Why world's strongest ocean current is slowing down
What's the story
The Antarctic Circumpolar Current (ACC), the world's strongest ocean current, is slowing down.
This development has been associated with the unchecked melting of the Antarctic ice sheet and was discovered by scientists at the University of Melbourne.
The ACC, which flows clockwise from west to east around Antarctica, is critical in regulating global climate and ocean circulation.
Climate impact
Melting ice sheets alter ocean salinity and density
"The ocean is extremely complex and finely balanced. If this current 'engine' breaks down, there could be severe consequences, including more climate variability, with greater extremes in certain regions," warned Associate Professor Bishakhdatta Gayen.
He also pointed out the risk of accelerated global warming due to the ocean's reduced ability to serve as a carbon sink.
This is because melting Antarctic ice dumps massive amounts of freshwater into the Southern Ocean, changing its salinity and density.
Ecosystem threat
Weakening ACC threatens Antarctic ecosystems and global climate
The ACC plays a key role in powering the global ocean conveyor belt, which distributes heat, nutrients, and carbon dioxide across the world's major oceans.
It also acts as a natural barrier, preventing invasive species from reaching Antarctica.
A weakened ACC could allow non-native marine life to upset local ecosystems, impacting food sources for native species like penguins.
If fossil fuel emissions increase over the next 25 years (a so-called high emissions scenario), the current might slow by roughly 20%.
Research findings
Supercomputer-aided research contradicts previous ACC studies
For their study, the researchers utilized Australia's fastest supercomputer, GADI, and a high-resolution climate model, ACCESS-OM2-01.
Their findings, published in Environmental Research Letters, contradict earlier studies that indicated that the ACC might accelerate due to temperature disparities across latitudes.
Instead, this new research highlights that ice melt plays a dominant role in slowing down the current.