Researchers from the Woods Hole Oceanographic Institution drilled three ice cores at Allan Hills, Antarctica (150 m, 159 m, 206 m) and recovered microscopic bubbles containing the oldest measured atmosphere—about 6 million years old. Argon isotope dating established the age, while water isotopes suggest Antarctica was roughly 12 °C warmer then. The team now plans to analyze ancient greenhouse gases to better understand long-term climate change.
Scientists Recover Earth’s Oldest Measured Air — 6 Million-Year-Old Atmosphere Trapped in Antarctic Ice
Researchers from the Woods Hole Oceanographic Institution drilled three ice cores at Allan Hills, Antarctica (150 m, 159 m, 206 m) and recovered microscopic bubbles containing the oldest measured atmosphere—about 6 million years old. Argon isotope dating established the age, while water isotopes suggest Antarctica was roughly 12 °C warmer then. The team now plans to analyze ancient greenhouse gases to better understand long-term climate change.
09:32 PM, 11/14/2025Science
6 Million-Year-Old Air Found in Allan Hills, Antarctica
It’s easy to imagine dramatic discoveries hidden beneath Antarctica’s thick, ancient ice — from alien life to prehistoric viruses — but the latest finding is simpler and scientifically profound. Researchers from the Woods Hole Oceanographic Institution recovered microscopic air bubbles trapped in ice at Allan Hills that contain the oldest directly measured atmosphere yet: about 6 million years old.
Why this site is special
Antarctica’s cold, stable conditions can lock particles and pockets of air into snow and ice, forming natural time capsules. In most places, very old ice lies far below the surface, but in Allan Hills unusually ancient layers are closer to the top. The team is still studying why; lead scientist Sarah Shackleton suggests a combination of persistent katabatic winds that scour fresh snow away and extremely low temperatures that nearly halt ice flow.
How the discovery was made
Described in a paper in Earth, Atmospheric, and Planetary Sciences, the team drilled three vertical cores to depths of 150 m, 159 m, and 206 m. The cores contained densely packed, microscopic air bubbles whose composition was analyzed using argon isotope dating to determine their age. Water isotope measurements from the ice indicate that Antarctica’s climate was roughly 12 °C warmer when that air was trapped—consistent with a very different Antarctic environment millions of years ago.
“We’re still working out the exact conditions,” said Sarah Shackleton, noting the likely role of strong winds and extreme cold in preserving shallow, very old ice.
Implications and next steps
Originally the team hoped to recover air from the Pliocene (around 2.6 million years ago); the 6-million-year result far exceeded expectations and opens a rare window into Earth’s mid-Pliocene and late-Miocene atmosphere. Next, researchers plan to measure greenhouse gas concentrations in these bubbles to track long-term changes in atmospheric composition and to refine models of past and future climate behavior.
Why it matters: Direct samples of ancient air provide ground-truth data for how greenhouse gases and temperatures co-varied in Earth’s deep past—critical inputs for understanding long-term climate sensitivity and future change.