What does the 23‑million‑year Antarctic core show?

A continuous climate record from beneath the ice

An international drilling campaign has recovered the longest sediment core taken from beneath an ice sheet, opening a 23‑million‑year window into Earth’s polar climate. The sediments stack up as a layered archive: changes in grain size, chemistry and biological remains preserve signals of ice‑sheet growth and retreat, ocean temperature and the delivery of meltwater and sediment from surrounding continents.

Scientists can now connect those local signals to global climate shifts. The core records repeated cycles of colder and warmer conditions, shifts in ocean productivity and episodes when meltwater reorganized ocean circulation. Because the material came from under an ice sheet, it captures how marine‑terminating ice margins behaved during past warm intervals—information that is otherwise sparse. That helps researchers test and improve models of ice‑sheet sensitivity to warming and of how quickly ice contributes to sea‑level rise.

Why this matters now

• It provides empirical constraints on how Antarctic ice and surrounding oceans responded to past climate forcings.
• The record supplies timelines for when and how fast ice loss and meltwater pulses occurred.
• Geochemical proxies in the core reveal changes in ocean circulation and carbon cycling tied to polar processes.

Policy and science implications

The new core gives modelers real world benchmarks for projecting future sea‑level rise and for estimating carbon feedbacks from polar regions. It also highlights where uncertainties remain: dating precision, spatial representativeness and connecting local signals to global impacts. Taken together, the dataset narrows the gap between paleoclimate evidence and future projections, making assessments of coastal risks more grounded in Earth’s long‑term behavior.