major challenge scientists face today in collecting ice cores: some glaciers are disappearing faster than expected. This realization sparks a renewed urgency, forcing those who specialize in harvesting ice cores to speed up missions, rethink where to target next, and increase storage capacity.
Almost all of the world’s glaciers are shrinking, according to the United Nations. In its most comprehensive climate report to date, released in August, the UN concluded that “human influence is quite possibly the main driver of the near universal retreat of the world’s glaciers since the 1990s.”
The rate at which glaciers are losing mass is also increasing. A study published in April in the scientific journal Nature found that glaciers lost 227 gigatons of ice per year from 2000 to 2004, but that figure rose to an average of 298 gigatons per year after 2015.
A gigaton is equivalent to a billion tonnes. A gigaton of ice would fill Central Park in New York City and rise 341 meters high.
Selon le National Snow and Ice Data Center de Boulder, Co.
If a glacier is melting and no longer accumulating snow, that means it is also not capturing atmospheric gases today for scientists to study in the future.
For Schwikowski, the disappearance of glaciers is not just a professional blow; it is also an emotional blow.
“Mountains are different without them, barren,” she said.
This past September, Schwikowski was bundled up in snow gear as wet ice cylinders were pulled from Grand Combin’s boreholes. The humidity surprised her, she said. Ice-cold meltwater dripped from chunks of ice cores that should have been solid. And the core, which should have been translucent, had perfectly sharp sections.
What ice cores tell us about the past climate
Ice cores like those at Grand Combin have helped scientists illustrate humanity’s impact on Earth’s climate by providing a greenhouse gas record dating back long before industrialization. Ice preserves tiny air bubbles – direct evidence of past atmospheres. Ice also captures air pollutants, pollen, and other temperature and precipitation measurements in a single archive, all at the same timescale, sometimes at the resolution of individual seasons.
Another member of the Grand Combin expedition, Italian climatologist Carlo Barbante, said the rate at which the ice in the Alpine massif had melted in recent years was “much higher than before”. The discovery of the wet carrots was a “total shock,” he said.
As a result, Barbante and other scientists – including Schwikowski – accelerated plans to extract a core from the Colle Gnifetti glacier on top of Monte Rosa in the Alps, a few hundred meters higher than Grand Combin.
Mount Kilamanjaro glaciers under threat
Barbante said he also hopes to organize a trip to Mount Kilimanjaro soon, Africa’s highest mountain and the only possible ice core site on the continent.
A 2009 discovery by American scientist Douglas Hardy of the mummified remains of a 19th-century pig on one of the highest points of the mountain’s glaciers suggests that part of the climate history scientists hope to recover is already gone.
“The implication of this is that we have lost the value of the last 200 years of recorded time,” said Hardy.
Barbante and Schwikowski are part of a group led by scientists called Ice Memory that is trying to create an archive of ice cores from glaciers around the world.
Long-term storage in Antarctica?
So far they have drilled in Europe, Bolivia and Russia. The carrots are temporarily stored in Europe, but the plan is to ship them to Antarctica for long-term storage as the site would not be dependent on electricity, which could suffer an outage.
Beyond greenhouse gases, scientists say they may be able to use ice cores to study the DNA of ancient bacteria and viruses that may reappear as the world warms. Frozen insects and plant pollen could also reveal the story of the world’s forests and their fire cycles.
Another team of scientists, whose results were published in July in the scientific journal Microbiome, found viruses nearly 15,000 years old in two samples of ice cores taken from the Tibetan Plateau in China. The results identified genetic codes for 33 viruses, at least 28 of which were new to scientists.
This team of scientists included American paleoclimatologists Lonnie Thompson and Ellen Mosley-Thompson, who are husband and wife.
Lonnie Thompson said the speed at which the ice was disappearing led to plans to expand his ice core storage facilities at Ohio State University, for which he began raising funds last year.
Some of the carrots that Thompson and his team collected are the only ice left from some glaciers. Two of the six ice core sites on Kilimanjaro in Africa that his team drilled in 2000 have disappeared. The same goes for the sites they drilled in 2010 in Papua, Indonesia. Others will likely be gone within 50 years, Thompson said.
In some cases, lakes have formed on the surface of glaciers as the ice melted, with a red flag indicating that the melting could be faster than previously predicted patterns.
“Ice has a wonderful record not only of climate, but also of climate forcings,” the main causes of climate change, ”said Thompson.
“These stories are under threat as the earth warms and glaciers retreat. “