A BBC story on the new study, “The spatial and temporal evolution of Pine Island Glacier thinning, 1995 – 2006,” (subs. req’d) explains:
Calculations based on the rate of melting 15 years ago had suggested the glacier would last for 600 years. But the new data points to a lifespan for the vast ice stream of only another 100 years.
The rate of loss is fastest in the centre of the glacier and the concern is that if the process continues, the glacier may break up and start to affect the ice sheet further inland.
One of the authors, Professor Andrew Shepherd of Leeds University, said that the melting from the centre of the glacier would add about 3cm to global sea level.
“But the ice trapped behind it is about 20-30cm of sea level rise and as soon as we destabilise or remove the middle of the glacier we don’t know really know what’s going to happen to the ice behind it,” he told BBC News.
When we last left Antarctic research, it turned out that the great ice sheet’s temperature had risen by up to about 3°C (5.4 °F) in the past 50 years, which is the fastest increase in the southern hemisphere (see “Antarctica has warmed significantly over past 50 years, revisited“):
Antarctica is disintegrating much faster than almost anybody imagined. In 2001, the IPCC “consensus” said neither Greenland nor Antarctica would lose significant mass by 2100. They both already are. As Penn State climatologist Richard Alley said in March 2006, the ice sheets appear to be shrinking “100 years ahead of schedule.”