The front of Iceland Jakobshavn Glacier, where icebergs calve off.
Greenland is the fastest-flowing and fastest-thinning glacier recently threw a real brain bender of 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 is on Greenland’s west coast — is still contributing to the increase of the sea level, but it is less ice than expected. Instead of thinning and retreating in the interior, the ice is thick create and promote the direction of the ocean, the researchers found.
The big question: Why is this happening? [Images: Greenland’s Gorgeous Glaciers]
After a lot of research, a team of scientists from the United States and the Netherlands found that the glacier is likely to grow as a result of the colder currents. In 2016, a stream that runs through Jakobshavn Glacier was cooler than normal, so the waters in the vicinity of the glacier, the coldest they had since the mid-1980s.
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This cooler current from the North Atlantic Ocean, more than 600 miles (966 km) south of the glacier, according to data from NASA’s Oceans Melting Greenland (OMG) mission and other notes.
The finding took the scientists completely by surprise. “In the beginning we didn’t believe it,” study principal investigator Ala Khazendar, a scientist at NASA’s Jet Propulsion Laboratory in Pasadena, California, said in a statement. “We had pretty much assumed that Jakobshavn’d just go as it was in the last 20 years.” But the cold water is not a one-off. Information of OMG indicates that the water is cold now for three years in a row.
It turns out that the cold water is the result of a climate that is known as the North Atlantic Oscillation (NAO), which the north Atlantic Ocean slowly alternate between hot and cold water about once every 20 years, the researchers said. The cold phase recently started, and it is cooled off the Atlantic Ocean, in general, they said. In addition, a number of additional cooling of the waters around Greenland west coast helped to make the glacier cold.
But this clear change will not last forever. As soon as the NAO climate pattern mirrored back, the Jakobshavn will probably start melting faster and thinner, the researchers said.
“Jakobshavn is getting a temporary break of this climate pattern,” Josh Willis of the Jet Propulsion Laboratory and the principal investigator of OMG, said in the statement. “But in the long term, the oceans are warming. And seeing the oceans have a huge impact on the glaciers is bad news for the Greenland ice sheet.”
Massive ice loss … than small profit
Scientists have looked at Jakobshavn with care for decades. After the loss of the ice sheet in the beginning of the years 2000 (a ice shelf forces a glacier to flow slowly into the ocean, such as debris blockage of a drain), Jakobshavn started to lose ice at an alarming rate. Between 2003 and 2016, the thickness (top to bottom) are taken at 500 feet (152 meters).
But in 2016, the waters off Greenland’s southern tip on the west side cooled by more than 2.7 degrees Fahrenheit (1.5 degrees Celsius). In the meantime, the NAO climate pattern caused in the Atlantic Ocean near Greenland cooling by about 0.5 F (1 C) between 2013 and 2016. In the summer of 2016, this cooler water reaches the glacier, and they are probably also the reason that Jakobshavn slowed down the speed of ice loss to the ocean, the researchers said. [Image: Greenland’s dramatic Landscape]
In all, Jakobshavn increased by approximately 100 ft (30 m) is greater between 2016 and 2017, the researchers found. But, as I said, the glacier is still contributing to the ocean level is rising worldwide, as it is still losing more ice to the ocean, than is the obtaining of snow accumulation, the researchers said.
The findings shed light on how ocean temperatures can have an impact on the glacier of the growth, says Tom Wagner, a NASA Headquarters program scientist for the cryosphere, the frozen part of the Earth.
“The OMG mission deployed new technologies that have allowed us to observe in a natural experiment , just as we would do in a laboratory, where variations in the ocean temperatures were used to control the flow of a glacier,” Wagner, who was not involved in the study, said in the statement. “Their findings, especially about how fast the ice is responding — it will be important to projecting sea-level rise in both the near and distant future.”
The study is published online March 25 in the journal Nature Geoscience.
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Originally published on Live Science.