Massive slabs of ancient Antarctic ice have drawn the world’s attention once again. An international team has retrieved a 9,186-foot (2,800 meter) ice core from a remote part of the icy continent, and its layers may shed light on a dramatic chapter in Earth’s climate history.
The core stretches almost the length of 25 soccer fields laid end to end, or reaches a height equivalent to six and a half Empire State Buildings, including its antenna.
Ice core reveals climate history
Scientists say the newly collected core reached down to the bedrock beneath the Antarctic Ice Sheet and it extends back 1.2 million years in time.
The research took place in a challenging region called Little Dome C, which is situated 21 miles (34 kilometers) from the Italian-French Concordia research station.
Temperatures there often remain below minus 40 degrees Fahrenheit, and gusty winds make work conditions tough.
A time machine
Shortly after the drilling was complete, team members called the sample a “time machine.”
The description reflects the fact that each segment of ice captures evidence of our planet’s temperature, atmospheric composition, and greenhouse gas levels at the time the ice was formed.
The efforts are part of the Beyond EPICA project that is coordinated by Professor Carlo Barbante of Italy’s Ca’ Foscari University of Venice and the Institute of Polar Sciences of the National Research Council of Italy.
Professor Barbante explained that tiny bubbles of air trapped in the ice preserve past levels of gases like carbon dioxide and methane.
These clues allow experts to investigate how volcanic activity, Earth’s orbital cycles, and solar fluctuations affected global temperatures over millennia.
Why does the ice matter?
Researchers have been searching for ice that predates a puzzling event known as the Mid-Pleistocene Transition.
Before about 1 million years ago, our world’s ice ages lasted around 41,000 years each. Then they shifted to a 100,000-year rhythm for reasons that remain uncertain.
This change could have had a profound influence on early human populations. Studying ancient air trapped in these deep layers of ice cores might show how and why the glacial cycles altered so dramatically.
A near-miss for humanity?
Some researchers suspect the planet’s harsh climate swings nearly caused the extinction of our own ancestors around this time.
According to a recent study in Science, the global breeding population of humans may have plummeted to about 1,280 individuals between 930,000 and 813,000 years ago.
Although opinions vary on how close our lineage came to disappearing, this finding highlights the possible severity of those changing conditions.
If the newly recovered ice records support the same timeframe, the data could help clarify whether environmental shifts had an outsized impact on survival.
Preserving the oldest ice cores
The bottommost 688 feet (210 meters) of this core appear to hold exceptionally old and possibly deformed ice. The drilling team is eager to examine these compressed bands and understand how they refroze.
Dr. Robert Mulvaney, a glaciologist with the British Antarctic Survey, noted that intense heat from Earth’s mantle can melt the lowest layers if they are too thick.
“This can happen when the heat escaping from the Earth’s mantle is trapped by a thick insulating blanket of ice,” said Mulvaney. Scientists hope that studying these lower sections will reveal whether ice older than 1.2 million years might still exist in Antarctica.
Potential for even earlier timelines
Experts want to see if the ice can confirm whether sections from the pre-Quaternary Period (2.58 million years ago or more) are hidden below. Findings from these layers might point to moments when Antarctica was ice-free.
Clues in the lowest strata might also test long-standing hypotheses about when major ice sheets first expanded across the continent. The search for deep records is ongoing, with team members expecting more sophisticated drilling technologies and surveys in the future.
Worth of ice cores
Ice cores have proven their worth for decades.
They contain annual layers of snowfall, compressed into translucent columns of time. By analyzing each band’s trapped gases and microscopic particles, scientists reconstruct long-term trends in temperature, precipitation, and greenhouse gas activity.
“Antarctic ice cores are like Rosetta Stones. They are unique in that they speak the language of temperature as well as the language of (carbon dioxide) levels,” said Jim White, Craver Family Dean at the University of North Carolina at Chapel Hill.
Experts believe these markers will improve climate prediction models by revealing the timing of ancient changes.
Long-term outlook
The ice core sections will soon be transported to Europe in special containers. Once there, teams will carry out extensive analysis of dust particles, greenhouse gases, and trapped chemical compounds.
The multi-year journey of scientific discovery may provide deeper insights into how Earth balances complex forces such as solar radiation, volcanic eruptions, and shifting atmospheric currents.
“We have to find other places in Antarctica where we can retrieve continuous climate record(s) similar to the one we are studying,” said Barbante.
Professor Barbante sees future work expanding into other remote areas where ancient ice could hide.
The recent update is published in the Astrophysics Data System.
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