Antarctic Circulating Current (ACC), which is more than four times as strong as the Gulf Stream, is the world’s strongest ocean current and plays an unbalanced role in the climate system due to its role as a major basin conduit. Scientists at the University of Melbourne and the Research Centre in Nordic Norway have shown that ACC will slow by about 20% by 2050 in high carbon emission scenarios. This influx of freshwater into the southern ocean is expected to alter the properties such as the density (salinity) of the ocean and its circulation patterns.
Sohail et al. High-resolution ocean and sea ice simulations of ocean currents, heat transport, and other factors were analyzed to diagnose the effects of temperature changes, saltiness, and wind conditions. Image credit: Sohail et al. , doi: 10.1088/1748-9326/adb31c.
“The oceans are extremely complex, finely balanced,” says Dr. Bishakhdatta Gayen, liquid mechanic at the University of Melbourne.
“If this current ‘engine’ collapses, serious consequences, including more climate change, including extreme extreme climate variability in certain regions, will accelerate global warming due to a decline in the ability of the ocean to function as a carbon sink. “
The ACC acts as a barrier to invasive species, like the southern burkelp and marine vectors such as shrimp and mollusks, which travel in the current from other continents reaching Antarctica.
If this current slows and weakens, it is more likely that such species will head towards the fragile Antarctica, potentially serious effects on food webs, which could change the available diet of Antarctic penguins, for example.
The ACC is an important part of the marine conveyor belt around the world, moving water around the world and linking the Atlantic, Pacific and Indian seas. These are the main mechanisms of exchange of heat, carbon dioxide, chemicals and biology throughout these basins.
In their study, the authors used Gadi, the fastest supercomputer in Australia located on the Access National Research Infrastructure.
They discovered that transport of seawater from the surface to the deepest could also be slower in the future.
“If ice melting accelerates as predicted by other studies, slowdowns are predicted to be similar in low emission scenarios,” Dr. Sohail said.
“The 2015 Paris Agreement aims to limit global warming to 1.5 degrees Celsius above pre-industrial levels.”
“Many scientists agree that we have already reached this 1.5 degree target, which could have an impact on the melting of Antarctic ice, making it even hotter.”
“Cooperative efforts to limit global warming (by reducing carbon emissions) will limit the melting of Antarctic ice and avoid the expected slowdown in ACC.”
This study reveals that the effects of ice melting and ocean warming on ACC are more complicated than previously thought.
“The melted ice sheets throw a large amount of fresh water from salt water into the salty sea.”
“This sudden change in ocean salinity has a series of results, including weakening of subsidence to the depths of surface seawater (called Antarctic bottom water), and based on this study, it includes weakening of the powerful marine jets surrounding Antarctica,” Dr. Gayen said.
study Published in the journal Environmental Survey Letter.
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Taimoor Sohail et al. 2025. Decreasing the polar current in the Antarctic due to polarization. environment. res. Rent 20, 034046; doi:10.1088/1748-9326/adb31c
Source: www.sci.news
