Scientists predict a 20% slowdown of the Antarctic Circumpolar Current (ACC) by 2050 under high carbon emissions scenarios, echoing concerns over the Atlantic Meridional Overturning Circulation (AMOC). Researchers from University of Melbourne and NORCE Norway Research Centre found a robust link between Antarctic ice melting and ACC slowdown. The ACC plays a crucial role in controlling oceanic heat distribution and carbon absorption on a global scale, making its decline potentially catastrophic.
The ACC is the world’s most powerful ocean current, 100 times stronger than the Amazon River, and helps to sustain Antarctic biodiversity by excluding invasive species. A slowdown could lead to more climate variability, greater extremes in certain regions, and accelerated global warming due to reduced carbon absorption.
As the global ocean absorbs around 90% of heat building up in the atmosphere, the ACC’s decline would exacerbate global warming. A weakening ACC also threatens to allow warm waters to reach the Antarctic shelf, accelerating ice melting. This creates a vicious cycle where ice loss causes more ACC deceleration, hastening further slowdown.
The researchers used Australia’s fastest supercomputer and climate simulator to analyze model simulations from 2000 out to 2050. Their findings suggest that concerted efforts to limit global warming, such as reducing carbon emissions, would limit Antarctic ice melting and avert the projected ACC slowdown.
Source: https://cosmosmagazine.com/earth/oceans/antarctic-circumpolar-current