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By Cassandra Garrison, Clare Baldwin and Marco Hernandez
Sept 13 (Reuters) - Scientists are racing to collect ice cores along with long-frozen records they hold of climate cycles as global warming melts glaciers and ice sheets. Some say they are running out of time. And, in some cases, it's already too late.
Late last year, German-born chemist Margit Schwikowski and a team of international scientists attempted to gather ice cores from the Grand Combin glacier, high on the Swiss-Italian border, for a United Nations-backed climate monitoring effort.
In 2018, they had scouted the site by helicopter and drilled a shallow test core. The core was in good shape, said Schwikowski: It had well-preserved atmospheric gases and chemical evidence of past climates, and ground-penetrating radar showed a deep glacier. Not all glaciers in the Alps preserve both summer and winter snowfall; if all went as planned, these cores would have been the oldest to date that did, she said.
But in the two years it took for the scientists to return with a full drilling set-up, some of the information that had been trapped in the ice had vanished. Freeze-thaw cycles had created icy layers and meltwater pools throughout the glacier, what another team member described as a water-laden sponge, rendering the core useless for basic climate science.
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 on Grand Combin underscores the major challenge scientists face today in collecting ice cores: Some glaciers are disappearing faster than expected. The realization is prompting renewed urgency, causing those who specialize in harvesting ice cores to accelerate missions, rethink where to target next, and expand storage capacity.
Almost all of the world's glaciers are shrinking, according to the United Nations. In its most comprehensive climate report to date, published in August, the UN concluded that "human influence is very likely the main driver of the near-universal retreat of glaciers globally since the 1990s." The report also said that without immediate, large-scale action, the average global temperature will reach or exceed 1.5 degrees Celsius above the preindustrial temperature average within 20 years.
The pace at which glaciers are losing mass is also increasing. A study published in April in the science journal Nature found glaciers lost 227 gigatons of ice annually from 2000 to 2004, but that increased to an average of 298 gigatons a year after 2015. A gigaton is the equivalent of one billion metric tons. One gigaton of ice would fill New York City's Central Park and stand 341 meters (1,119 feet) high.
About 10% of the land area on earth is currently covered with glacial ice, according to the National Snow and Ice Data Center in Boulder, Colorado.
If a glacier is melting and no longer accumulating snow, it means it also isn't capturing atmospheric gases from today for scientists to study in the future.
Two years ago, the south peak of Sweden's Kebnekaise mountain lost its designation as the country's highest point after a third of its summit glacier melted.
For Schwikowski, the disappearance of glaciers isn't just a professional blow; it's an emotional hit, too. "The mountains look different without them, barren," she said. In the Alps, the mountains without glaciers are "absolutely frightening."
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