Greenland Will Continue To Melt Faster, New Study Reveals

First Posted: May 03, 2016 04:00 AM EDT

Scientists have recently found more reasons to believe that Greenland will melt faster, according to a recent study. Greenland's tidewater glaciers are losing ice mass due to the surface meltwater flowing through and underneath them.

According to a report in the Annals of Glaciology, Greenland alone could end up adding six or seven meters of rise in global sea level through ice mass drained out of large tidewater glaciers. The findings observed in the study will be applied to understand how glacier melt is influenced by water, comprehend the link between meltwater and subglacial discharge, glacier stability and flow, and predict global rise in sea level for Intergovernmental Panel on Climate Change reports.

"Our results show meltwater from these glaciers is playing a larger role in glacier stability than previously thought," said Kristin Schild, from Dartmouth's Department of Earth Sciences. "A clearer understanding of subglacial hydrology at tidewater outlet glaciers is important for understanding the mechanisms controlling fluctuations in ice flow and submarine melt as well as gauging the impact of rapid freshwater delivery to the fjord system."

It is quite common to read media report about how glaciers are melting, however not much attention is paid to the reason behind the cause, i.e. how glaciers are losing mass. The weakness in glaciers can be accelerated by surface meltwater, by further weakening and fracturing the ice as it goes to the bottom. Water beneath the glaciers lowers the friction between rock and ice, which causes the glaciers to move faster. When the fresh meltwater exits the glacier and drains into the ocean, it carries along the warm saltwater to the glacier terminus which leads to submarine melting, meaning the glacier melt from below.

Consequently, once the freshwater meets the ocean, it disintegrates the newly calved sea ice and icebergs that stabilize the glacier terminus. Therefore, tidewater outlet glaciers drain out most of Greenland's ice sheet mass via meltwater runoff, submarine melting and iceberg calving, according to the report. Furthermore, though remote sensing observations can be used to assess calving, it is tough to analyze the melting beneath and within the glaciers or figure out how meltwater is drained.

The study was conducted by researchers from Dartmouth by observing fast flowing West Greenland tidewater glacier. Tools like ground and satellite imagery, time-lapse photography and modeled runoff estimates were used to calculate how much of the glacier was experiencing melt and when the meltwater was exiting the glacier and entering fjords. The time taken between the onset of the melt and the emergence of meltwater showed how meltwater meanders through and below the glacier.

According to the results, numerous intense plumes of sediment-rich meltwater can take place across the terminus of a glacier, a fact which hasn't been documented previously. The phenomenon can raise the occurrence of calving and melting, which makes the stability of the glacier terminus weak. Furthermore, when meltwater gets stored under the glacier, it can speed the latter's velocity.

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