An international scientific team has achieved a significant milestone in Antarctica, successfully drilling a 2.8-kilometer-deep ice core that contains ice at least 1.2 million years old. This remarkable feat, accomplished at the remote Little Dome C site near the Concordia research station, offers an unparalleled view into Earth's atmospheric and climate evolution over an extended period.
The Beyond EPICA project, led by Carlo Barbante from Italy's National Research Council's Institute of Polar Sciences, spearheaded this ambitious drilling operation. This achievement nearly doubles the age of previously retrieved ice cores, which extended back 800,000 years. The team, consisting of 16 scientists and support staff, endured four Antarctic summers and average temperatures of approximately -35°C to reach the bedrock at a depth of 2.8 kilometers.
This ancient ice core, described as a time capsule, contains tiny air bubbles trapped during the Mid-Pleistocene Transition. This critical period, approximately between 1.2 million and 750,000 years ago, marked a significant shift in Earth's glacial cycles, transitioning from a 41,000-year pattern to a more pronounced 100,000-year cycle. The precise causes for this transition are still under scientific investigation, with hypotheses suggesting changes in the ocean carbon cycle and atmospheric CO2 levels.
The ice sample, extracted from the East Antarctic Plateau, serves as a unique natural archive. It contains gases such as carbon dioxide and methane, along with traces of dust, volcanic ash, and microorganisms, providing vital clues about past winds, temperatures, and ocean conditions from over a million years ago. Researchers from the British Antarctic Survey and 11 other institutions across 10 countries will employ a pioneering technique of slowly melting the ice to measure the chemical composition of each layer in real-time.
This meticulous analysis aims to construct a detailed climate chronology, essential for understanding the drivers behind the shift in glacial cycles. The ultimate goal extends beyond reconstructing past climates; it involves validating current climate models and understanding the factors influencing today's climate. The research highlights that while greenhouse gas levels over a million years ago were similar to today's, the planet's climatic behavior was different. This ancient ice provides a crucial baseline for comparing natural climate variability with human-induced changes, offering invaluable tools for assessing current climate trends and developing more effective climate change mitigation and adaptation strategies.