Greenland ice melt is changing the shape of its coast: Study

Greenland is losing 500 gigatons of ice each year

New Delhi (NVI): The rapid melt of ice from the Greenland Ice Sheet has accelerated over the past two decades, transforming the shape of the coastal Greenland, according to a new study.

The study by the National Snow and Ice Data Center (NSIDC) informed that these changes to the ice sheet could have far-reaching impacts on ecosystems and communities along the country’s coast.

Researchers found that the ice retreat in Greenland has changed the way glaciers flow and where they dump into the sea. These changes could impact ice loss from Greenland in the future.

The study led by NSIDC research scientist Twila Moon, compiled data from NASA, the United States Geological Survey and other satellites from 1985 to 2015 to compare ice edge position, ice sheet surface elevation, and glacier flow over the decades.

It showed that Greenland is losing 500 gigatons of ice each year, more than can be replenished by new snowfall.

Meanwhile, the annual ice loss is 14 percent greater today than it was between 1985 and 1999 and the meltwater from this ice loss is lubricating the ice sheet so that it slides more easily on its underlying bedrock, hastening the continued melt.

Moon said, “The speed of ice loss in Greenland is stunning. “We can now see many signs of a transformed landscape from space. And as the ice sheet edge responds to rapid ice loss, the character and behavior of the system as a whole is changing, with the potential to influence ecosystems and people who depend on them.”

The team of researchers combined two types of data from satellite imagery, how fast the ice sheet is moving and where glaciers terminate on their path downhill. When a glacier retreats, its terminus doesn’t reach as far down-valley as it once did.

They found, first, that glacier retreat is now the norm in Greenland. Around 80 per cent of glaciers had retreated substantially within the last decade, the study said.

However, this reshaping of glaciers translated into a variety of changes in glacier movement and some glaciers were speeding up, flowing more rapidly toward the sea.

Furthermore, the researchers found that others were flowing more slowly and over several years to a decade, a single glacier could do both, depending on the topography around it.

The researchers also saw evidence of ice channels narrowing, of re-routing meltwater paths and even of the slowing of new ice so that glaciers are stranded in place, more like lakes than rivers.

“All of this local variation may be very important for predicting how quickly Greenland’s ice will disappear in the future,” the researchers said, noting, the changes will also likely affect how and where nutrients enter the water, where there are open fjords versus ice, and where freshwater is available.

This will also expose new land areas, opening new fjord waters and altering ecosystems and physical landscapes, the study said.

Alex Gardner, study co-authorĀ  a research scientist at NASA’s Jet Propulsion Laboratory, said in a statement, “As the Arctic ocean and atmosphere warm, we can clearly see the flow of ice into the ocean accelerate and the ice edge retreat.”

Gardner added that understanding the complexity of individual glacier response is critical to improving projections of ice sheet change and the associated sea level rise that will arrive at our shores.

-RJV