Dec 13, 2021 - Energy & Environment

Cracks could cause key ice shelf holding back "Doomsday Glacier" to collapse

Close look at the Thwaites Ice Shelf edge
Close look at the Thwaites Ice Shelf edge. Photo: NASA/James Yungel

Scientists have detected new cracks in the key ice shelf that buttresses Antarctica's Thwaites Glacier, indicating that the ice shelf could break apart within the next five years.

Why it matters: The destruction of the ice shelf could accelerate the movement of inland ice into the sea, eventually causing sea levels to rise by several feet and endangering coastal communities worldwide, per the Washington Post.

State of play: The Thwaites Glacier is known as the "doomsday glacier," due to the possibility that it may already be past a tipping point into a virtually unstoppable, runaway melt.

  • Roughly the size of Florida, the Thwaites Glacier's meltwater already contributes to about 4% of global sea level rise.
  • The Thwaites Eastern Ice Shelf acts as a brace preventing faster flow of meltwater from the glacier, and the shelf is held in place by an underwater mountain, according to the Cooperative Institute for Research in Environmental Sciences at the University of Colorado, Boulder.
  • This part of the ice shelf was previously thought to be stable until scientists took new measurements during a field campaign over the past two years.

Warming ocean water is melting the ice from below, meaning the shelf is gradually losing its grip on the underwater mountain and satellite imagery has revealed fractures in the shelf.

  • "Similar to a growing crack in the windshield of a car, a slowly growing crack means the windshield is weak and a small bump to the car might cause the windshield to suddenly break apart into hundreds of panes of glass," reads a summary of the findings.
  • The breaking of the ice shelf will increase the flow of ice off Antarctica, it adds.

The big picture: The Thwaites Glacier is situated in a deep basin, so if it collapses, neighboring glaciers would follow, and over the next few centuries it could lead to the loss of the entire West Antarctic Ice Sheet, contributing to a large rise in sea levels, according to Science.

  • “That would be a global change,” Robert DeConto, a glaciologist at the University of Massachusetts, Amherst, told Science. “Our coastlines will look different from space.”
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