An incredible new satellite image taken by NASA shows the world’s largest iceberg, A23a, rapidly breaking apart as it remains lodged off the coast of South Georgia, a remote island in the South Atlantic Ocean.
Captured by MODIS (Moderate Resolution Imaging Spectroradiometer) on NASA’s Aqua satellite, the images show the iceberg shedding thousands of smaller ice chunks, especially along its northern edge.
The image perfectly captures the iceberg’s enormous size thanks to its proximity to South Geogia which it rivals in size; South Georgia is approximately 1,4000 square miles and is famously the island Ernest Shackleton and crew walked over to rescue the stranded members of Endurance.
“Thousands of iceberg pieces litter the ocean surface near the main berg, creating a scene reminiscent of a dark starry night,” NASA writes in a statement. The disintegration, a process known as “edge wasting,” has already reduced the berg’s area by roughly 200 square miles since March.
At its peak in November 2023, A23a spanned approximately 1,700 square miles — comparable to the size of Rhode Island. It has since shrunk to about 1,200 square miles, only marginally larger than the next-biggest iceberg, D15A, according to the U.S. National Ice Center. The largest fragment to split from A23a so far, named A23c, is about 50 square miles in size and has drifted south.
A23a originally split from Antarctica’s Filchner-Ronne Ice Shelf in 1986 but remained grounded on the seafloor of the Weddell Sea for over three decades. It finally began drifting in 2020, gradually making its way north along the Antarctic Peninsula. In early 2024, the iceberg was caught in a Taylor column — a swirling ocean current — above the Pirie Bank. After months of spinning in place, it broke free in December and drifted into the Scotia Sea.
By March 2025, the iceberg had become grounded once more, about 60 miles off South Georgia. NASA had anticipated this trajectory since late 2024. “Many [fragments] measure at least a kilometer across and would pose a risk to ships,” the space agency notes.
The iceberg’s proximity to South Georgia, home to over two million penguins and other marine life, has raised questions about its ecological impact. While the berg’s distance from shore likely reduces its immediate disruption, the presence of such a large body of ice can still affect local marine conditions, including salinity and temperature. Some researchers also suggest that melting icebergs can enrich the ecosystem by releasing nutrients.
Jan Lieser, an ice specialist with the Antarctic Meteorological Service, describes A23a’s prolonged entrapment earlier in its journey as unusual. “I am not aware of an iceberg that has been trapped in such a persistent manner in such a small area,” he says.
As climate change accelerates the melting of Antarctica’s ice shelves, scientists warn that similar events may become more frequent. For now, A23a is expected to continue breaking up over the coming months — possibly years — losing its title as the world’s largest iceberg in the near future.
Image credits: NASA
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