Examining How Fast Polar Ice Sheets Are Melting
06.04.2010 - Atmosphere & Space, Water & Oceans, Ice & Snow, Bi-polar
While the melting of the gigantic ice sheets in Greenland and Antarctica as a consequence of global warming is well-established, researchers have sought to determine how fast sea level rise may occur. Current sea level rise is calculated at only about 2.5cm per decade; however this rate could increase over the next 50 years as warming continues.
According to Sridhar Anandakrishnan of Penn State University’s College of Earth and Mineral Sciences, knowing how glaciers will respond requires knowing more about their dynamics. A particularly tricky question has been what makes ice streams flow faster at some times and slow down at others.
Using seismographic instruments, Prenn State researchers were able to determine that ice streams in the West Antarctic Ice Sheet flow faster in response to the fluctuations of the tides, which was surprising. In 2008, the same team showed that these tidal responses trigger slow-motion “earthquakes” as the moving ice sticks and slips on the bedrock of the continent underneath.
Other research also highlights other complicating factors. Scientists at the Scripps Oceanographic Institute posited that wave energy originating from storms in the North Pacific Ocean travelling south destabilized ice shelves in Antarctica, which has the potential to trigger the creation or widening of crevasses on Antarctica’s ice shelves. These crevasses in turn can speed melting by draining melt-water straight to the glacier’s base, lubricating the ice sheet as the ice flows towards the sea.
These studies show that the oceans and the glaciers strongly interact with each other, underlining the importance of studying the processes that govern their behaviour to ultimately better predict sea-level rise.
