World’s strongest ocean current is slowing down as ice sheets pump water

The most powerful ocean current in the world is experiencing a slowdown, with scientists attributing this phenomenon to the unregulated melting of the Antarctic ice sheet.The Antarctic Circumpolar Current (ACC), which traverses Antarctica from west to east, is essential for maintaining global climate and ocean circulation.

Researchers at the University of Melbourne conducted an analysis using a high-resolution simulation of ocean and sea ice dynamics, examining factors such as ocean currents, heat transport, and other variables to assess the effects of changing temperatures, salinity, and wind patterns.

As the Antarctic ice continues to melt, significant volumes of freshwater are introduced into the Southern Ocean, leading to alterations in its salinity and density. These modifications impact the flow of ocean currents, including the ACC, which is a vital component of the global ocean conveyor belt that distributes heat, nutrients, and carbon dioxide across the Atlantic, Pacific, and Indian Oceans. In addition to its climate-regulating function, the ACC acts as a natural barrier that prevents invasive species from reaching Antarctica. A weakened current could facilitate the entry of non-native marine organisms, such as bull kelp or mollusks, potentially disrupting Antarctic ecosystems and affecting the food sources of indigenous species like penguins.

The researchers utilized Australia’s most advanced supercomputer, GADI, along with the high-resolution climate model ACCESS-OM2-01.Their findings, published in Environmental Research Letters, challenge earlier studies that proposed the ACC might accelerate due to temperature variations across different latitudes.

In contrast, the new research emphasizes that the melting ice is the primary factor contributing to the current’s deceleration.