The crack in the Larsen C ice shelf in Antarctica has just gotten larger, growing another six miles (10 kilometers) over the past few weeks and exceeding a length of over 100 miles long.
Ice shelves, wrote USA TODAY, are primarily found in Antarctica, surrounding the continent’s coast and connecting to a land mass a permanently floating sheets of ice. The Larsen C ice shelf is found on the Antarctic Peninsula, which extends outward to the direction of South America’s southernmost point.
Depending on the source of the report, the size of this giant iceberg that would calve, or split off when the Larsen C ice shelf rift is “completed,” has been compared to a few geographical locations. USA TODAY wrote that the iceberg may be larger than the state of Rhode Island, while BBC said its size may be about a fourth the size of Wales. Regardless of the comparisons, all it would take is another 12-mile (20-kilometer) growth for the gap to free the iceberg.
— Erik Michaels (@ErikMichaels) January 21, 2017
Researchers from the United Kingdom working on the Antarctic-centric Project MIDAS believe that the giant iceberg will turn out to be one of the largest ever recorded in history. And the growing crack in Larsen C has these scientists concerned, as the European Union’s Sentinel-1 satellite system continues monitoring the ice shelf, using its radar to see through clouds and track the fissure regardless of the weather.
While the crack now measures close to 110 miles (175 kilometers), it’s still not sure how long it would take before the iceberg breaks loose from the Larsen C ice shelf, said Project MIDAS leader Adrian Luckman of Swansea University in an interview with BBC.
“The rift tip has just entered a new area of softer ice, which will slow its progress. Although you might expect any extension to hasten the point of calving, it actually remains impossible to predict when it will break because the fracture process is so complex.
“My feeling is that this new development suggests something will happen within weeks to months, but there is an outside chance that further growth will be slow for longer than that. Sometimes rift growth is triggered by ocean swell originating elsewhere, which is also hard to predict.”
— SKJ Traveler (@SKJtraveler) January 12, 2017
On a positive note, the giant iceberg’s potential split from Larsen C might not pose any direct risk to global sea levels. Speaking to USA TODAY, National Snow and Ice Data Center scientist Ted Scambos said sea levels should remain mostly unaffected as the iceberg is already floating, with levels rising just about 1/16ths of an inch if such a large piece of ice would drop into the sea. But another expert, NASA scientist Thomas Wagner, warned that any land ice blocked by the iceberg may make it into the sea and raise sea levels.
“Ice shelves serve a critical role in buttressing ice that’s on land.”
The BBC report stressed that the most interesting aspect of the giant iceberg’s breakaway from Larsen C would be what happens to the shelf itself once the calving occurs. Back in 2002, a major calving event had caused the destruction of the Larsen B ice shelf. With glaciers speeding up in movement without Larsen B as a buttress, this led to sea level rise, and as mentioned above, a similar rise may take place if the same thing happens to Larsen C.
After breaking off from the Larsen C ice shelf, the giant iceberg is expected to move along the Antarctic coast, and break into smaller pieces once it reaches the Southern Ocean. Luckman and his fellow Project MIDAS researchers do not have enough data to determine with certainty whether climate change has caused the rift to keep growing, but said there is “good scientific evidence” that Larsen C has become thinner because of these largely man-made factors.
[Featured Image by NASA/AP Images]