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AP Photo/Brennan Linsley
Reaching the oldest ice ever drilled will take three years.
DRILL BABY DRILL

This ancient ice core could reveal 1.5 million years of climate history

By Zoë Schlanger

Selecting the right spot for ice-core drilling is a difficult pursuit. And after three years of searching with radar and on-the-ground sampling, an international team just struck gold: They found a spot on Antarctica where the ice is thick enough to reveal 1.5 million years of climatic history. It will take another three years to drill down that far.

Ice cores reveal what the climate was like on Earth throughout time. Air bubbles trapped in the ice can be sampled to measure how much carbon, methane, and other gases were in the atmosphere at the moment the ice froze. A single meter-long piece could contain 10,000 years of climate history, if selected carefully. And the deeper the ice core, the farther back in time the samples can go.

The research team, known as the “Beyond EPICA-Oldest Ice (BE-OI) consortium,” is a collaboration between scientists from institutions in 10 European countries to conduct worldwide search for the best places to drill for ice cores. “Beyond EPICA” refers to the oldest ice cores taken to date, known as the EPICA cores, which allowed scientists to peer back 800,000 years into the past. Those cores were taken between 1996 and 2004, and reached just over two miles (10,728 ft, or 3,270 meters) deep into the ice. EPICA stands for the European Project for Ice Coring in Antarctica.

The BE-OI team, along with researchers from the US, Japan, Russia, and Australia, scoured Antarctica for three summer seasons looking for the right spot. Eventually the decided that “Little Dome C,” three hours by snowmobile from the nearest Antarctic research base, has the best potential to contain ice that is at least 1.5 million years old, and still in good enough condition to drill. In some cases, ice that old melts due to the pressure created by the immense layers of ice above it, but Little Dome C is in good shape, according to a press release. The team presented its findings at the General Assembly of the European Geosciences Union in Vienna on April 9.

If the European Union approves funding to drill the new cores, they will be taken at 1.7 miles (8,957 ft, or 2,730 meters) deep—shallower than the EPICA cores, but expected to reveal air bubbles from a more ancient time, thanks to the excellent condition of the ice.

The drilling would begin in 2021, and continue for three Antarctic summers. By 2025, preliminary data should be available to paint a much older picture of how the Earth’s climate has changed over time.