In January 2025, a drilling team working in East Antarctica reached bedrock, roughly 2,800 metres beneath the surface, and pulled up ice that had been sitting there, undisturbed, since long before modern humans existed. Preliminary field analysis of the deepest ice suggests it formed from snow that fell around 1.2 million years ago, roughly 50 percent further back than any ice core had reached before.

The drilling was carried out at a site called Little Dome C, part of the Beyond EPICA – Oldest Ice project, a consortium of ten European countries coordinated through the Italian National Research Council, with major partners including the Alfred Wegener Institute in Germany, the French national research agency CNRS, and the British Antarctic Survey. The project’s stated aim was to beat the previous record holder, the original EPICA Dome C core, which had reached back about 800,000 years, and the new core does that by a wide margin, if the preliminary dating holds up.

What’s confirmed, and what’s still pending

The 1.2-million-year figure comes from continuous-flow isotope measurements taken in the field as the ice was extracted, a method that gives researchers a fast, workable estimate but not the final word. Full chronological dating requires laboratory analysis back in Europe, cross-checking the field estimate against multiple independent methods, including trapped gas ratios and other geochemical markers layered through the ice.

That distinction matters. Reaching bedrock and recovering a continuous ice column of this length is itself confirmed and uncontested; multiple independent sources, including the consortium’s own announcements and national funding agencies, place that milestone in January 2025. The precise age of the deepest ice is, for now, a strong preliminary estimate rather than a settled figure, and the project’s own scientists have described it that way in their public statements.

Why the age of the ice matters

Ice cores work because snow falling year after year traps tiny bubbles of the atmosphere at the time it fell, along with dust, volcanic ash and other markers, and compresses into layers that can, in principle, be read in order like the pages of a very slow diary. An ice core reaching back 1.2 million years would let researchers sample the actual air from a period called the Mid-Pleistocene Transition, when Earth’s glacial cycles are thought to have shifted from a rhythm of roughly 41,000 years between ice ages to one closer to 100,000 years.

Why that shift happened is one of the more persistent open questions in climate science. Existing evidence, largely reconstructed from ocean sediment cores rather than direct atmospheric samples, suggests atmospheric carbon dioxide levels may have played a role, but sediment-based reconstructions are indirect. An ice core spanning the transition would, for the first time, let researchers measure greenhouse gas concentrations from that period directly, rather than infer them.

That analysis hasn’t been done yet on the Little Dome C core. The bedrock recovery is the beginning of a multi-year laboratory process, not the end of one.

A project two decades in the planning

Beyond EPICA traces its roots to site-selection surveys that began around 2016, using radar to map the thickness and internal structure of the East Antarctic ice sheet in search of a location where old, undisturbed ice might sit close enough to bedrock to be reachable. Little Dome C was chosen in part because radar surveys suggested the ice there had not been significantly deformed or melted at its base, a risk that can scramble or destroy the oldest, deepest layers at other sites.

Drilling itself began in the 2021-2022 Antarctic field season and continued across subsequent summers, constrained by the short window each year when conditions allow safe fieldwork at the site, roughly 35 kilometres from the existing Concordia research station. Reaching bedrock in January 2025 came after several seasons of incremental progress, each one adding to a core that now stretches, when accounting for compression at depth, across roughly 2,800 vertical metres of accumulated snowfall.

What comes next

The ice itself is now being transported, in refrigerated sections, back to laboratories across the consortium’s member countries for detailed analysis. That process is expected to take years rather than months, involving multiple dating techniques applied independently before researchers will treat the deepest ice’s age as settled rather than preliminary.

If the 1.2-million-year figure holds up under full laboratory dating, the core would give climate scientists their first direct atmospheric window into the Mid-Pleistocene Transition, a period currently understood mostly through indirect proxies. Whether that window changes the leading explanations for why Earth’s ice ages slowed and lengthened, or simply adds detail to them, is a question the ice itself hasn’t answered yet.