Sooraj Shah ’24
The devastating impact of global warming on the human race is a frightening possibility, which may be more imminent than expected. Recent evidence suggests that the rising atmospheric carbon dioxide levels are not the only factor to blame, but that the surface of Earth itself may also be a contributing factor. A study conducted by Dr. Andrew Christ, professor in the department of Geology at the University of Vermont, focused on analyzing plant sediment at the bottom of the ice sheets in Greenland and found evidence hinting at a new wave of global melting.
The study was conducted using sample sediment recovered from a military base from the Cold War called Camp Century, which was stationed in the ice sheet during the 1960s. A 4,590 foot hole was drilled out and a sample of sediment from below the ice was collected in 1966, but was not analyzed until now. Christ and his team used infrared stimulated luminescence to determine how long it had been since the material was exposed to sunlight, allowing the researchers to date the sample. Scanning electron microscopy was used to study the surface and topography of the sample, providing an image that the researchers could analyze. In addition, the team analyzed oxygen isotopes present in the sample to estimate the elevation at which precipitation was falling at the time the sample formed, which was revealed to be much lower than the current height of the ice sheet.
The study provided evidence to support that Greenland’s ice sheet has not always been ice. It has melted and reformed at least one time during the last million years.The tests concluded that the sample contained plant fossils and biomolecules, which resided at the bottom of the ice sheet, indicating the presence of vegetation and greenery within the last million years. In today’s warming world, Christ suggests that the volatility of Greenland’s ice sheets is a cause of concern, as the fate of civilization is at risk if these sheets melt at an accelerated rate. The revealed susceptibility for these ice sheets to melt once again is now apparent, and the water level in the oceans would then rise enough to sink cities and alter the landscape of humanity. Further analysis of ice sheets across Greenland and other parts of the world will be the basis for future research.
. P. Bierman, et. al., A multimillion-year-old record of Greenland vegetation and glacial history preserved in sediment beneath 1.4 km of ice at Camp Century. Proceedings of the National Academy of Sciences 13, 118 (2021). DOI: 10.1073/pnas.2021442118
. Image retrieved from: