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  • Review Article
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Antarctic Bottom Water in a changing climate

Nature Reviews Earth & Environment volume 7, pages 86–102 (2026)Cite this article

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Abstract

Antarctic Bottom Water (AABW) is derived from dense water that sinks from the Antarctic continental shelf to the deep ocean. The sinking of AABW is balanced by a return flow of lighter water, and the resulting overturning circulation determines the density stratification of the deep ocean, regulates ocean storage of heat and carbon, and supplies oxygen to the deep sea. In this Review, we highlight progress in understanding how and why AABW is changing and the consequences for the deep overturning circulation. Since the mid-1980s, ocean heat content below 4,000 dbar has increased at a rate of 12.9 (±1.8) trillion watts, and the AABW has thinned by more than 50 dbar decade−1, with more rapid thinning observed closer to the sources of AABW. The abyssal overturning circulation has slowed in response to freshening of shelf waters by glacial melt and changes in sea ice formation. Numerical model simulations indicate that these trends will accelerate under projected increases in meltwater input. Future research priorities include sustained observations in the deep ocean and on the Antarctic continental shelf; exploration of feedbacks between ocean circulation, sea ice, dense water formation and ice shelf melt; and improved representation of AABW in ocean and climate models.

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Fig. 1: Sources and circulation pathways of AABW.
Fig. 2: Antarctic Bottom Water formation and export in the Weddell Sea and Ross Sea.
Fig. 3: Pathways and processes of the deep and abyssal overturning circulation.
Fig. 4: Change in properties of AABW.
Fig. 5: Contraction of AABW between 1990 and 2024.
Fig. 6: Projected changes in AABW.
Fig. 7: Changes in AABW and deep overturning circulation with increased freshwater input.

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References

  1. Brennecke, W. Die ozeanographischen arbeiten der Deutschen Antarktischen expedition 1911–1912. Aus Ark. Dtsch. Seewarte 39, 214 (1921).

    Google Scholar 

  2. Mosby, H. The waters of the Atlantic Antarctic Ocean. Scient. Res. Norw. Antarct. Exped. 11, 131 (1934).

    Google Scholar 

  3. Wüst, G. in Wissenschaftliche Ergebnisse der Deutschen Atlantischen Expedition auf dem Forschungs—und Vermessungsschiff “Meteor” 1925–1927 Vol. 6. (ed. Emery, W. J.) 112 (Amerind, 1935).

  4. Deacon, G. E. R. The hydrography of the Southern Ocean. Discov. Rep. 14, 124 (1937).

    Google Scholar 

  5. Gill, A. E. Circulation and bottom water production in the Weddell Sea. Deep Sea Res. 20, 111–140 (1973).

    Google Scholar 

  6. Foster, T. D. & Carmack, E. C. Frontal zone mixing and Antarctic Bottom Water formation in the southern Weddell Sea. Deep Sea Res. 23, 301–317 (1976).

    CAS  Google Scholar 

  7. Foldvik, A. et al. Ice shelf water overflow and bottom water formation in the southern Weddell Sea. J. Geophys. Res. Oceans 109, C02015 (2004).

    Article  Google Scholar 

  8. Lynn, R. J. & Reid, J. L. Characteristics and circulation of deep and abyssal waters. Deep Sea Res. Oceanogr. Abstr. 15, 577–598 (1968).

    Article  Google Scholar 

  9. Orsi, A. H., Johnson, G. C. & Bullister, J. L. Circulation, mixing, and production of Antarctic Bottom Water. Prog. Oceanogr. 43, 55–109 (1999).

    Article  Google Scholar 

  10. Purkey, S. G. et al. A synoptic view of the ventilation and circulation of Antarctic Bottom Water from chlorofluorocarbons and natural tracers. Annu. Rev. Mar. Sci. https://doi.org/10.1146/annurev-marine-121916-063414 (2018).

  11. Johnson, G. C. Quantifying Antarctic Bottom Water and North Atlantic Deep Water volumes. J. Geophys. Res. 113, C05027 (2008).

    Google Scholar 

  12. Solodoch, A. et al. How does Antarctic Bottom Water cross the Southern Ocean? Geophys. Res. Lett. 49, e2021GL097211 (2022).

    Article  Google Scholar 

  13. Schmitz, W. J. On the World Ocean Circulation: Volume I. Some Global Features/North Atlantic Circulation. Report No. WHOI-96-03 (Woods Hole Oceanographic Institution, 1996).

  14. Marshall, J. & Speer, K. Closure of the meridional overturning circulation through Southern Ocean upwelling. Nat. Geosci. 5, 171–180 (2012).

    Article  CAS  Google Scholar 

  15. Talley, L. D. Closure of the global overturning circulation through the Indian, Pacific, and Southern oceans: schematics and transports. Oceanography 26, 80–97 (2013).

    Article  Google Scholar 

  16. Sun, S., Eisenman, I. & Stewart, A. The influence of Southern Ocean surface buoyancy forcing on glacial-interglacial changes in the global deep ocean stratification. Geophys. Res. Lett. 43, 8124–8132 (2016).

    Article  Google Scholar 

  17. Jansen, M. F. & Nadeau, L. The effect of Southern Ocean surface buoyancy loss on the deep-ocean circulation and stratification. J. Phys. Oceanogr. 46, 3455–3470 (2016).

    Article  Google Scholar 

  18. Schmidtko, S., Stramma, L. & Visbeck, M. Decline in global oceanic oxygen content during the past five decades. Nature 542, 335–339 (2017).

    Article  CAS  Google Scholar 

  19. Marinov, I., Gnanadesikan, A., Toggweiler, J. R. & Sarmiento, J. L. The Southern Ocean biogeochemical divide. Nature 441, 964–967 (2006).

    Article  CAS  Google Scholar 

  20. Gray, A. R. The four-dimensional carbon cycle of the Southern Ocean. Annu. Rev. Mar. Sci. 16, 163–190 (2024).

    Article  Google Scholar 

  21. Purkey, S. G. & Johnson, G. C. Warming of global abyssal and deep Southern Ocean waters between the 1990s and 2000s: contributions to global heat and sea level rise budgets. J. Clim. 23, 6336–6351 (2010).

