Letter

The multi-millennial Antarctic commitment to future sea-level rise

Received:
Accepted:
Published online:

Abstract

Atmospheric warming is projected to increase global mean surface temperatures by 0.3 to 4.8 degrees Celsius above pre-industrial values by the end of this century1. If anthropogenic emissions continue unchecked, the warming increase may reach 8–10 degrees Celsius by 2300 (ref. 2). The contribution that large ice sheets will make to sea-level rise under such warming scenarios is difficult to quantify because the equilibrium-response timescale of ice sheets is longer than those of the atmosphere or ocean. Here we use a coupled ice-sheet/ice-shelf model to show that if atmospheric warming exceeds 1.5 to 2 degrees Celsius above present, collapse of the major Antarctic ice shelves triggers a centennial- to millennial-scale response of the Antarctic ice sheet in which enhanced viscous flow produces a long-term commitment (an unstoppable contribution) to sea-level rise. Our simulations represent the response of the present-day Antarctic ice-sheet system to the oceanic and climatic changes of four representative concentration pathways (RCPs) from the Fifth Assessment Report of the Intergovernmental Panel on Climate Change3. We find that substantial Antarctic ice loss can be prevented only by limiting greenhouse gas emissions to RCP 2.6 levels. Higher-emissions scenarios lead to ice loss from Antarctic that will raise sea level by 0.6–3 metres by the year 2300. Our results imply that greenhouse gas emissions in the next few decades will strongly influence the long-term contribution of the Antarctic ice sheet to global sea level.

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References

  1. 1.

    et al. The RCP greenhouse gas concentrations and their extensions from 1765 to 2300. Clim. Change 109, 213–241 (2011)

  2. 2.

    , & Global warming under old and new scenarios using IPCC climate sensitivity range estimates. Nature Clim. Change 2, 248–253 (2012)

  3. 3.

    et al. in Climate Change 2013: The Physical Science Basis. Contribution of Working Group I to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change (eds et al.) 1029–1136 (Cambridge Univ. Press, 2013)

  4. 4.

    et al. Antarctic ice-sheet loss driven by basal melting of ice shelves. Nature 484, 502–505 (2012)

  5. 5.

    et al. Dynamic thinning of glaciers on the Southern Antarctic Peninsula. Science 348, 899–903 (2015)

  6. 6.

    & Stability of the West Antarctic ice sheet in a warming world. Nature Geosci. 4, 506–513 (2011)

  7. 7.

    , , & Glacier acceleration and thinning after ice shelf collapse in the Larsen B embayment, Antarctica. Geophys. Res. Lett. 31, L18402 (2004)

  8. 8.

    & Recent atmospheric warming and retreat of ice shelves on the Antarctic Peninsula. Nature 379, 328–331 (1996)

  9. 9.

    et al. Ocean-driven thinning enhances iceberg calving and retreat of Antarctic ice shelves. Proc. Natl Acad. Sci. USA 112, 3263–3268 (2015)

  10. 10.

    , & Volume loss from Antarctic ice shelves is accelerating. Science 348, 327–331 (2015)

  11. 11.

    et al. Unabated planetary warming and its ocean structure since 2006. Nature Clim. Change 5, 240–245 (2015)

  12. 12.

    , , & Multidecadal warming of Antarctic waters. Science 346, 1227–1231 (2014)

  13. 13.

    et al. Warming of the Antarctic ice-sheet surface since the 1957 International Geophysical Year. Nature 457, 459–462 (2009)

  14. 14.

    & Accelerated West Antarctic ice mass loss continues to outpace East Antarctic gains. Earth Planet. Sci. Lett. 415, 134–141 (2015)

  15. 15.

    , , & Probabilistic reanalysis of twentieth-century sea-level rise. Nature 517, 481–484 (2015)

  16. 16.

    , & Marine ice sheet collapse potentially under way for the Thwaites Glacier basin, West Antarctica. Science 344, 735–738 (2014)

  17. 17.

    , , , & Widespread, rapid grounding line retreat of Pine Island, Thwaites, Smith, and Kohler glaciers, West Antarctica, from 1992 to 2011. Geophys. Res. Lett. 41, 3502–3509 (2014)

  18. 18.

    et al. Ice-sheet model sensitivities to environmental forcing and their use in projecting future sea-level (The SeaRISE Project). J. Glaciol. 59, 195–224 (2013)

  19. 19.

    et al. Projecting Antarctic ice discharge using response functions from SeaRISE ice-sheet models. Earth Syst. Dyn. 5, 271–293 (2014)

  20. 20.

    et al. The multimillennial sea-level commitment of global warming. Proc. Natl Acad. Sci. USA 110, 13745–13750 (2013)

  21. 21.

    et al. Obliquity-paced Pliocene West Antarctic ice sheet oscillations. Nature 458, 322–328 (2009)

  22. 22.

