Newly Discovered Water Reservoir In Greenland Ice Sheet Could Affect How We Predict Rising Sea Levels
The discovery of an extensive, 27,000-square-mile aquifer in the Greenland Ice Sheet may likely enhance our understanding of the way snow and ice melts and eventually leads to rising sea levels. Researchers at the University of Utah reported the details of the aquifer's discovery in the journal Nature Geoscience.
A study, measuring snowfall accumulation and how it varies from year to year, has been ongoing in southeast Greenland since 2010 under Rick Forster, the study's lead author and a professor of geography at the University of Utah. The study, which covers 14 percent of southeast Greenland, is intriguing because the small area gets 32 percent of the entire ice sheet's snowfall.
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In order to analyze the ice, the team drilled for samples in 2010 and 2011. The first set of samples was from three locations. A year later, the team took four more samples from about the same location, but at a lower elevation. Of these four samples, two emerged with liquid water pouring off the drill, even though it was minus four degrees Fahrenheit. The water was found at the first and second hole, at depths of 33 feet and 82 feet, respectively.
The most surprising thing about the reservoir, known as a "perennial firn aquifer," is that it is body of water in an otherwise frozen landscape. Previously, there had been reports of water discharged from streams during the winter, "and snow temperature data implied small amounts of water, no one had yet reported observing water in the firn that had persisted through the winter," Forster said in a press release.
"Of the current sea level rise, the Greenland Ice Sheet is the largest contributor - and it is melting at record levels," Forster said in the press release. "So understanding the aquifers capacity to store water from year to year is important because it fills a major gap in the overall equation of meltwater runoff and sea levels."
At 27,000 square miles, the size of the aquifer is truly amazing - it measures larger than the state of West Virginia. The water persists yearlong due to large amounts of snowfall on the surface during the late summer, which subsequently insulates the water from subfreezing air temperatures above, Forster said. The Greenland Ice Sheet measures 5,000 feet thick, and is as large as Arizona, California, Colorado, New Mexico, and Utah combined.
The study is important because should the Greenland Ice Sheet melt, there can be catastrophic consequences. Scientists are worried about the rapid ice melt and runoff witnessed in recent years. In 2012 for instance, a record chunk of the ice sheet - 60 cubic miles - was lost. It is estimated that sea levels would surge 21 feet higher if the entire Greenland Ice Sheet melted, Forster said. No one is predicting that all the ice is going to melt at once, Forster said, however, ice formation, runoff, and water movement are critical aspects of predicting sea level changes.
The current study, with the recent discovery of the perennial aquifer could be quite different from previous studies. No previous study has considered a year-round storage mechanism of liquid water for calculations of the ice sheet mass changes. The movement and temperature of water within the ice sheet will call for altogether different, but precise calculations, which promise to alter previous models of rising sea level predictions.
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