The ice dome located in northern Greenland has previously melted completely under temperatures expected to return this century. This significant discovery offers valuable insights into the speed at which melting ice sheets can influence global sea levels.

In a groundbreaking study, researchers drilled 500 meters into Prudhoe Dome, an extensive ice formation the size of Luxembourg situated in northwestern Greenland, gathering seven meters of sediment and rock core. Infrared dating indicated that the core’s surface sand was sun-bleached approximately 7,000 years ago—corroborating that the dome fully melted as the planet emerged from its last glacial maximum due to cyclical changes in Earth’s orbital dynamics.

During that era, summer temperatures were 3°C to 5°C warmer than today’s averages. Alarmingly, human-induced climate change could bring back similar temperatures by 2100.

“This provides direct evidence that the ice sheet is highly sensitive to even the modest warming seen during the Holocene,” stated Yarrow Axford, a Northwestern University researcher not involved in the study.

With the ongoing melting of Greenland’s ice sheet, projections indicate a potential sea level rise of tens of centimeters to a meter within this century. To refine these predictions, scientists must enhance their understanding of how quickly various sections of the ice sheet are dissipating.

The Prudhoe Dome core is the first of multiple cores analyzed by the GreenDrill project, funded by the National Science Foundation and featuring researchers from various U.S. universities. Their goal is to extract crucial climate data from beneath the ice sheets, one of Earth’s least-explored areas.

Notably, deposits excavated in 1966 from beneath the ice at Camp Century—a U.S. nuclear military facility operational for eight years during the Cold War—revealed that Greenland lacked ice around 400,000 years ago. Further, a rock core taken in 1993 from underneath Summit Station illustrated that the entire ice sheet has melted as recently as 1.1 million years ago.

However, the GreenDrill project extends its research deeper beneath the ice, collecting samples from multiple locations near Greenland’s northern coast.

“The crucial question is when did the edge of Greenland experience melting in the past?” posed Caleb Walcott-George, part of a new research team at the University of Kentucky. “This is where the initial sea level rise will transpire.”

Current ice sheet models indicate uncertainty regarding whether northern or southern Greenland will melt at a faster rate in the future. This study bolsters the evidence that warming post-last glacial maximum manifested earlier and with greater intensity in northern Greenland, according to Axford.

Potential explanations may involve feedback mechanisms, such as the loss of Arctic sea ice, which could have allowed more ocean heat to penetrate the atmosphere in the far north.

By confirming that Prudhoe Dome melted under a warming of 3°C to 5°C, this study adds credibility to ice sheet models that predict similar outcomes, asserted Edward Gasson, who was not part of the research at the University of Exeter, UK.

“This research is vital for recalibrating surface melting models: When will we really begin to lose this ice?” Gasson emphasized.