Historic drilling campaign in Antarctica reaches more than 1.2 million years old ice

The European-funded project “Beyond EPICA - Oldest Ice” has achieved a historic milestone for climate science. An international team of scientists successfully drilled a 2,800 meters long ice core, reaching the bedrock beneath the Antarctic ice sheet. These ice samples are expected to unveil, for the first time, critical details about Earth's climate and atmospheric history, extending beyond 800,000 years ago and showing a continuous record of the history of our climate as far back as 1.2 million years, and probably beyond. The project aims to resolve one of climate science's most complex mysteries.

The drill site Little Dome C in Antarctica. Credit: Domesi©PNRA/IPEV

At the remote Little Dome C site in Antarctica, a research team representing twelve scientific institutions from ten European nations has just achieved a historic milestone for climate science. As part of the European-funded Beyond EPICA - Oldest Ice project, the team successfully concluded a decisive drilling campaign, reaching the depth of 2,800 meters, where the Antarctic ice sheet meets the bedrock.

The extracted ice preserves an unprecedented record of Earth’s climate history, continuous information on atmospheric temperatures and pristine samples of old air with greenhouse gases spanning over 1.2 million years old ice and probably beyond. The right location was identified using cutting-edge radio echo sounding technologies and ice flow modeling.

A harsh environment

The European teams in the field have accomplished an impressive achievement: a total of more than 200 days of successful drilling and ice core processing operations across four field seasons in the harsh environment of the central Antarctic plateau at an altitude of 3,200 meters above sea level and with an average summer temperature of -35°C.

We have marked a historic moment for climate and environmental science comments Carlo Barbante, professor at Ca' Foscari University of Venice and coordinator of Beyond EPICA.

- This is the longest continuous record of our past climate from an ice core, and it can reveal the interlink between the carbon cycle and temperature of our planet. This achievement was made possible through the extraordinary collaboration of various European research institutions and the dedicated work of scientists and logistical personnel in the field over the last ten years, says Carlo.

Measurements on an ice core at the drilling site Little Dome C. Credit: Scoto@PNRA/IPEV

From preliminary analyses recorded at Little Dome C, there is a strong indication that the uppermost 2,480 meters contain a climate record that goes back to 1.2 million years in a high-resolution record where up to 13,000 years are compressed into one meter of ice.

Below the ice harbouring the climate record of more than 1.2 million years, the lowest 210 meters of the ice core above the bedrock consist of old ice that is heavily deformed, possibly mixed or refrozen and of unknown origin. Advanced analysis could help test previous theories about the behavior of refrozen ice under the Antarctic ice sheet and reveal East Antarctica's glaciation history.

Stored ice cores on the way to Europe. Credit: Westhoff©PNRA/IPEV

The precious ice cores extracted during this campaign will be transported back to Europe on board the icebreaker Laura Bassi, maintaining the -50°C cold chain, a significant challenge for the logistics of the project. To reach this goal, a strategy was developed involving the design of specialized cold containers and precise scheduling of the National Antarctic Research Program (PNRA) air and naval assets.

Resolve one of climate science's most complex mysteries

As soon as these ice cores are in Europe, the project will focus on analyzing the ice samples to uncover the Earth's climate and atmospheric history over the past 1.2 million years and probably beyond. In the most basal sections of the core, even older pre-Quaternary ice might be present. Dating of the underlying rocks will be undertaken to unravel when this region of Antarctica was ice-free for the last time.

The ice core from Beyond EPICA will offer unprecedented insights into the Mid-Pleistocene Transition, a remarkable period between 900,000 and 1.2 million years ago when glacial cycles slowed down from 41,000 years to 100,000 years intervals. The reasons behind this shift remain one of climate science's enduring mysteries, which this project aims to unravel.