Images from European Space Agency’s Sentinel-1A satellite show that Greenland’s Jakobshavn glacier, the fastest moving glacier in the world, shed a chunk of ice measuring 12.5 square km past week – one of the most significant calving events on record.
Jakobshavn glacier, also known as Sermeq Kujalleq and the Jakobshavn Isbræ, is a large glacier in West Greenland and is among the world’s most dynamic glaciers. Radar images from ESA’s Sentinel-1A captured the glacier before and after a massive calving event, which took place between 14 and 16 August 2015. The image composite includes different Sentinel-1A images from 27 July, and 13 and 19 August. The red, green and blue indicate the position of the calving front and other dynamic features on each respective date. Image credit: Copernicus Sentinel data /ESA.
Comparing images taken by Sentinel-1A on 27 July, and 13 and 19 August, the new face of Jakobshavn glacier has been pushed inland by several km to what appears to be its furthest easterly location since monitoring began in the mid-1880s.
The image time series suggests that between 27 July and 13 August, the glacier advanced westward before the calving caused rapid retreat of the ice front to its position on 19 August.
It is estimated that the glacier lost a total area of 12.5 square km.
Assuming the ice is about 1.4 km deep, this equates a volume of 17.5 cubic km – which could cover the whole of Manhattan Island by a layer of ice about 300 m thick.
The history of this calving event is also revealed in images taken by ESA’s Sentinel-2A satellite on 6 and 16 August.
Though large, this event is not unusual for Jakobshavn or other glaciers.
Greenland’s many glaciers drain ice from the central ice sheet; but even in a land of glaciers, Jakobshavn glacier is prolific.
Since 2000, Greenland has lost roughly 739 gigatons of ice, and around 30% of that loss came from Jakobshavn and four other large glaciers.
That loss, along with surface melting, has caused Greenland’s ice sheet to start losing more ice than it gains.
According to scientists, Jakobshavn glacier has contributed one millimeter to sea level rise between 2000 and 2011 from calving events like this one.
