The Remarkable Thickness of the World’s Largest Iceberg is Astonishing

Recent satellite data has unveiled the impressive thickness of the world’s largest iceberg, A-23a, measuring just over 280 meters. Spanning an area of 3,900 square kilometers and weighing around a trillion tonnes, this massive iceberg broke away from Antarctica in 1986. For over thirty years, it remained stationary in the Weddell Sea, but it has now become mobile.

The European Space Agency’s CryoSat-2 mission provided these measurements using radar altimeter technology, which captures the height of the iceberg that sits above the water. Dr Anne Braakmann-Folgmann, from the University of Tromso, highlights that this method allows for continuous monitoring of iceberg thickness and examines how warmer ocean temperatures affect its structure.

A-23a has recently shifted from being grounded to drifting. After remaining attached to the seabed for decades, it is now moving towards warmer waters. The next few weeks are crucial to see where this gigantic iceberg will go in the Southern Ocean.

Data from CryoSat shows a part of A-23a with a deep underwater extension, or keel, which in 2018 reached almost 350 meters deep. Over the past ten years, the iceberg has been thinning consistently, likely due to rising temperatures in the Weddell Sea.

The iceberg’s structure, particularly its surface crevasses formed from intense contact with the seafloor, provides valuable insights. As A-23a approaches the Antarctic Peninsula, it meets converging water currents that move clockwise around the continent. This, along with the prevailing westerly winds, will influence the iceberg’s path, likely leading it down “iceberg alley” towards South Georgia.

This new information about A-23a’s thickness is a major advancement in our understanding of iceberg dynamics. The scientific community is keenly observing its interactions with ocean currents and winds to forecast its journey and potential impact on the Southern Ocean’s unique ecosystem.