NASA scientists identified Camp Century, an abandoned U.S. military base buried approximately 100 feet beneath the Greenland Ice Sheet, using airborne radar during an April 2024 flight. The Cold War-era installation, once home to a network of tunnels and an experimental nuclear reactor, has been sealed under decades of accumulated ice and snow. The detection raises fresh questions about what happens when Arctic warming begins to expose the chemical and nuclear waste left behind.
Radar Pierces the Ice to Find a Cold War Ghost
During an April 2024 airborne radar survey, a team from NASA’s Jet Propulsion Laboratory captured a novel radar image that revealed structural elements of Camp Century sitting roughly 30 meters, or about 100 feet, below the surface. Alex Gardner, a JPL researcher, was among the scientists who described the moment the buried base came into focus on their instruments. The image showed features consistent with the tunnels and infrastructure that once made up what military planners called “the city under the ice,” including elongated reflections that align with the known layout of the camp’s subsurface corridors.
This was not the first time radar had detected Camp Century from above. A May 2, 2011 airborne radar profile conducted as part of Operation IceBridge had already picked up signatures of buried structures and a waste field at depths of approximately 100 feet. The April 2024 data, however, offered a sharper and more detailed picture, confirming earlier findings while adding new resolution to the site’s subsurface layout. Together, the two datasets span more than a decade of observation and establish that Camp Century’s footprint remains intact and detectable well below the ice. This provides a baseline for tracking any future changes as the ice sheet evolves.
Ground-Penetrating Radar Maps the Debris Field
Beyond NASA’s airborne passes, a separate peer-reviewed study published in Cold Regions Science and Technology documented a dense ground-penetrating radar survey conducted directly over the Camp Century site. That research identified specific infrastructure and debris locations, interpreting radar features that included what appeared to be possible liquid-filled sumps left behind when the base was abandoned. The study’s authors traced linear and point-like reflections that match the dimensions of tunnels, storage areas, and waste pits, building a three-dimensional picture of how the base was carved into the ice and what was left when U.S. forces departed.
The combination of airborne and ground-level radar data paints a clearer picture than either method alone. Airborne instruments can cover large swaths of the ice sheet quickly, flagging anomalies beneath the surface that suggest human-made structures or concentrated debris. Ground-penetrating radar, by contrast, operates at closer range and higher resolution, allowing researchers to distinguish between tunnel walls, debris piles, and potential liquid waste containers. The convergence of these two approaches means scientists now have a reliable, repeatable toolkit for monitoring buried Cold War sites across the Arctic, not just Camp Century, and for detecting any structural changes that might indicate thawing, collapse, or the mobilization of contaminants within the ice.
A Nuclear Reactor Beneath the Snow
Camp Century was not a typical military outpost. At its core sat the PM-2A, a portable nuclear power plant designed to generate electricity and heat for the base’s personnel in one of the harshest environments on Earth. A primary technical report detailing the reactor’s systems, instrumentation, and plant arrangement is preserved in the archives of the University of North Texas, originally produced for the U.S. Atomic Energy Commission by Alco Products, Inc. That document records startup testing results covering reactor physics, shielding performance, thermal and hydraulic behavior, and radiochemistry, offering a granular look at how the PM-2A was engineered and how it performed during its operational life beneath the Greenland ice.
The reactor was removed before the base was abandoned, but the technical record raises a question that most coverage of Camp Century glosses over: what residual contamination, if any, was left in the tunnels and surrounding ice after decommissioning? The startup testing data shows the PM-2A was a functioning nuclear system with real radiochemical outputs, not a theoretical exercise. Without publicly available primary records from the U.S. Department of Defense detailing environmental remediation at the site, the scope of any remaining contamination is difficult to assess from open sources alone. That gap in the public record is itself significant, because it means current risk estimates for the site rest on inference rather than direct measurement of what was left behind, leaving scientists and policymakers to extrapolate from reactor operations rather than from comprehensive cleanup documentation.
The 1951 Agreement That Made It Possible
The legal framework that allowed the United States to build a secret nuclear-powered base on Danish territory traces back to a defense agreement signed on April 27, 1951. The full text of that bilateral accord governs U.S. defense facilities and areas in Greenland, establishing the terms under which American forces could operate on the island. The agreement was a product of early Cold War strategy, when both nations saw Greenland’s position between North America and the Soviet Union as critical to Arctic defense and long-range early warning systems.
What the agreement did not anticipate was the long-term environmental liability that would come with burying military infrastructure, chemical waste, and nuclear-adjacent materials under ice that was assumed to be permanent. Historical texts of the agreement are available, but direct institutional records from Danish government archives detailing exactly what Copenhagen was told about Camp Century’s nuclear mission remain difficult to access. That ambiguity has diplomatic weight. As warming temperatures thin the Greenland Ice Sheet, the question of who bears responsibility for cleanup is no longer hypothetical. It is a live issue between two NATO allies, and the 1951 agreement offers no clear answer on whether environmental remediation obligations follow the flag, the territory, or some negotiated combination of both.
What Warming Means for What Lies Below
The reason U.S. Earth-observing missions keep returning to Camp Century with increasingly advanced radar is not purely archaeological curiosity. The base was abandoned on the assumption that the ice sheet would bury it permanently, sealing its waste in a frozen tomb. That assumption now looks uncertain. While no primary geophysical dataset currently published measures ice melt rates specifically over the Camp Century site, the broader trend of Arctic warming suggests that surface melt, refreezing, and changing snow accumulation could eventually alter the delicate balance that has kept the tunnels entombed. Researchers are therefore using Camp Century as a test case for how legacy infrastructure interacts with a changing cryosphere.
NASA has been expanding the ways it communicates these kinds of climate and cryosphere findings, from short-form explainers on digital video platforms to in-depth interviews on its podcast and audio channels, and through technical summaries in its recent research updates. Camp Century sits at the intersection of those efforts: it is both a story about Cold War secrecy and a case study in how a warming planet can turn yesterday’s buried infrastructure into tomorrow’s environmental hazard. As radar and climate models improve, the site will continue to serve as a focal point for discussions about responsibility, remediation, and the long memory of ice in an era when even the thickest ice can no longer be assumed to last forever.
More from Morning Overview
*This article was researched with the help of AI, with human editors creating the final content.
