For my presentation to Space and the Arctic 2009 I took a look at the retreat of Jakobshavn Isbrae, a glacier of the west Greenland ice sheet. The glacier is well known for its rapid retreat. In fact it has lost all of the floating part of this formerly tidewater glacier (tidewater glaciers are glaciers that terminate in sea fjords). Using high resolution Radarsat-1 images (pixel spacing 6.5 m) from NASAs Alaska Satellite Facility, I mapped the glacier front in 2000, 2004, 2005 and 2007. The result is a graphic picture of how some glaciers are responding to climate change.
In just seven years, the glacier front retreated almost 15 km in places, losing around 82 km2 of ice. The glacier front is now aligned along the grounding line (the shoreline). Jakobshavn is something of an extreme example; not all glaciers are retreating so fast and tidewater glaciers are particularly complex systems, so we should be careful about drawing simplistic conclusions. Neverthess, the glacier has lost a lot of area (and mass) in a very short time. Climate change in action.