The largest iceberg in the world, comparable in size to Rhode Island, is currently drifting towards a remote island located off Antarctica, which serves as a habitat for millions of seals and penguins.
This massive ice block, referred to as a megaberg, weighs around a trillion tons and is named A23a. Its potential collision with South Georgia Island raises concerns about its impact on the local wildlife. If the iceberg becomes lodged in the island’s shallower waters, it may hinder penguin parents from accessing food for their chicks, leading to starvation in some young penguins. Nevertheless, scientists remain optimistic about the overall threat posed by this iceberg, emphasizing that the situation is more awe-inspiring than perilous.
Experts have indicated that the situation is a natural occurrence, becoming increasingly common due to climate change driven by human activities. Andrew Meijers, a physical oceanographer with the British Antarctic Survey, had the opportunity to study the iceberg closely in December 2023 when it was visible from the research vessel RRS Sir David Attenborough. “The iceberg is truly magnificent, stretching from the horizon to horizon,” Meijers remarked, noting its towering height of 130 feet (or 40 meters), resembling a formidable barrier of ice similar to those depicted in fantasy series like Game of Thrones.
Meijers described the dramatic sight, with waves crashing against the iceberg and sunlight piercing through the clouds. He pointed out that for every part of the iceberg visible above sea level, there is an enormous mass—ten times larger—hidden beneath the surface.
The iceberg is not racing towards its destination; rather, it is progressing slowly at a rate of about one meter every three to seven seconds, which translates to much less than a mile per hour. The iceberg is expected to near South Georgia within two to four weeks, where it may either become confined to shallow waters or glide past the island entirely.
Icebergs often float past the shoals surrounding South Georgia each year, and this area has been recognized as a significant route for such large ice masses since the era of Sir Ernest Shackleton, a prominent figure in early Antarctic exploration. Ice scientist Ted Scambos from the University of Colorado noted that while icebergs generally traverse these waters at a somewhat leisurely pace, they are a common sight.
Over time, the immense iceberg will eventually fracture into smaller pieces and melt, which is a typical fate for icebergs. With its considerable size, the iceberg does not pose much of a threat to local fishermen, who can easily spot it. The primary concern lies with the penguins, who are currently in their summer breeding season.
Meijers highlighted the ecological significance of South Georgia Island, which hosts a diverse range of wildlife, serving as a breeding area for vast numbers of penguins and seals. “Pups and chicks rely heavily on their parents for sustenance,” he explained, as penguin parents venture out into the ocean to forage.
However, the presence of icebergs can obstruct feeding routes, forcing adult penguins to swim longer distances to find food, which in turn can lead to higher energy expenditure and fewer resources brought back to their young. “This unfortunate pattern can significantly increase mortality rates for the chicks and has occurred in previous instances,” Meijers noted.
While these circumstances may adversely affect individual penguin colonies, they do not signify a broader issue for global penguin populations. Scambos reassured that the entire ecosystem of the Southern Ocean is resilient and has adapted to the ebb and flow of iceberg-related events over thousands of years.
Interestingly, this particular iceberg, which was formed through a calving process in 1986, has been ensconced within a densely packed expanse of sea ice for decades until relatively recently, according to Meijers. He further explained that calving is a natural phenomenon, although it is becoming more frequent with the warming climate and the increasing influx of freshwater into the ocean.
