The fourth Antarctic campaign of the Beyond EPICA-Oldest Ice project has achieved a historic milestone this week, by successfully drilling a 2800-metre-long ice core, consisting of ice from the Antarctic ice sheet which is more than 1.2 million years old.
Funded by the European Commission and coordinated by the Institute of Polar Sciences of the CNR (National Research Council of Italy), the drilling campaign was conducted at the remote 'Little Dome C' site by an international team of researchers. With scientists representing twelve scientific institutions from ten European nations, the project is collecting these ice samples in the hope of unveiling, for the first time, a continuous record of Earth's climate and atmospheric past stretching back 1.2 million years, and potentially beyond.
The extracted ice core harbours data such as historical atmospheric temperatures, as well as incredibly preserved samples of air - and the greenhouse gases within it – spanning thousands of years. Both, along with other information locked away in the samples, will aid scientists to paint a more detailed image of the Earth's past, and hopefully reveal critical details about large shifts in our planet's past climate record.
Dr Robert Mulvaney, a glaciologist and palaeoclimatologist at British Antarctic Survey who took part in one of the earlier drilling seasons, expressed his anticipation at reaching such a historic moment in climate history research:
"It was exciting to see the ice age as we drilled deeper, and especially when we knew we were drilling ice older than the EPICA record, which ended at 800,000 years ago; this record of 1.2 million-years will give us several 41,000-year glacial cycles to compare with the more recent data from the original EPICA core."
Not only have the field teams tasked with drilling this colossal ice core achieved a world-first, but they have done so dedicatedly in incredibly difficult conditions. More than two hundred days of successful drilling and ice core processing operations occurred across four field seasons, and in the harsh environment of the central Antarctic plateau. At an altitude of approximately 3,200 metres (around 10,500 feet) above sea level, and an average summer temperature of -35°C, sustained work at Little Dome C has been tough for the team, but necessary.
Dr Mulvaney was also one of the team who carried out the initial radar surveys to identify the perfect drilling site:
"We needed a Goldilocks site – ice thick enough for a well-resolved climate record at the greatest depth, but not too thick that the oldest ice had already melted away - this can happen when the heat escaping from the Earth's mantle is trapped by a thick insulating blanket of ice – if the ice is too thick, we can lose the lowest and oldest layers of ice to melting. That's why we spent a lot of effort in surveying the candidate areas to find the right site before drilling started."
The oldest ice, at the greatest depth from the surface, exists at the lowest 210 metres of the ice core - just above the bedrock. The old ice forming this base segment is heavily deformed – possibly mixed or refrozen, and of unknown origin. It is hoped that advanced analysis of this segment could help test previous theories about the behaviour of refrozen ice under the Antarctic ice sheet and reveal East Antarctica's glaciation history. There is even potential for yet older ice, dating back to the pre-Quaternary period (2.58 million years ago) to be discovered within these base sections of the core, with dating of the rocks underlying the drilled core possibly determining exactly when this region of Antarctica was ice-free for the last time.
The 2800-metre ice core samples will now be transported carefully to Europe using specialised cold containers, maintained under a strict logistics strategy. Once reaching their destinations, the project will focus on analysing the ice samples to uncover the Earth's climate and atmospheric history over the past 1.2 million years and likely, beyond.
Participants in the 2024/2025 campaign: Université Libre de Bruxelles (BE): Lisa Ardoin; University of Bern (CH): Barbara Seth and Lison Soussaintjean; AWI (DE): Matthias Hüther, Manuela Krebs, Gunther Lawer, Johannes Lemburg, Martin Leonhardt, and Frank Wilhelms; University of Copenhagen (DK): Julien Westhoff; CNRS (FR): Marie Bouchet and Ailsa Chung; IPEV (FR): Inès Gay; ENEA (IT): Danilo Collino and Michele Scalet; Cnr-Isp (IT): Federico Scoto.
Learn more about the Beyond EPICA - Oldest Ice project here
Learn more about the BAS Ice Dynamics and Palaeoclimate team here
Learn more about the original EPICA project here
