Greenland site was ice-free 416,000 years ago, study finds
Researchers found that summers at the former Camp Century military base were 4.7°C warmer than modern conditions during Marine Isotope Stage 11.
Researchers examining sediment from Camp Century in northwestern Greenland have found that the area was ice-free approximately 416,000 years ago, according to a report by the Times of India.
The study, published in Climate of the Past, used a 3.44-metre sediment core recovered from beneath the Greenland Ice Sheet to reconstruct ancient environmental conditions.
The findings indicate that summer temperatures during Marine Isotope Stage 11 were about 4.7°C warmer than modern reference periods.
The presence of plant and aquatic biomarkers in the sediment suggests the landscape once contained lakes, streams, and tundra, despite the site now being buried under 1,387 metres of ice.
Scientists analysed lipid biomarkers, such as plant waxes and bacterial compounds, to determine that summer atmospheric water vapour was also enriched in deuterium compared to modern conditions.
The researchers noted that the warm interval during Marine Isotope Stage 11 lasted considerably longer than the Holocene, suggesting that the duration of warmth is crucial to ice-sheet loss.
Camp Century was originally built by the US Army Corps of Engineers in 1959 as a military experiment and research station before being abandoned in 1967.