Sampriti Roy, University of Calcutta
Several large cracks were seen in the iceberg A-68A (that was once colossal) towards the end of January, as revealed by satellite images. The iceberg has since broken into multiple pieces.
(“Antarctic icebergs are named after the Antarctic quadrant in which they were originally sighted followed by a sequential number and then if a breakage in the iceberg is seen, a sequential letter.”)
It was in 2017 that one of the largest icebergs of all time called A-68A broke off from the Larsen ice shelf. It has been closely monitored over the recent months as it was seen veering close to South Georgia in the South Atlantic. South Georgia hosts a fragile ecosystem and the iceberg would have impacted it through the scraping of the seabed or release of cold freshwater into the surrounding ocean, had it not been diverted by ocean surface currents. This could’ve been environmentally concerning in the long run.
But something else happened when the A-68G broke free.
Soon after the breaking free of the A-68, a large crack was seen developing in the A-68A resulting in the formation of two more icebergs as given below:
| Name | Length | Width |
| A-68A | Around 20 km | Around 9 km |
| A-68I | Around 30 km | Around 5 km |
The Copernicus fleet of satellites has captured images that have recorded the process of A-68A on its journey over the past 3 years. Some of the other findings of Copernicus are:
- The Copernicus Sentinel-1 radar mission shows that the iceberg has suffered further damages in 2021 as a new iceberg calved from A-68A. The smaller slab has been named A-68G (by following previously stated naming rules) by the US National Ice Centre. It measures 18 km in its widest point and around 53 km in length.
- Copernicus Sentinel-3 mission has revealed great details of the A-68A but is only available in cloud-free conditions. But Sentinel-1 radar imagery is not affected by clouds and thus, has been vital in tracking the A-68A break-up.
- Sentinel-3 (also Sentinel-6) radar altimeter measurements can be used to monitor iceberg trajectories and also be used to estimate the geostrophic ocean currents that carry the A-68A and the parts formed from its breakage on their journey.
Present status: Danger to South Georgia most likely averted
- The collective group of icebergs is observed to be drifting apart. The A-68H iceberg is seen to be moving towards the north.
- The main A-68A iceberg appears to be moving south and is currently about 225 km from South Georgia.
- With the latest events related to calving, the bergs are expected to most likely travel away from the island, no longer threatening the wildlife of the island.
Also read: D614G: NEW CORONAVIRUS MUTATIONS MAKES THE VIRUS EIGHT TIMES MORE INFECTIOUS
Source: European Space Agency https://www.esa.int/Applications/Observing_the_Earth/Giant_A-68A_iceberg_loses_chunk_of_ice
https://scitechdaily.com/a-68a-is-this-the-end-of-one-of-the-largest-icebergs-of-all-time/
Image Source: ESA
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