It's still unclear why the rift grew so quickly in recent months. There's a lot of evidence that climate change contributed to Larsen C's thinning, but ice shelves normally produce icebergs every few decades anyway. Whatever the reason is, the calving could accelerate the flow of glaciers stoppered by Larsen C into the ocean. It'll be like popping out a wine bottle's cork and letting the contents pour out. That's what happened when icebergs broke away from the Larsen A and Larsen B ice shelves in the past.

The glaciers flowing into Larsen C are enough to raise global sea levels by a centimeter -- much, much more than the usual three millimeters they rise every year. Scientists can't say how quickly the glaciers will flow into the ocean after the calving, but they're keeping a close eye on the expanding rift for now.