Greenland's glaciers flowing into the ocean are grounded deeper below
sea level than previously measured, allowing intruding ocean water to
badly undercut the glacier faces. That process will raise sea levels
around the world much faster than currently estimated, according to a
team of researchers led by Eric Rignot of the University of California,
Irvine (UCI), and NASA's Jet Propulsion Laboratory, Pasadena,
California.
The researchers battled rough waters and an onslaught of icebergs for
three summers to map the remote channels below Greenland's
marine-terminating glaciers for the first time. Their results have been
accepted for publication in the journal Geophysical Research Letters and
are now available online.
"Measurements are challenging to obtain beneath hundreds of meters of
seawater in poorly charted, ice-infested fjords," Rignot wrote. He and
co-authors Ian Fenty of JPL, Cilan Cai and Yun Xu of UCI, and Chris Kemp
of Terrasond Ltd., Seattle, obtained and analyzed around-the-clock
measurements of the depth, salinity and temperature of channel waters
and their intersection with the coastal edge of Greenland's ice sheet.
The team found some glaciers perched on giant earthen sills, protecting
them from the punishing salt waters for now, while others were being
severely eroded out of sight beneath the surface, meaning they could
collapse and melt much sooner. "Numerical ice sheet models do not take
into account these interactions and as a result underestimate how fast
the glaciers will respond to climate warming," said Rignot.
See video, photos and a narrative of the August 2014 expedition."
