Recent research has revealed groundbreaking evidence suggesting that Greenland, currently 98% covered by ice, was virtually ice-free less than a million years ago. This discovery challenges the long-held belief that Greenland has been continuously covered by ice since the beginning of the Pleistocene epoch, around 2.7 million years ago. The new findings, published in the journal PNAS, provide the first direct evidence that the Greenland ice sheet not only melted at its edges but also in its central regions during recent geological history.
Led by Paul Bierman, a geologist at the University of Vermont, the research team reexamined an ice core sample extracted in 1993. Upon analysis, they discovered an array of fossils, including willow, fungi, and insect remains, along with an exceptionally well-preserved Arctic poppy seed. These fossils were a surprising find, as the original intention was to measure carbon-dating isotopes, not to uncover evidence of past life. One particularly notable find was a specimen of rock spike moss (Selaginella rupestris), which typically grows in sandy and rocky environments—conditions impossible to find on top of an ice sheet. This discovery strongly supports the idea that the central Greenland ice sheet had melted away and was replaced by a tundra ecosystem within the last million years.
A previous study in 2016 suggested that the current Greenland ice sheet might be no older than 1.1 million years. It was estimated that if the ice had indeed melted at a site called GISP2, then 90% of Greenland would have been ice-free at that time. Additional evidence came from another core extracted from Greenland’s northwest coast in 1966, which was analyzed by Bierman and his team in 2019. This core contained fossils, including seeds, twigs, and insect parts, indicating that this region of Greenland was ice-free within the past 500,000 years.
The latest findings suggest that the center of Greenland was also free of ice at some point in the last million years. This region, now buried under a 2-mile-thick ice layer, once supported a diverse tundra ecosystem, possibly including flowers and small trees. The ice core reexamined by Bierman and graduate student Halley Mastro had been stored at the National Science Foundation Ice Core Facility in Colorado for over 30 years and was nearly overlooked. The ice portion of the core had been extensively analyzed, but the sediment beneath had largely been ignored until this recent study.
These findings have significant implications for the present day. The fact that Greenland was once ice-free at lower levels of atmospheric carbon dioxide than today’s levels suggests that the Greenland ice sheet could melt again, potentially raising sea levels drastically. While this process would take decades or even centuries, the majority of sea-level rise currently originates from Greenland. Despite the concerning nature of these discoveries, Bierman points out that the ice sheet has melted and reformed in the past, offering a glimmer of hope for the future.