Antarctica's Ice Sheets Are Melting Faster — And From Beneath
http://www.npr.org/sections/thetwo-way/2016/10/25/499206005/antarcticas-ice-sheets-are-melting-faster-and-from-beneath
A team from JPL has been studying that grounding line in several places along the edge of the West Antarctic ice sheet. They used radar to look beneath the ice. In particular, overflights have targeted ice shelves along the West Antarctic ice sheet known as the Amundsen Sea Embayment.
They've found that the ice is melting faster than they've ever seen. The researchers believe the cause is warm water circulating beneath the ice shelf. The melting was most pronounced from 2002 to 2009. (The influx of warmer water to the region stalled recently, and the rate of melting seems to have slowed somewhat.)
Khazendar says the more the bottom of the shelves melt, the more ice is exposed to warm water. "It becomes a runaway process," he explains, "which makes it unstable."
Where's the warmer water coming from? The team, whose findings appear in the journal Nature Communications, points to global warming that's heating up the oceans. There's been a spate of research lately showing that Antarctic ice is melting faster than previously thought and raising global sea levels.
Per another source, the Smith Glacier alone lost almost 1,000 FEET of ice from below in only 7 years!
http://www.gizmodo.com.au/2016/10/the-west-antarctic-ice-sheet-is-wasting-away-fast/
When Khazendar examined changes in the thickness of three glaciers Smith, Pope and Kohler he discovered significant thinning near the grounding lines. Smith glacier, in particular, stuck out like a sore thumb: In just seven years, this ice sheet shed 300 to 490m of ice from its underbelly. What we have observed is rates [of melting] under Smith and other glaciers that are tens of meters per year out of balance, Khazendar said. This was really staggering.