Greenland’s Petermann Glacier could calve after rift appears

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After a major calving event earlier this year, we could be due for another with the Petermann Glacier in Greenland showing signs of stress after a growing rift was observed by a remote sensing satellite operated by the Netherlands’ Delft University of Technology. The Petermann Glacier is located on Greenland’s north-west coast and covers almost 1,300 square kilometres. Its floating ice tongue is the Northern Hemispheres’ largest, and has now formed a new rift.

Associate professor Stef Lhermitte, who first spotted the rift, was able to trace back its’ initial crack to July 2016, and it has been growing steadily since. Lhermitte alerted an expedition team based at Petermann Glacier, who, along with NASA were able to confirm the rift and its’ position. In subsequent images, the rift can be seen forming nearby larger, older ones. Until now, the glacier had seemed stable, but if the rift continues and meets with another, it could lead to a calving event, creating a sizeable iceberg. In a statement on its’ social media page, NASA warned that the rift “whose presence may exert a stagnating effect on the propagation of the new rift toward the older one”.

This isn’t the first time that the Petermann Glacier has produced icebergs through calvings, with its’ ice shelf shedding 87 square kilometres of ice between 2000 and 2001, as well as suffering a major 29 square kilometre loss in July 2008. However, concern was at its highest following the event in 2008, when scientists monitored a massive rift farther upstream of the glacier. Had it managed to extend completely across, it would have reduced fractured over 160 square kilometres off of the ice shelf – a third of its current length.

Whilst that rift thankfully failed to extend to that level, the Petermann Glacier continued to become a point of interest for scientists monitoring ice movements, especially in recent years, as the threat of climate change adds more pressure to the area’s already delicate environment. Indeed, as recent research shows, some of Greenland’s glaciers will never recover from current melting rates. Should they all melt, it would add an extra 4 centimetres to global sea levels.

However, scientists are more worried about the country’s major ice shelf further north, which also represent the Northern Hemisphere’s largest, and would potentially add seven metres to global sea levels should it disappear completely. That being said, the height of its’ highest caps has so far protected from major harm, and it is considered safe for the time being.