by Matt Owens December 30, 2012
A new study by Karina Nielsen and others has estimated rates of bedrock rebound in one particular coastal area of Greenland which is losing ice mass at a rapid rate. The rebound is estimated to be nearly 2 centimeters per year in one area, which is quite a high rate of change.
updated January 4, 2013:
Such a finding raises questions about the potential for earthquakes triggered by, or perhaps even induced by ice loss. Aside from jostling a few polar bears, an earthquake at the North Pole might seem harmless. However, at the opposite end of the globe, Antarctica is experiencing ice loss similar to Greenland, and earthquakes could be much less benign there.
A little-known process called MISI (marine ice sheet instability) is the concern here. The MISI hypothesis originated in the 1970's, and it was just in the past few years that it has been confirmed. MISI states that certain types of marine terminating glaciers (in fact, most of the West Antarctic Ice Sheet, and a decent portion of the East Antarctic too) are inherently unstable and they are either growing or collapsing (all are in the collapse mode at present). Basically, when an ice sheet's edge (also called its end, or terminus) is located in the ocean AND its base is also below sea level AND the slope of the bedrock is rising towards the ocean, the ice sheet is governed by MISI. As of now, the rate at which the MISI process will destroy the vulnerable Antarctic ice sheets is unknown [generally mainstream media sources and scientists studying other topics will say that the ice sheets won't collapse "in our lifetimes" ...insert evil-laughter-while-pointing-at-a-helpless-baby here...].