The glacier section broke off the fjord called Nioghalvfjerdsfjorden, which is about 80 kilometres long and 20 kilometres wide, the National Geological Survey of Denmark and Greenland (GEUS) reported.
"We should be very concerned about what appears to be progressive disintegration at the Arctic's largest remaining ice shelf", GEUS professor Jason Box said.
But new satellite images show a massive chunk of it, the Spalte Glacier, has recently broken away and shattered into small pieces.
The ice shelf has lost 160 square miles (62 square miles), an area almost twice that of Manhattan in NY, since 1999.
"What is thought-provoking is that if we ... had seen this meltdown 30 years ago, we would have called it extreme", she said.
The territory's ice sheet is the second biggest in the world behind Antarctica's, and its annual melt contributes more than a millimeter rise to sea levels every year.
"Each summer, water drains from the Greenland ice sheet onto the tongue of the glacier, forming rivers and ponds on the surface".
"The atmosphere in this region has warmed by about 3C since 1980".
According to Jenny Turton, a researcher at Germany's Friedrich-Alexander Universitat Erlangen-Nurnberg, heatwaves in recent years have accelerated the melting. "Refreezing of the water in winter creates additional pressure on the floating tongue, which can lead to calving events", Turston said in a statement published by GEUS.