A gigantic iceberg is currently moving toward the island of South Georgia, a remote wildlife haven in the South Atlantic.
While it is common for icebergs to break away from Antarctica and drift into the ocean, scientists say climate change is making this process happen more frequently, with bigger icebergs appearing in Antarctic waters.
Icebergs form when large chunks of ice break off, or “calve,” from Antarctica’s ice cap.
This happens naturally over time as snow builds up and gravity pulls the ice toward the sea. If the ice cap grows at the same rate that icebergs break off, it remains stable.
However, rising temperatures in both the air and ocean are causing ice to melt more quickly and weaken, leading to more frequent iceberg break-offs.
The waters around South Georgia are known as “Iceberg Alley” because they are a natural path for icebergs drifting away from Antarctica.
Scientists from Utrecht University are studying how icebergs move during periods of rapid ice cap melting, such as at the end of ice ages. This research can help us understand how melting ice affects ocean conditions and the future of our planet.
Researchers were surprised to find debris from Antarctica near South Orkney, an island southwest of South Georgia.
This was a mystery because the sediments were 37 million years old—three million years older than Antarctica’s large ice cap. Scientists wondered how icebergs carrying Antarctic rock fragments could have reached South Orkney at a time when Antarctica was thought to be much warmer.
Utrecht University student Mark Elbertsen recently solved this puzzle. Using computer models, he found that the Weddell Sea was cold enough during the late Eocene period to allow icebergs to survive the journey to South Orkney. His research showed that Antarctica already had small ice caps back then, proving that snowfall and ice buildup began earlier than previously thought.
Researchers are also studying how melting icebergs affect the ocean. When icebergs melt, they release fresh water into the ocean, which can change currents and impact the ocean’s ability to absorb carbon.
This could have serious effects on climate patterns worldwide. Scientists are now using computer models to track how much fresh water will enter the ocean as icebergs continue to melt due to climate change.
A giant iceberg named A23a, which broke off from Antarctica in 1986, has been stuck in shallow waters for decades. In 2020, it started drifting again and is now heading toward South Georgia. Scientists are watching closely because the island is home to large colonies of penguins, seals, and albatrosses. If A23a crashes into South Georgia, it could block animals from reaching their feeding and breeding grounds.
However, experts believe the iceberg will likely run aground on the shallow seabed before reaching the island. If this happens, it could actually benefit wildlife by bringing nutrient-rich waters that attract fish and krill, providing more food for marine life. If the iceberg avoids the island, it will continue drifting and eventually melt away in the open ocean.
As climate change continues, more icebergs will likely break off from Antarctica, increasing the amount of fresh water entering the Southern Ocean. Scientists are working to understand what this means for global ocean currents, marine ecosystems, and the future climate.
For now, researchers are keeping a close eye on A23a’s journey and its potential impact on South Georgia’s wildlife. Whether it runs aground or drifts past the island, this mega-iceberg’s movement is another reminder of the changing conditions in our world’s polar regions.
