QUICK FACTS
Where is it? Scotia Sea, South Atlantic Ocean [-54.4957805, -37.7561759]
What’s in the photo? Iceberg A23a, which is beginning to break apart alongside South Georgia island
Which satellite took the photo? NASA’s Aqua satellite
When was it taken? May 3, 2025
A striking new satellite photo has revealed that the world’s largest iceberg is starting to break apart into thousands of smaller pieces as it remains stuck alongside a wildlife refuge in Antarctica. But it could take months, if not years, for the entire slab to disappear.
The “megaberg,” dubbed A23a, currently has a surface area of around 1,200 square miles (3,100 square kilometers) — roughly the size of Long Island. It first calved off of the Filchner-Ronne Ice Shelf in 1986, but it became trapped when its underside caught on the seafloor. It remained stranded until January 2023, when it finally began to move away from mainland Antarctica. During this time, it has repeatedly held the title of “world’s largest iceberg” as bigger bergs have come and gone, most recently regaining the title in June 2023.
The giant iceberg became trapped again in early 2024 after getting caught in a large ocean vortex. It remained spinning on the spot for several months before eventually breaking free in December 2024 and resuming its journey north through the Drake Passage — also known as the “iceberg graveyard,” where large Antarctic icebergs get swept away to their eventual doom.
But in January, it became clear that A23a was on a collision course with South Georgia in the Scotia Sea. By March, the megaberg came to a halt as it grounded on the seafloor around 60 miles (100 kilometers) off the island’s southwest coast, where it became trapped for the third — and likely final — time in its lengthy lifespan.
Now, photos from NASA‘s Aqua satellite have revealed that the edges of A23a are starting to disintegrate, especially along its northern edge, blanketing the surrounding area with icy debris, according to NASA’s Earth Observatory. “Thousands of iceberg pieces litter the ocean surface near the main berg, creating a scene reminiscent of a dark starry night,” NASA representatives wrote.
Related: See all the best images of Earth from space
The numerous new icebergs appear extremely small compared with A23a. However, “many measure at least a kilometer across and would pose a risk to ships,” NASA representatives wrote. The largest piece to break off from the megaberg, which has been dubbed A23c, has an area of around 50 square miles (130 square km) and is currently drifting south (just out of the satellite photo).
This type of iceberg disintegration is known as “edge wasting” and has shrunk A23a by around 200 square miles (520 square km) since it became stuck in March, according to NASA. At this rate, it will likely take several months, if not years, for the berg to fully break apart, assuming larger cracks do not rip it apart first.
However, A23a may not hold its size title for long, because as of May 16, it is only around 12 square miles (31 square km) larger than the next-biggest iceberg, D15A, according to the U.S. National Ice Center.
Wildlife refuge
South Georgia is not inhabited by people, aside from a few dozen researchers who visit throughout the year. However, it is home to an abundance of wildlife, such as seals and seabirds, including more than 2 million penguins, according to BirdLife International.
Having a large iceberg moored just offshore can be problematic for these species, especially for penguins that may have to travel several hundred extra miles around the obstruction to reach their prey, depending on where the iceberg is located. Meltwater coming from trapped bergs can also alter the temperature and salinity of their surroundings.
It is currently unclear how much of an impact A23a is having on the local wildlife. However, the iceberg is quite far off the coast, meaning it will be less disruptive than it could have been. Some researchers have claimed the melting slab could benefit the marine ecosystem by releasing nutrients into the ocean.
This is not the first time that South Georgia has been put under siege by giant icebergs. In 2020, one of the world’s previous largest icebergs, A68, became stuck even closer to the island, sparking fears that it could disrupt penguin colonies. However, unlike A23a, it quickly broke up into dozens of sizable chunks after ocean currents ripped it in half, causing it to quickly melt away and thus averting disaster.
As human-caused climate change continues to cause increased melting of Antarctica’s ice sheets, many more hefty bergs could soon pass by South Georgia in the coming decades.
