The Greenland Ice Sheet melted and reformed at least once during the past million years, a study suggests. Relatively little is known about the history of the Greenland Ice Sheet, or the island's ice-free ecosystems, before the Last Interglacial. Andrew Christ and colleagues analyzed samples of subglacial sediment at the bottom of the Camp Century ice core, frozen under nearly 1.4 km of ice in northwestern Greenland. The sediment preserved a unique, multi-million-year-old record of glaciation and vegetation. Enriched stable isotopes in the pore ice suggested that precipitation must have occurred at lower elevations than the present ice surface elevation, implying the absence of ice sheets. Additional analysis of isotope ratios indicated that the Greenland Ice Sheet persisted through interglacial periods for much of the Pleistocene. However, there were at least two episodes of warm, ice-free, vegetated conditions: one in the Early Pleistocene and the other during the past 1.1 million years. According to the authors, these insights into the history of the Greenland Ice Sheet could hold critical information for predicting future sea-level rise in response to climate change.
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Article #20-21442:
"A multi-million-year-old record of Greenland vegetation and glacial history preserved in sediment beneath 1.4 km of ice at Camp Century," by Andrew Christ, et al.
MEDIA CONTACT:
Andrew Christ,
University of Vermont,
Burlington, VT;
tel: 303-929-6646;
email: <andrew.christ@uvm.edu>