'Extraordinary': Almost 1/4 of West Antarctic ice is now 'unstable'
More unsettling news from the bottom of the world.
Almost one-quarter of the ice in the West Antarctic ice sheet has been classified as "unstable," according to a new study released this week.
This is due to the huge volume of ice that's melted from the ice sheet over the past 25 years. Some areas are losing ice five times faster than they were in the early 1990s.
“In parts of Antarctica, the ice sheet has thinned by extraordinary amounts," said study lead author Andy Shepherd, a polar scientist at the University of Leeds in the United Kingdom.
The ice has thinned by some 400 feet in some places, the study said. The ice sheet and its glaciers are melting from underneath as warming sea water – overheated due to man-made climate change – chews away at it from below.
“Along an 1,850-mile stretch of West Antarctica, the water in front of the glaciers is too hot,” Shepherd told the Guardian. "This causes melting of the underside of the glaciers where they grind against the seabed. The melting lessens the friction and allows the glaciers then to slide more quickly into the ocean and therefore become thinner."
A reminder: This isn't the floating sea ice around Antarctica, which melts and refreezes with the seasons. This is freshwater ice on the gigantic ice sheets and in the glaciers that cover most of the continent.
The ice is unstable because melting and calving (the breaking off of ice chunks) is reducing their mass faster than it can be replenished by snowfall, CNN reported.
The melting contributes to rising sea levels around the world: "Altogether, ice losses from East and West Antarctica have contributed 4.6 millimeters (about 1/5 of an inch) to global sea level rise since 1992," Shepherd said.
The study was published in the peer-reviewed journal Geophysical Research Letters, a publication of the American Geophysical Union.
This article originally appeared on USA TODAY: 'Extraordinary': Almost 1/4 of West Antarctic ice is now 'unstable'
