Climate scientists await birth of world’s largest iceberg

Climate scientists are watching Antarctica closely these days. A massive crack in the Larsen C Ice Shelf is about to create what could be the world’s largest current and recent iceberg.

The giant 120 mile crack in the Larsen C Ice Shelf recently took a sharp right turn and is now within 8 miles if reaching open ocean. The massive soon to be iceberg is roughly the size of Delaware and 1,750 feet thick.

British Antarctic Survey

Uncorking

Since Larsen C already floats, the new iceberg will not have much affect on sea level. But as ice shelves like Larsen C disintegrate, that opens the door to faster slippage of land based ice flows. That “uncorking” can speed up future sea level rise.

The New York Times has a good description.

If it breaks at the crack, Larsen C will be at its smallest size ever recorded.

The ice front would also be left much closer to the ice shelf’s compressive arch, a line that scientists say is critical for structural support. If the front retreats past that line, the northernmost part of the shelf could collapse within months. It could also significantly change the landscape of the Antarctic peninsula.

“At that point in time, the glaciers will react,” Dr. Rignot said. “If the ice shelf breaks apart, it will remove a buttressing force on the glaciers that flow into it. The glaciers will feel less resistance to flow, effectively removing a cork in front of them.”

Climate Cast: Watching Larsen C

On today’s edition of MPR News Climate Cast, I ask University of St. Thomas thermal sciences professor John Abraham about why climate scientists are watching Larsen C so closely. John’s recent piece in the Guardian elaborates.

When people ask, how much will sea levels rise by 2100, my answer is “one meter”. Why do experts think this when we’ve only had a fifth of that over the past 100 years? Sea level rise is accelerating – it’s getting faster and faster as the accumulated heat from greenhouse gases takes hold. Part of the reason for the acceleration is phenomena such as ice shelf loss. It may take a while for an ice shelf to melt but when it does, the losses occur quickly.

  1. Listen Paul Huttner’s full interview with scientist John Abraham.

    June. 15, 2017

Crack in the Larsen C ice shelf. Image via Ted Scambos, NSIDC