Year: 2026
Type: article
Abstract: Antarctic sea ice extent began declining in 2015, reaching its minimum in the post-1970s observational era in 2023. To diagnose the drivers of this decline, we analyze an observationally constrained sea ice-ocean model spanning 2013-2023 and identify three distinct phases of sea ice retreat. First, intensifying westerlies preconditioned the Southern Ocean via increased upwelling of warm, saline circumpolar deep water (CDW). Second, strong winds in 2015-2016 enhanced the mixing of CDW into the upper ocean, thereby initiating sea ice loss, particularly in East Antarctica. Third, sustained mixing of CDW into the surface layer, combined with reduced equatorward sea ice-derived freshwater export, maintained an unprecedentedly low sea ice state. East Antarctic sea ice loss was primarily subsurface driven via enhanced upward CDW flux, whereas West Antarctic sea ice loss was also forced by longwave radiative flux anomalies. Our findings suggest that persistent upwelling-favorable conditions under anthropogenic forcing may push the Southern Ocean into a prolonged low sea ice state.
Source: Science Advances
Institutions: UNSW Sydney, University of Southampton, Australian Centre for Excellence in Antarctic Science, National Oceanography Centre, Alfred-Wegener-Institut Helmholtz-Zentrum für Polar- und Meeresforschung, Ludwig-Maximilians-Universität München, Scripps Institution of Oceanography, University of California San Diego, University of Gothenburg, British Antarctic Survey
Language: English
Subfield: Atmospheric Science
Field: Earth and Planetary Sciences
Domain: Physical Sciences
SDG: Climate action
Open Access status: gold
Estimated APC paid: $4,500
Awards: G1373676184, G1646091363, G2411764356, Collaborative Research: Diagnosing the Role of Ocean Eddies in Carbon Cycling from a High-resolution Data Assimilating Ocean Biogeochemical Model, Collaborative Research: Deep Madagascar Basin (DMB) Experiment: A Quest to Find the Abyssal Water Pathways in the Southwest Indian Ocean, VERTical EXchange in the Southern Ocean, G765073026, SOCCOM3: Science to Predict the Future of the Southern Ocean and its Global Impacts, G809596922, Collaborative Research: Constraining the Role of the Antarctic Slope Current on Tracer Exchange at the Antarctic Margin using Model Hierarchies
OpenAlex ID: W7160704850