Greenland Ice Sheet Has Unique 'Plumbing' System, New Study Shows

Hidden under Greenland's ice sheet is a unique "plumbing system," say researchers from the University of Exeter who recently studied the path water takes as it flows from subglacial lakes and found that the subglacial lake fills and drains periodically.

"Our research reveals details about the plumbing system beneath the Greenland ice sheet, which is important because the configuration of that system has an impact on the flow speed of the overlying ice," Dr. Steven Palmer, lead author of the study from the Geography Department at the University of Exeter, explained in a news release.

For their study, researchers examined the flow paths of a subglacial lake that drained beneath the ice sheet in 2011. They discovered that the water drained from the lake via a subglacial tunnel which suggests the subglacial lake fills and drains periodically like a kitchen sink. Using satellite observations, the team found that a similar drainage event occurred in 1995.   

While previous studies have observed the draining of subglacial lakes in Antarctica, this study is the first to discover a similar underground plumbing system in Greenland. 

Compared to Antarctica subglacial lakes that are sustained through melting of the ice sheet base, Greenland's subglacial lake is fed by surface melt that flows down a nearby vertical shaft within the glacier. This suggests that as the Arctic continues to warm, increasing amounts of water melt could lead to more frequent subglacial lake drainage, ultimately increasing the ice sheet's sensitivity to climate change and impacting the rate of sea level changes.

"We have made the first observations of how the Greenland ice sheet responds to subglacial lake drainage, but more research is required to understand the long-term impacts of these events," Dr. Palmer added in the release. "It is possible that draining subglacial lakes act to release the pressure at the ice sheet base, meaning that if they drain more frequently in the future, they may actually result in slower ice sheet flow overall."

Their study was recently published in the journal Nature Communications.

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