Much of the ice has separated from the largest remaining Arctic ice shelf – 79N or Nioghalvfjerdsfjorden – in northeast Greenland.
The projectile section covers approximately 110 square kilometers; Satellite images show it is shredded into many small pieces.
The loss is another clue that scientists say of the rapid climate change occurring in Greenland.
“The air temperature in this region has increased by about 3 degrees Celsius since 1980,” said Dr. Jenny Turton.
“In the years 2019 and 2020, they witnessed record summer temperatures,” a polar researcher at Friedrich Alexander University in Germany told BBC News.
Nioghalvfjerdsfjorden is about 80 km long and 20 km wide and is the floating front end of the glacier in northeastern Greenland – as it flows from land into the ocean to become buoyant.
At its forward edge, the 79N Glacier splits in two, with a secondary shift just north. This branch, or tributary, called the Spalte Glacier, which has now disintegrated.
Image copyright
Copernicus / ESA / Sentinel-2B data
Ice is attacked from above and below
The ice has already been largely broken in 2019; This summer’s warmth was the last downturn. Spalte Glacier became a fleet of icebergs.
Look closely at the satellite images and you will see that the high air temperatures recorded in the area are evident from the large number of melt pools at the top of the ice shelf.
The presence of such liquid water is often a problem for ice platforms. If it fills in the cracks, it can help open them up. The water will push the cracks down and push them into the base of the shelf in a process known as hydrocracking. This will weaken the ice shelf.
Oceanologists have also documented warmer sea temperatures which means it is almost certain that shelf ice is melting from below as well.
Professor Jason Books of the Geological Survey of Denmark and Greenland (GEUS) explained that “79N became the” largest arctic ice shelf “somewhat recently, after the Petermann Glacier River in northwest Greenland lost a large area in 2010 and 2012.” .
“What makes 79N so important is the way it connects to the inner ice sheets, meaning that someday – if the climate is as warm as we’d expect – this area will likely become one of the major centers of ice disposal in Greenland.”
Image copyright
Copernicus / ESA / Sentinel-2B data
The trunk of N79 is covered with puddles and melt streams
The Northeast Greenland Ice Current drains about 15% of the inland ice sheet. The stream directs its ice either down N79 or the glacier organ just south, Zachariae Isstrom. Zachariah has already lost most of the floating ice shelf.
Professor Box said the N79 could last longer because it was placed on its front end by some islands. This lends a degree of stability. But he added that the shelf continues to be thin, albeit mostly along the trunk.
“This would potentially lead to the N79 disintegrating from the middle, which is kind of unique. I think, however, that this won’t happen for another 10 or 20 years. Who knows?” He told BBC News.
July saw another major loss of the Arctic ice shelf over a large area. This was the Milne Ice Shelf on the northern margin of the Canadian island of Ellismere.
Eighty square kilometers liberated from Milne, leaving a still safe strip of only 106 square kilometers. Milne was the largest intact remnant of a wider shelf feature covering 8,600 square kilometers at the beginning of the twentieth century.
The rapid rate of melting in Greenland was confirmed in a study last month that analyzed data from the US-German Grace-FO satellites. These spacecraft are able to track changes in ice mass by sensing shifts in local gravitational pull. They basically weigh the ice sheet.
Grace’s mission found that 2019 was a record year, with ice cap tossing around 530 billion tons. That’s enough meltwater flowing from the land into the ocean to raise the sea level by 1.5 mm
