The calving off of the 2,500-square-mile iceberg from the Larsen C ice shelf was detected and confirmed in data from NASA, but scientists say the iceberg was already floating before it separated and therefore has no immediate impact on sea level. The iceberg had been closely monitored by scientists for months, as a deep crack slowly extended for over 120 miles. On July 6th, satellite data showed that only 2.8 miles of ice kept the iceberg attached to the larger ice shelf, called Larsen C.
Larsen C is the fourth largest ice shelf in Antarctica with an area of about 20,000 square miles, according to NASA. Ice shelves are barriers that keep land-based ice from flowing into the sea resulting in higher sea levels.
At 5,800 sq km the new iceberg, expected to be dubbed A68, is half as big as the record-holding iceberg B-15 which split off from the Ross ice shelf in the year 2000, but it is nonetheless believed to be among the 10 largest icebergs ever recorded.
The huge crack that spawned the new iceberg grew over a period of years, but between 25 May and 31 May alone, the rift grew by 17km – the largest increase since January. Between the 24 June and 27 June the movement of the ice sped up, reaching a rate of more than 10 metres per day for the already-severed section.
But in the end it wasn’t a simple break – data collected just days before the iceberg calved revealed that the rift had branched multiple times. “We see one large [iceberg] for now. It is likely that this will break into smaller pieces as time goes by.
There is enough ice in Antarctica that if it all melted, or even just flowed into the ocean, sea levels [would] rise by 60 metres.
But while the birth of the huge iceberg might look dramatic, experts say it will not itself result in sea level rises. It’s like your ice cube in your gin and tonic – it is already floating and if it melts it doesn’t change the volume of water in the glass by very much at all.
