A Greenland glacier that holds the equivalent of 19
inches of sea-level rise has been melting at an accelerated rate since
2012, shedding as much as 5 billion metric tons a year, according to a
new study published in the journal
Science.
While scientists have
observed the melting
of Greenland’s southern glaciers, the Zachariæ Isstrøm glacier is the
first major glacier in the northern part of the country to show similar
losses.
“That may be an indication that
climate warming is spreading
toward the poles,” said Jeremie Mouginot, the study’s lead author and
an associate project scientist at the University of California, Irvine.
Working with researchers at NASA’s Jet Propulsion
Laboratory and the University of Kansas, the team used aerial surveys,
radar, laser profiling systems, and satellite observations from multiple
international space agencies to piece together 40 years of data for the
study.
They found that the Zachariæ glacier is rapidly
eroding from the bottom thanks to warmer ocean water and increasing
levels of meltwater that are affecting the ice sheet surface.
RELATED: Here’s What the World’s Cities Would Look Like After Catastrophic Sea-Level Rise
“The top of the glacier is melting away as a result
of decades of steadily increasing air temperatures, while its underside
is compromised by currents carrying warmer ocean water, and the glacier
is now breaking away into bits and pieces and retreating into deeper
ground,” Eric Rignot, study coauthor and UCI professor of earth system
science, said in a statement.
“From our record, it is the first time Zachariæ has retreated so far inland and has lost its floating ice shelf,” Mouginot said.
The researchers also pointed out a neighboring
glacier, Nioghalvfjerdsfjorden, which is experiencing rapid ice melts
but at a slower pace than Zachariæ. The two glaciers make up 12 percent
of Greenland’s ice sheet. If both fully collapsed, it would mean 39
inches of sea-level rise for the world.
“At the present rate of mass loss, it would take
millennia for the glacier to completely disappear,” Mouginot said. “But
we do not know how fast the glacier will flow in the coming decades.”
Scientists estimate Greenland’s 650,000-square-mile ice sheet is losing
303 billion tons of ice
on average per year. But more ice loss from the north could mean an
acceleration of the Intergovernmental Panel on Climate Change’s
projection of sea-level rise of 1.6 feet to 3.2 feet by the end of the
century. If the entire ice sheet melted, it would raise sea levels by
more than 20 feet worldwide.
“Not long ago, we wondered about the effect
on sea levels if Earth’s major glaciers were to start retreating,”
Rignot said. “We no longer need to wonder; for a couple of decades now,
we’ve been able to directly observe the results of climate warming on
polar glaciers. The changes are staggering and are now affecting the
four corners of Greenland.”
Related stories on TakePart:
• NASA Says Three Feet of Sea Level Rise Is Unavoidable
• What the World’s Cities Would Look Like If Every Glacier Melted
• Shell May Be Leaving the Arctic, but Norway's High North Is Open for Business
No comments:
Post a Comment