    Article  Google Scholar 

  22. Purkey, S. G. & Johnson, G. C. Global contraction of Antarctic Bottom Water between the 1980s and 2000s. J. Clim. 25, 5830–5844 (2012).

    Article  Google Scholar 

  23. Purkey, S. G. & Johnson, G. C. Antarctic Bottom Water warming and freshening: contributions to sea level rise, ocean freshwater budgets, and global heat gain. J. Clim. 26, 6105–6122 (2013).

    Article  Google Scholar 

  24. Gordon, A. L. in Ocean, Ice and Atmosphere: Interactions at the Antarctic Continental Margin Vol. 75 (eds Jacobs, S. S. & Weiss, R. F.) 215–240 (American Geophysical Union, 1998).

  25. Nicholls, K. W., Østerhus, S., Makinson, K., Gammelsrød, T. & Fahrbach, E. Ice-ocean processes over the continental shelf of the southern Weddell Sea, Antarctica: a review. Rev. Geophys. 47, RG3003 (2009).

    Article  Google Scholar 

  26. Gordon, A. L. Deep Antarctic convection west of Maud Rise. J. Phys. Oceanogr. 8, 600–612 (1978).

    Article  Google Scholar 

  27. Goosse, H., Dalaiden, Q., Cavitte, M. G. P. & Zhang, L. Can we reconstruct the formation of large open-ocean polynyas in the Southern Ocean using ice core records? Clim. Past 17, 111–131 (2021).

    Article  Google Scholar 

  28. Pellichero, V. et al. The Southern Ocean meridional overturning in the sea-ice sector is driven by freshwater fluxes. Nat. Comm. 9, 1789 (2018).

    Article  Google Scholar 

  29. Whitworth III, T., Orsi, A. H., Kim, S.-J., Nowlin Jr., W. D. & Locarni, R. A. in Ocean, Ice and Atmosphere: Interactions at the Antarctic Continental Margin Vol. 75 (eds Jacobs, S. S. & Weiss, R. F.) 1–27 (American Geophysical Union, 1998).

  30. Foldvik, A., Gammelsrod, T. & Torresen, T. in Oceanology of the Antarctic Continental Shelf Vol. 43, (ed. Jacobs, S. S.) 5–20 (American Geophysical Union, 1985).

  31. Killworth, P. D. Mixing on the Weddell Sea continental slope. Deep Sea Res. 24, 427–448 (1977).

    Article  Google Scholar 

  32. Matsumura, Y. & Hasumi, H. Modeling ice shelf water overflow and Bottom Water formation in the southern Weddell Sea. J. Geophys. Res. 115, C10033 (2010).

    Google Scholar 

  33. Yan, L. et al. The salinity budget of the Ross Sea continental shelf, Antarctica. J. Geophys. Res. Oceans 128, e2022JC018979 (2023).

    Article  Google Scholar 

  34. Silvano, A. et al. Freshening by glacial meltwater enhances melting of ice shelves and reduces formation of Antarctic Bottom Water. Sci. Adv. 4, eaap9467 (2018).

    Article  Google Scholar 

  35. Nakayama, Y., Timmermann, R., Rodehacke, C. B., Schröder, M. & Hellmer, H. H. Modeling the spreading of glacial meltwater from the Amundsen and Bellingshausen Seas. Geophys. Res. Lett. 41, 7942–7949 (2014).

    Article  Google Scholar 

  36. Dawson, H. R. S., Morrison, A. K., England, M. H. & Tamsitt, V. Pathways and timescales of connectivity around the Antarctic continental shelf. J. Geophys. Res. Oceans 128, e2022JC018962 (2023).

    Article  Google Scholar 

  37. Janout, M. A. et al. FRIS revisited in 2018: On the circulation and water masses at the Filchner and Ronne ice shelves in the southern Weddell Sea. J. Geophys. Res. Oceans 126, e2021JC017269 (2021).

    Article  Google Scholar 

  38. Davis, P. E. D. et al. Observations of modified warm deep water beneath Ronne Ice Shelf, Antarctica, from an autonomous underwater vehicle. J. Geophys. Res. Oceans 127, e2022JC019103 (2022).

    Article  Google Scholar 

  39. Baines, P. G. & Condie, S. A. in Ocean, Ice and Atmosphere: Interactions at the Antarctic Continental Margin Vol. 75 (eds Jacobs, S. S. & Weiss, R. F.) 29–49 (American Geophysical Union, 1998).

  40. Jacobs, S. S., Amos, A. F. & Bruchhausen, P. M. Ross Sea oceanography and Antarctic Bottom Water formation. Deep Sea Res. Oceanogr. Abstr. 17, 935–962 (1970).

    Article  Google Scholar 

  41. Orsi, A. H. & Wiederwohl, C. L. A recount of Ross Sea waters. Deep Sea Res. II 56, 778–795 (2009).

    Article  Google Scholar 

  42. Miller, U. K. et al. The coupling of winds, ocean turbulence, and High Salinity Shelf Water in the Terra Nova Bay Polynya. Deep Sea Res. II 218, 105412 (2024).

    Article  Google Scholar 

  43. Miller, U. K. et al. High Salinity Shelf Water production rates in Terra Nova Bay, Ross Sea from high-resolution salinity observations. Nat. Commun. 15, 373 (2024).

    Article  CAS  Google Scholar 

  44. Jacobs, S. S. & Giulivi, C. F. Large multidecadal salinity trends near the Pacific–Antarctic continental margin. J. Clim. 23, 4508–4524 (2010).

    Article  Google Scholar 

  45. Jacobs, S. S., Giulivi, C. F. & Dutrieux, P. Persistent Ross Sea freshening from imbalance West Antarctic Ice Shelf melting. J. Geophys. Res. Oceans 127, e2021JC017808 (2022).

    Article  Google Scholar 

  46. Stewart, A. L. & Thompson, A. F. Eddy-mediated transport of warm Circumpolar Deep Water across the Antarctic Shelf Break. Geophys. Res. Lett. 42, 432–440 (2015).

    Article  Google Scholar 

  47. Morrison, A. K., Hogg, A. M., England, M. H. & Spence, P. Warm Circumpolar Deep Water transport toward Antarctica driven by local dense water export in canyons. Sci. Adv. 6, eaav2516 (2020).

