The international study, led by Lancaster University and the UK Centre for Polar Observation and Modelling, focused on a previously uncharted subglacial lake buried deep beneath the ice. With support from ESA's Earth Observation FutureEO programme, the team used 3D ArcticDEM models and decades of satellite observations from missions such as ERS and Envisat to trace the evolution of the 2014 drainage event.
Published in Nature Geoscience, the findings reveal that over a 10-day span in 2014, 90 million cubic meters of water surged upward, breaching the ice sheet and carving out a 2-square-kilometer crater 85 meters deep. The torrent rivaled the volume of Niagara Falls at peak flow, making it one of Greenland's largest recorded subglacial floods.
The outburst also unleashed destructive forces: 25-meter-high ice blocks were torn free, deep surface fractures appeared, and the surrounding area was heavily scoured. Lead author Jade Bowling recalled, "When we first saw this, because it was so unexpected, we thought there was an issue with our data. However, as we went deeper into our analysis, it became clear that what we were observing was the aftermath of a huge flood of water escaping from underneath the ice."
Bowling emphasized that the discovery highlights just how little is known about Greenland's subglacial lake systems. "Importantly, our work demonstrates the need to better understand how often they drain, and, critically, what the consequences are for the surrounding ice sheet," she added.
Traditionally, meltwater was believed to flow from the surface downward to the ice bed and then seaward. However, this event proved that under sufficient pressure, water can force its way upward-even through areas where the ice base was thought to be frozen solid. Such vertical, fracture-driven hydrology is not included in current climate models.
Mal McMillan, Co-Director of the Centre of Excellence in Environmental Data Science and a key contributor to the study, remarked, "This research demonstrates the unique value of long-term satellite measurements of Earth's polar ice sheets, which - due to their vast size - would otherwise be impossible to monitor."
Diego Fernandez, ESA's Head of Earth Observation Science, praised the findings as a milestone in polar science. "This discovery is remarkable, and we're proud that our Science for Society 4D Greenland project has played a key role in making it possible," he said. "Gaining insight into its hydrology is crucial for understanding these changes - and for predicting how the ice sheet will contribute to global sea-level rise in a warming climate."
Research Report:Greenland ice-sheet uplift and drainage from the 2014-2015 collapse of a subglacial lake
Related Links
FutureEO
Beyond the Ice Age
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