The latest stable glaciers in Greenland accelerate their melting – the Fair

The latest stable glaciers in Greenland accelerate their melting

The frozen rivers of the north of the island have rushed their way to the sea losing billions of tons of ice every year

by Agencies Saturday November 14, 2015 – 1:13:57

The latest stable glaciers in Greenland, located so far north that still escaped the impact of climate change, have accelerated the thaw in the last decade. A study using data from the past 40 years shows that air and increasingly warm waters are undermining the foundations of one of the largest glaciers of the island. It is so great that, if melted, by itself raise the mean sea level meter.

The Danish and scientists know it as Zachariae Isstrøm, which roughly translates as stream or river ice Zechariah. Glacier with another unpronounceable name for a Spanish (Nioghalvfjerdsfjorden or NG), drain the ice that accumulates in northeastern Greenland. For scientists, the study of the two glaciers is important for three reasons. Combined, occupying over 200,000 km2 and accumulate 12% of the ice is in Greenland. The analysis of evolution can serve as a representation of all this huge island, as large as almost five times Spain. In addition, the glaciers of the north basin seemed stable so far.

Combining data from various satellite, aerial and field missions, researchers from several US universities have been able to see how that stability is breaking . In the mid-seventies, first date with reliable data on the area, Zachariae Isstrøm showed a leisurely pace and sustained progress towards the sea. Its imposing front of tens of kilometers into the sea as fearless. Your land line, the point where the glacier begins to float on water, was half a kilometer below the sea level. His death was slow in the ocean, a few meters a year.

However, since late last century, especially in Zachariae Isstrøm has changed. The ground line has continued to recede in favor of the sea, especially in the last four years. In 2002, a large portion of the glacier broke off in dozens of large icebergs. The bankruptcy of new parts has increased in the last decade. In 20 years, the thickness of the ice at the height of their land line has been reduced by 200 meters. All this makes the course of the glacier to the sea has accelerated and with it, the ice discharge. As published in the journal Science, the researchers estimate that Zachariae Isstrøm loses 5,000 million tons of ice every year.

“The glacier is melting by the steady increase in air temperature and currents carrying warmer ocean waters, “says the researcher from the University of California Irvine and lead author of the research, Jeremie Mouginot. “He started to accelerate after he lost the floating layer in 2002, but this acceleration has intensified since 2012, when the glacier broke socket seabed on which it rested,” he adds.

So River ice is being eroded Zechariah, up by warmer air and below, by ever more temperate waters. Other studies have shown that the temperature of the Atlantic current that goes up to the Arctic in this area has risen by one degree since 1997.

As for his colleague basin, the glacier NG, its dynamics is essentially the same although more moderate. Both its forward speed sea as the withdrawal of their land line has accelerated. The thickness of the ice has also been reduced. But in the three processes, their numbers are much lower than those presented Zachariae Isstrøm.

“Nioghalvfjerdsfjorden shown small signs of acceleration, but also the glacier is melting from below,” says Mouginot. For researchers, the fact that this subglacial merger has not yet been translated into increased his advance to the sea could be circumstantial. “Your bed is raised in its first 10 kilometers inland, while the Zachariae slopes downward,” explains the French researcher. Moreover, the geography of the fjord protects the ice. “However, it is likely that NG and Petermann (another important glacier in northern Greenland) follow the path of Zachariae Isstrøm in the coming decades,” he added.

If so, the last stable glacier Greenland cease to be, providing an increasing amount of sea ice and increasing their level. Similar, even major changes are already occurring in the South, where glaciers are losing ice due to the combined effect of surface melting and increased discharge into the ocean. In 2014, another research encrypted this thaw in 243,000 million tons. But what is important here, as Mouginot says, is that “one of the largest glaciers in the northeast of Greenland, the north in a stable industry so far, is beginning to lose mass.”