Researchers at Scripps Institution of Oceanography have recently reported that Antarctica’s floating ice shelves have decreased in thickness by as much as 18 percent during the past two decades. Satellite radar altimetry mission data from the European Space Agency were used between 1994 and 2012 to determine the change.
The new high-resolution record of ice shelf thickness was created by merging data from three overlapping missions. The study shows total ice shelf volume (mean thickness multiplied by ice shelf area) across Antarctica changed little from 1994 to 2003, then declined rapidly. West Antarctic ice shelves lost ice throughout the entire observation period, with accelerated loss in the most recent decade. Earlier gains in East Antarctic ice shelf volume ceased after about 2003.
Although melting ice shelves don’t contribute directly to sea-level rise, the researchers indicate there is an important indirect effect.
“The ice shelves buttress the flow from grounded ice into the ocean, and that flow impacts sea-level rise, so that’s a key concern from our new study,” said Scripps Glaciologist Helen Amanda Fricker.
Under current rates of thinning, the researchers estimate the ice shelves restraining the unstable sector of West Antarctica could lose half their volume within the next 200 years.
“This work demonstrates the power of satellite observations to understand change in the great polar ice sheets,” said Thomas Wagner, program manager for Cryospheric Sciences at NASA headquarters. “And with data spanning decades, we can understand some of the most important changes and their implications for sea-level rise.”
The study, supported by NASA, was published on March 26, 2015, in the journal Science.