 In Greenland , glacier retreat has been observed in outlet glaciers , resulting in an increase of the ice flow rate and destabilization of the mass balance of the ice sheet that is their source . The net loss in volume and hence sea level contribution of the Greenland Ice Sheet ( GIS ) has doubled in recent years from 90 km3 ( 22 cu mi ) to 220 km3 ( 53 cu mi ) per year . Researchers also noted that the acceleration was widespread affecting almost all glaciers south of 70 N by 2005 . The period since 2000 has brought retreat to several very large glaciers that had long been stable . Three glaciers that have been researched — Helheim Glacier , Kangerdlugssuaq Glacier , and Jakobshavn Isbræ — jointly drain more than 16 % of the Greenland Ice Sheet . In the case of Helheim Glacier , researchers used satellite images to determine the movement and retreat of the glacier . Satellite images and aerial photographs from the 1950s and 1970s show that the front of the glacier had remained in the same place for decades . In 2001 the glacier began retreating rapidly , and by 2005 the glacier had retreated a total of 7 @.@ 2 km ( 4 @.@ 5 mi ) , accelerating from 20 m ( 66 ft ) per day to 35 m ( 115 ft ) per day during that period . 
