World's Largest Iceberg

The world's largest iceberg is drifting from the Antarctic Circle toward the Southern Ocean, scientists confirmed late last week. The floating mass sheared from the Filchner-Ronne Ice Shelf in 1986 but became stuck on the floor of the Weddell Sea.

Labeled A23a, the iceberg is roughly 1,500 square miles in size (five times the land area of New York City) and about 1,300 feet thick (taller than the Empire State Building). Satellite imagery suggested the block had begun moving in 2020 before becoming fully adrift in recent months.

As A23a melts, its effect on sea level increase will be minimal—floating objects displace their own weight in water (see 101), with small differences due to salinity—though researchers say it may threaten wildlife if it runs aground at the nearby island of South Georgia.

Read more about the iceberg's trajectory here.