Fun facts about this Founding Father
Deep in the Southern Ocean, an icy colossus is on the move. After nearly four decades of being trapped on the ocean floor, A23a (the world’s largest iceberg) has finally broken free. Now, this trillion-ton megaberg, covering an area larger than New York City, Los Angeles, and Houston combined, is drifting northward.
Scientists and conservationists alike are watching closely as this massive block of ice drifts along ocean currents, inching closer to a remote yet ecologically vital island. With its sheer size and unpredictable path, A23a’s journey is more than just a spectacle—it could alter landscapes, disrupt ecosystems, and serve as a stark reminder of the forces shaping our planet.
What does this iceberg’s movement mean for the delicate balance of life in the Southern Ocean? Could its arrival bring unforeseen challenges, or might it hold hidden benefits? Click through this gallery to find out.
When seen from above, A23a appears like a gargantuan piece of icy land, drifting away from Antarctica along cold waters. The iceberg is currently heading toward the remote island of South Georgia, a crucial wildlife sanctuary teeming with seals and penguins.
A23a was born in 1986 when it split away from the Filchner Ice Shelf in Antarctica. Unlike most icebergs, it got stuck on the ocean floor due to its massive size, which prevented it from drifting freely. For decades, it remained lodged in shallow Antarctic waters.
At over 1,400 sq. miles (3,625 sq. km), A23a is larger than Tokyo, the biggest city on the planet. It’s not just wide, but deep—so deep that its keel scraped the seabed and kept it trapped for nearly 40 years.
Image credit: NASA Earth Observatory
Astonishingly, A23a’s cliffs tower up to over 1,310 feet (400 meters) in height, making it comparable to a skyscraper. However, most of its bulk remains hidden beneath the water, with its deep keel extending far below the surface.
Although icebergs appear enormous above the ocean’s surface, about 90% of their mass is submerged underwater. This hidden bulk makes them unpredictable and dangerous, as only a fraction of their full size is visible.
The iceberg didn’t suddenly start moving—it was a gradual process. Over time, ocean currents, melting, and wind erosion chipped away at its edges. By 2020, it had finally dislodged enough to begin its long-awaited journey into deeper waters.
Now drifting freely, A23a has been caught in the Antarctic Circumpolar Current (ACC), the strongest ocean current on Earth. This relentless force is carrying it straight toward South Georgia, 155 miles (250 km) away, where it may become lodged once again or continue its unpredictable journey.
Past icebergs from the area have typically drifted into the Drake Passage, a turbulent waterway between South America’s Cape Horn and Antarctica’s South Shetland Islands. From there, they moved north into the South Atlantic, where they melted quickly in warmer waters. A23a could possibly follow suit.
Despite its colossal size, A23a moves at a sluggish pace of 1.5 mph (2.4 km/h). Though slow, it is steady, and its enormous mass means that turning or stopping it is nearly impossible. It will go where the ocean takes it.
Experts can’t predict exactly how A23a will impact the region and where it will end up. It has already grounded itself in shallow waters near South Georgia, potentially blocking vital feeding routes for wildlife. Alternatively, it may continue to drift and slowly melt, releasing fresh water and nutrients into the ocean.
If A23a grounds itself, it could cut off critical migration paths for penguins and seals. These animals rely on open waters to travel between breeding and feeding areas, and an obstacle of this size could force them into life-threatening detours.
For South Georgia’s penguins, access to food is essential for survival. If A23a blocks their usual foraging paths, adult penguins will have to travel farther, burning more energy and bringing back less food. This could potentially lead to starvation, particularly for chicks.
The seal and penguin populations on the island are already struggling due to a severe bird flu outbreak. If the iceberg disrupts their feeding routes, it could significantly worsen conditions and further devastate these vulnerable species.
Fur seals, which rely on predictable feeding routes, could also be impacted if A23a settles in the wrong location. With food sources harder to reach, they may experience increased mortality rates, particularly among pups and nursing mothers who require frequent nourishment.
The timing of A23a’s arrival will determine its impact. If it disrupts the ecosystem in October (when penguins begin nesting), the consequences could be dire. But if it arrives after February (when chicks are self-sufficient), the effects might be less severe.
