Greenland subglacial flood bursts via ice sheet floor

Partially funded by ESA’s Earth Observation FutureEO programme, a world staff of researchers, led by scientists at Lancaster University and the Centre for Polar Observation and Modelling within the UK, studied a beforehand undetected lake beneath the ice sheet in a distant area of northern Greenland.

Using 3D fashions of the ice sheet floor from the ArcticDEM mission, alongside knowledge from a number of satellite tv for pc missions together with ESA’s ERS, Envisat and CryoSat, and Europe’s Copernicus Sentinel-1 and Sentinel-2, and NASA’s ICESat-2 missions, the researchers found that, in 2014, this subglacial lake all of a sudden drained.

Their research, printed at the moment in Nature Geoscience, reveals how, beneath excessive situations, flooding from the drainage of a lake beneath the ice may pressure its means upwards and escape on the ice sheet floor. 

These new finds shed new mild on the damaging potential of meltwater saved beneath the ice sheet.

Over a 10-day interval in the summertime of 2014, a large crater – 85 meters deep and spanning 2 sq. kilometres – fashioned on the floor of the ice sheet as 90 million cubic metres of water had been all of a sudden launched from this hidden subglacial lake.

This is equal to about 9 hours’ price of water thundering over Niagara Falls at peak stream, making it one of many largest recorded subglacial floods in Greenland.

While the sudden surge of meltwater was startling in itself, much more alarming was the accompanying injury – towering 25-metre-high ice blocks torn from the floor, deep fractures within the ice sheet, and the ice floor scoured by the flood’s damaging pressure.

Jade Bowling, who led this work as a part of her PhD at Lancaster University, mentioned, “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.

“The existence of subglacial lakes beneath the Greenland Ice Sheet is still a relatively recent discovery, and – as our study shows – there is still much we don’t know about how they evolve and how they can impact on the ice sheet system.

“Importantly, our work demonstrates the need to better understand how often they drain, and, critically, what the consequences are for the surrounding ice sheet.”

While it was beforehand believed that meltwater travels downwards from the floor of the ice sheet to its base and finally flows into the ocean, these new findings reveal that water also can transfer in the other way – upwards via the ice.

Even extra sudden was the invention that the flood came about in an space the place fashions had indicated that the ice mattress was frozen. This led researchers to recommend that intense stress triggered fractures beneath and thru the ice sheet, creating channels via which the water may rise.

Current fashions that predict how ice sheets will reply to local weather change and elevated melting don’t account for these upward-flowing, fracture-driven processes.

Mal McMillan, Co-Director of the Centre of Excellence in Environmental Data Science at Lancaster University, and Co-Director of Science on the UK Centre for Polar Observation and Modelling, mentioned, “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.

“Satellites represent an essential tool for monitoring the impacts of climate change, and provide critical information to build realistic models of how our planet may change in the future.

“This is something that all of us depend upon for building societal resilience and mitigating the impacts of climate change.”

ESA’s Diego Fernandez, Head of the Earth Observation Science Section, famous, “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.

“The project’s goal is to deepen our understanding of the hydrology of the Greenland Ice Sheet by leveraging data from Earth observation satellites, and, in particular, to shed light on how the ice sheet is responding to climate change.

“This result adds to the body of knowledge we are establishing through the ESA Polar Science Cluster on how the Arctic is changing in response to increased warming. 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.

“We congratulate the research team on advancing our understanding of this vulnerable region.”