Earth's strongest ocean current is slowing, posing a serious climate threat
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A new study warns that the Antarctic Circumpolar Current (ACC), the most powerful ocean current on Earth, is slowing down due to climate change - potentially leading to rising sea levels, ocean warming, and disruptions to marine ecosystems.
Researchers at the University of Melbourne, in a study published in Environmental Research Letters, predict that the ACC could weaken by approximately 20% by 2050 if carbon emissions remain high. This decline is linked to the increasing melting of Antarctic ice shelves, which is altering ocean salinity and disrupting deep water circulation.
"The ACC acts as a crucial 'engine' regulating global climate," explained lead researcher Associate Professor Bishakhdatta Gayen. "If this system weakens, we could see greater climate variability, more extreme weather patterns, and a reduction in the ocean’s ability to absorb carbon dioxide - ultimately accelerating global warming."
The study also highlights that the ACC serves as a natural barrier, preventing invasive marine species from reaching Antarctica. If the current continues to weaken, species like southern bull kelp, shrimp, and mollusks from other continents could enter Antarctic waters, potentially disrupting the fragile ecosystem and altering food sources for species such as penguins.
"The melting ice sheets release vast amounts of freshwater into the ocean, reducing salinity and weakening deep-water circulation," added Gayen. "This, in turn, impacts the strength of the ACC, which has far-reaching consequences for global climate stability."
The research was conducted using GADI, Australia's most advanced supercomputer, located at the National Research Infrastructure in Canberra. The findings further emphasise the urgency of limiting global warming.
Climate scientist Dr. Taimoor Sohail, who contributed to the study, pointed out that the 2015 Paris Agreement aimed to keep temperature rise within 1.5°C above pre-industrial levels. However, many experts believe this threshold has already been reached, making Antarctic ice melt and its associated impacts even more concerning.