A23a is not the first massive iceberg to threaten South Georgia. In 2004, iceberg A38 ran aground, devastating local wildlife. In 2020, A68 (pictured) barely missed the island. A23a’s fate remains uncertain, but history shows that such events can be disastrous.
Icebergs aren’t named randomly. Each iceberg is assigned a letter corresponding to the Antarctic region where it was first spotted, followed by a sequential number. A23a, for example, originated in Quadrant A (the sector of the Weddell Sea) and was the 23rd iceberg recorded from that region. The lowercase letter at the end is added when a large iceberg splits into smaller pieces.
A23a’s size could also have unintended consequences beneath the waves. By shading large areas of the ocean, it could reduce sunlight penetration and potentially stunt the growth of phytoplankton (the microscopic organisms that form the foundation of the marine food web).
While icebergs can disrupt ecosystems, they also provide nutrients. As A23a melts, it will release iron and other minerals into the water, which could promote phytoplankton blooms. This would indirectly support krill populations and the marine animals that rely on them.
Despite its potential dangers, A23a may also create a temporary oasis. Icebergs often attract marine life, including krill and fish. If the megaberg drifts close to South Georgia, penguins and seals could benefit from an unexpected food source.
If A23a breaks apart, it could create a network of smaller icebergs that would make navigation treacherous for ships. The Southern Ocean is already one of the most dangerous waters on Earth, and additional ice hazards would make it even riskier.
A23a’s creation wasn’t directly caused by climate change, but Antarctica’s ice loss is accelerating due to global warming. More icebergs are breaking off, which raises concerns about their long-term impact on sea levels and global ocean circulation patterns.
Antarctica is losing ice six times faster than it was 30 years ago. While icebergs naturally split away, climate change is increasing the frequency of these events and also contributing to more melting, which is altering the balance of the Southern Ocean.
Even if emissions were cut today, melting Antarctic ice has already locked in at least 6.5 feet (two meters) of sea-level rise. Coastal cities around the world will face the consequences, making ice loss a global issue, not just an Antarctic concern.
Icebergs like A23a contain ice that has been frozen for thousands of years. As they melt, they release clues about past climate conditions, providing valuable insights for scientists studying the history and future of Earth’s changing environment.
A23a is more than just an iceberg—it’s a massive experiment in oceanography and ecology. Scientists are using its journey to study how icebergs influence marine ecosystems and even ocean currents.
For now, both scientists and South Georgia’s wildlife can do nothing but wait. A23a is on a path that could shake up the region’s ecosystem, but until it reaches its destination its ultimate impact remains unknown.
Iceberg A23a is not the largest to have been recorded in history. The largest iceberg was B15, which split from Antarctica’s Ross Ice Shelf in 2000. It initially measured 4,200 sq. miles (10,880 sq. km), but it fragmented over time before fully disintegrating two decades later.
For now, A23a’s final fate remains a mystery. Scientists, conservationists, and nature enthusiasts around the world are watching closely as it drifts through the ocean. Whether it brings destruction or unexpected benefits, its journey will leave a lasting mark on the environment.
Sources: (National Geographic) (NASA) (BBC) (Space.com) (Live Science)
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LIFESTYLE Megaberg
Deep in the Southern Ocean, an icy colossus is on the move. After nearly four decades of being trapped on the ocean floor, A23a (the world’s largest iceberg) has finally broken free. Now, this trillion-ton megaberg, covering an area larger than New York City, Los Angeles, and Houston combined, is drifting northward.
Scientists and conservationists alike are watching closely as this massive block of ice drifts along ocean currents, inching closer to a remote yet ecologically vital island. With its sheer size and unpredictable path, A23a’s journey is more than just a spectacle—it could alter landscapes, disrupt ecosystems, and serve as a stark reminder of the forces shaping our planet.
What does this iceberg’s movement mean for the delicate balance of life in the Southern Ocean? Could its arrival bring unforeseen challenges, or might it hold hidden benefits? Click through this gallery to find out.