    Article  CAS  Google Scholar 

  48. Thompson, A. F., Stewart, A. L., Spence, P. & Heywood, K. J. The Antarctic slope current in a changing climate. Rev. Geophys. 56, 741–770 (2018).

    Article  Google Scholar 

  49. Gordon, A. L., Huber, B. A. & Busecke, J. Bottom Water export from the western Ross Sea, 2007 through 2010. Geophys. Res. Lett. 42, 5387–5394 (2015).

    Article  Google Scholar 

  50. Whitworth, T. I. I. I. & Orsi, A. H. Antarctic Bottom Water production and export by tides in the Ross Sea. Geophys. Res. Lett. 33, L12609 (2006).

    Article  Google Scholar 

  51. Budillon, G., Castagno, P., Aliani, S., Spezie, G. & Padman, L. Thermohaline variability and Antarctic Bottom Water formation at the Ross Sea Shelf Break. Deep Sea Res. I 58, 1002–1018 (2011).

    Article  Google Scholar 

  52. Gordon, A. L., Huber, B., McKee, D. & Visbeck, M. A seasonal cycle in the export of Bottom Water from the Weddell Sea. Nat. Geosci. 3, 551–556 (2010).

    Article  CAS  Google Scholar 

  53. Padman, L., Howard, S. L., Orsi, A. H. & Muench, R. D. Tides of the northwestern Ross Sea and their impact on dense outflows of Antarctic Bottom Water. Deep Sea Res. II 56, 818–834 (2009).

    Article  Google Scholar 

  54. Wang, Q. et al. Enhanced cross-shelf exchange by tides in the western Ross Sea. Geophys. Res. Lett. 40, 5735–5739 (2013).

    Article  Google Scholar 

  55. Han, X. et al. Tidal enhancement of Antarctic Dense Shelf Water export via suppression of continental slope mixing. J. Phys. Oceanogr. 55, 2179–2195 (2025).

    Article  Google Scholar 

  56. Bowen, M. M. et al. The role of tides in Bottom Water export from the western Ross Sea. Sci. Rep. 11, 2246 (2021).

    Article  CAS  Google Scholar 

  57. Bowen, M. M. et al. Tides regulate the flow and density of Antarctic Bottom Water from the western Ross Sea. Sci. Rep. 13, 3873 (2023).

    Article  CAS  Google Scholar 

  58. Gordon, A. L., Visbeck, M. & Huber, B. Export of Weddell Sea Deep and Bottom Water. J. Geophys. Res. 106, 9005–9017 (2001).

    Article  Google Scholar 

  59. Gordon, A. L. et al. Western Ross Sea continental slope gravity currents. Deep Sea Res. II 56, 796–817 (2009).

    Article  Google Scholar 

  60. Marques, G. M., Padman, L., Springer, S. R., Howard, S. L. & Özgökmen, T. M. Topographic vorticity waves forced by Antarctic Dense Shelf Water outflows. Geophys. Res. Lett. 41, 1247–1254 (2014).

    Article  Google Scholar 

  61. Han, X. et al. Circum-Antarctic Bottom Water formation mediated by tides and topographic waves. Nat. Commun. 15, 2049 (2024).

    Article  CAS  Google Scholar 

  62. Wåhlin, A. K. Topographic steering of dense currents with application to submarine canyons. Deep Sea Res. I 49, 305–320 (2002).

    Article  Google Scholar 

  63. Darelius, E. & Wåhlin, A. Downward flow of dense water leaning on a submarine ridge. Deep Sea Res. I 54, 1173–1188 (2007).

    Article  Google Scholar 

  64. Gordon, A. L., Huber, B. A. & Abrahamsen, E. P. Interannual variability of the outflow of Weddell Sea Bottom Water. Geophys. Res. Lett. 47, e2020GL087014 (2020).

    Article  Google Scholar 

  65. Price, J. F. & Barringer, M. O. Outflows and deep water production by marginal seas. Prog. Oceanogr. 33, 161–200 (1994).

    Article  Google Scholar 

  66. Akhoudas, C. H. et al. Ventilation of the abyss in the Atlantic sector of the Southern Ocean. Sci. Rep. 11, 1–13 (2021).

    Google Scholar 

  67. Carmack, E. C. & Killworth, P. D. Formation and interleaving of abyssal water masses off Wilkes Land, Antarctica. Deep Sea Res. 25, 357–369 (1978).

    Article  Google Scholar 

  68. Shimada, K. et al. Shoaling of abyssal ventilation in the Eastern Indian Sector of the Southern Ocean. Commun. Earth Environ. 3, 120 (2022).

    Article  Google Scholar 

  69. Orsi, A. H., Smethie Jr., W. M. & Bullister, J. L. On the total input of Antarctic waters to the deep ocean: a preliminary estimate from chlorofluorocarbon measurements, J. Geophys. Res. https://doi.org/10.1029/2001JC000976 (2002).

  70. Huhn, O. et al. 2008. Evidence of deep- and bottom-water formation in the western Weddell Sea. Deep Sea Res. II 558–559, 1098–1116 (2008).

    Article  Google Scholar 

  71. Schlosser, P., Bullister, J. L. & Bayer, R. Studies of deep water formation and circulation in the Weddell Sea using natural and anthropogenic tracers. Mar. Chem. 35, 97–122 (1991).

    Article  CAS  Google Scholar 

  72. Schlosser, P. et al. Oxygen 18 and helium as tracers of ice shelf water and water/ice interaction in the Weddell Sea. J. Geophys. Res. 95, 3253–3263 (1990).

    Article  Google Scholar 

  73. Garabato, A. C. N. et al. On the export of Antarctic Bottom Water from the Weddell Sea. Deep Sea Res. II 49, 4715–4742 (2002).

    Article  Google Scholar 

  74. Jullion, L. et al. The contribution of the Weddell Gyre to the lower limb of the global overturning circulation. J. Geophys. Res. Oceans 119, 3357–3377 (2014).

    Article  Google Scholar 

  75. Fukamachi, Y. et al. Strong export of Antarctic Bottom Water east of the Kerguelen Plateau. Nat. Geosci. 3, 327–331 (2010).

    Article  CAS  Google Scholar 

  76. Aoki, S. et al. Deep western boundary current and southern frontal systems of the Antarctic Circumpolar Current southeast of the Kerguelen Plateau. J. Geophys. Res. 113, C08038 (2008).

