Breaking Antarctic Ice Shelf Could Portend Higher than Expected, Longer Term Contribution to Global Sea Level Rise

A section of the Larsen C Ice Shelf, nearly the size of Delaware, broke off today--a natural process that was aided by increasingly warmer ocean temperatures.

"It's concerning that the ocean and air temperatures around the Larsen C Ice Shelf are so warm," said Brenda Ekwurzel, director of climate science and senior scientist at the Union of Concerned Scientists. "This is likely a harbinger of the pace and size of future ice shelf breaks in the Antarctic Peninsula."

Though the Larsen C Ice Shelf is already floating on water and the section that broke off will only negligibly affect sea level rise, the calving of this portion of the ice shelf allows the warmer ocean waters to lap at a new ice shelf front while continuing to erode the shelf from underneath. This process could eventually lead to the loss of the entire Larsen C Ice Shelf.

When an ice shelf collapses, the land-based glaciers behind it are no longer held back and can directly contribute to sea level rise.

"Ocean warming could affect other ice shelves in Antarctica that are holding back massive ice sheets," said Ekwurzel. "Scientists, aware of these processes, are likely to adjust sea level rise calculations, reflecting higher levels arriving sooner than now projected."