Giant iceberg releases 152 billion tons of fresh water around remote Atlantic island

An iceberg that was once the largest on the planet, dubbed A68a, recently released 152 billion tons of fresh water close to the sub-Antarctic island of South Georgia, potentially impacting the region’s ecosystem, a study published earlier this month found.

A68a captured the world’s attention in 2017 when it broke off the Larsen-C ice shelf, located near the tip of the Antarctic Peninsula. The largest iceberg in the world at the time of its formation, it initially floated around the Weddell Sea close to Antarctica before making its way its way across the Drake Passage between southern South America and the northern reaches of Antarctica. As it approached the southern Atlantic island of South Georgia in December 2020, researchers became concerned that it would disrupt wildlife in the remote region.

Image: European Space Agency

The new study shows that the colossal iceberg did have a big effect on the local environment. Over a three-month span between 2020 and 2021, A68a melted rapidly as it encountered warmer water in the Drake Passage. While researchers initially feared that the keel of the iceberg, the part of the iceberg beneath the water’s surface, would run aground on the seafloor, blocking currents and predator foraging routes, that doesn’t appear to have happened, according to the British Antarctic Survey. But the giant pulse of fresh water released by the iceberg likely still impacted the South Georgia ecosystem.

The next step is to determine exactly what that impact looked like, Anne Braakmann-Folgmann, the lead author of the study, says. Braakmann-Folgmann also noted that A68a’s route across the Drake Passage could help researchers learn more about future icebergs and “how they influence the polar oceans.”

That will be valuable information to have, considering climate change is expected to accelerate ice shelf collapse, leading to more big icebergs breaking off Antarctica in the future.