In a monumental occurrence this week, a gigantic iceberg, weighing more than a trillion tonnes, broke away from the Larsen C Ice Shelf in Western Antarctica and is now floating free in the icy Antarctic waters.
Scientists had been anticipating the event since a couple of years at least. The eastern Antarctica located Larsen C Ice Shelf had developed a rift as early as the 1960s and 1970s, which had remained dormant for decades. However, the crack had been growing in size since 2014, and in the last year, its growth had accelerated at a tremendous rate.
Consequently, its breaking off had long been anticipated by scientists. It was just a question of when it happened.
Finally, sometime between July 10 and July 12, the crack covered the final 5,800-square kilometer distance and a new iceberg, dubbed A68, was born. The new iceberg is 8 times the size of Mumbai city and weighs more than a trillion tonnes. The break was detected by NASA satellites
It will be monitored closely by the U.S National Ice Center, just as the center monitors other icebergs in the area. It is unlikely, however,that A68 will pose a problem for navigation.
The break in the Larsen C Ice Shelf follows similar breaks in the Larsen A Ice Shelf in 1995 and the Larsen B Ice Shelf in 2002. Those particular breaks had led to the complete collapse of the entire A and B Ice Shelves. It remains to be seen how the Larsen C will respond to this break- whether it will lead to the complete disintegration of the Larsen C Ice Shelf or whether Larsen C will manage to hold its ground.
With the breaking away of the approximately 5,800-square kilometer chunk of ice, the Larsen C shelf has shrunk by almost 10 %. At present, the remaining 90 % of Larsen C is held in place by two pinning points- the Bawden Ice Rise to the north of the rift and the Gipps Ice Rise to its south. These two supports ensure that there is no imminent danger of the ice shelf collapsing. Not that there isn’t a possibility of that happening anytime in the future.
The Antarctic region has seen a rapidly accelerating rate of warming throughout the latter half of the 20th century. The collapse of the Larsen A and B shelves could be attributed to this accelerated rate of warming. And the warming up of Antarctica could lead to warmer ocean waters that would definitely erode away the base of the Larsen C Ice Shelf, causing it to collapse.
The formation of the new iceberg will not contribute to a rise in sea levels, since this portion of the ice shelf was already floating in the Antarctic waters. In fact, ice sheets calving off from ice shelves are a pretty normal occurrence in the icy Polar Regions. What is cause for concern, however, is that this ice shelf acted as a buffer for the glaciers that flowed in the region, absorbing all the ice that flowed through those glaciers.
With this barrier gone, these glaciers will now pour their ice directly into the ocean, causing a substantial rise in sea levels. And we all know the consequences of that one.