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An iceberg the size of Delaware has broken off from Antarctica

Blaming climate change isn’t so easy. 

The rift in the ice sheet, as seen in 2016.
Brian Resnick is Vox’s science and health editor, and is the co-creator of Unexplainable, Vox's podcast about unanswered questions in science. Previously, Brian was a reporter at Vox and at National Journal.

The world has a new iceberg that’s so massive in size that maps of Antarctica will soon have to be redrawn.

The trillion-ton piece of ice just broke off from the Larsen-C ice shelf on the Antarctic peninsula. It totals about 2,240 square miles — about the size of the state of Delaware — and its volume, 40 trillion cubic feet of ice, is twice that of Lake Erie, reports Project Midas, a UK-based science group dedicated to studying the ice shelf.

Scientists have been expecting this event for months, and say it wasn’t caused by climate change. Sea levels won’t rise from this new iceberg because the ice was already in the ocean. But it’s still worrying because of the long-term impact it could have on the rest of the shelf’s ice.

“Although this is a natural event, and we’re not aware of any link to human-induced climate change, this puts the ice shelf in a very vulnerable position,” Martin O’Leary, a glaciologist on the Midas team, said in a statement. “This is the furthest back that the ice front has been in recorded history. We’re going to be watching very carefully for signs that the rest of the shelf is becoming unstable.”

Since at least 2010, a portion of the 19,000 square-mile Larsen-C has been tearing away from the shelf like a broken zipper. Over the past few years the crack has accelerated dramatically, spreading 33 feet per day to a distance topping 120 miles. On Friday, the European Space Agency reported there were just 3 miles left to go before detachment.

On Wednesday, the ESO confirmed the break with additional satellite imagery.

This is what the final satellite image of the break looks like.

Project MIDAS

An ice shelf forms when glaciers on land start to spread out over the sea. And they serve as a doorstop — keeping glacial ice on the continent from drifting out to sea. Eventually, pieces of the glacier flake off to form icebergs. This is a natural process. What’s different is the humongous size of this one — it’s about 12 percent of the total area of the Larsen-C. “The landscape of the Antarctic Peninsula changed forever,” Project Midas said in a blog post.

“We don’t think this is caused by climate change,” Christopher Shuman, a scientist with the Cryospheric Sciences Laboratory at NASA Goddard, says in an interview. He explains that Larsen-C, at large, still maintains critical anchors to the sea floor bedrock. “If we had seen the Larsen-C lose connection with these grounding points … that would have been much stronger evidence the whole shelf is becoming destabilized.”

More research is need to understand if this event is a precursor to more breakaways from the Larsen-C still to come.

“At this time we don’t see any signs this is going to cause further break,” Shuman says. “On the other hand, this is over 10 percent of the ice shelf area, so that’s not a good sign.”

It’s undeniable the Antarctic peninsula has been losing ice over the past few decades. “And it’s pretty clear … there’s a connection to an overall warming that part of Antarctica has experienced,” Shuman says.

Ice loss on Antarctic ice shelves is accelerating, a 2015 Science study found. It matters because the ice shelves help keep the land ice in place. And if the shelves destabilize from events like this, it could destabilize the land ice that could drastically contribute to sea level rise.

“Although the remaining ice shelf will continue naturally to regrow … researchers have previously shown that the new configuration is potentially less stable than it was prior to the rift,” Adrian Luckman, another Midas team member, explained in a press statement.

In 2002, the smaller Larsen-B ice shelf, which had existed for 10,000 years, partially collapsed and formed an iceberg the size of Rhode Island. NASA doesn’t expect the rest of Larsen-B to survive the decade. Before that, in 1995, the Larsen-A broke apart.

Climate Nexus

Let’s try to imagine what 40 trillion cubic feet of ice looks like

It’s hard to wrap your head around the sheer amount of water and ice involved in the new iceberg. Let’s try to put it in perspective.

The Larsen-C shelf is the continent’s fourth-largest ice shelf. It’s located on the Antarctic Peninsula — the bit of the continent that looks like a crooked finger pointing up toward the Southern tip of South America. The Larsen-C is located on the Northeastern side of the peninsula.

Wikimedia Commons

Now, the whole Larsen-C ice sheet isn’t ripping off from the continent — only around 12 percent. But it’s still huge and dramatic.

Forty trillion cubic feet of ice is a pretty mind-boggling figure. When a huge snowstorm dumped 6.6 trillion cubic feet of snow on the East Coast of the US in 2015, Vox’s Javier Zarracina illustrated it like this:

The volume of ice ripping off of Antarctica is six times larger than this snowball.

The resulting iceberg will also be around 623.36 feet thick, the ESA reports. Again, that’s huge: about 68 feet taller than the Washington Monument. In area, it will be roughly the size of the state of Delaware (which takes two-ish hours to drive across). For some reference, here’s what Delaware (in red) looks like laid over New York City (in blue).

And here it is laid over Los Angeles.

So: big. It will be one of the largest icebergs in all of the ocean.

Where does it go from here? Project Midas reports it will likely travel the path of previous icebergs that have broken off of Larsen ice shelves.

Project MIDAS

Why this doesn’t mean the sea levels will rise

The ice shelf breaking apart will not contribute to sea level rise. That’s because this portion of ice was already in the water. And when ice melts, the volume of water produced is equal to the volume of water displaced by the ice. That is, when an ice cube melts into a glass of ice water, the water level doesn’t rise. See:

Again, the danger is that the break makes the land ice unstable. But we’re just going to have to wait and see if that happens. It’s possible this portion of the ice shelf grows back.

“In the ensuing months and years, the ice shelf could either gradually regrow, or may suffer further calving events which may eventually lead to collapse — opinions in the scientific community are divided,” Luckman said. “Our models say it will be less stable, but any future collapse remains years or decades away.”

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