by Matt Simongrist
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High in the Ötztal Alps near the border of Austria and Italy, sprawled across the closest thing you can get — scientifically, at least — is a time machine. Over thousands of years, snow has fallen and frozen here, forming layer upon layer of the Weißseespitze glacier and storing invaluable information. For example, as mining and melted 1,000 years ago metals were precipitated across Europe, carrying pollutants such as arsenic into the air and falling onto the ice. There are also natural signatures, such as chemicals from wildfires that provide clues to climate in the distant past.
Scientists fear that as glaciers disappear, they are taking critical insights with them. Meanwhile, warmer temperatures have taken their toll on the Weisspitze glacier, as the upper layers – dating back to the 1600s – have melted. What remains to researchers is a historical record between the 2nd and 17th centuries. And the race is on: About 30 percent of the glaciers in the Ötztal Alps could disappear in the next five years.
“It’s really a race against time, because we have this unique opportunity to visit this glacial memory,” said Azura Spagnesi, a paleoclimatologist at Ca’ Foscari University in Venice and lead author. A recent paper that analyzed pollutant records Preserved in the ice of the Weißseespitze.
Think of the Weißseespitze – or any glacier – as a layer cake. As snow falls on glaciers, it brings with it whatever compounds are in the air at the time. All that snow freezes continuously, year after year. To interrogate the timeline within the glacier, Spagnesi’s colleagues drilled down more than 30 feet until they hit bedrock, pulling up a core. The lower the ice layer, the older the frozen water and its constituent contaminants – a kind of time-cake, if you will.
In the middle of densely populated Europe – the birthplace of the Industrial Revolution – the Weißseespitze and its neighboring glaciers have higher-resolution data than ice cores taken in more distant places like Greenland and Antarctica. “These local glaciers tell you more about what’s going on nearby,” said Paul Bierman, a geoscientist at the University of Vermont who has written a book about the lessons the history of the Greenland Ice Sheet holds. “So they’re both valuable — they’re just different.”
By analyzing these pollutants, researchers can get an idea of what was in the atmosphere — and, by extension, what was happening in the world at any given moment in history. For example, in samples from the Weißseespitze, Spagnesi and his team observed contaminants such as lead from human activity over a millennium ago. “These peaks indicate that human activity has already left a detectable mark on the atmosphere,” Spagnesse said.
Human-caused pollution on the Weißseespitze glacier has been chronic for centuries. But ice cores also reveal intense levels of pollution from natural disasters, such as major volcanic eruptions: volcanoes release trace elements, including arsenic and copper, into the atmosphere, which float around and eventually fall to the ground. Researchers found spikes of such metals in the 13th and 16th centuries CE, suggesting some serious eruptions.
Spagnesi and his colleagues can also sniff out ancient climates based on natural contamination found in the cores. In layers around 1000 CE, they discovered spikes in levoglucosan, a chemical released when plants are burned. This matched the high levels of charcoal found in cores sampled from another nearby ecosystem: peatlands. Much like glaciers, these landscapes accumulate material over the years, only here instead of ice Organic matter that accumulates and prevents erosion. Together, the two samples from vastly different environments suggest an outbreak of wildfire, which covered ice and peat in smoke signature elements.
The underlying cause of these ancient fires may be similar to what we see today. The ice core and peat signals correspond to century-long droughts, when rainfall would encourage vegetation growth, which would then dry out and become fuel for wildfires. We are witnessing the same dynamic in places like the American West. Where climate change is driving “climate whiplash”. — Years of heavy rainfall followed by years of extreme drought.
That’s why the race to take cores from disappearing glaciers is so important: The more information scientists have about how glaciers and ice sheets responded to climate change in previous centuries, the more accurate their calculations of modern-day climate change will be. “We need to provide modelers with precise information about changes in past atmospheric composition, and even environmental variability, to train the models,” Spagnesi said.
But the Weißespitze and other glaciers in the Alps are disappearing fast. Spagnesi’s colleagues took that 30-foot core in 2019, stopping at the bed — but in 2025, another drilling in the area reached just 18 feet below the glacier. With each lost inch, the available historical record returns inch by inch in time, until scientists are left with only the very distant past. They are now scrambling to get more cores of what is left.
“Glaciers are not just ice,” Spagnesse said. “They are Earth’s memory archives. And when they disappear, we don’t just lose frozen water, we lose irreplaceable knowledge about how our climate system works and how human activity has changed it.”
This article originally appeared on grist A https://grist.org/science/scientists-race-to-decode-climate-data-from-europes-vanishing-glaciers/.
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This is the story Originally published by grist.
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Photo credit: splash
