Imagine holding a piece of Earth's history in your hands, a frozen time capsule from a world that was dramatically warmer than today. That's exactly what a team of scientists has done, uncovering six-million-year-old ice in Antarctica—the oldest dated ice ever found. But here's where it gets controversial: this discovery could challenge our understanding of Earth's climate history and its future trajectory. Could studying this ancient ice reveal insights that contradict current climate models? Let’s dive in.
A collaborative effort led by the NSF COLDEX team, which includes researchers from the University of Minnesota and other U.S. institutions, successfully recovered this ancient ice in the Allan Hills region of Antarctica during the 2019-20 and 2022-23 austral summer seasons. Supported by the United States Antarctic Program, the team drilled ice cores that contain tiny air bubbles—a treasure trove of information about Earth’s past climate. Their findings, published in PNAS, offer a rare glimpse into a time when global temperatures were higher and sea levels were significantly elevated, long before human activity began influencing the climate.
And this is the part most people miss: the ice was dated using Argon-40 isotopes, a method pioneered in the 1930s and 40s by physicist Al Nier at the University of Minnesota. These isotopes, produced by the radioactive decay of Potassium-40 in Earth’s crust, accumulate in the atmosphere over millions of years, acting as a geologic clock. Nier’s groundbreaking work laid the foundation for using isotopes to measure deep time, and this discovery highlights the enduring impact of his research.
The NSF COLDEX team made several groundbreaking observations:
- Age and Significance: The six-million-year-old ice is more than double the age of the next oldest samples found at the same site and nearly six times older than the current continuous ice core record, which only stretches back 800,000 years.
- Climate Insights: Isotopic measurements reveal a pattern of progressive cooling in Antarctica during the Pliocene epoch (5.3 to 2.6 million years ago), with even warmer temperatures preceding this period. This provides a unique opportunity to study Earth’s climate during a naturally warmer era, independent of human-induced changes.
- Implications for the Future: Co-author Peter Neff, an assistant professor at the University of Minnesota, emphasizes that this ice archive could shed light on critical questions in paleoclimate science. How stable was the Antarctic ice sheet during warmer periods? What was the relationship between greenhouse gases, ocean temperatures, and sea levels? These answers could refine predictions about future ice sheet behavior, sea-level rise, and global warming.
But here's the controversial question: If Earth was naturally warmer in the past without human influence, does this challenge the urgency of current climate action? Or does it underscore the unprecedented rate of modern warming? We’d love to hear your thoughts in the comments.
The University of Minnesota’s involvement extends beyond Neff. Collaborators include Heidi Roop, co-director for knowledge transfer and director of the Climate Adaptation Partnership, and graduate student Bridget Hall, who joined an NSF COLDEX geophysical survey team at the South Pole in 2024. Martin Froger Silva, a digital communications coordinator, is currently in Antarctica collecting more ice cores and sharing the experience on Instagram. Future plans include a second phase of NSF COLDEX research from 2026 to 2031, promising even more discoveries.
Supported by the NSF Office of Polar Programs, Oregon State University, and the U.S. Antarctic Program, this research exemplifies the power of interdisciplinary collaboration. The ice cores are curated at the NSF Ice Core Facility in Denver, ensuring these ancient samples are preserved for future study.
The College of Food, Agricultural and Natural Resource Sciences (CFANS) at the University of Minnesota plays a pivotal role in this work. With a mission to inspire minds, nourish people, and sustainably enhance the natural environment, CFANS combines innovation, education, and research to tackle global challenges. From its 12 academic departments to its statewide research centers, CFANS is shaping the future of science and leadership. Learn more at cfans.umn.edu.
This discovery isn’t just about ancient ice—it’s about understanding our planet’s past to navigate its future. What do you think? Does this research make you more hopeful, or does it raise new concerns? Let us know in the comments below!
