Greenland’s glaciers are melting 100 times faster than previously calculated, according to a new model that takes into account the unique interaction between ice and water in the island’s fjords.
New mathematical representation of glacial melt factors in recent observations of how ice is eroding away from the stark vertical faces at the ends of glaciers in GGreenland. Previously, scientists used models developed in Antarcticawhere icy tongues float above sea water – a completely different order.
“For years, people have taken a model of the melt rate of Antarctic floating glaciers and applied it to green landVertical ice fronts,” lead author Christine Schulza research associate at the Odin Institute for Engineering and Computational Sciences at the University of Texas at Austin, said V statment. “But there is more and more evidence that the conventional approach produces very low melt rates on vertical glacier fronts in Greenland.”
The researchers published their findings in September in the journal Geophysical Research Letters.
The researchers already knew that their Antarctica-based understanding of Arctic glaciers wasn’t quite a match. But it’s hard to get close to the edges of Greenland’s glaciers, because they lie at the ends of fjords — long, narrow inlets of seawater flanked by high cliffs — where warm waters erode the ice. This leads to dramatic events in the birth of the calves as pieces of ice the size of buildings fall into the water without warning, creating small tsunamis, according to the researchers.
Researchers led by an oceanographer physicist Rebecca Jackson of Rutgers University uses motorized boats to get up close to these dangerous ice slopes and take measurements. They’ve done this at LeConte Glacier in Alaska as well as Kangerlussuup Sermia in Greenland. (An upcoming mission led by scientists at the University of Texas at Austin will send robotic submarines to Wuhu Three glaciers in western Greenland.Jackon’s measurements indicate that models based on Antarctica greatly underestimate Arctic ice melt. LeConte, for example, is disappearing 100 times faster than models predicted.
The combination of cold fresh water from the glaciers and warmer seawater causes the ocean to circulate closer to the glaciers and further into the ocean, which means that the melt has far-reaching effects. The Greenland Ice Sheet is also important to sea level rise; Greenland’s ice contains enough water to raise sea level by 20 feet (6 meters).
The new model uses the latest data from subglacial expeditions along with a more realistic understanding of how the steep, slope-like faces of glaciers affect ice loss. The results are consistent with Jackson’s findings, showing 100 times more melt than older models would have predicted.
“Ocean climate model results are very relevant to humanity for predicting trends associated with climate change, so you really want to get it right,” said Schulz. “This was a very important step for improving climate models.”
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