“A historic achievement”: ice at least a million years old extracted in Antarctica

This is crucial information for knowing the Earth’s past climate. In Antarctica, a drilling campaign has reached ice dating back 1.2 million years, an international consortium of scientists from twelve European scientific institutions announced this Thursday. This discovery pushes back by 400,000 years the previous record established in 2024 by the same project. “An international team of scientists successfully drilled a 2,800 meter long ice core, reaching the rocky ground beneath the Antarctic ice sheet“, revealed the program “Beyond EPICA-Oldest Ice”.

“The samples collected will make it possible to reconstruct, for the first time, important parameters of the Earth’s climate and the composition of its atmosphere beyond 800,000 years in the past”the previous record, congratulate themselves in a press release (new window) the CNRS and the French Polar Institute, members of the consortium, also welcoming a “historic achievement”. “According to the first analysis results, this layer of ice would provide a continuous climate record of at least 1.2 million years,” note the two institutes in a press release.

Several million years?

And potentially beyond: “Although it has a priori lost part of its paleoclimatic information, samples from the deepest 200 meters are likely to contain ice dating back several million years”continues the press release. However, additional analyzes are necessary to determine whether this ice is usable, once brought back to Europe by boat, stored at -50°C.

“This is the longest continuous record of our past climate from an ice core, and it may reveal the link between the carbon cycle and our planet’s temperature”said Professor Carlo Barbante of the Italian Polar Institute, coordinator of the exploration campaign.

More than 200 days of drilling operations

Each meter of compressed ice records climatic data (temperatures, CO2 concentration, etc.) for a period of up to 13,000 years. “The analyzes should help elucidate the reasons for the mysterious transition that occurred during the mid-Pleistocene, a period between 900,000 years ago and 1.2 million years in the past, during which glacial cycles saw their amplitude increase and their period goes from 41,000 years to 100,000 years”potentially under the effect of variations in the concentration of CO2 in the atmosphere, the press release continues.

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It took scientists “more than 200 days of drilling and ice core processing operations” over four austral summers in a row “in the difficult environment of the central plateau of Antarcticaat 3200 meters above sea level and with an average summer temperature of -35°C”explains another press release from the consortium. “Dating of the underlying rocks will be undertaken to determine when this region of Antarctica was last ice-free.”it is added.