Jakobshavn is widely believed to be the glacier that produced the large iceberg that sank the Titanic in 1912.Researchers from the University of Washington and the German Space Agency measured the speed of the glacier in 2012 and 2013 and say it is moving ice from the Greenland ice sheet into the ocean at the fastest speed ever recorded

As the glacier's calving front retreats into deeper regions, it loses ice - the ice in front that is holding back the flow - causing it to speed up

The speed up means that the glacier is contributing to sea-level rise. 

Scientists fear that by the end of the century, global warming could lead to the Jakobshavn Glacier in the south west of Greenland moving at 10 times the present speed. 

Researchers now believe that Jakobshavn is in an unstable state. By the end of this century, its calving front could retreat as far back as the head of the fjord through which the glacier flows, about 50 km upstream from where it is today. 

The glacier that may have produced the iceberg responsible for sinking the Titanic has been found to be moving at record speed - four times faster into the sea than it was in 1960s. 

http://www.mnn.com/lifestyle/arts-culture/blogs/glacier-that-may-have-doomed-the-titanic-becomes-more-dangerous