The world’s largest iceberg, A23a, has run aground off South Georgia after drifting in the Southern Ocean since 2020. This significant event was reported on March 4, 2025, by the British Antarctic Survey, highlighting the iceberg’s massive size and weight.
- Iceberg A23a has run aground near Antarctica.
- Weighs nearly a trillion metric tonnes.
- Spanned 3,672 square kilometers in August 2024.
- Grounding may benefit local wildlife.
- Smaller icebergs will pose navigation hazards.
- Global warming affects Antarctic ice dynamics.
A23a, weighing nearly a trillion metric tonnes (1.1 trillion tons), measures approximately 3,672 square kilometers (1,418 square miles), making it slightly smaller than Rhode Island. It calved from the Filchner Ice Shelf in Antarctica in 1986 and spent over 30 years resting on the seabed in the Weddell Sea before drifting with ocean currents in 2020. The iceberg became stuck near an undersea mountain in late 2024, delaying its journey north.
Concerns arose that A23a could obstruct access to feeding grounds for seals and penguins on South Georgia. However, it is currently grounded about 90 kilometers (56 miles) from shore, which has alleviated these worries. According to Andrew Meijers, an oceanographer at the British Antarctic Survey, if the iceberg remains grounded, it is not expected to significantly impact local wildlife. In fact, the nutrients released from its melting could enhance food availability for the regional ecosystem.
While A23a appears stable for now, large icebergs that follow this path typically break up and melt within a few years. Once it does disintegrate, the smaller icebergs created may pose navigation hazards for fishing and shipping operations. Past experiences indicate that smaller icebergs can create dangerous conditions for vessels, complicating fishing activities in affected areas. Scientists assert that A23a’s calving is part of the natural cycle of ice shelf growth, rather than a direct result of climate change, although global warming continues to impact Antarctic conditions.
The grounding of iceberg A23a presents a unique ecological situation. While it may disrupt local wildlife temporarily, it could also provide benefits through nutrient enrichment in the surrounding waters. The future behavior of A23a remains uncertain, as it could eventually break up, leading to potential hazards for maritime activities.
