It’s October 16, 2018, and NASA scientists are flying a routine surveying mission. More specifically, the team are traveling across the Antarctic wastes as part of research project Operation IceBridge. Then one of the men aboard, scientific programmer Jeremy P. Harbeck, spots something highly unusual and snaps a picture of it. And the shot of the extraordinary-looking iceberg quickly spreads worldwide.
The particular iceberg that Harbeck spotted had calved from the Larsen C ice shelf; Larsen C had in turn previously broken off from the bigger Larsen Ice Shelf. And the Larsen Ice Shelf itself lies across the Antarctic Peninsula in the northwest of the Weddell Sea.
The shelf is named after Captain Carl Anton Larsen, a Norwegian who sailed his whaler along the length of the ice in 1893. Renowned as having been an intrepid explorer, Larsen is also distinguished as the first human to ever ski on the shelf.
Today, helping to define its expanse, the Larsen Ice Shelf is divided into several sections, named alphabetically – from Larsen A to G – with the smaller areas on the south of the Antarctic Peninsula. The shelf has increasingly featured in news reports, too, as it has broken up, shedding massive icebergs in its wake.
Firstly, Larsen A disintegrated in early 1995. Then, seven years later, Larsen B started to crumble, with this section of the shelf losing a 1,250 square-mile, 720-foot-thick chunk of ice. The resulting iceberg’s surface area was around the size of the state of Rhode Island.
At a minimum, Larsen B had been more or less secure for 10,000 years before it started to fall apart. But now that process appears to be accelerating; a 2015 paper from NASA, for example, predicted that Larsen B will likely have disappeared altogether by 2020.
NASA scientists had noted in particular that Larsen B was rapidly developing huge cracks, with one of the team, Ala Khazendar, speaking of his fears for the section in a press release. “Although it’s fascinating scientifically to have a front-row seat to watch the ice shelf becoming unstable and breaking up, it’s bad news for our planet,” he lamented.
But let’s take a closer look at Larsen C, which produced the bizarre iceberg that Harbeck photographed. In July 2017 the shelf had a surface area of 17,100 square miles, making it Antarctica’s fourth largest of its kind. The previous year, however, scientists had recorded a massive crack that had appeared along the shelf. This fissure extended for some 68 miles and measured nearly 300 feet wide.
You definitely wouldn’t have wanted to tumble into that crack, either, as it was 1,600 feet deep. Then in July 2017 the seemingly inevitable happened: an enormous iceberg calved from the shelf. Dubbed A-68, this giant weighed in at over a trillion tons and boasted a thickness of in excess of 700 feet.
And the aftermath of that gigantic calving produced the iceberg whose image went viral. Harbeck’s photograph showed a sheet of ice so rectangular in its shape that it’s almost unbelievable. But the snap is 100 percent genuine. There were, moreover, actually two rectangular bergs, although it was the one with the best-defined edges that ultimately became the most popular.
Scientists call these giant lumps of ice with cleanly defined lines “tabular icebergs.” Speaking to the website Live Science in October 2018, NASA scientist Kelly Brunt explained the phenomenon. “We get two types of icebergs,” she said. “We get the type that everyone can envision in their head that sank the Titanic. They look like prisms or triangles at the surface, and you know they have a crazy subsurface.”
“And then you have what are called ‘tabular icebergs,’” Brunt continued. She further explained that the process that forms these bergs is a bit like what happens when a fingernail snaps off, with the part that breaks often having a well-defined straight edge. Brunt also reckoned that this particular berg probably sprawled across more than a mile. “What makes this one a bit unusual is that it looks almost like a square,” she concluded.
Which brings us back to Harbeck and his astonishing sighting. The photographer was, after all, flying not far from the Larsen C shelf to the east of the Antarctic Peninsula when he spotted the tabular berg. Most likely, the block of ice had calved from Larsen C not long before he had traveled over it. And in a NASA press release, the scientist would go on to describe the moment when he had first seen the berg.
“I thought it was pretty interesting; I often see icebergs with relatively straight edges, but I’ve not really seen one before with two corners at such right angles like this one had,” Harbeck recalled. He added, “I was actually more interested in capturing the A-68 iceberg that we were about to fly over, but I thought this rectangular iceberg was visually interesting and fairly photogenic. So, on a lark, I just took a couple [of] photos.”
As we’ve mentioned, Harbeck was on a flight that was part of NASA’s IceBridge project. This ambitious operation aims to create a unique 3D record of the ice caps in both the Arctic and Antarctic. Flights are routed over the ice each year so that changes can be observed over time.
In particular, the project’s aircraft fly over the Greenland Arctic ice sheet from March to May and across Antarctica from October to November. And the mission takes readings that measure annual fluctuations in sea ice, ice sheets and glaciers.
Meanwhile, IceBridge is part of NASA’s wider Cryosphere Program, which has two operational priorities. Firstly, the program seeks to use information collected to create models that can predict how the behavior of the ice caps will affect future sea levels. Secondly, it plans to increase our understanding of the factors that impact on changes to polar ice.
And scientists have good cause to be concerned about what’s happening on the Antarctic Peninsula, where Larsen C broke off in 2017. Measurements taken between 1951 and 2004 showed that summer temperatures on the peninsula have shot up by 5.3° F. That’s faster than the overall trend on Earth.
Scientists have also linked global warming to ice loss in Antarctica – especially in the peninsula and in West Antarctica. And that melting ice, in turn, has had a significant impact on our environment. Researchers have calculated, for instance, that the amount of ice loss in Antarctica in the 25 years up to 2017 has contributed nearly a third of an inch to rising sea levels.
So on that October day in 2018, Harbeck’s trip across the Antarctic may have been a little more surprising than he had first anticipated. After all, not only did he engage in an important mission in aid of Antarctic science, but his travels also ended up producing one of the year’s most widely viewed viral images.