Flowing clockwise around Antarctica, the Antarctic Circumpolar Current is the strongest ocean current on the planet. It’s five times stronger than the Gulf Stream and more than 100 times stronger than the Amazon River. It also plays a critical role in the climate system by influencing the uptake of heat and carbon dioxide in the ocean and preventing warmer waters from reaching Antarctica.

An Australian-led study used climate models to analyse the impact of changing temperature, ice melting and wind conditions on the Antarctic Circumpolar Current. They found in a high emissions future, the world’s strongest ocean current could slow down by 20% by 2050, further accelerating Antarctic ice sheet melting and sea level rise.

Their results revealed a clear link between meltwater from Antarctic ice shelves and circumpolar current slowdown, and comes less than a week after another paper anticipated a weakening in vital Atlantic Ocean currents.

Co-author Assoc Prof Bishakhdatta Gayen, from the University of Melbourne, described the result as “quite alarming” with “far-reaching impacts on global climate patterns, oceanic heat distribution, and marine ecosystems”. However, the researchers emphasise “ the future is not predetermined. Concerted efforts to reduce greenhouse gas emissions could still limit melting around Antarctica.”