Greenland’s Helheim glacier is believed to be melting at unusually high rates as a result of warming conditions. The dire discovery came as a surprise to researchers at the New York University Abu Dhabi Center for Global Sea Level Change. Outlet glaciers like Helheim typically sit at the freezing point and researchers do not expect to see much ice melt. But overall warming conditions in the region are causing the glacier, one of the largest in Greenland, to melt at alarming rates.
David Holland from NYU Abu Dhabi said: “We are surprised to learn that increased surface glacier melt due to warming atmosphere can trigger increased ocean melting of the glacier.
“Essentially, the warming air and warming ocean water are delivering a troubling ‘one-two punch’ that is rapidly accelerating glacier melt.”
Greenland’s glacier is being affected by warmer waters from the tropics that have displaced colder, polar waters.
At the glacier’s so-called calving front, the warmer waters are accelerating ice melt.
On August 5, Professor Holland and his team deployed a temperature probe at glacier’s terminus or lowest end.
According to the researchers, the warmer waters have created a pond-like opening in front of the terminus, instead of it being thick and frozen solid.
Warmer and saltier waters are carried to Greenland on the Gulf Stream where they encounter cold, fresh water from the polar region.
Because of their high salt content, the warmer waters will plunger under the polar waters and sink.
Professor Holland and his team have, however, found the ocean water temperatures around the base of the glacier down to a depth of 2,624ft (800m) were a uniform 39F degrees (4C).
Professor Holland said: “This is unsustainable from the point of view of glacier mass balance as the warm waters are melting the glacier much faster than they can be replenished.”
Ice that melts at the surface of the Greenland glacier, leaks back into the oceans by flying under the glacier.
When the fresh waters appear at the glacier’s calving front they are buoyant enough to want to return to the surface.
But the researchers have found the process draws the warmer tropical waters back up to the surface as well.
Warmer typical waters are being found at certain depths at many fjord locations, depending on the movements of the Gulf Stream.
Over the last 20 years, the researcher said, warm tropical waters have been abundant.
Because of this, Greenland glaciers like Helheim are rapidly melting and retreating.