World's largest iceberg A23a shatters near penguin habitats
A23a, the largest iceberg in the world, is breaking into thousands of pieces near South Georgia Island. It is now anchored right next to penguin habitats. This phenomenon could last for months, or even years, before the glacier completely vanishes.
The iceberg A23a, recognized as the largest globally, is starting to break into thousands of smaller fragments near South Georgia Island in the Atlantic Ocean. The latest satellite images captured by NASA’s Aqua satellite reveal that the glacier, covering an area of about 1,200 square miles, is beginning to crumble, especially on its northern edge. “Thousands of iceberg pieces litter the ocean surface near the main berg, creating a scene reminiscent of a dark starry night,” wrote researchers from NASA Earth Observatory.
What are the consequences of the A23a glacier breaking up?
Although these fragments appear small in photos, many of them are at least 0.6 miles wide and pose a threat to ships. Such calving has occurred at various stages of A23a’s journey, even when it circled in a vortex in the Drake Passage in 2024. However, there are currently signs that the glacier is becoming increasingly fragile. On its northern side, a strip of ice debris is visible, a result of a sudden break of the edge, partly caused by several days of warm, sunny weather.
The breakup of the A23a glacier has so far reduced its surface area by about 200 square miles since March when it got stuck on the seafloor. Although it remains the largest floating iceberg, its edges are gradually being eroded by waves and seasonal weather conditions. This process could take months, or even years, to fully disintegrate unless larger fractures accelerate it. The largest fragment that broke off from A23a, named A23c, has an area of about 50 square miles and is drifting south.
Satellite images taken by MODIS on NASA’s Aqua satellite a few days ago show that the glacier is less than 62 miles from South Georgia Island. The glacier probably got stuck on a shallow underwater shelf around the island, which has previously stopped other Antarctic glaciers in their northern drift to the warmer southern Atlantic waters. Although its position remains largely unchanged, the glacier's surface has shrunk significantly in just two months.
Though uninhabited by humans, South Georgia Island is home to numerous species of wild fauna, including over 2 million penguins, with one of the largest colonies of king penguins, Aptenodytes patagonicus. The proximity of a large glacier can be problematic for them, as penguins might be forced to travel hundreds of additional miles to reach their food sources. “Meltwater from trapped icebergs may also change the temperature and salinity of the surroundings,” scientists note.
Penguins threatened by sudden appearance of a glacier
The A23a glacier is currently at nearly 55°S, far from the coldest waters around Antarctica. Although it has repeatedly held the title of the largest in the world since 1986, it is now only slightly larger than the next largest iceberg, D15A. As climate change accelerates Antarctic glacier melting, more such giant icebergs are expected to drift near South Georgia in the coming decades.