    Google Scholar 

  77. Orsi, A. H., Nowlin, W. D. & Whitworth, T. On the circulation and stratification of the Weddell Gyre. Deep Sea Res. I 40, 169–203 (1993).

    Article  Google Scholar 

  78. Meredith, M. P., Naveira Garabato, A. C., Gordon, A. L. & Johnson, G. C. Evolution of the deep and bottom waters of the Scotia Sea, Southern Ocean, during 1995–2005. J. Clim. 21, 3327–3343 (2008).

    Article  Google Scholar 

  79. Polzin, K. L., Garabato, A. C. N., Abrahamsen, E. P., Jullion, L. & Meredith, M. P. Boundary mixing in Orkney Passage outflow. J. Geophys. Res. Oceans 119, 8627–8645 (2014).

    Article  Google Scholar 

  80. Cusack, J. M. et al. Persistent turbulence in the Samoan Passage. J. Phys. Oceanogr. 49, 3179–3197 (2019).

    Article  Google Scholar 

  81. MacKinnon, J., Johnston, T. & Pinkel, R. Strong transport and mixing of deep water through the Southwest Indian Ridge. Nat. Geosci. 1, 755–758 (2008).

    Article  CAS  Google Scholar 

  82. Hogg, N. G. in Encyclopedia of Ocean Sciences 2nd edn 564–571 (Academic, 2009).

  83. Lumpkin, R. & Speer, K. Global ocean meridional overturning. J. Phys. Oceanogr. 37, 2550–2562 (2007).

    Article  Google Scholar 

  84. Naveira Garabato, A. C. et al. The thermodynamic balance of the Weddell Gyre. Geophys. Res. Lett. 43, 317–325 (2016).

    Article  Google Scholar 

  85. Cessi, P. The global overturning circulation. Annu. Rev. Mar. Sci. 11, 249–270 (2019).

    Article  Google Scholar 

  86. Naveira Garabato, A. C., Williams, A. P. & Bacon, S. The three-dimensional overturning circulation of the Southern Ocean during the WOCE era. Prog. Oceanogr. 120, 41–78 (2014).

    Article  Google Scholar 

  87. McCartney, M. S. & Curry, R. A. Transequatorial flow of Antarctic Bottom Water in the western Atlantic Ocean: abyssal geostrophy at the equator. J. Phys. Oceanogr. 23, 1264–1276 (1993).

    Article  Google Scholar 

  88. Schmidgall, C. R., Si, Y., Stewart, A. L., Thompson, A. F. & Hogg, A. McC. Dynamical controls on bottom water transport and transformation across the Antarctic Circumpolar Current. J. Phys. Oceanogr. 53, 1917–1940 (2023).

    Article  Google Scholar 

  89. de Lavergne, C., Madec, G., Le Sommer, J., Nurser, A. G. & Naveira Garabato, A. C. On the consumption of Antarctic Bottom Water in the abyssal ocean. J. Phys. Oceanogr. 46, 635–661 (2016).

    Article  Google Scholar 

  90. Newsom, E. R., Bitz, C. M., Bryan, F. O., Abernathey, R. & Gent, P. R. Southern Ocean deep circulation and heat uptake in a high-resolution climate model. J. Clim. 29, 2597–2619 (2016).

    Article  Google Scholar 

  91. Millet, B. et al. Deep ocean ventilation: a comparison between a general circulation model and data-constrained inverse models. J. Adv. Model. Earth Syst. 17, e2024MS004914 (2025).

    Article  Google Scholar 

  92. Munk, W. Abyssal recipes. Deep Sea Res. 13, 707–730 (1966).

    Google Scholar 

  93. Munk, W. & Wunsch, C. Abyssal recipes II: energetics of tidal and wind mixing. Deep Sea Res. I 45, 1977–2010 (1998).

    Article  Google Scholar 

  94. Nikurashin, M. & Vallis, G. A theory of the interhemispheric meridional overturning circulation and associated stratification. J. Phys. Oceanogr. 42, 1652–1667 (2012).

    Article  Google Scholar 

  95. Garrett, C. & Munk, W. Oceanic mixing by breaking internal waves. Deep Sea Res. Oceanogr. Abstr. 19, 823–832 (1972).

    Article  Google Scholar 

  96. Wunsch, C. & Ferrari, R. Vertical mixing, energy, and the general circulation of the oceans. Annu. Rev. Fluid Mech. 36, 281–314 (2004).

    Article  Google Scholar 

  97. Waterhouse, A. F. et al. Global patterns of diapycnal mixing from measurements of the turbulent dissipation rate. J. Phys. Oceanogr. 44, 1854–1872 (2014).

    Article  Google Scholar 

  98. Ferrari, R., Mashayek, A., McDougall, T. J., Nikurashin, M. & Campin, J. M. Turning ocean mixing upside down. J. Phys. Oceanogr. 46, 2239–2261 (2016).

    Article  Google Scholar 

  99. de Lavergne, C., Madec, G., Roquet, F., Holmes, R. M. & McDougall, T. J. Abyssal ocean overturning shaped by seafloor distribution. Nature 551, 181–186 (2017).

    Article  Google Scholar 

  100. Thurnherr, A. M., Clément, L., St. Laurent, L., Ferrari, R. & Ijichi, T. Transformation and upwelling of bottom water in fracture zone valleys. J. Phys. Oceanogr. 50, 715–726 (2020).

    Article  Google Scholar 

  101. Wynne-Cattanach, B. L. et al. Observations of diapycnal upwelling within a sloping submarine canyon. Nature 630, 884–890 (2024).

    Article  CAS  Google Scholar 

  102. Armi, L. Effects of variations in eddy diffusivity on property distributions in the oceans. J. Mar. Res. 37, 515–530 (1979).

    Google Scholar 

  103. Gula, J., Molemaker, M. J. & McWilliams, J. C. Topographic generation of submesoscale centrifugal instability and energy dissipation. Nat. Commun. 7, 12811 (2016).

    Article  CAS  Google Scholar 

  104. Mashayek, A. et al. On the role of seamounts in upwelling deep-ocean waters through turbulent mixing. Proc. Natl Acad. Sci. USA 121, e2322163121 (2024).

