— Holding enough ice to raise sea levels by nearly 200 feet if it all melted, Antarctica is a major factor when it comes to climate change.
That's partly why NASA, yeah the space agency, also sponsors science here on Earth — and right now it's got several dozen scientists criss-crossing the western coast of the continent to measure sea ice and glaciers — the huge rivers of ice that hold back the two vast ice sheets covering Antarctica.
A DC-8 carrying seven instruments, and the researchers, has been making flights along Antarctica's west coast since Oct. 26 — and as weather conditions permit. Flying from a base in Punta Arenas, Chile, the mission hopes to have 11-12 flights completed before packing up on Sunday.
All this research is part of Operation IceBridge, a six-year mission that NASA calls "the largest airborne survey of Earth's polar ice ever flown."
Now in its second year, the mission has also been measuring ice at the other end of Earth — the Arctic. It was launched to "bridge the gap" in polar observations caused when a NASA satellite stopped collecting data in 2009 and the next similar satellite isn't planned until 2015.
But why bother? Why not wait a few years and let the new satellite resume measuring then?
Parts of western Antarctica are "sensitive, rapidly changing areas," Seeley Martin, a sea ice expert at the University of Washington, told a press conference Monday. "We wanted to avoid an 'Oh my God!' moment when we come back" in 2015.
There's also the need for having data from lots of years to make strong conclusions.
"You need a really long series to understand how glaciers and ice sheets respond to a changing climate," said Michael Studinger, the chief NASA scientist for IceBridge. "And if you only measure one glacier, you won't be able to draw any conclusions."
Sea ice and glaciers act as defenses that slow the natural tendency of ice on a landmass such as Antarctica to flow towards the sea.
Antarctica's ice is seen as much more stable than the ice sheet covering Greenland, where rapid melt has tracked a dramatic rise in Arctic air temperatures.
But even parts of Antarctica are now vulnerable and showing more rapid ice loss where temperatures have risen. Two western areas, in particular, are of concern: the tip of the Antarctic Peninsula and the Pine Island Glacier region.Antarctica is already contributing a third of the total rise in global sea level, which is about one-tenth of an inch a year, Studinger said.
And there's already an example of what the collapse of ice defenses can do. In 2002, Antarctica's Larsen B ice shelf collapsed, allowing several glaciers to speed up the flow of ice off the continent and into the sea — thus adding to sea level rise.
That "trigger event" caused "very dramatic changes," said Chris Shuman, a NASA scientist who specializes in glaciers.
"The loss of the large area of floating ice of the ice shelf triggered the changes within a number of the glaciers inland from it including the Crane, Hektoria, Green, Evans, and Jorum Glaciers," he added. "The losses were largest on the Crane with about 295 feet of elevation lost between late 2004 and late 2005 and a total of 557 feet lost over 2002-2009."
Data from this year's mission still has to be processed for comparisons to past measurements, and that can take up to six months given the large volume of digital data involved.
Once it is ready, however, it will be posted online for any researcher to work with.