🧊 Ice Cores
Deep in the ice sheets of Antarctica and Greenland lies one of the most remarkable archives in science: a continuous record of Earth's climate stretching back 800,000 years, preserved in annual layers of compacted snow. Each layer contains bubbles of ancient atmosphere — direct samples of the air that existed when the snow fell — along with dust particles, pollen, volcanic ash, and chemical signatures that encode information about temperature, precipitation, atmospheric composition, and distant events like volcanic eruptions and forest fires. Extracting and analysing this archive requires drilling operations in some of the world's most hostile environments, but the scientific return is extraordinary.
years of climate record in Antarctic cores
depth of deepest Antarctic ice core
glacial cycles recorded in ice cores
current CO₂ — highest in 800,000 years
Ice core drilling is a technically demanding operation conducted in extreme conditions. A hollow drill bit, rotating under controlled pressure, cuts through the ice and collects a cylindrical core — typically 10 centimetres in diameter — that is retrieved in sections of approximately one metre. At the surface, the core sections are logged, photographed, and stored at -20°C to prevent deterioration. Drilling a deep Antarctic core can take multiple field seasons over several years: the deepest core yet recovered — drilled at Dome C, Antarctica by the EPICA project — reached 3.2 kilometres depth, recovering a climate record stretching back 800,000 years.
The primary measurements extracted from ice cores include atmospheric greenhouse gas concentrations (CO₂, methane, nitrous oxide) from the bubbles of trapped ancient air; temperature reconstructions from the ratio of oxygen isotopes in the ice (heavier isotopes are more abundant in ice formed during warmer periods); and records of volcanic eruptions (identified by sulphate spikes), dust storms, sea ice extent, and forest fire frequency. The combined record from multiple Antarctic cores shows that current atmospheric CO₂ concentrations of approximately 415 parts per million are higher than at any point in the 800,000-year record — and that the rate of increase is unprecedented in this entire period.
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Dr. Svensson has spent 15 years developing satellite and drone-based methods for monitoring Arctic and Antarctic ice change. Her research bridges the gap between raw satellite data and actionable climate science, drawing on missions from NASA, ESA, and the European Copernicus programme.