London: The world’s largest iceberg, A23a, appears to have run aground approximately 70km (43 miles) from South Georgia Island, potentially sparing the vital wildlife habitat from disruption, according to the British Antarctic Survey (BAS).
The iceberg, which measures roughly 3,300 sq km and weighs nearly 1tn tonnes, has been drifting north from Antarctica since 2020.
Scientists had feared the colossal iceberg could collide with the island or run aground in shallower waters nearby, making it harder for penguins and seals to feed their young.
However, since March 1, A23a has remained stationary 73km from South Georgia, reducing the immediate threat to wildlife. BAS oceanographer Andrew Meijers noted that if it stays in place, significant disruptions are unlikely.
A23a calved from the Antarctic ice shelf in 1986 but remained stuck for over 30 years before breaking free in 2020. Its journey north has been slow, at times stalled by ocean currents. While satellite imagery previously showed minimal fragmentation, a 19km-long section broke off in January.
If the iceberg remains grounded, it could provide ecological benefits. Meijers explained that nutrients stirred up by its grounding and melting could enhance food availability for the regional ecosystem, including seals and penguins.
South Georgia and the nearby South Sandwich Islands support around 5 million seals and 65 million breeding birds from 30 species. However, the region has already suffered a difficult season due to a bird flu outbreak.
Although A23a does not currently pose a risk to shipping, its eventual breakup could create hazardous “bergy bits” that may restrict commercial fishing activities.
Scientists emphasize that while icebergs of this size are rare, they are a natural part of the Antarctic ice sheet cycle. However, climate change is accelerating ice loss, with Antarctic ice shelves shedding 6,000bn tonnes of mass since 2000.
Researchers warn that if global temperatures rise between 1.5 and 2.0 degrees Celsius above pre-industrial levels, enough ice could melt to raise sea levels by several meters, potentially reaching an irreversible tipping point. Last year, which saw record-breaking heat, marked the first full calendar year above 1.5°C.
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