A massive iceberg which broke off Antarctica’s Larsen C ice shelf in 2017 is now drifting northeast towards the island of South Georgia, a potential threat for penguin and seal populations as well as the local fishing industry.

Known as A-68a, the iceberg measures some 150km long by 48km wide and 200m deep. It is currently travelling through an area known as ‘Iceberg Alley’ and is now just a few hundred kilometres away from South Georgia’s southwestern shore. When it broke from the Larsen C shelf in 2017, the iceberg weighed an estimated trillion tons – the third biggest ever recorded.

If it runs aground near the island, say scientists, it could remain there for a decade, disrupting not only South Georgia’s economy but also the region’s ecosystem. It might create a barrier to the resident penguin and seal populations’ foraging routes, hampering their ability to feed their young.

Scientists also point out that the monster running aground near South Georgia could have some ‘positive’ impacts: it appears icebergs carry significant amounts of dust that help to fertilise the ocean plankton as the bergs melt. That would benefit much of the food chain.

Of course, the prevailing currents and weather will affect A-68a’s course – it may miss South Georgia altogether and eventually break up. Given the number of fissures and cracks revealed in it (courtesy of European Space Agency satellite imagery), the break-up is a likely scenario as it drifts into warmer water.

It’s a moot point as to whether climate change is responsible for the rogue berg breaking away from the Larsen C shelf – many scientists believe it may simply reflect an ice shelf’s natural growth-and-decay calving cycle.