A team of University of Georgia researchers has solved the mystery of what happens to the meltwater that results from the melting glacial land ice on Greenland that makes its way into the ocean. The findings shed light on the concerns surrounding the effects of this meltwater on global sea level rise and the long-term effects of atmospheric warming.
"Understanding the fate of meltwater is important, because research has shown that it can carry a variety of nutrients, which may impact biological production in the ocean," said Renato Castelao, an associate professor of marine sciences in UGA's Franklin College of Arts and Sciences and co-author of the study. "There is also evidence that large freshwater inputs could alter ocean currents and affect the normal formation of sea ice."
Using a simulation that tracks meltwater runoff under various atmospheric conditions, the team found that most of the meltwater off the west coast of Greenland originates from ice on the east coast.
"Meltwater from Greenland is directed by the surrounding ocean currents, but its fate depends on when and where the runoff occurs and the wind fields driving ocean currents," said Thomas Mote, a professor of geography at UGA and co-author of the study.
The model reveals that wind and ocean currents move meltwater around the southern tip of Greenland west on a journey that lasts more than 60 days. After the meltwater finishes its journey, it settles in the Labrador Sea, a part of the Atlantic that lies between Canada's Labrador Peninsula and the east coast of Greenland. Conversely, meltwater with origins in the west coast of Greenland is typically restricted to the coastline by strong winds that bring it north towards Baffin Bay.
Although these patterns of Greenland ice sheet meltwater movement can vary due to shifts in prevailing winds, they are nevertheless important in understanding the relationship between meltwater and the environment.
"The meltwater that comes from the east coast could have different qualities from the meltwater on the west coast, including different nutrient compositions," Castelao said. "We need to take the origins of this meltwater into account when we study the effects of ice sheet melt, as it could impact the oceans differently depending on where it comes from."
Castelao believes that this problem will continue to get worse, suggesting that without intervention, Greenland meltwater runoff could increase by more than double by the end of the century.
"We need to pay careful attention to where melt and runoff is occurring and how it interacts with surrounding ocean currents, in addition to measuring the total amount of melt," Mote added.
The findings were published in the April 25 issue of Nature Geoscience.
