The Antarctic Circumpolar Current (ACC), the world's strongest ocean current, is slowing down due to climate change, according to a study by the University of Melbourne published in Environmental Research Letters. Researchers found that the current could slow by about 20% by 2050 under a high carbon emissions scenario, which may have serious consequences, including sea level rise and ocean warming.

Impact on Climate and Carbon Absorption

The ACC, which moves clockwise around Antarctica, plays a key role in regulating global climate. It influences the ocean's ability to absorb heat and carbon dioxide and prevents warm waters from reaching Antarctica. Lead researcher Expert feels that if this current 'engine' breaks down, there could be severe consequences, including more climate variability, with greater extremes in certain regions, and accelerated global warming due to a reduction in the ocean's capacity to act as a carbon sink."

Threat to Antarctic Ecosystem

The study also highlights the potential for invasive species to reach Antarctica as the ACC slows. Currently, the current acts as a barrier preventing species like southern bull kelp, shrimp, and mollusks from reaching the continent. If these species establish themselves in Antarctica, they could disrupt the food web, potentially affecting the feeding patterns of native species such as penguins.

Melting Ice Sheets Affecting Ocean Circulation

Researchers noted that melting ice shelves are a major factor in this slowdown. "The melting ice sheets dump vast quantities of fresh water into the salty ocean. This sudden change in ocean 'salinity' has a series of consequences—including the weakening of the sinking of surface ocean water to the deep (called the Antarctic Bottom Water), and, based on this study, a weakening of the strong ocean jet that surrounds Antarctica," Gayen explained.

Findings Supported by Climate Simulations

As per reports, the findings were derived using Australia's fastest supercomputer and climate simulator, GADI, located at Access National Research Infrastructure in Canberra.