The most enlightened Greenland glacier has thrown a loop to NASA scientists. He really pushes.

The fastest-flowing and fastest-clearing Greenland glacier recently launched a real brain teaser for scientists, who realized that instead of shrinking, the glacier s & # 39; It really thickens, they reported in a new study.

The glacier – known as Jakobshavn, located on the west coast of Greenland – still contributes to the rise in sea level, but loses less ice than expected. Instead of lightening and rolling back inland, the researchers found that its ice thickened and was heading towards the ocean.

The big question: why is this happening? [Images: Greenland’s Gorgeous Glaciers]

After a long day of research, a team of scientists from the United States and the Netherlands discovered that the glacier was probably developing because of colder ocean currents. In 2016, a current flowing through the Jakobshavn glacier was colder than usual, making the waters near the glacier coldest since the mid-1980s.

This colder current came from the North Atlantic, more than 966 km south of the glacier, according to data from NASA's Oceans Melting Greenland Mission (OMG) and other observations.

The discovery took the scientists completely by surprise. "At first, we did not believe it," said Ala Khazendar, a research scientist at NASA's Jet Propulsion Laboratory in Pasadena, California, in a statement. "We thought pretty much that Jakobshavn would continue as if nothing had happened in the last 20 years." But cold water is not unique. The OMG data show that the water has been cold for three years in a row.

It seems that the cold waters result from a climatic pattern known as the North Atlantic Oscillation (NAO), which causes the North Atlantic Ocean to tip slowly between warm and cold waters about a year. every 20 years, the researchers said. The cold phase has recently started and has cooled the Atlantic Ocean in general, they said. In addition, further cooling of the waters around the southwest coast of Greenland has kept the glacier cold.

But this net change will not last forever. Once the climate of the NAO declines, the Jakobshavn will probably begin to melt faster and clear up again, the researchers said.

"Jakobshavn stands out temporarily from this climate," said Josh Willis of the Jet Propulsion Laboratory and OMG's principal investigator, in a statement. "But in the long run, the oceans are warming up, and seeing the oceans have a huge impact on the glaciers is bad news for the Greenland icecap."

Huge ice loss … then small gain

Scientists have been watching Jakobshavn with concern for decades. After losing its pack ice in the early 2000s (an ice floe forced a glacier to flow more slowly into the ocean, like earth clogged with a drain), Jakobshavn started losing ice at an alarming rate. Between 2003 and 2016, its thickness (from top to bottom) decreased by 152 meters.

But in 2016, the waters flowing from the southern tip of Greenland to its west side cooled by more than 2.7 degrees Fahrenheit (1.5 degrees Celsius). Meanwhile, the NAO's climate regime caused the Atlantic Ocean to cool near Greenland by about 1 ° C between 2013 and 2016. In the summer of 2016, these colder waters reached the glacier. rate of ice loss in the ocean, the researchers said. [Image: Greenland’s Dramatic Landscape]

In total, Jakobshavn has grown about 30 meters between 2016 and 2017, found the researchers. But, as mentioned, the glacier still contributes to raising the level of the ocean around the world because it is always losing more ice to the benefit of the ocean than it does. 39, gains by accumulating snow, said the researchers.

The results highlighted the effects of ocean temperature on glacier growth, said Tom Wagner, scientist at NASA's headquarters for the cryosphere, the frozen part of the Earth.

"The OMG mission has deployed new technologies that have allowed us to observe a natural experiment, such as in a laboratory, where ocean temperature variations were used to control the flow of a fluid. glacier, "said Wagner, who did not participate in the study. , said in the statement. "Their discoveries – particularly on how quickly the ice reacts – will be important in projecting sea level rise in the near and distant future."

The study was published online March 25 in the journal Nature Geoscience.

Originally published on Science live.