Largest iceberg A23a enters its 'rotational phase' while drifting towards warmer waters

The massive iceberg known as A23a, which is located near Antarctica and weighs around a thousand tonnes, has performed a graceful 360-degree turn, rotating in a circle.

While it's not uncommon for icebergs to exhibit such behaviour, A23a, which is four times the size of New York City, initiated its rotation a bit earlier than its counterparts.

December marked the start of the iceberg's journey as it broke away from the Weddell Sea floor close to northwest Antarctica. It had broken away from the continent's Filchner Ice Shelf in 1986, but for several years, it was trapped to the ocean floor.

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According to the British Antarctic Survey scientists, A23a's maneuvers are part of its "spinning era," describing the dance-like movements along 'iceberg alley' as integral to the iceberg's prolonged journey into warmer waters, as shared on Facebook, Instagram, and X.

Measuring over 1,500 square miles (about 4,000 square kilometres), A23a is more than twice the size of Greater London. It has seemingly drifted for the past year, gaining speed in late 2023. 

Andrew Fleming, a remote sensing expert from the British Antarctic Survey, noted that the iceberg's acceleration was not attributed to changes in shelf water temperatures but rather to the inevitable passage of time.

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Currently, the iceberg is executing its spin in the stretch of water between Elephant Island and the South Orkney Islands at the tip of the Antarctic Peninsula. It is expected to continue its northeast movement at a speed of about 30 miles per hour towards "iceberg alley," heading for the sub-Antarctic island of South Georgia.

Imagery from NASA satellites using MODIS has allowed the British Antarctic Survey to assess A23a, revealing no major changes in the iceberg's shape, though a few smaller fragments are moving ahead to the North East.

A British research team aboard the RRS Sir David Attenborough encountered the iceberg in December 2023, collecting seawater samples along its route to study the impact of icebergs on ocean life and carbon.

The ongoing research not only sheds light on icebergs but also holds broader implications for global climate change. The story of A23a is intricately tied to the narrative of global warming, with concerns raised about the stability of ice shelves and the potential acceleration of sea-level rise.

Recent drone footage captured by EYOS Expeditions shows significant erosion and transformation of A23a, with waves creating cascades of ice, leading to the formation of caves and arches. This erosion will eventually cause the top layers of the iceberg to collapse.

A23a joins the ranks of other notable icebergs, such as A68 and A76, contributing to the ongoing discourse on the consequences of iceberg calving and its connection to climate change.

As a stark reminder of Earth's changing climate, A23a emphasises the shared responsibility to understand and protect the planet's polar regions for future generations, highlighting the interconnectedness of our global environment.

(With inputs from agencies)