Core Concepts
Changes in Antarctic Circumpolar Current strength are linked to long-term climate shifts and oceanic reconfigurations.
Abstract
The Antarctic Circumpolar Current (ACC) is a crucial ocean-current system impacting global ocean circulation, climate, and Antarctic ice-sheet stability. While ACC dynamics are influenced by various factors like atmospheric forcing, oceanic density gradients, and eddy activity, the long-term evolution of ACC strength remains poorly understood. This study examines changes in ACC strength over 5.3 million years using sediment cores from the Pacific Southern Ocean. The research reveals no consistent long-term trend in ACC flow, with fluctuations observed on a million-year timescale. These variations in ACC strength are associated with Southern Ocean reconfigurations, 400,000-year eccentricity cycles, and changes in the South Pacific jet stream. The study suggests a potential increase in ACC flow with future climate warming, highlighting the complex interplay between the ACC and global climate dynamics.
Stats
Today, ACC dynamics are controlled by atmospheric forcing, oceanic density gradients, and eddy activity.
We find no linear long-term trend in ACC flow since 5.3 million years ago.
ACC strength changes are closely linked to 400,000-year eccentricity cycles.
The strongest ACC flow occurred during warmer-than-present intervals of the Plio-Pleistocene.
Quotes
"The strongest ACC flow occurred during warmer-than-present intervals of the Plio-Pleistocene, providing evidence of potentially increasing ACC flow with future climate warming."
"We find ACC strength changes to be closely linked to 400,000-year eccentricity cycles, probably originating from modulation of precessional changes in the South Pacific jet stream linked to tropical Pacific temperature variability."