Sediment recovered from beneath a forgotten Cold War military base in northwestern Greenland reveals that regional summers were once 4.7°C warmer than modern conditions during an interglacial period about 416,000 years ago.
The US Army Corps of Engineers Built Camp Century
The Cold War era featured competition between the United States and the Soviet Union encompassing weapons development and a Space Race. Within that geopolitical climate, the U.S. decided to construct Camp Century in northwestern Greenland beneath the surface of the Greenland Ice Sheet. The US Army Corps of Engineers built the base in 1959. Seasonal operations continued until the facility was abandoned in 1967, leaving the structures buried beneath accumulating snow and ice.
The site was built 26 feet into the ice sheet’s upper layer of compacting snow, and soldiers lived inside the same snow that held the base up, making the snow itself central to the experiment. The Army supported Camp Century through hauling supplies across an over-snow trail that came directly from Thule Air Base, now known as Pituffik Space Base, according to a 2016 study published in Geophysical Research Letters.
While publicly described as a scientific research station, the base was part military experiment and part research station, with the US Army investigating whether infrastructure and ballistic missiles could operate beneath the ice. The installation served as a test for whether the Army could build something much larger and more complex: a concealed network capable of supporting up to 600 nuclear missiles that could strike the Soviet Union. Project Iceworm was the name given to the silo construction plan, which envisioned an area covering around 50,000 square miles in Greenland.
Army engineers excavated trenches, covered them with steel arches and snow, and installed prefabricated buildings inside, with airspace around the buildings helping to limit melting. Power for the installation came from the Army’s PM-2A nuclear reactor, which began operating in 1960 and ran for approximately 33 months before the Army deactivated and removed it, according to the Atomic Heritage Foundation.
Ultimately, the environment undermined the concept because Greenland’s ice sheet moves and deforms, threatening the tunnels that a much larger missile system would depend on.
In April 2024, NASA scientists flying over Greenland were testing radar equipment when the remains of the Cold War Army installation appeared beneath them. We were looking for the bed of the ice and out pops Camp Century,
Alex Gardner, a scientist at NASA’s Jet Propulsion Laboratory, told NASA.
The abandoned base’s structures now sit at least 100 feet below the surface, and the Camp Century site is now covered by about 1,387 metres of ice.
Ancient Tundra Beneath the Ice Sheet
Sediment buried beneath the ice sheet was extracted. The study, titled ‘Holocene-like summer climate during Marine Isotope Stage 11 in northwestern Greenland’ and published in Climate of the Past, focuses on a 3.44-metre sediment core recovered from beneath the Greenland Ice Sheet at Camp Century.
The upper sediment units were dated to about 416,000 ± 38,000 years ago and linked to Marine Isotope Stage 11, an interglacial period lasting from 424,000 to 374,000 years ago that resulted in a global sea level rise of at least 5 feet.
Researchers analysed lipid biomarkers, including plant waxes and bacterial compounds known as branched GDGTs. These molecular traces preserve information about the temperatures and water sources present when the organisms lived, allowing scientists to reconstruct ancient environmental conditions.
The biomarkers indicated that the temperature during the months above freezing in northwestern Greenland was 4.7 ± 3.2°C higher than the modern reference period, showing that summers were about 4.7°C warmer than modern conditions while the site was ice-free. The sediments also contain evidence of aquatic and terrestrial plant life, consistent with an ice-free area containing lakes, streams, and tundra with grasses, shrubs, and moss.
Researchers interpreted this isotopic enrichment as evidence that a greater share of the moisture reaching northwestern Greenland came from nearby sources, as more ice-free land and vegetation increased evapotranspiration, sending locally sourced moisture into the atmosphere. Paul Bierman, one of the researchers involved in the study, told Phys.org, It’s really the first bulletproof evidence that much of the Greenland ice sheet vanished when it got warm.
The discovery offers clues as to what the world looked like before modern humans evolved, and it also indicates the global impact of melted ice sheets on sea levels and how best we might stave off climate change.
The authors argue that limiting both the magnitude and duration of summer warming in coming centuries will be important for reducing future ice-sheet loss, turning a site once created as a Cold War military experiment into an archive for understanding how Greenland responds when temperatures remain elevated for long periods.
Earlier coverage: Barnes Ice Cap Growth Halted by Human-Driven Climate Change