Acceleration and Thinning
The speed of Pine Island Glacier increased by 73 percent from 1974 to the end of 2007, with an 8 percent increase over the last 16 months of this period alone. This speed up has meant that by the end of 2007 the Pine Island Glacier system had a negative mass balance of 46 gigatonnes per year, which is equivalent to 0.13 mm (0.0051 in) per year global sea level rise. In other words, much more water was being put into the sea by PIG than was being replaced by snowfall. Measurements along the centre of the ice stream by GPS demonstrated that this acceleration is still high nearly 200 km (120 mi) inland, at around 4 percent over 2007. It has been suggested that this recent acceleration could have been triggered by warm ocean waters at the end of PIG, where it has a floating section (ice shelf) approximately 50 km (31 mi) long.
As the ice stream accelerates it is also getting steeper. The rate of thinning within the central trunk has quadrupled from 1995 to 2006. If the current rate of acceleration were to continue the main trunk of the glacier could be afloat within 100 years.
Read more about this topic: Pine Island Glacier
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