Earth from Space: The Fate of a Giant
Source: Hacker News
Overview
This Copernicus Sentinel‑2 image over the South Atlantic Ocean shows a close‑up view of iceberg A23a, once the world’s largest. The unusually cloud‑free image captures the first signs that the iceberg will soon disintegrate completely.
Zoom in to explore the image at its full 10 m resolution.
History of A23a
- Calving: A23a broke off from the Filchner‑Ronne ice shelf in West Antarctica in 1986. At that time it measured around 4 000 km², more than three times the size of Rome, making it the largest iceberg on record.
- Grounding: After decades of being grounded on the ocean floor, the iceberg lost its grip in 2020 and began drifting in the Weddell Sea.
- Northward Drift: In November 2023 it started drifting quickly away from Antarctic waters, driven by winds and currents.
Recent Observations (2025)
- May 2025: The iceberg reached South Georgia Island, as shown in ESA imagery of its arrival (source).
- December 20 2025: A new Sentinel‑2 image places A23a approximately 150 km northwest of South Georgia, surrounded by numerous smaller icebergs. By this time the iceberg had lost about three‑quarters of its original surface area, now covering roughly 1 000 km².
The bright blue patches visible on A23a’s surface and on nearby icebergs are ponds of meltwater, clear indicators of rapid melting.
Future Outlook
The disintegration observed is typical for icebergs that travel this far north. Warmer sea temperatures and harsher weather conditions accelerate breakup. As A23a continues moving toward even warmer waters, it is expected to follow a similar fate to other megabergs that have already disintegrated in these regions.