Antarctic ice cores are like a time capsule, preserving tiny pockets of ancient air from the distant past. In a remarkable logistical milestone, European researchers have extracted data from an ice core 1.7 miles (2.8 kilometers) long—a gargantuan sample totaling up to 1.2 million years of Earth’s history.
In a recent statement, the Beyond EPICA–Oldest Ice project announced the completion of its final Antarctic campaign, which successfully retrieved what represents the longest continuous record of Earth’s climate as captured inside an ice core. Experts from 14 laboratories across 10 European countries participated in this project, which began in late 2019. The drilling concluded in 2025, but it was only last month that the last ice core samples (divided into smaller, manageable chunks) arrived in European labs, according to the British Antarctic Survey (BAS), which was involved in the project.
“We faced technological and engineering challenges never before encountered in Antarctic glaciology; success was far from certain,” Carlo Barbante, the project’s coordinator, said in the release. “We have achieved a historic result: enabling science to leaf through the oldest history book—namely, analyzing ice formed over the past 1.2 million years.”
Peering into the ice
The Beyond EPICA collaboration is the official successor of the European Project for Ice Coring in Antarctica (EPICA), Europe’s region-wide deep ice core investigations that began in 1996. The earlier project drilled at Dome C in southeastern Antarctica and successfully revealed up to 800,000 years of climate history, the BAS explained.
EPICA’s successor wanted to go even further back in time, to use ice cores for describing the Mid-Pleistocene Transition. During this period, Earth’s climate experienced drastic shifts in its interglacial and glacial cycles, the exact reasons for which remain unknown.
“It is thought that greenhouse gases had a minor role before the transition compared to after—but what caused the change is not firmly established,” Barbante told Nature News. “That’s why we need a record from which we can extract both gas concentrations and temperatures.”
Weathering barren lands
Ice cores are just that—a unique, direct source for information on the atmosphere at different times in Earth’s history, explained Huang Yu and Janani Venkatesh, two PhD students at Cambridge University in the U.K., in a blog post. Yu and Venkatesh, both involved in analyzing ice cores from Beyond EPICA, added that in very cold places like Antarctica, accumulated snowfall eventually compresses to form ice. This process also traps atmospheric air between the ice crystals in tiny bubbles.
Although ice cores are very valuable, it’s no easy feat to collect or analyze them. For one, researchers on-site in Antarctica had to endure two months of working in average temperatures of -31 degrees Fahrenheit (-35 degrees Celsius) to drill over a mile deep into the thick ice—and make sure that they were digging into the right layer, according to the collaboration statement.
Back at the lab, researchers melted a stick of ice, and a special membrane sorted the gaseous components into instruments for further analysis. “Nothing is wasted,” Yu and Venkatesh noted, as everything from particulate dust to meltwater is collected to extract as much information as possible.
In that sense, logistically speaking, the project’s achievements are truly impressive. Now that drilling is done, scientists will be hard at work picking apart the information hidden deep inside the samples.
