Ice From the Last Ice Age Still Survives—Here’s Where
Yes—ice formed during the last ice age still survives today, preserved in places such as Antarctica, Greenland, and high mountain glaciers. Ice cores taken from these deposits contain layers and trapped air that scientists use to reconstruct past climates, including conditions dating back hundreds of thousands of years.
What scientists mean by “ice age”
The phrase can mean either a long geological period when Earth has large ice sheets, or, in everyday use, the coldest part of the most recent glacial period. Earth is currently in an ice age in the broad geological sense: permanent ice remains at the poles. The last glacial period ended roughly 11,700 years ago, when the current warmer interval, the Holocene, began.
At the height of that glacial period, vast ice sheets covered much of northern North America and northern Europe. They retreated as the climate warmed. Those continental ice sheets did not simply remain intact until today, but ice from the same broad period does survive in the polar regions, where snowfall accumulated and was compressed over time. Some of today’s oldest sampled ice is far older than the end of the last glacial period.
Where ancient ice is found
Antarctica and Greenland hold the largest and most continuous ice archives. In Antarctica, snowfall builds up over the ice sheet; deeper snow is compacted into firn, then dense glacier ice. Greenland’s ice sheet preserves a similarly valuable record, although its climate and melting history differ from Antarctica’s.
Old ice can also survive in mountain glaciers and in permanently frozen ground, but those records are generally more local or discontinuous. Examples include ice in the Andes, the Himalaya, and Arctic regions. How old an individual glacier’s ice is depends on its location, movement, melting, and the rate of new snowfall. It is therefore misleading to assume that every glacier contains ice from the last glacial period.
Scientists have drilled deep cores in both polar ice sheets. The European Project for Ice Coring in Antarctica (EPICA) Dome C core, for example, preserves a climate record extending about 800,000 years. A separate international Antarctic project reported in 2025 that it had recovered ice at least 1.2 million years old from a location near Little Dome C. That result is a notable discovery, but it does not mean that all the ice in Antarctica is that old.
How ice cores preserve a climate record
Ice cores are long cylinders drilled from glaciers or ice sheets. As each year’s snow is buried, pressure transforms it into ice and preserves clues about the environment. In favorable locations, seasonal differences create recognizable layers, much like rings in a tree, though layers can become harder to distinguish with depth and ice flow.
Researchers study several kinds of evidence in a core:
- Isotopes in the ice: Ratios of oxygen and hydrogen isotopes vary with temperature and the conditions under which snow formed. They provide evidence about past temperatures, but require interpretation and calibration.
- Trapped air: Tiny bubbles preserve samples of ancient atmosphere, including carbon dioxide and methane. These bubbles form after snow has fallen, so the age of the gas is younger than the surrounding ice at the same depth.
- Dust and particles: Mineral dust, sea salts, volcanic ash, and other particles can indicate atmospheric circulation, aridity, or volcanic eruptions.
- Chemical signals: Acidity and trace chemicals can help identify volcanic layers and other events that can be compared across records.
Scientists combine these signals with ice-flow models, measurements, and records from ocean sediments and other archives. A core is not a simple thermometer: it offers evidence that must be dated and interpreted, with uncertainty that can increase in the oldest, thinnest layers.
Why million-year-old ice matters
One important question is how Earth’s climate cycles changed over time. For much of the past 800,000 years, major glacial cycles repeated on a roughly 100,000-year rhythm. Older marine sediment records suggest that before that, cycles were more often closer to 41,000 years. A long, well-dated ice record could help researchers understand when and how this transition occurred.
The oldest Antarctic ice can also preserve ancient air, allowing comparisons between greenhouse-gas concentrations and climate. Such comparisons help researchers examine how temperature, ice volume, and atmospheric composition changed together. They do not, by themselves, predict the exact course of future climate; modern greenhouse-gas emissions and other influences must be assessed separately.
Very old ice is especially valuable because it is scarce and difficult to interpret. Deep ice can be stretched, thinned, folded, or mixed as it flows toward the coast. The oldest layers may be only a small fraction of the core’s total thickness, so choosing a drilling site where the ice has remained relatively undisturbed is crucial.
What “ice from the last ice age” does—and doesn’t—mean
Finding ancient ice does not mean the last ice age is still happening in the everyday sense, or that an unchanged glacier from that period survives everywhere. It means that some ice formed long ago remains frozen in present-day deposits. Ice sheets are dynamic: they gain snow, flow under gravity, lose ice at their edges, and can preserve some layers while destroying or distorting others.
Also, the age of ice and the age of the air trapped inside it are not identical. Snow first becomes porous firn, through which air continues to move. Only later are bubbles sealed off. Dating methods account for this separation; overlooking it could make a climate comparison appear to pair the wrong ice and atmosphere.
Frequently Asked Questions
Is there still ice from the last ice age?
Yes. Ice formed during the last glacial period survives in parts of today’s polar ice sheets and other frozen environments, although its age and condition vary by location.
How old is the oldest ice found?
In 2025, a scientific drilling project in Antarctica reported recovering ice at least 1.2 million years old. The record is tied to a particular site and sample, not to every part of the Antarctic ice sheet.
Can scientists tell the temperature from an ice core?
They can estimate past temperature using isotope ratios in the ice, alongside other evidence and calibration. The estimate is not a direct thermometer reading, and researchers report uncertainties.
Are the air bubbles the same age as the ice?
No. Air is trapped only after snow has been buried and pores close, so the gas is generally younger than the surrounding ice. Scientists account for that age difference in their analyses.
Does ancient Antarctic ice mean the planet is still in an ice age?
Earth is in an ice age in the broad geological definition because permanent polar ice exists. The last glacial period ended about 11,700 years ago; ancient ice remaining today does not mean that glacial period continues.
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