December 11, 2013
An expedition of international scientists to the far reaches of Antarctica’s remote Pine Island Glacier has yielded exact measurements of an undersea process glaciologists have long called the “biggest source of uncertainty in global sea level projections.”
The research, which recently appeared in Science magazine, was conducted by scientists at NYU’s Courant Institute of Mathematical Sciences, the Naval Postgraduate School (NPS), the University of Alaska, Pennsylvania State University, NASA, and the British Antarctic Survey.
The article details the landmark results of the Pine Island Glacier expedition, giving scientists an extensive look beneath the ice at one of the most remote research sites on the planet—a site whose fate could affect the lives of millions.
“Intensive melting under the Pine Island ice shelf, as observed in our study, could potentially lead to the speedup and ultimate breakup of the ice shelf,” says Courant’s David Holland, one of the paper’s co-authors. “That’s important, as this ice shelf is currently holding back inland ice and without that restraining force, the Pine Island catchment basin could further contribute to global sea-level rise.”
Given the flow of warm sea water beneath the glacier, scientists have long known that Pine Island Glacier was melting from below—the accelerated flow of West Antarctic Ice Sheet glacial ice into the Amundsen Sea has been a concern of scientists since the late 1980s. An exhaustive expedition to the 50-km-long floating ice shelf at the outer reaches of the glacier field, and 500 meters down into it, revealed the first measurements detailing ice-shelf melting rates and processes within melt channels that bore into the shelf underbelly.
“What we have brought to the table are detailed measurements of melt rates that will allow simple physical models of the melting processes to be plugged into computer models of the coupled ocean/glacier system,” says NPS research professor Tim Stanton. “These improved models are critical to our ability to predict future changes in the ice shelf, and glacier-melt rates of the potentially unstable West Antarctic Ice Sheet in response to changing ocean forces.”
The measured glacial melt rate at the site, and through the channel on Pine Island, at approximately six centimeters per day, reveals a critical need to understand channelized melting underneath massive glaciers, as they are major contributors to global sea-level rise now and into the future.