And just like that, a trillion-ton iceberg calved from the Larsen C ice shelf in Antarctica and the third largest iceberg ever recorded was born.

But instead of celebrating the birth, scientists around the world are holding their breath for what comes next. If the calving event destabilizes the rest of the Larsen C ice shelf, it will mark a turning point in our understanding of the warming climate — and an irrevocable change to the continent of Antarctica.

So what exactly is calving?

Calving, the formal name for the birth of an iceberg, is a fairly common process typically stimulated by warming waters. The heat creates melty spots within the ice sheet that weaken the ice and allow it to split apart. When an iceberg calves, as it just did in Antarctica, it leaves in its wake an original glacier and a new “baby” iceberg. (Though, at a trillion metric tonnes, this new iceberg is far from baby-sized.)

What’s more, ice sheets like the recently ruptured Larsen C are responsible for the structural integrity of the continent. “The remaining shelf will be at its smallest ever known size,” researcher Adrian Luckman of Project MIDAS told The New York Times. “This is a big change. Maps will need to be redrawn.”

Scientists fear that this isn’t an isolated event, and that it could trigger a calving cascade across the region.

That’s because ice sheets help keep ice out of the ocean. Though Larsen C wasn’t a particularly heavy lifter in this department, many other ice sheets on Antarctica certainly are. If these cold cubes keep breaking, the ice that pours into the ocean could eventually contribute significantly to sea level rise.

The Larsen A, Larsen B, Larsen C, and Larsen D ice shelves on the Antarctic Peninsula.
Here are all the Larsen ice shelves on the Antarctic Peninsula. 

Up north in the Arctic, where most icebergs form, there’s concern melting will release viruses, gases, and other spooky things the ice once covered up. The melt is already destroying habitats for animals that thrive in their cold climes. And just a friendly reminder that calving is ultimately what caused the sinking of the Titanic.

The true impact of the Larsen C calving has yet to be seen. Glaciologists have been predicting this icy event for a long time after a 120-mile long crack appeared in Antarctica’s Larsen C ice sheet, indicating calving was eminent.

The ultimate cause of the calving also has yet to be determined. While calving is certainly a natural occurrence, climate change probably stacks the deck on events like these. As the world and its oceans warm, we’ll probably see more melty spots develop — and more dramatic instances of calving.

Photos via Wikimedia Commons, Giphy