A Gargantuan Iceberg Dumps 152 Billion Tons of Freshwater As it Melts

A new study conducted with satellites has revealed that 152 billion tonnes of freshwater, equivalent to 20 times the amount of water in Loch Ness or 61 million Olympic-sized swimming pools, is dumped into the seas as the megaberg A68A melts. The gargantuan iceberg melted around the sub-Antarctic island of South Georgia over 3 months in 2020/2021.

The A68A iceberg originated from the Larsen-C Ice Shelf on the Antarctic Peninsula. In July 2017, it separated from its source and began its 3.5-year, 2,500-mile (4,000 km) journey across the Southern Ocean. At the time of its formation, it was considered the biggest iceberg on Earth (2,208 sq mi - 5,719 sq km)  and the sixth-largest on record.

Researchers from the University of Leeds, Centre for Polar Observation and Modelling (CPOM), and British Antarctic Survey (BAS) have been using satellite measurements to track the A68A iceberg’s evolution. It has also been found that its melting could have a significant impact on South Georgia’s marine habitat where the iceberg has now landed.

“This is a huge amount of meltwater, and the next thing we want to learn is whether it had a positive or negative impact on the ecosystem around South Georgia," said Anne Braakmann-Folgmann, a researcher at CPOM, Ph.D. candidate at the University of Leeds’ School of Earth and Environment and lead author of the study. “Because A68A took a common route across the Drake Passage, we hope to learn more about icebergs taking a similar trajectory, and how they influence the polar oceans.”

The researchers have also been tracking the iceberg to make sure it does not get stuck on the seafloor as this can be very disruptive both for fauna and ocean currents. This, however, was not a danger for A68A as by the time it reached South Georgia, its keel had been reduced to 462 ft (141 meters) below the ocean surface, meaning it could easily avoid the seabed. And even better, the iceberg will give local plankton something to feed on and change the local biome.