    Article  CAS  Google Scholar 

  105. Bryden, H. L. & Nurser, A. G. Effects of strait mixing on ocean stratification. J. Phys. Oceanogr. 33, 1870–1872 (2003).

    Article  Google Scholar 

  106. Desbruyères, D. G., Purkey, S. G., McDonagh, E. L., Johnson, G. C. & King, B. A. Deep and abyssal ocean warming from 35 years of repeat hydrography. Geophys. Res. Lett. 43, 10356–10365 (2016).

    Article  Google Scholar 

  107. Johnson, G. C. & Purkey, S. G. Refined estimates of global ocean deep and abyssal decadal warming trends. Geophys. Res. Lett. 51, e2024GL111229 (2024).

    Article  Google Scholar 

  108. Rintoul, S. R. Rapid freshening of Antarctic Bottom Water formed in the Indian and Pacific Oceans. Geophys. Res. Lett. 34, L06606 (2007).

    Article  Google Scholar 

  109. van Wijk, E. M. & Rintoul, S. R. Freshening drives contraction of Antarctic Bottom Water in the Australian Antarctic Basin. Geophys. Res. Lett. 41, 1657–1664 (2014).

    Article  Google Scholar 

  110. Shimada, K., Aoki, S., Oshima, K. I. & Rintoul, S. R. Influence of the Ross Sea Bottom Water changes on the warming and freshening of the Antarctic Bottom Water in the Australian–Antarctic Basin. Ocean Sci. 8, 419–432 (2012).

    Article  Google Scholar 

  111. Katsumata, K., Nakano, H. & Kumamoto, Y. Dissolved oxygen change and freshening of Antarctic Bottom Water along 62°S in the Australian-Antarctic Basin between 1995/1996 and 2012/2013. Deep Sea Res. II 114, 27–38 (2015).

    Article  CAS  Google Scholar 

  112. Silvano, A. et al. Recovery of Antarctic Bottom Water formation in the Ross Sea driven by climate anomalies. Nat. Geosci. 13, 780–786 (2020).

    Article  CAS  Google Scholar 

  113. Abrahamsen, E. P. et al. Stabilization of dense Antarctic water supply to the Atlantic Ocean overturning circulation. Nat. Clim. Change 9, 742–746 (2019).

    Article  Google Scholar 

  114. Silvano, A. et al. Observing Antarctic Bottom Water in the Southern Ocean. Front. Mar. Sci. https://doi.org/10.3389/fmars.2023.1221701 (2023).

  115. Schmidt, C., Morrison, A. K. & England, M. H. Wind- and sea-ice-driven interannual variability of Antarctic Bottom Water formation. J. Geophys. Res. Oceans 128, e2023JC019774 (2023).

    Article  Google Scholar 

  116. Castagno, P. et al. Rebound of shelf water salinity in the Ross Sea. Nat. Commun. 10, 1–6 (2019).

    Article  CAS  Google Scholar 

  117. Paolo, F. S., Fricker, H. A. & Padman, L. Volume loss from Antarctic ice shelves is accelerating. Science 348, 327–331 (2015).

    Article  CAS  Google Scholar 

  118. Rignot, E. et al. Four decades of Antarctic ice sheet mass balance from 1979–2017. Proc. Natl Acad. Sci. USA 116, 1095–1103 (2019).

    Article  CAS  Google Scholar 

  119. Nihashi, S. & Ohshima, K. I. Circumpolar mapping of Antarctic coastal polynyas and landfast sea ice: relationship and variability. J. Clim. 28, 3650–3670 (2015).

    Article  Google Scholar 

  120. Nihashi, S., Ohshima, K. I. & Tamura, T. Sea-ice production in Antarctic coastal polynyas estimated from AMSR2 data and its validation using AMSR-E and SSM/I-SSMIS data. IEEE J. Sel. Top. Appl. Earth Obs. Remote Sens. 10, 3912–3922 (2017).

    Article  Google Scholar 

  121. Nihashi, S., Ohshima, K. I. & Tamura, T. Reconstruct the AMSR-E/2 thin ice thickness algorithm to create a long-term time series of sea-ice production in Antarctic coastal polynyas. Polar Sci. 39, 100978 (2024).

    Article  Google Scholar 

  122. Hattermann, T. et al. Observed interannual changes beneath Filchner–Ronne Ice Shelf linked to large-scale atmospheric circulation. Nat. Commun. 12, 2961 (2021).

    Article  CAS  Google Scholar 

  123. Holland, P. R. & Kimura, N. Observed concentration budgets of Arctic and Antarctic sea ice. J. Clim. 29, 5241–5249 (2016).

    Article  Google Scholar 

  124. Zhou, S. et al. Slowdown of Antarctic Bottom Water export driven by climatic wind and sea-ice changes. Nat. Clim. Change 13, 701–709 (2023).

    Article  Google Scholar 

  125. Hellmer, H. H., Huhn, O., Gomis, D. & Timmermann, R. On the freshening of the northwestern Weddell Sea continental shelf. Ocean Sci. 7, 305–316 (2011).

    Article  Google Scholar 

  126. Spence, P., Menviel, L., Morrison, A. K., Foppert, A. & Silvano, A. On the relationship between the Weddell polynya and Antarctic Bottom Water trends. J. Clim. (in the press).

  127. Shadwick, E. H. et al. Glacier tongue calving reduced dense water formation and enhanced carbon uptake. Geophys. Res. Lett. 40, 904–909 (2013).

    Article  Google Scholar 

  128. Snow, K., Rintoul, S. R., Sloyan, B. & Hogg, A. McC. Decrease in density and volume of Adélie Land Bottom Water induced by iceberg calving. Geophys. Res. Lett. 45, 2380–2387 (2018).

    Article  Google Scholar 

  129. Diao, X. et al. Impact of anthropogenic climate change on Antarctic Dense Shelf Water in a high-resolution Community Earth System Model (CESM1.3). Clim. Dyn. 63, 363 (2025).

    Article  Google Scholar 

  130. Tamura, T., Ohshima, K. I. & Nihashi, S. Mapping of sea ice production for Antarctic coastal polynyas. Geophys. Res. Lett. 35, L07606 (2008).

