In line with predictions that sea levels will rise due to calving ice sheets, scientists have spotted the largest piece of Greenland ice to float into the sea ever seen. Jakobshavn Glacier lost a 12.4 km section between 13 and 19 August to the sea [photo]. Jakobshavn is the major drainage channel for Greenland's ice sheet and is believed to be the source of the iceberg that sank the "unsinkable" Titanic. Assuming the ice is about 1400m deep, the volume of ice lost to the sea is about 17.5cu km. Despite the gigantic amount lost from Greenland's sheet, it is still small compared to Antarctica's tabular bergs that can be thousand of square kilometers in area.