In 2019, researchers collected a 9.5-meter ice core from Austria’s Weißseespitze ice cap, which covers the top sections of Gepatschferner Glacier in the eastern Alps, near the Austrian-Italian border. They analyzed 18 trace elements and organic acids in the core to paint a picture of Earth’s climate and atmosphere over more than a thousand years.
“When this glacier disappears, we don’t lose only the ice: We’ll lose irreplaceable knowledge about the Earth’s climate history.”
But Weißseespitze Glacier is melting quickly: As of 2025, the ice was only 5.5 meters thick in the area where scientists collected the core.
“When this glacier disappears, we don’t lose only the ice: We’ll lose irreplaceable knowledge about the Earth’s climate history and how it has evolved and how human activity has influenced it,” said Azzurra Spagnesi, a paleoclimatologist at Università Ca’ Foscari Venezia and lead author of the new research published in Frontiers in Earth Science. “So we are, in this sense, in a race against time.”
Cores in Low Places
Most ice cores in the Alps are gathered from glaciers in the western part of the mountain range, where elevations are higher and colder temperatures help preserve climate records.
“For a long time, scientists believed that glaciers at this altitude in the eastern Alps could not preserve the undisturbed climate records because the ice there would be temperate, and this would have affected the melting,” Spagnesi said. “We reveal instead that, at the Weißseespitze Glacier, under certain conditions…the ice can still survive even below 3,500 meters.”
Joe McConnell, a climate and environmental researcher at the Desert Research Institute in Reno, Nev., focused on developing and interpreting ice core records, said that aerosols such as dust and sea salts, as well as emissions from wildfires, volcanic eruptions, and industrial processes, remain in the air only days at a time before being deposited on a surface.
“The uppermost 5 meters of ice layers have already disappeared.”
“This means that ice core (and peat) records from the eastern Alps potentially provide different information on past environmental history than records from the western Alps, just as polar ice cores provide different information than low- or mid-latitude ice cores,” McConnell wrote in an email to Eos.
Andrea Fischer, a glaciologist at the Institute for Interdisciplinary Mountain Research at Österreichische Akademie der Wissenschaften, has gone up to the glacier to gather ice cores so many times she’s lost count. It takes about an hour and a half of driving, followed by a 2-minute helicopter ride, to get from her office to Weißseespitze. This proximity makes it possible for Fischer to visit the site often, and on short notice, to drill cores. But she noted that the cores drilled in 2019 hold the most information.
“We have only 5 meters of ice left,” she said, “and so everything we drilled in [2019] is most valuable, as the uppermost 5 meters of ice layers have already disappeared.”
A Growing Human Signal
The researchers used argon isotope data to determine that the glacier’s surface formed between 1552 and 1708 CE, and they used modeling to estimate that its deepest layer formed between 349 BCE and 420 CE.
They used a technique called continuous flow analysis to measure the chemical composition of the samples, testing levels of carboxylic and dicarboxylic acids, ionic compounds, and 18 trace elements, including uranium and lead. They also measured levels of levoglucosan, a compound that forms when wood burns and can therefore indicate when wildfires occurred.
In continuous flow analysis, an ice core is slowly melted, vaporized, and injected directly into tools that can analyze the composition of the vapor. One such tool is a cavity ring-down spectrometer, which can measure levels of trace gases in a sample down to the parts-per-trillion level on the basis of how the different gases reflect light. The researchers’ use of continuous flow analysis eliminated the extensive processing time and risk of contamination that often come from directly handling a sample.
From about 950 CE onward, the researchers saw peaks in arsenic, lead, and copper, which corresponded to intensified levels of mining and smelting across Europe. The peaks also coincided with volcanic eruptions that occurred in the 13th and 14th centuries.
Most of the findings matched what previous research had found in other glaciers and peat cores. But there were some differences. For instance, concentrations of thallium and bismuth were about 20 times higher, and uranium concentrations were about 5 times higher in the Weißseespitze ice core than in cores taken from a glacier farther east in 2018.
Spagnesi suggested this discrepancy could be a matter of transport and deposition, but ultimately, it was unclear why the concentrations of these particular elements didn’t match those seen in other glacier cores from the area, whereas the quantities of other elements did match.
“I think that one of our key findings here is that before the industrial period, human influence on the atmospheric composition was detectable, as we saw from this ice core, but still very small,” Spagnesi said, explaining that natural processes such as dust transport and volcanic eruption dominated the signal recorded by the ice. “This provides for us an important baseline that helps us to understand how dramatically the atmosphere has changed in modern times.”
—Emily Gardner (@emfurd.bsky.social), Associate Editor