As the Antarctic ice melts, the Earth’s ocean “conveyor belt” grinds

The world’s most powerful ocean current is the loss of steam, and the melting ice in Antarctica is the blame for the cause.

Antarctic circulating current (ACC) — a huge flow that surrounds the entire Antarctic continent — could slow down by about 20% by 2050, according to new research published in the Environmental Research Letter on March 3. This potential damage to one of the most critical marine systems on Earth could reshape global climate patterns and marine ecosystems in ways scientists only began to understand.

Unlike other major ocean currents that encounter continental barriers, the ACC flows uninterrupted around Antarctica, connecting the Atlantic, Pacific and Indian Oceans, which oceanographers describe as the most important “ocean conveyor belt” on Earth. This current is more than four times higher than the Gulf Stream and plays a crucial role in global heat distribution and carbon cycle.

Freshwater destroys ocean balance

The research team, led by scientists from the University of Melbourne and North Norwegian Research Centre, uses high-resolution computer simulations to understand how the ACC responds to climate change factors, especially the influx of freshwater from the rapidly melting Antarctic ice sheet.

“The ocean is very complex and balanced. If the current “engine” breaks down, it can have serious consequences, including more climate variability, extremes in some regions, and accelerate global warming as the ocean’s capacity decreases its capacity as a carbon sink,” said Associate Professor Bishakhdatta Gayen, a mobile mechanic at the University of Melbourne, a fluid dynamics expert and research at the University of Melbourne.

These findings contradict previous studies, suggesting that ACC may increase with climate change. The difference seems to be that the researchers use more complex modeling, which captures small-scale marine processes that are often missed in low-resolution simulations.

How Ice Melting Slows Ocean Giant

This study represents a significant advancement in understanding how polar fresh cultures affect ocean circulation. As the Antarctic ice sheet melts at an accelerated rate, they release a large amount of fresh water into the surrounding saltwater ocean. This freshwater is denser than salt water and changes the delicate density gradient that helps drive ocean currents.

The team used Australia’s fastest supercomputer GADI to analyze how this freshwater influx interacts with warm temperature and wind pattern changes. Their model reveals a complex interaction in which fresh waters ultimately weaken the deep currents that contribute to the ACC.

The melted ice sheet pours a lot of fresh water into the Aral Sea. This sudden change in ocean “salinity” has a series of consequences – including the sinking of seawater sinking deep into the depths (called Antarctic bottom water), and based on this study, weakening of strong sea jets surrounding Antarctica,” explained Associate Professor Gain.

When these deep water formation processes slow down, they reduce the overall energy available to drive large amounts of pole-round currents, which are expected to slow down by 20% by the middle of the century in high emission scenarios.

Ecological barrier decomposition

In addition to its role in climate regulation, the ACC also serves as a natural barrier to long-term protection of Antarctica from invasive species. With the current weakening, this protection may be reduced.

“The ACC acts as a barrier to invasive species, such as the North-South continents that arrive from other continents to Antarctica, and southern cattle kelp or ocean-borne animals that ride rivers, such as shrimp or molluscs,” the researchers noted.

Slower ACC can allow more non-native species to enter Antarctic waters, thereby destroying the region’s delicate food network through the ecosystem and through the ecosystem casing effect, even affecting the available diets of Antarctic penguins.

Match against time

The researchers stress that despite their high-resolution simulations that provide important insights, the South Ocean remains one of the most unobservable regions on Earth. More direct measurements and continuous model improvements are crucial to fully understand how ACC will respond to ongoing climate change.

Dr Taimoor Sohail, a climate scientist at the University of Melbourne and author of the study, showed that even at lower emissions, a similar ACC slowdown would occur even at lower emissions if Antarctic ice melt continues to follow the forecasts of other studies.

“The Paris Agreement in 2015 aims to limit global warming to 1.5 degrees Celsius above pre-industrial levels. Many scientists agree that we have reached this 1.5 degree goal and may get hotter and have an impact on the melting of Antarctic ice,” Dr. Sohail said.

The study highlights the complexity of marine systems and highlights how one person can change the changes of Bingbing – a series of effects that can trigger the entire global ocean. With the ACC transporting approximately 173 million cubic meters of water per second, even a 20% reduction represents a huge change in the ocean cycle pattern.

While the full meaning of slower ACC remains to be seen, the researchers highlighted a clear gain: “The synergistic efforts to limit global warming (by reducing carbon emissions) will limit the melting of Antarctic ice, thus avoiding the expected slowdown in ACC.”

As climate scientists work to refine their understanding of these ocean processes, the study adds to growing evidence that the Earth’s ocean cycle patterns (on the one hand thinks it’s too big to change with significant changes in human activities) are indeed changing in response to the warm world.