A23a: Biography of an iceberg
Summary
This episode chronicles the life of A-23a, the world’s largest iceberg, from its 1986 calving to its recent melting near South Georgia. Glaciologist Dr. Catherine Walker interviews experts who studied the iceberg’s massive scale, ancient trapped air, and role in fertilizing ocean ecosystems. The narrative highlights how megabergs serve as critical indicators of Antarctic ice loss and the accelerating climate crisis driving global sea-level rise.
Topics discussed
Intro: Washington Wise podcast and sponsor ads
Introduction to A-23a: The world's largest iceberg
How icebergs form: Glaciers, ice shelves, and calving
The birth of A-23a: Rifts, cracks, and the 1986 calving event
A-23a's long grounding and the sounds of ancient air bubbles
A-23a breaks free and drifts into the Southern Ocean
Scientific expedition: A-23a grounds near South Georgia
The final chapter: Melting and disappearance of A-23a
Climate change implications: Sea level rise and future risks
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