    Article  Google Scholar 

  131. Jeong, H. et al. Future changes in Antarctic coastal polynyas and bottom water formation simulated by a high-resolution coupled model. Commun. Earth Environ. 4, 490 (2023).

    Article  Google Scholar 

  132. Aoki, S. et al. Reversal of freshening trend of Antarctic Bottom Water in the Australian-Antarctic Basin during 2010s. Sci. Rep. 10, 14415 (2020).

    Article  CAS  Google Scholar 

  133. Purkey, S. G. et al. Unabated bottom water freshening in the South Pacific Ocean. J. Geophys. Res. Oceans 124, 1778–1794 (2019).

    Article  Google Scholar 

  134. Oschlies, A., Brandt, P., Stramma, L. & Schmidtko, S. Drivers and mechanisms of ocean deoxygenation. Nat. Geosci. 11, 467–473 (2018).

    Article  CAS  Google Scholar 

  135. Gunn, K. L., Rintoul, S. R., England, M. H. & Bowen, M. M. Recent reduced abyssal overturning and ventilation in the Australian Antarctic Basin. Nat. Clim. Change 13, 537–544 (2023).

    Article  Google Scholar 

  136. Aoki, S., Rintoul, S. R., Ushio, S., Watanabe, S. & Bindoff, N. L. Freshening of the Adelie Land Bottom Water near 140°E. Geophys. Res. Lett. 32, L23601 (2005).

    Article  Google Scholar 

  137. Aoki, S. et al. Widespread freshening in the seasonal ice zone near 140°E off the Adélie Land Coast, Antarctica, from 1994 to 2012. J. Geophys. Res. Oceans 118, 1–18 (2013).

    Article  Google Scholar 

  138. Johnson, G. C. Antarctic Bottom Water warming and circulation slowdown in the Argentine Basin from analyses of Deep Argo and historical shipboard temperature data. Geophys. Res. Lett. 49, e2022GL100526 (2022).

    Article  Google Scholar 

  139. Kouketsu, S. et al. Deep ocean heat content changes estimated from observation and reanalysis product and their influence on sea level change. J. Geophys. Res. 116, C03012 (2011).

    Google Scholar 

  140. Biló, T. C. et al. Weakening of the Atlantic meridional overturning circulation abyssal limb in the North Atlantic. Nat. Geosci. 17, 419–425 (2024).

    Article  Google Scholar 

  141. Heuzé, C., Heywood, K. J., Stevens, D. P. & Ridley, J. K. Southern Ocean Bottom Water characteristics in CMIP5 models. Geophys. Res. Lett. 40, 1409–1414 (2013).

    Article  Google Scholar 

  142. Heuzé, C. Antarctic Bottom Water and North Atlantic Deep Water in CMIP6 models. Ocean Sci. 17, 59–90 (2021).

    Article  Google Scholar 

  143. Mohrmann, M., Heuzé, C. & Swart, S. Southern Ocean polynyas in CMIP6 models. Cryosphere 15, 4281–4313 (2021).

    Article  Google Scholar 

  144. Legg, S. et al. Improving oceanic overflow representation in climate models: the Gravity Current Entrainment Climate Process Team. Bull. Am. Meteorol. Soc. 90, 657–670 (2009).

    Article  Google Scholar 

  145. Heuzé, C., Heywood, K. J., Stevens, D. P. & Ridley, J. K. Changes in global ocean bottom properties and volume transports in CMIP5 models under climate change scenarios. J. Clim. 28, 2917–2944 (2015).

    Article  Google Scholar 

  146. Chen, J.-J. et al. Reduced deep convection and bottom water formation due to Antarctic meltwater in a multi-model ensemble. Geophys. Res. Lett. 50, e2023GL106492 (2023).

    Article  Google Scholar 

  147. Mensah, V., Nakayama, Y., Fujii, M., Nogi, Y. & Ohshima, K. I. Dense water downslope flow and AABW production in a numerical model: sensitivity to horizontal and vertical resolution in the region off Cape Darnley polynya. Ocean Model. 165, 101843 (2021).

    Article  Google Scholar 

  148. Moorman, R., Morrison, A. K. & Hogg, A. McC. Thermal responses to Antarctic Ice Shelf melt in an eddy-rich global ocean–sea ice model. J. Clim. 33, 6599–6620 (2020).

    Article  Google Scholar 

  149. Lockwood, J. W., Dufour, C. O., Griffies, S. M. & Winton, M. On the role of the Antarctic Slope Front on the occurrence of the Weddell Sea polynya under climate change. J. Clim. 34, 2529–2548 (2021).

    Article  Google Scholar 

  150. Li, Q., England, M. H., Hogg, A. McC., Rintoul, S. R. & Morrison, A. K. Abyssal ocean overturning slowdown and warming driven by Antarctic meltwater. Nature 615, 841–847 (2023).

    Article  CAS  Google Scholar 

  151. Xie, C., Zhang, Z., Chen, Y. & Wang, C. Substantial contraction of Dense Shelf Water in the Ross Sea under future climate scenarios. Geophys, Res. Lett. 52, e2024GL112581 (2025).

    Article  Google Scholar 

  152. Golledge, N. R. et al. Global environmental consequences of twenty-first-century ice-sheet melt. Nature 566, 65–72 (2019).

    Article  CAS  Google Scholar 

  153. Song, P. et al. Regional conditions determine thresholds of accelerated Antarctic basal melt in climate projection. Nat. Clim. Change 15, 521–527 (2025).

    Article  Google Scholar 

  154. Bronselaer, B. et al. Change in future climate due to Antarctic meltwater. Nature 564, 53–58 (2018).

    Article  CAS  Google Scholar 

  155. Naughten, K. A. et al. Future projections of Antarctic Ice Shelf melting based on CMIP5 scenarios. J. Clim. 31, 5243–5261 (2018).

    Article  Google Scholar 

  156. Tesdal, J.-E. et al. Revisiting interior water mass responses to surface forcing changes and the subsequent effects on overturning in the Southern Ocean. J. Geophys. Res. Oceans 128, e2022JC019105 (2023).

    Article  Google Scholar 

  157. Dinniman, M. S., Klinck, J. M., Hofmann, E. E. & Smith, W. O. Jr. Effects of projected changes in wind, atmospheric temperature, and freshwater inflow on the Ross Sea. J. Clim. 31, 1619–1635 (2018).

