Greenland - It's Fastest "Thinning" Glacier, Is Currently Growing!
Mar 30, 2019 16:47:04 GMT
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Post by MCDemuth on Mar 30, 2019 16:47:04 GMT
Fastest-Thinning Greenland Glacier Threw NASA Scientists for a Loop. It's Actually Growing.
Greenland's fastest-flowing and fastest-thinning glacier recently threw a real brain bender at scientists, who realized that instead of shrinking, the glacier is actually growing thicker, they reported in a new study.
The glacier — known as Jakobshavn, which sits on Greenland's west coast — is still contributing to sea level rise, but it's losing less ice than expected. Instead of thinning and retreating inland, its ice is thickening and advancing toward the ocean, the researchers found.
After much sleuthing, a team of scientists from the United States and the Netherlands found that the glacier is likely growing due to colder ocean currents. In 2016, a current that passes by Jakobshavn Glacier was cooler than usual, making waters near the glacier the coldest they'd been since the mid-1980s.
This cooler current came from the North Atlantic Ocean, more than 600 miles (966 kilometers) south of the glacier, according to data from NASA's Oceans Melting Greenland (OMG) mission and other observations.
The finding took the scientists completely by surprise. "At first, we didn't believe it," study lead researcher Ala Khazendar, a scientist at NASA's Jet Propulsion Laboratory in Pasadena, California, said in a statement. "We had pretty much assumed that Jakobshavn would just keep going on as it had over the last 20 years." But the cold water isn't a one-off. Data from OMG shows that the water has been cold now for three years in a row.
It appears that the cold water is the result of a climate pattern known as the North Atlantic Oscillation (NAO), which makes the northern Atlantic Ocean slowly switch between warm and cold water about once every 20 years, the researchers said. The cold phase just recently started, and has cooled the Atlantic Ocean in general, they said. In addition, some extra cooling of the waters around Greenland's southwest coast helped keep the glacier chilly.
But this crisp change won't last forever. Once the NAO climate pattern flips back, the Jakobshavn will likely start melting faster and thinning again, the researchers said.
"Jakobshavn is getting a temporary break from this climate pattern," Josh Willis, of the Jet Propulsion Laboratory and the principal investigator of OMG, said in the statement. "But in the long run, the oceans are warming. And seeing the oceans have such a huge impact on the glaciers is bad news for Greenland's ice sheet."
Huge ice loss … then small gain
In all, Jakobshavn grew about 100 feet (30 m) taller between 2016 and 2017, the researchers found. But, as mentioned, the glacier is still contributing to ocean level rise worldwide, as it's still losing more ice to the ocean than it is gaining from snow accumulation, the researchers said.
Read More Here:
www.space.com/greenland-glacier-growing.html