NASA released a set of satellite images of Greenland glaciers capturing the transformation of the ice cover from 1972 to 2019. Glaciers that feed into the Sermilik Fjord from 50 years ago, look increasingly barren with rocky peaks being more exposed.
According to the National Snow and Ice Data Center, around 90 per cent of the surface of Greenland’s ice sheet melted at some point between July 30 and Aug 2, during which time an estimated 55 billion tons of ice melted into the ocean.
The NASA satellite images taken from Landsat 8 satellite on August 12, 2019, show the glaciers appearing brownish grey in colour, confirming the retreat of ice fronts. NASA says that the colour indicates the melted surface– a process that concentrates dust and rock particles and leads to a darker recrystallized ice sheet surface.
“There’s a lot more bare rock visible now, which used to be covered with ice,” said Christopher Shuman, a glaciologist with the University of Maryland at NASA Goddard Space Flight Center in Greenbelt, Maryland.
“And all these little glaciers are all getting slammed, as well as the bigger ones like Helheim, Fenris and Midgard. There are scores of examples of change just in this one area.”
According to NASA, the Helheim Glacier, one of the largest and fastest flowing of its kind in Greenland, has retreated around 4.7 miles or 7.5 kilometres as visible in Landsat images taken at 50 years of interval. Similarly, the Midgard Glacier has retreated around 10 miles or 16 kilometres, splitting into two branches farther up the fjord.
In a close-up of the Helheim Glacier, a patch of open water is visible right at the calving front. NASA’s Oceans Melting Greenland (OMG) project flew over that open patch in an airplane and dropped a temperature-measuring probe to detect warm water at the ice front.
The OMG is examining how oceans melt glaciers from below, even as air temperatures warm the ice from above. NASA says that unusually warm air temperatures this summer are to be blamed for the record melt across Greenland.
The melting of Greenland’s ice sheet is among one of the most visible signs of man-made climate change spurred by the burning of fossil fuels. The melting has contributed to a rapid sea-level rise which puts the coastal areas around the world at risk. Experts have warned that if the entire Greenland ice sheet melts, it could add 20 feet or more to global sea level.