    Article  Google Scholar 

  158. Holland, P. R., Bracegirdle, T. J., Dutrieux, P., Jenkins, A. & Steig, E. J. West Antarctic ice loss influenced by internal climate variability and anthropogenic forcing. Nat. Geosci. 12, 718–724 (2019).

    Article  CAS  Google Scholar 

  159. Bonan, D. B., Dörr, J., Wills, R. C. J., Thompson, A. F. & Årthun, M. Sources of low-frequency variability in observed Antarctic sea ice. Cryosphere 18, 2141–2159 (2024).

    Article  Google Scholar 

  160. Goosse & Zunz, H.&V. Decadal trends in the Antarctic sea ice extent ultimately controlled by ice–ocean feedback. Cryosphere 8, 453–470 (2014).

    Article  Google Scholar 

  161. Meehl, G. A., Arblaster, J. M., Bitz, C. M., Chung, C. T. Y. & Teng, H. Antarctic sea-ice expansion between 2000 and 2014 driven by tropical Pacific decadal climate variability. Nat. Geosci. 9, 590–595 (2016).

    Article  CAS  Google Scholar 

  162. Crosta, X. et al. Multi-decadal trends in Antarctic sea-ice extent driven by ENSO–SAM over the last 2,000 years. Nat. Geosci. 14, 156–160 (2021).

    Article  CAS  Google Scholar 

  163. Seroussi, H. et al. Insights into the vulnerability of Antarctic glaciers from the ISMIP6 ice sheet model ensemble and associated uncertainty. Cryosphere 17, 5197–5217 (2023).

    Article  Google Scholar 

  164. Bradley, A. T. & Hewitt, I. J. Tipping point in ice-sheet grounding-zone melting due to ocean water intrusion. Nat. Geosci. 17, 631–637 (2024).

    Article  CAS  Google Scholar 

  165. Liu, Y. et al. Reduced CO2 uptake and growing nutrient sequestration from slowing overturning circulation. Nat. Clim. Change 13, 83–90 (2023).

    Article  Google Scholar 

  166. Abram, N. J. et al. Emerging evidence of abrupt changes in the Antarctic environment. Nature 644, 621–633 (2025).

    Article  CAS  Google Scholar 

  167. Swart, N. C. et al. The Southern Ocean Freshwater Input from Antarctica (SOFIA) initiative: scientific objectives and experimental design. Geosci. Model Dev. 16, 7289–7309 (2023).

    Article  Google Scholar 

  168. Wilson, E. A. et al. Future priorities for observing the dynamics of the Southern Ocean. Bull. Am. Meteorol. Soc. 105, E2316–E2323 (2024).

    Article  Google Scholar 

  169. Bennetts, L. G. et al. Closing the loops on Southern Ocean dynamics: from the circumpolar current to ice shelves and from bottom mixing to surface waves. Rev. Geophys. 62, e2022RG000781 (2024).

    Article  Google Scholar 

  170. Sloyan, B. M. et al. The Global Ocean Ship-Based Hydrographic Investigations Program (GO-SHIP): a platform for integrated multidisciplinary ocean science. Front. Mar. Sci. https://doi.org/10.3389/fmars.2019.00445 (2019).

  171. Zilberman, N. V. et al. Observing the full ocean volume using Deep Argo floats. Front. Mar. Sci. https://doi.org/10.3389/fmars.2023.1287867 (2023).

  172. Foppert, A. et al. Deep Argo reveals bottom water properties and pathways in the Australian-Antarctic Basin. J. Geophys. Res. Oceans 126, e2021JC017935 (2021).

    Article  Google Scholar 

  173. Thomas, G., Purkey, S. G., Roemmich, D., Foppert, A. & Rintoul, S. R. Spatial variability of Antarctic Bottom Water in the Australian Antarctic Basin from 2018-2020 captured by Deep Argo. Geophys. Res. Lett. https://doi.org/10.1029/2020GL089467 (2020).

  174. Kobayashi, T. Rapid volume reduction in Antarctic Bottom Water off the Adélie/George V Land coast observed by deep floats. Deep Sea Res. I 140, 95–117 (2018).

    Article  Google Scholar 

  175. Silvano, A. et al. Observing Antarctic Bottom Water. Front. Mar. Sci. https://doi.org/10.3389/fmars.2023.1221701 (2023).

  176. Auger, M., Spence, P., Morrison, A. K., Naveira Garabato, A. C. & Silvano, A. The variability of Antarctic dense water overflows can be observed from space. Commun. Earth Environ. 6, 286 (2025).

    Article  Google Scholar 

  177. Stewart, A. L., Klocker, A. & Menemenlis, D. Acceleration and overturning of the Antarctic slope current by winds, eddies, and tides. J. Phys. Oceanogr. 49, 2043–2074 (2019).

    Article  Google Scholar 

  178. Han, X., Stewart, A. L., Chen, D., Liu, X. & Lian, T. Controls of topographic Rossby wave properties and downslope transport in dense overflows. J. Phys. Oceanogr. 53, 1805–1820 (2023).

    Article  Google Scholar 

  179. Dorschel, B. The International Bathymetric Chart of the Southern Ocean Version 2 (IBCSO v2). PANGAEA https://doi.org/10.1594/PANGAEA.937574 (2022).

  180. Lavin, P. D. Innovative Observational Global and Regional Ocean Water Mass, Circulation, and Mixing Analyses. PhD Dissertation, Univ. of Washington (2021).

  181. Sallée J.-B. Hydrological and current data for the southern Weddell Sea, collected as part of the WAPITI oceanographic survey (JR16004). SEANOE https://doi.org/10.17882/54012 (2018).

  182. Voet, G. et al. Pathways, volume transport, and mixing of abyssal water in the Samoan Passage. J. Phys. Oceanogr. 45, 562–588 (2015).

    Article  Google Scholar 

  183. Roemmich, D., Hautala, S. & Rudnick, D. Northward abyssal transport through the Samoan Passage and adjacent regions. J. Geophys. Res. 101, 14039–14055 (1996).

    Article  Google Scholar 

  184. Holzer, M., DeVries, T. & de Lavergne, C. Diffusion controls the ventilation of a Pacific shadow zone above abyssal overturning. Nat. Commun. 12, 4348 (2021).

