An international consortium of scientists from twelve institutions, including, for France, the CNRS and the French Polar Institute, has managed to reach ice dating back more than 1.2 million years by drilling a 2,800-meter-long ice core in the Antarctic ice sheet
The samples collected will make it possible, for the first time, to reconstruct key parameters of Earth’s climate and the composition of its atmosphere beyond 800,000 years into the past. This historic achievement marks the culmination of the fourth field campaign of the European project “Beyond EPICA – Oldest Ice,” which aims to solve one of the great mysteries of climate science: the cause of the slowing pace of glaciations around one million years ago.
At the Little Dome C site in Antarctica, a research team representing twelve institutions from ten European nations has just achieved a major milestone in climate science: they successfully conducted a drilling campaign to reach the subglacial continent at a depth of 2,800 meters. According to initial analysis, this layer of ice could provide a continuous climate record of at least 1.2 million years. This is the longest continuous climate record extracted from ice cores, surpassing the previous record of 800,000 years held by the EPICA project following its 2004 drilling campaign at Dome C.
However, further analyses are needed to determine whether even older ice can be studied. Although it appears to have lost part of its paleoclimate information, the samples from the deepest 200 meters may contain ice dating back several million years.
The ice extracted during this fourth campaign, which began in November 2024, has preserved a record of Earth’s climate history, offering a direct glimpse into atmospheric temperatures and greenhouse gas concentrations over the past 1.2 million years.
Once the ice cores return to Europe, they will be analyzed with the goal of reconstructing Earth’s climate history and atmospheric composition over this extended period up to the present day. More specifically, these analyses are expected to shed light on the reasons behind the mysterious transition that occurred during the mid-Pleistocene, a period between 900,000 and 1.2 million years ago, during which glacial cycles increased in amplitude and shifted from a 41,000-year to a 100,000-year periodicity. Indeed, only polar ice can reliably reconstruct CO2 concentrations, a gas suspected of playing a key role in this transition.
