Scientists have issued a warning that the world’s strongest ocean current is slowing down due to climate change which could have serious implications such as sea level rise and ocean warming. The Antarctic Circumpolar Current (ACC), a clockwise current more than four times stronger than the Gulf Stream, plays a pivotal part in the overall climate health of the planet. It influences the uptake of heat and carbon dioxide in the ocean and prevents warmer waters from reaching Antarctica.
The study conducted by researchers at the University of Melbourne and published in Environmental Research Letters shows that current might slow down by around 20 per cent by 2050 in the “high carbon emissions scenario”. This decline is driven by melting ice shelves around Antarctica.
“If this current ‘engine’ breaks down, there could be severe consequences, including more climate variability, with greater extremes in certain regions, and accelerated global warming due to a reduction in the ocean’s capacity to act as a carbon sink,” said Associate Professor Bishakhdatta Gayen, lead researcher of the study in a statement.
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Invasion in Antarctica
The study highlighted that ACC keeps invasive species such as southern bull kelp, shrimp and molluscs from other continents from reaching Antarctica. However, if ACC continues to slow down, there is a higher likelihood such species will make their way onto the fragile Antarctic continent, with a potentially severe impact on the food web. For example, the food choices of Antarctic penguins could be altered.
“The melting ice sheets dump vast quantities of fresh water into the salty ocean. This sudden change in ocean ‘salinity’ has a series of consequences – including the weakening of the sinking of surface ocean water to the deep (called the Antarctic Bottom Water), and, based on this study, a weakening of the strong ocean jet that surrounds Antarctica,” added Mr Gayen.
Notably, the researchers used Australia’s fastest supercomputer and climate simulator, GADI, located at Access National Research Infrastructure in Canberra to produce the damning findings.
“The 2015 Paris Agreement aimed 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, and it is likely to get hotter, with flow-on impacts on Antarctic ice melting,” climate scientist Dr Taimoor Sohail, associated with the study added.