Antarctic sea ice over the past 130 000 years – Part 2: A review of its role in the Earth system
Abstract
Abstract. Antarctic sea-ice cover reached historically low levels in 2023, consistent with the simulated decrease in sea-ice extent in response to anthropogenic warming. Antarctic sea ice is closely linked to multiple components of the Earth system, thus its demise could precipitate widespread, cascading changes across the cryosphere, atmosphere, and ocean. However, the nature and strength of these interconnections are poorly understood, and they are often inadequately represented in models. In this review paper we use modern observations, models and paleoclimate archives covering the last glacial cycle to gain insights into how reductions in sea ice may affect other components of the Earth system. We review how Antarctic sea ice interacts with ocean and atmosphere circulation, ice sheets and ice shelves, marine productivity, and the carbon cycle over the last glacial cycle, for which we have the most robust sea-ice reconstructions. The review finds strong evidence from theory and models for impacts of Antarctic sea ice on the Earth system. Paleo-proxy reconstructions provide examples where changes in sea ice co-occur with changes in the carbon cycle, marine productivity, and ocean circulation. However, challenges remain in isolating the impact of sea ice in a highly interconnected system.
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Authors: Zanna Chase, Karen Elizabeth Kohfeld, Amy R. Leventer, Xavier Crosta, Laurie Menviel, Helen Bostock, Matthew Chadwick, Samuel L. Jaccard, Jacob L. Jones, Alice Marzocchi, Katrin Juliane Meissner, Elisabeth L. Sikes, Louise Claire Sime, Luke Cameron Skinner
Institutions: University of California, Los Angeles, The University of Queensland, Colgate University, UNSW Sydney, University of Connecticut, University of Cambridge, Centre National de la Recherche Scientifique, Rutgers, The State University of New Jersey, Université de Bordeaux, University of Lausanne, University of Tasmania, Simon Fraser University, National Oceanography Centre, Environnements et Paléoenvironnements Océaniques et Continentaux, British Antarctic Survey, Institute for Marine and Antarctic Studies, Australian Centre for Excellence in Antarctic Science, Climate Change Research Centre, ARC Centre of Excellence for Climate Extremes