Massive ice structures as wide as Manhattan and as tall as skyscrapers have been discovered beneath Greenland’s ice sheet.
Researchers, using radar, learnt that the structures were not, as they had previously believed, rock, but actually ice. The structures were formed when ice at the foot of glaciers melted and then refroze in a process that takes centuries. The process could, according to the researchers, quicken the speed at which the glaciers drift into the sea.
Geophysicist Kirsty Tinto, from the Lamont-Doherty Earth Observatory at Columbia University, said that when flying over the landscape it’s so boring you could fall asleep, but when the ice structures appear on the screen it becomes extremely exciting as there’s a sense of the invisible process happening beneath.
The new discoveries may help researchers predict more accurately how climate change could affect Greenland and Antarctica’s ice sheets and cause sea levels around the world to rise. Aside Antarctica, Greenland is the only place in the world with an ice sheet, and its melting over the past two decades has been among the biggest contributors to sea levels rising.
Blue and Green Tomorrow explained that the structures were bigger and more common in places where the ice moves more rapidly, indicating that the refreezing process warms the ice above and, in turn, speeds up their movement towards the sea.
Science World Report noted that it appears as though the rivers and lakes flow over the ice sheet’s edges, before the water falls through the crevasses to the foot of the ice sheet. Some of it then refreezes, with the resulting deformation potentially causing the ice above to melt faster.
Climate change has resulted in the Greenland ice sheet’s northeast corner, which was previously considered stable, losing in excess of 10 billion tonnes of ice annually since 2003.