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Future decline of Antarctic Circumpolar Current due to polar ocean freshening
  • Taimoor Sohail,
  • Bishakhdatta Gayen,
  • Andreas Klocker
Taimoor Sohail
Australian Center for Excellence in Antarctic Science, University of New South Wales, School of Mathematics and Statis-tics, University of New South Wales

Corresponding Author:[email protected]

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Bishakhdatta Gayen
Australian Center for Excellence in Antarctic Science, University of Melbourne, Centre for Atmospheric and Oceanic Sciences, Indian Institute of Science, Department of Mechanical Engineering, University of Melbourne
Andreas Klocker
NORCE Norwe-gian Research Centre, Bjerknes Centre for Climate Research


The Antarctic Circumpolar Current is the world's strongest ocean current and plays a disproportionate role in the climate system due to its role as a conduit for major ocean basins. This vast current system is linked to the ocean's vertical overturning circulation, and is thus pivotal to the uptake of heat and CO 2 in the ocean. The strength of the Antarctic Circumpolar Current has varied substantially across warm and cold climates in Earth's past, but the exact dynamical drivers of this change remain elusive. This is in part because ocean models were not able to adequately resolve the eddies and dense shelf water formation that control current strength. Here, we use a global ocean model which resolves such processes to diagnose the impact of future thermal, haline and wind conditions on the strength of the Antarctic Circumpolar Current. By 2050, our model suggests the strength of the Antarctic Circumpolar Current will decline by ∼ 20% in an extreme scenario. This decline is further supported by simple scaling theory, and is driven by ice shelf melting around Antarctica, which weakens the zonal density stratification historically supported by surface temperature gradients. Such a strong decline in transport would have critical implications for the entire global ocean circulation, and hence the Earth's climate system. Southern Ocean | Antarctic Circumpolar Current | Ocean Freshening | Antarctic Bottom Water
18 Dec 2023Submitted to ESS Open Archive
18 Dec 2023Published in ESS Open Archive