Q&A: A trillion-ton iceberg is floating in the sea. Now what?
Posted July 13
A trillion-ton iceberg, one of the biggest ever recorded, splintered off western Antarctica and is now floating at sea.
Sometime between Monday and Wednesday, a portion of an Antarctic ice shelf, almost the size of Delaware, broke off.
The massive iceberg isn't expected to cause any imminent danger to people, ships, or nearby areas, scientists say. But they're worried about what this could mean in the long run for Antarctica and rising sea levels.
Where will the iceberg go?
Its future is difficult to predict, said Adrian Luckman, lead investigator of the MIDAS Project, which monitored the break.
"It may remain in one piece but is more likely to break into fragments. Some of the ice may remain in the area for decades, while parts of the iceberg may drift north into warmer waters," said Luckman in a statement.
This iceberg is probably going to doodle around in the area of where it broke off for quite awhile, said Tas van Ommen, program leader with the Australian Antarctic Division.
"An iceberg this big is going to last for years to a decade or longer," he said. It would take a "combination of melting and breaking up into smaller icebergs and eventually dissipating."
Will the giant iceberg affect humans?
"This event does not directly affect anyone, and repercussions, if there are any, will not be felt for years. However, it is a spectacular and enormous geographical event which has changed the landscape," Luckman said.
Read: Is it time to stop vacationing in Antarctica?
Will it affect shipping lanes or continents closest to Antarctica?
For now, the only shipping hazard is to research vessels that frequent the Antarctic area, said van Ommen. Given its significant girth, it should be easy to spot.
"When you think of the big monolith that's there at the moment, it's not going anywhere in a hurry," he said. "Because these things are so thick, it's probably going to get stuck in the ocean floor at various times."
In a few years, the iceberg may start to drift into the open ocean. It will probably break into two or three significant chunks and break down into even smaller pieces that may drift into shipping lanes, van Ommen said.
"In the long run, it could be something that interferes with shipping and has to be watched," he said.
It's unlikely to come up to areas like South America or South Africa, he added. A few years ago, a larger iceberg came within visible range of New Zealand's south island, he said.
Will the iceberg raise the sea level?
No, because it was already floating when it was part of the Larsen C Ice Shelf. So it has no immediate impact on the sea level.
Think of an ice cube that's in your drink. When that ice cube melts, you don't see a rise in the liquid. Likewise, for the iceberg.
But it's a different matter when it comes to land ice that falls into the ocean.
Are scientists concerned about this?
It's less about the iceberg and more about what the break-up could mean.
Scientists are worried about the increasingly fragile ice shelves in the Antarctic.
An ice shelf is a floating chunk of ice that's connected to land -- most of them are in Antarctica.
Ice shelves play a critical gatekeeping role as they hold back glaciers and ice streams from flowing into the ocean. They've even been described as corks in bottles.
If the ice shelves collapse, this would quicken the pace of land ice falling into the ocean. This -- unlike the massive iceberg -- raises the sea level.
The recent breakage occurred in Larsen C Ice Shelf and took more than 12% of its total area. When chunks of ice break off, it's known as calving.
Calving is a natural occurrence, but scientists have noted that the recent event was quite enormous. They're exploring whether climate change may have played a role in expediting the rift.
"Even though it looks natural, it's unusual," said van Ommen. "When you start to see unusual things in an environment where you know there's warming occurring, you know there are uncertainties. We're really concerned to try to understand what's going on."
Larsen C Ice Shelf may regrow or it could disintegrate.
Scientists will be monitoring what's left of Larsen C to see how it handles the extra strain and whether it shows signs of breaking and cracking.
Read: Two big changes in Antarctica have scientists worried
Did it break off due to climate change?
Scientific opinion is divided on that.
"We have no evidence to link this directly to climate change, and no reason to believe that it would not have happened without the extra warming that human activity has caused," said Luckman, who is also a professor at Swansea University.
"But the ice shelf is now at its most retreated position ever recorded and regional warming may have played a part in that," he added.
Not all scientists agree though, especially given the context of climate change.
It's clear that global warming is contributing to the broader destabilization of Antarctica, said Eric Rignot, professor of Earth systems sciences at the University of California, Irvine, and a senior research scientist at NASA's Jet Propulsion Laboratory.
He said Larsen C followed a similar pathway as Larsen B Ice Shelf, which collapsed in 2002.
"The ice front starts to retreats, it does that because the ice shelf is thinning from warming," he told CNN. "At some point, it reaches a threshold in which the whole ice shelf can collapse in a domino effect like it did for Larsen B."
Larsen C needs to calve back further before it can collapse, but he warned the trend seemed familiar.
"This is yet another wake up call..." he said, "We should be concerned about what that means for future sea level."
How does this affect the map of Antarctica?
The calving changed the landscape of the Antarctic Peninsula forever, according to scientists from Project MIDAS.
Expect that map to be redone.