Once this iceberg drifts into the ocean, the shelf behind it might collapse. That’s similar to what happened at Larsen B, which will likely disintegrate completely by 2020. However, NASA JPL ice shelf scientist Ala Khazendar cautions that Larsen C’s future remains uncertain. Ice shelves naturally shed icebergs, and this ice shelf could recover and avoid the fate of Larsens A and B.

If the floating Larsen C does collapse, it won’t raise sea levels directly. But once an ice shelf is gone, the glacier feeding it flows faster to the sea. And that will speed up sea level rise. Beyond that, scientists also worry what the collapse would mean for the rest of the continent as warming continues. “If the fourth-largest ice shelf in Antarctica disintegrates, bigger ice shelves with bigger drainage basins could also be in danger,” Khazendar says.