A colossal chunk of ice that had been slowly separating from an Antarctic ice shelf broke free this week, researchers said Wednesday — notable because it created one of the largest icebergs ever recorded and will require maps of the peninsula to be redrawn.
British scientists studying the process, which is known as calving, say the fate of the area, and the iceberg itself, remain unclear and worry that the Larsen C ice shelf it was tethered to could one day collapse. That, in turn, could threaten to dump more ice into the ocean and raise sea levels.
For scientists, this event is only a small sliver in a wider discussion about what is happening in the Antarctic, why it's happening and how rising global temperatures and human activity are playing a role.
NBC News interviewed Ted Scambos, a senior research scientist with the National Snow and Ice Data Center in Boulder, Colorado, to get a better understanding. An email interview with him has been edited for clarity and length.
Q: What is the significance of this more than 2,000-square-mile iceberg breaking off?
SCAMBOS: It's a major change to this ice shelf — a very large iceberg and the remaining ice shelf is smaller than it has ever been in human experience. It's an example of how the polar regions can change on a massive scale, even in just a few years or decades. And it shows us that, while we can observe this continent in great detail now, we're only seeing it clearly for the past few decades and it still has a lot to teach us.
SCAMBOS: There's no doubt that the warming and melting and other changes in this region are a part of the global climate change story. But exactly how the changes in this area led to this iceberg is a bit of a puzzle. The new event is not all that unusual for an ice shelf generally, but this large of a berg, at this time, in this area — it's suspicious.
Q: Will this event cause sea levels to rise significantly or even a little?
SCAMBOS: By itself, no, absolutely no. But if in the next few years the ice shelf and glaciers begin to flow a bit faster, we would see a small rise in the rate of sea level change. Overall, though, this place is more of an "Area 51" for glaciology — we get to see how warming plays out in an area of Antarctica that does not have huge consequences for us. If the same thing happened in some of the other regions, it would be a serious concern.
Q. As the new iceberg potentially drifts north to warmer waters and melts, do you think it could raise the sea levels of the area it's in?
SCAMBOS: No, an iceberg has no impact on sea level — it has already displaced all the water that it represents. It's floating, so it is already "stepped into the bathtub." When this iceberg breaks apart, it could be a small hazard to navigation, but there's not a lot of navigation in these areas.
Q. If the collapse of other ice shelves are a precursor to what might befall Larsen C, is this event a canary in a coal mine situation for the Antarctic Peninsula?
SCAMBOS: For the Antarctic Peninsula, the canary died a while ago. This is more a case of showing us how big a change may have been initiated back in 1995 (when another ice shelf known as Larsen A collapsed).
SCAMBOS: Calving of icebergs happens all the time from Antarctica. No big deal. This one is large, but not really even in the Top 10 since the 1960s. It's more important when the last parts of an ice shelf break away, when the fingernail breaks back too far and the glaciers really jump forward. We've seen that a few times, further north in the Larsen, but this area has a long way to go for that.