Researchers from the University of Melbourne and NORCE Norway Research Centre have discovered that melting Antarctic ice sheets will significantly slow the Antarctic Circumpolar Current by 2050, with profound effects on global climate systems and marine ecosystems.
In a startling discovery, scientists from the University of Melbourne and the NORCE Norway Research Centre have found that the rapid melting of Antarctic ice sheets could slow down the world’s strongest ocean current, the Antarctic Circumpolar Current (ACC), by approximately 20% by the year 2050 if high carbon emissions persist. This revelation carries far-reaching implications for global climate patterns and marine ecosystems.
The ACC, more than four times stronger than the Gulf Stream, is a critical component of the planet’s “ocean conveyor belt.” It circulates water across the Atlantic, Pacific and Indian Oceans, facilitating the exchange of heat, carbon dioxide and various chemicals. Its disruption could have a cascade of severe consequences.
“The ocean is extremely complex and finely balanced. 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,” Bishakhdatta Gayen, an associate professor in the Department of Mechanical Engineering at the University of Melbourne, said in a news release.
The study employed high-resolution ocean and sea ice simulations run on Australia’s most powerful supercomputer, GADI, to investigate the impacts of changing temperature, salinity and wind conditions. The research points to a future where fresh water inflowing from melting ice alters the ocean’s densities, thus affecting its circulation patterns.
“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,” added Taimoor Sohail, a climate scientist at the University of Melbourne.
As the ACC weakens, invasive species like the southern bull kelp, shrimps and mollusks are likelier to disrupt the delicate Antarctic ecosystem. Such ecological invasions could dramatically alter the Antarctic food web, impacting species like penguins.
This new research, published in Environmental Research Letters, challenges previous studies that suggested the ACC might accelerate due to steeper temperature gradients, highlighting the need for further observational and modeling studies to accurately predict the current’s response to ongoing climate change.
Source: University of Melbourne