Thursday, March 31, 2016

Climate Model Predicts West Antarctic Ice Sheet Could Melt Rapidly

By Justin Gillis  March 30, 2016

A view from a NASA airplane of large icebergs that have broken from the calving side of Thwaites Glacier in Antarctica in November 2014. A disaster scenario of West Antarctic ice sheet disintegration could occur much sooner than previously thought, new research suggests.
Credit  Image: Jim Yungel/NASA

For half a century, climate scientists have seen the West Antarctic ice sheet, a remnant of the last ice age, as a sword of Damocles hanging over human civilization.

The great ice sheet, larger than Mexico, is thought to be potentially vulnerable to disintegration from a relatively small amount of global warming, and capable of raising the sea level by 12 feet or more should it break up. But researchers long assumed the worst effects would take hundreds — if not thousands — of years to occur.

Now, new research suggests the disaster scenario could play out much sooner.

Continued high emissions of heat-trapping gases could launch a disintegration of the ice sheet within decades, according to a study published Wednesday, heaving enough water into the ocean to raise the sea level as much as three feet by the end of this century.

With ice melting in other regions, too, the total rise of the sea could reach five or six feet by 2100, the researchers found. That is roughly twice the increase reported as a plausible worst-case scenario by a United Nations panel just three years ago, and so high it would likely provoke a profound crisis within the lifetimes of children being born today.





Under the Ice Sheet

The vast West Antarctic ice sheet sits on bedrock that dips thousands of feet below sea level. New computer simulations suggest that the warming atmosphere and ocean could attack the ice sheet from above and below, causing sea levels to rise much faster than previously thought.

Current
extent of
Antarctic
ice sheet
RONNE
ICE
SHELF
ANTARCTICA
WEST
ANTARCTICA
ROSS
ICE
SHELF
Bedrock
elevation
Above
sea level
Below
sea level

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