A new study of glacial rivers in Greenland has important implications for how scientists might model future ice melts in the region and subsequent sea level rise.
What is Happening?
- Researchers previously thought that they could measure how ice melts in Greenland simply by looking at the amount of meltwater sitting on top of glaciers and in moulins- shafts in the glacier that empty rivers from the surface to the interior. However, a new study, published in the journal Geophysical Research Letters, found that a glacier’s speed increased when water pressure rapidly changed beneath the ice sheet.
Laurence Smith, study coauthor and Brown University environmental studies professor, told Earther, “These findings will help to refine ice sliding models, which are critically important for predicting future ice sheet contributions to global sea level rise.”
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- The Greenland ice sheet is very important when it comes to global sea level rise. It currently contributes more to rising sea levels than any other source; if all of the ice sheet was to melt, it would increase water levels by more than 6 metres.
- The team travelled to the Russell Glacier in southwestern Greenland in 2016 to study a glacial river. The researchers recorded the forward motion of the glacier itself, the amount of meltwater pouring into the moulin and the amount of meltwater pouring out from beneath the glacier at the water’s edge. They determined that changes in subterranean water pressure were driving the glacier’s overall speed.
- NASA Glaciologist Dr. Lauren Andrews compared a glacier moving over subterranean meltwater to car tires sliding on a wet road, saying “If you have a rapid perturbation of water going into the subglacial system, you overwhelm the system, and so you create essentially a layer of water at the interface that’s not contained in channels or cavities anymore.”
- NASA says that the way that water pressure drives glacier speed had never before been studied in the field. This new research now adds 168 hours of “rare in situ” measurements to understand the dynamics of glacial rivers, which had previously been overlooked.
Smith says, “In 2015 when we started this study, there was surprisingly little attention paid to the hydrology of streams and rivers on the ice sheet, especially inland away from the ice edge, and we felt that this was a critical scientific gap. These findings affirm the importance of supraglacial rivers to subglacial water pressure and ice dynamics, even in relatively thick ice,” the researchers wrote.
Featured image by: Flickr