World's Largest Iceberg Leaves Antarctica
Iceberg A23a, considered the world's largest iceberg, recently began free-drifting southward from Antarctica after spending 30 years grounded, as reported by the Daily Mail. Polar researchers state that this gigantic "fragment of the white continent" has reached a critical point in its journey, and within the next few weeks, its future trajectory across the global ocean can be determined.
A23a broke away from the coast of the Filchner-Ronne Ice Shelf in August 1986; however, it immediately halted and sank to the bottom in the nearshore Weddell Sea. For three decades, the iceberg "slimmed down" by about 2.5 meters per year until it eventually became light enough to resume its course. Movement of the "megaberg" was documented in 2020, and three years later, A23a lost contact with the seabed and began free-floating.
Measurements of A23a, obtained during the CryoSat-2 mission of the European Space Agency, revealed that this ice chunk now covers an area of about 1.5 thousand square miles (3.9 thousand sq. km) and has a mass of just under a trillion tons. The object is under close scrutiny by scientists because there is reason to believe that soon A23a may collide with the Antarctic Circumpolar Current, which will alter its course towards the so-called "iceberg alley" in the Southern Ocean, as reported by Popular Mechanics.
Researchers believe that an iceberg of this size has a good chance of persisting in the Southern Ocean for an extended period, despite a warmer climate, and significantly advancing towards the shipping routes of South Africa. This poses an additional hazard to maritime shipping. Among other trajectory possibilities, A23a may head towards South Georgia Island, where the ice giant will once again run aground. Alternatively, it might remain near the coast of Antarctica, gradually breaking into smaller ice floes that pose no threat to shipping and the local wildlife.
Such massive icebergs can have a profound impact on the environment, according to Professor Mike Meredith in a BBC News comment. They "stir up" ocean waters, bringing up mud and plankton to the surface, effectively "fertilizing" the ocean. After such a giant iceberg "plows" through ocean waters, increased phytoplankton blooms are observed.