As of: February 10, 2024, 6:29 a.m
By: Tanja Banner
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A large amount of ice melted rapidly in Antarctica at the end of the last Ice Age, a new study shows.
Research is concerned.
Cambridge - A new study published in the journal
Nature Geoscience
shows a frightening glimpse into the past: Apparently the West Antarctic ice sheet suddenly shrank dramatically at the end of the last ice age.
This is suggested by ice drillings that researchers from the University of Cambridge and the British Antarctic Survey examined.
In one place, around 8,000 years ago, the ice sheet lost 450 meters of thickness in less than 200 years.
For comparison: The Empire State Building in New York is around 443 meters high up to the top of the antenna.
Antarctic ice sheet |
|
|---|---|
Area: |
14,000,000 km² |
Ice thickness: |
average 2126 meters, maximum 4897 meters |
Ice volume: |
26,500,000 km³ |
Special feature: |
the largest ice mass on earth, part of which, the West Antarctic ice sheet, is particularly at risk |
The West Antarctic Ice Sheet melted dramatically at the end of the Ice Age
The drilling is the first evidence of such rapid ice loss in Antarctica, according to a statement about the study.
The global research community fears that global warming could destabilize parts of the West Antarctic ice sheet in the future.
This could cause a tipping point to be exceeded and an uncontrolled collapse to occur.
One reason the research community is nervous about the Antarctic ice sheet: It contains enough fresh water to raise global sea levels by about 57 meters.
The West Antarctic ice sheet in particular is considered particularly at risk because a large part of it lies on rocks that are below sea level.
Models predict that a large part of the West Antarctic ice sheet could disappear in the coming centuries - with a huge rise in sea levels.
However, when and how quickly this will happen is unclear.
Ancient air bubbles and impurities are trapped in the ice core, which enable the research team to gain new insights.
At one point, the West Antarctic ice sheet has become 450 meters thinner in almost 200 years.
© University of Cambridge/British Antarctic Survey
Concern about the behavior of the ice in Antarctica
However, the new data can now be used in the models that predict the behavior of the ice sheet.
“We now have direct evidence that this ice sheet has experienced rapid ice loss in the past,” emphasizes the study’s lead author, Eric Wolff from the Cambridge Department of Earth Sciences.
“This scenario not only exists in our model predictions, but could repeat itself if parts of the ice sheet become unstable.”
His co-author Isobel Rowell adds: “We wanted to know what happened to the West Antarctic ice sheet at the end of the last ice age.” At the end of the last ice age, around 8,000 years ago, temperatures on Earth rose, “albeit more slowly than current anthropogenic warming,” as Rowell points out.
The researcher from the British Antarctic Survey explains how the new data will help science: “Using ice cores, we can go back to that time and estimate the thickness and extent of the ice sheet.”
The drilling and living tents in Antarctica.
© Eric Wolff
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Ice core provides a look into Antarctica's past
Ice cores consist of different layers of ice that were formed when snow fell on the ground.
Over the millennia they became ice crystals.
Each layer of ice contains bubbles of old air and contaminants from that time, which provide, among other things, clues about the changing climate.
The drill core examined for the current study was taken from the Skytrain Ice Ridge in 2019 and is 651 meters long.
In the drilling tent on the Skytrain ice ridge, engineers and scientists separate the inner tube of the drill from the outer tube between drillings.
© University of Cambridge / British Antarctic Survey
The measurements the researchers took showed them shocking things: “As soon as the ice became thinner, it shrank very quickly,” says Wolff, summarizing the new findings.
"This was clearly a tipping point - an uncontrollable process." The research team believes that the thinning of the ice may have been triggered by warm water getting under the West Antarctic ice sheet.
Warm water from below probably melted the ice
As a result, part of the ice probably broke away from the bedrock and was suddenly able to float - today's Ronne Ice Shelf was formed.
This allowed the neighboring Skytrain ice ridge, which was no longer held back by the ice on the ground, to rapidly decrease.
Concern about Thwaites Glacier
Researchers are also concerned about the Thwaites Glacier in Antarctica (nicknamed: “Doomsday Glacier”).
It is being intensively researched; an expensive research robot was recently lost under the glacier.
Ice in Antarctica became thinner at the end of the Ice Age
“We already knew from models that the ice was thinning around this time, but the timing was uncertain,” Rowell said.
Previous models indicated the decline between 12,000 and 5,000 years ago, but were unable to provide a more precise representation of how quickly it occurred.
“We now have a very precisely dated observation of this retreat that can be incorporated into improved models,” explains the researcher.
After rapidly retreating 8,000 years ago, the West Antarctic ice sheet stabilized at about its current extent.
According to lead author Wolff, one thing is now important: “We need to find out whether additional heat could destabilize the ice and trigger another retreat.”
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