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The rapid melting is reshaping the coast of Greenland, potentially altering the human and animal ecosystems along the country’s coast.
New research published in Journal of Geophysical Research: Earth Surface on October 27 he discovers that the retreat of Greenland’s ice has changed the way glaciers flow and where they drain into the sea. These changes could impact Greenland ice loss in the future, the researchers wrote.
Recent studies have shown that Greenland loses 500 gigatons of ice per year, more than can be replenished by new snowfall. The annual ice loss is now 14% greater than in the period between 1985 and 1999. And the meltwater from this ice loss lubricates the ice sheet so that it slides more easily onto the bedrock below, accelerating the continuous dissolution.
The new study, led by National Snow and Ice Data Center researcher Twila Moon, analyzes the changes in more detail.
Moon and his colleagues combined two types of data from satellite imagery: how fast the ice sheet is moving and where the glaciers end on their downhill path. When a glacier retreats, its terminus no longer reaches the valley as it once did.
They found, first, that glacier retreat is now the norm in Greenland. Eighty-nine percent of glaciers have substantially retreated over the past decade, the researchers wrote in their paper. Virtually no one was advanced.
However, this glacier remodeling has resulted in a variety of changes in glacier movement. Some glaciers were accelerating, flowing more rapidly towards the sea, the researchers found; others flowed more slowly. And from several years to a decade, a single glacier could do both, depending on the surrounding topography.
Glaciers are rivers of ice, so their flow is partially determined not only by the rate at which they melt, but by what’s beneath them.
For example, the Kjer and Hayes glaciers in northwestern Greenland accelerated their main outlets to the sea from the 1990s to 2010, but other ice outlets into the nearby ocean slowed. In one case, the southern part of one of those holds accelerated, then slowed down again.
Researchers have seen evidence of ice channel narrowing, re-routing of meltwater paths, and even slowing new ice so that glaciers are stuck in place, more like lakes than rivers.
All this local variation could be very important in predicting how fast Greenland ice will disappear in the future. The changes will also likely affect how and where nutrients enter the water, where there are open fjords against ice, and where fresh water is available.
“As the Arctic ocean and the atmosphere warms, we can clearly see the flow of ice in the ocean accelerate and the edge of the ice retreat,” said study co-author Alex Gardner, a researcher at NASA’s Jet Propulsion Laboratory in Pasadena, California. a declaration.
“When we look more closely, however, we can see the complexity of how individual glaciers respond, due to differences in the properties of ocean water reaching the glacier front, bedrock and as long as they are below, and in how meltwater runoff is directed below. Understanding the complexity of the response of individual glaciers is key to improving the projections of ice sheet change and related sea level rise that will arrive on our shores. “
This article was originally published by Live Science. Read the original article here.
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