Scientists warn that the Antarctic Circumpolar Current (ACC), the world’s strongest ocean current, is slowing due to climate change, with potential consequences like rising sea levels and increased ocean temperatures. Research from the University of Melbourne predicts a 20% slowdown by 2050 under high carbon emissions. This decline, driven by melting ice shelves, could disrupt climate stability, allowing invasive species to reach Antarctica and impact its fragile ecosystem, including penguin food sources. The study highlights the importance of the ACC in regulating heat and carbon dioxide in the ocean, emphasizing the urgent need to address climate change.
Researchers have raised alarms about the slowing of the world’s most powerful ocean current, which is attributed to climate change. This change could lead to serious consequences such as rising sea levels and increased ocean temperatures. The Antarctic Circumpolar Current (ACC), a clockwise current that is over four times more powerful than the Gulf Stream, is crucial for maintaining the planet’s climate balance. It plays a key role in the absorption of heat and carbon dioxide in the oceans while preventing warmer waters from approaching Antarctica.
A study from the University of Melbourne, published in Environmental Research Letters, indicates that the current could decrease in speed by approximately 20 percent by 2050 under a “high carbon emissions scenario.” This reduction is primarily driven by the melting of ice shelves surrounding Antarctica.
“If this current ‘engine’ fails, we could face dire consequences, including increased climate variability, heightened extremes in certain areas, and accelerated global warming due to lessening the ocean’s ability to serve as a carbon sink,” said Associate Professor Bishakhdatta Gayen, the study’s lead researcher, in a statement.
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Invasion in Antarctica
The study pointed out that the ACC helps prevent invasive species like southern bull kelp, shrimp, and mollusks from other regions from reaching Antarctica. However, if the ACC continues to decelerate, the likelihood of these species invading the delicate Antarctic ecosystem increases, which could severely disrupt the food web. For instance, the dietary options of Antarctic penguins may be affected.
“Melting ice sheets are introducing large amounts of fresh water into the salty ocean. This abrupt shift in ocean salinity leads to multiple consequences, such as the weakening of the process that allows surface ocean water to sink deep (referred to as Antarctic Bottom Water), and, as this study suggests, a weakening of the powerful ocean jet that encircles Antarctica,” Mr. Gayen added.
Importantly, the researchers utilized Australia’s fastest supercomputer and climate simulator, GADI, based at Access National Research Infrastructure in Canberra, to derive these alarming findings.
“The 2015 Paris Agreement sought to limit global warming to 1.5 degrees Celsius above pre-industrial levels. Many scientists believe we have already reached this 1.5-degree threshold, and it is likely to get warmer, with subsequent impacts on Antarctic ice melting,” remarked climate scientist Dr. Taimoor Sohail, who was associated with the study.