Retreat of Jakobshavn Glacier, Greenland
It's easy to think of ice as still and rigid. But glaciers are active-flowing and shifting, advancing and retreating. Among the world's most dynamic glaciers is Greenland's Jakobshavn Isbrae, which showed its active nature with a large calving event at the end of May 2014. Sometime before 01 June, when the Landsat 8 satellite acquired this image, the glacier shed kilometres of ice from its front.
Linear patterns mark the surface of the glacier, visible currents in a river of ice. The glacier has two branches, the primary southern branch (shown here) and a secondary northern branch (visible only in the wider larger image). In the image, a large area of the southern branch and a smaller section of the northern branch have changed. Ice has crumbled off of the glacier front into the mélange, the jumble of floating ice downstream from the glacier.
Though large and dramatic, this event is not unusual for Jakobshavn or other glaciers, which accumulate snow during the winter and shed ice by calving. Greenland's many glaciers drain ice from the central ice sheet; but even in a land of glaciers, Jakobshavn is prolific. Since 2000, Greenland has lost some 739 gigatons of ice, and approximately 30 percent of that loss came from Jakobshavn and four other glaciers. That loss, along with surface melting, has caused Greenland's ice sheet to start losing more ice than it gains. Jakobshavn has contributed one millimetre to sea level rise between 2000 and 2011 from calving events like this one.
View the full resolution image, and see comparison that highlights calving.
Credit: NASA Earth Observatory