A colossal ice core sample drilled in Antarctica may contain the oldest, unbroken timeline of Earth’s climate, stretching back more than a million years.
Laid horizontally, the entire ice core’s 2,800-meter (9,186-foot) length could extend across San Francisco’s Golden Gate Bridge, and then some.
Each meter-long segment contains up to 13,000 years of deep, compressed history, including bubbles of ancient air. Together, the evidence provides a baseline for our current climate crisis, and it could reveal more about past extreme climate change events that threatened human survival.
“We have a strong indication that the uppermost 2,480 meters contain a climate record that goes back to 1.2 million years,” says Julien Westhoff, chief scientist on the ground for the European Project for Ice Coring in Antarctica (EPICA).
Further analysis needs to be done, but there’s a chance that the deepest parts of the drilling could contain ice that dates back to the pre-Quaternary period, more than 2.5 million years ago.
The oldest ice uncovered in Antarctica so far dates back 2.7 million years, but Earth’s movements pushed this ice into a shallower patch of frozen material, so it doesn’t provide a continuous climate chronicle; it’s more of a snapshot.
Previously, the EPICA record for the oldest vertical ice core covered the last 740,000 years or so, and it was obtained in 2004.
Ice cores are precious to scientists, because they trap particles, water isotopes, and bubbles of atmospheric gases, like carbon dioxide and methane. This allows researchers to reconstruct climates and environments in our planet’s history.
The new drilling from East Antarctica covers a period of time when Earth’s cycles of glaciation inexplicably lengthened, sometime between 900,000 and 1.2 million years ago.
Some scientists suspect nearly 99 percent of early humans in Africa may have died out during this period of extreme cold swings, although that hypothesis remains contentious and is mostly based on modern genetic data.
The fresh ice core from Antarctica could reveal more details about Earth’s climate shifts during this time. It will probably also confirm just how far off track anthropogenic emissions have taken our planet’s natural cycles of glaciation.
“This transition remains a scientific mystery, particularly regarding the role of greenhouse gases and ice sheet dynamics,” Carlo Barbante, director of EPICA, told CNN.
“This data helps us understand the intricate relationship between greenhouse gases and global temperature over hundreds of thousands of years and now down to 1.2 million year(s) and hopefully beyond.”
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The extraction site of the recent drilling is called Little Dome C, in East Antarctica, and it was chosen because radar surveys revealed the presence of extremely thick ice here, layered like a cake, with a bottom that had not yet melted away.
At 3,200 meters above sea level – high on Antarctica’s central plateau – summer temperatures on Little Dome C sit around -35 ºC (-31 ºF) and often there are high wind speeds to contend with as well.
Researchers at EPICA, including scientists from the British Antarctic Survey, had their work cut out for them. It took about 20 days just to deliver all their infrastructure and cargo to the site from a nearby research station.
When drilling finally got underway, an isotopic analysis system was able to read out glacial and interglacial cycles almost in real time, as each bit of the ice core was extracted from the ground. That’s why scientists at EPICA are making such big claims, so early in their analysis.
Today, the Antarctic ice sheet holds 90 percent of our planet’s ice. A drilling like this one, straight from its belly, could reveal just how Earth’s southernmost continent came to hog most of its freshwater.
Climate scientist Richard Alley, who was not involved in the recent drilling effort, told the Associated Press that EPICA’s ice core was “truly, truly, amazingly fantastic.”
“They will learn wonderful things,” Alley predicted.
