Iceberg Breaking Patterns Revealed

Researchers were able to finally identify the mechanisms through which cracks appear in the large ice shelves covering Antarctica and Greenland, a process known as calving. Understanding exactly how this happens is crucial, as the two regions stock most of the ice on Earth, whose melting could increase sea levels by more than 60 meters (196 feet). What exactly caused the ice to break in some places rather than others was a total mystery until now.

 

"For iceberg calving, the important variable – the one that accounts for the largest portion of when the iceberg breaks – is the rate at which ice shelves spread," explained Richard Alley, at the Pennsylvania State University, the lead author of the study, published last week in the journal Science. "It won't help the Titanic, but a newly derived, simple law may help scientists improve their climate models."

 

Basically, the study says, the number of cracks that appear in an ice shelf is directly linked to the speed at which it spreads from the land above the sea. Scientists have long since concluded that the shelves hover above the water, and the best example for this is the Ross ice spread, which expands some 500 miles above the Southern ocean before it begins calving.

 

With this new data, researchers analyzing the influence of human-released greenhouse gases (GHG) on these regions will have a new way of looking at computer simulations, as they never fully captured all the factors necessary to accurately predict how icebergs break off under specific conditions. "The problem of when things break is a really hard problem because there is so much variability," Alley said.

 

The main goal of these researches is to help policy-makers devise legislation that would avert an 18 to 59 cm (7-23 inches) sea level rise of the world's waters by the end of the century. Only comprehensive analysis and thorough simulations could provide sound scientific data, to be used to this end. And recent investigations in the Antarctic were aimed at just that.