    Article  CAS  Google Scholar 

  185. Haine, T. W. N., Watson, A. J., Liddicoat, M. I. & Dickson, R. R. The flow of Antarctic Bottom Water to the Southwest Indian Ocean estimated using CFCs. J. Geophys. Res. 103, 27637–27653 (1998).

    Article  CAS  Google Scholar 

  186. de Lavergne, C., Groeskamp, S., Zika, J. & Johnson, H. L. in Ocean Mixing: Drivers, Mechanisms and Impacts (eds Meredith, M. & Naveira Garabato, A.) Ch. 3, 35–63 (Elsevier, 2022).

  187. Aoki, S. et al. Freshening of Antarctic Bottom Water off Cape Darnley, East Antarctica. J. Geophys. Res. Oceans 125, e2020JC016374 (2020).

    Article  Google Scholar 

  188. Slater, T. et al. Dataset for “Review article: Earth’s ice imbalance”. Zenodo https://doi.org/10.5281/ZENODO.7612514 (2023).

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Acknowledgements

G.C.J. was supported by NOAA Global Ocean Monitoring and Observation Program and NOAA Research (PMEL Contribution Number 5771). A.L.S. was supported by the National Aeronautics and Space Administration ROSES Physical Oceanography programme under grant number 80NSSC23K0357. S.R.R. and A.F. were supported by the Australian Antarctic Program Partnership (AAPP), through grant funding from the Australian Government as part of the Antarctic Science Collaboration Initiative programme. A.S. acknowledges funding from NERC (NE/V014285/1). A.K.M. and M.H.E. were supported by Australian Research Council (ARC) Discovery projects DP190100494 and DP250100759, and by the ARC Special Research Initiative, Australian Centre for Excellence in Antarctic Science (SR200100008). S.N. was supported by Grants-in-Aids for Scientific Research (24K15266 and 25H00002) of the Ministry of Education, Culture, Sports, Science and Technology in Japan. The authors also acknowledge support from the National Computational Infrastructure (NCI Australia) and Australian Community Climate and Earth System Simulator National Research Infrastructure (ACCESS-NRI), both funded by the Australian Government’s National Collaborative Research Infrastructure Strategy. The authors thank L. Bell for drafting the figures. The authors acknowledge the use of the CSIRO Marine National Facility in undertaking this research.

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Authors and Affiliations

  1. Commonwealth Scientific and Industrial Research Organisation (CSIRO) Environment, Hobart, Tasmania, Australia

    Stephen R. Rintoul

  2. Australian Antarctic Program Partnership, University of Tasmania, Hobart, Tasmania, Australia

    Stephen R. Rintoul & Annie Foppert

  3. Department of Atmospheric and Oceanic Sciences, University of California, Los Angeles, CA, USA

    Andrew L. Stewart

  4. NOAA Pacific Marine Environmental Laboratory, Seattle, WA, USA

    Gregory C. Johnson

  5. School of Oceanography, University of Washington, Seattle, WA, USA

    Gregory C. Johnson

  6. British Antarctic Survey, Cambridge, UK

    Shenjie Zhou

  7. Department of Earth, Ocean and Atmospheric Science, Florida State University, Tallahassee, FL, USA

    Qian Li

  8. Research School of Earth Sciences, Australian National University, Canberra, Australian Capital Territory, Australia

    Adele K. Morrison

  9. Australian Centre for Excellence in Antarctic Science, Australian National University, Canberra, Australian Capital Territory, Australia

    Adele K. Morrison

  10. School of Ocean and Earth Science, University of Southampton, Southampton, UK

    Alessandro Silvano & Kathryn L. Gunn

  11. University of New South Wales, Sydney, New South Wales, Australia

    Matthew H. England

  12. The Department of Engineering for Innovation, National Institute of Technology (KOSEN), Tomakomai College, Tomakomai, Japan

    Sohey Nihashi

  13. Institute of Low Temperature Science, Hokkaido University, Sapporo, Japan

    Shigeru Aoki

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Contributions

S.R.R., G.C.J., S.Z., Q.L., A.K.M, A.S. and S.N. researched data for the article. S.R.R., A.L.S, G.C.J., S.Z., A.F., Q.L., A.K.M., A.S., K.L.G., M.H.E. and S.A. contributed substantially to the discussion of the content. S.R.R., A.L.S, G.C.J., S.Z., A.F., Q.L., A.K.M. and S.N. wrote the article. All authors reviewed and/or edited the manuscript before submission.

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Glossary

Baroclinic instabilities

Dynamical instabilities involving release of potential energy of the mean flow to form time-varying eddies in the ocean or weather systems in the atmosphere.

Diapycnal

A process that moves water across density surfaces.

El Niño

A climate pattern involving interactions between the ocean and atmosphere in the tropical Pacific that oscillates irregularly over 2–7-year cycles, with extensive impacts on temperature and rainfall over much of the globe.

Isopycnals

Surfaces of constant seawater density.

Overturning circulation

An ocean circulation feature involving flow in different directions at different depths, joining to form a loop, such as equatorward flow of Antarctic Bottom Water balanced by poleward flow of lighter water at shallower depths.

Polynya

An area of open water surrounded by sea ice, usually formed by strong winds blowing sea ice offshore.

Potential vorticity

A measure of the rotation of a fluid, equal to the dot product of the vorticity (swirling motion) and the stratification (change in density with depth); the potential vorticity of a column of fluid in the ocean or atmosphere is analogous to angular momentum and is approximately conserved following the flow.

Sills

Low points in ocean ridges through which ocean currents can pass from one basin to another.

Southern Annular Mode

An index tracking north–south movements of the strong westerly winds at mid-latitude to high-latitude of the southern hemisphere.

Ventilate

Transport of surface waters and their physical and chemical properties (such as heat, oxygen and carbon dioxide) into the interior of the ocean.

Water mass

A volume of ocean with similar physical or chemical characteristics, such as Antarctic Bottom Water.

Winter Water

A volume of cold water formed at the sea surface by winter heat loss to the atmosphere.

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Rintoul, S.R., Stewart, A.L., Johnson, G.C. et al. Antarctic Bottom Water in a changing climate. Nat Rev Earth Environ 7, 86–102 (2026). https://doi.org/10.1038/s43017-025-00750-2

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