    & Modelling West Antarctic ice sheet growth and collapse through the past five million years. Nature 458, 329–332 (2009)

  23. 23.

    , , & Long-term sea-level rise implied by 1.5 °C and 2 °C warming levels. Nature Clim. Change 2, 867–870 (2012)

  24. 24.

    & Shallow shelf approximation as a “sliding law” in a thermomechanically coupled ice sheet model. J. Geophys. Res. 114, F03008 (2009)

  25. 25.

    et al. The Potsdam Parallel Ice Sheet Model (PISM-PIK)—Part 1: Model description. Cryosphere 5, 715–726 (2010)

  26. 26.

    & Interaction of marine ice-sheet instabilities in two drainage basins: simple scaling of geometry and transition time. Cryosphere 9, 631–645 (2015)

  27. 27.

    , , , & Resolution-dependent performance of grounding line motion in a shallow model compared to a full-Stokes model according to the MISMIP3d intercomparison. J. Glaciol. 60, 353–360 (2014)

  28. 28.

    , & Strain heating and creep instability in glaciers and ice sheets. Rev. Geophys. 15, 235–247 (1977)

  29. 29.

    , , & Increased future ice discharge from Antarctica owing to higher snowfall. Nature 492, 239–242 (2012)

  30. 30.

    et al. Greenhouse-gas emission targets for limiting global warming to 2 °C. Nature 458, 1158–1162 (2009)

  31. 31.

    et al. Retreat of Pine Island Glacier controlled by marine ice-sheet instability. Nature Clim. Change 4, 117–121 (2014)

  32. 32.

    et al. Century-scale simulations of the response of the West Antarctic Ice Sheet to a warming climate. Cryosphere 9, 1579–1600 (2015)

  33. 33.

    A variational approach to ice stream flow. J. Fluid Mech. 556, 227–251 (2006)

  34. 34.

    , & Parameterization of basal friction near grounding lines in a one-dimensional ice sheet model. Cryosphere 8, 1239–1259 (2014)

  35. 35.

    , & Marine ice-sheet profiles and stability under Coulomb basal conditions. J. Glaciol. 61, 205–215 (2015)

  36. 36.

    & Modeling thermodynamic ice-ocean interactions at the base of an ice shelf. J. Phys. Oceanogr. 29, 1787–1800 (1999)

  37. 37.

    & Fracture field for large-scale ice dynamics. J. Glaciol. 58, 165–176 (2012)

  38. 38.

    et al. Kinematic first-order calving law implies potential for abrupt ice-shelf retreat. Cryosphere 6, 273–286 (2012)

  39. 39.

    , & Fast computation of a viscoelastic deformable Earth model for ice-sheet simulations. Ann. Glaciol. 46, 97–105 (2007)

  40. 40.

    , , , & Evolution of a coupled marine ice sheet–sea level model. J. Geophys. Res. 117, F01013 (2012)

  41. 41.

    , , , & A new, high-resolution surface mass balance map of Antarctica (1979–2010) based on regional atmospheric climate modeling. Geophys. Res. Lett. 39, L04501 (2012)

  42. 42.

    Variability and trends in Antarctic surface temperatures from in situ and satellite infra-red measurements. J. Clim. 13, 1674–1696 (2000)

  43. 43.

    , & An improved Antarctic dataset for high resolution numerical ice sheet models (ALBMAP v1). Earth Syst. Sci. Data 2, 247–260 (2010)

  44. 44.

    & Greenland and Antarctic mass balances for present and doubled atmospheric CO2 from the genesis version-2 global climate model. J. Clim. 10, 871–900 (1997)

  45. 45.

    et al. Regional climate modeling for the developing world: the ICTP RegCM3 and RegCNET. Bull. Am. Meteorol. Soc. 88, 1395–1409 (2007)

  46. 46.

    , & Comparing ice discharge through West Antarctic Gateways: Weddell vs. Amundsen Sea warming. Cryosphere Discuss. 9, 1705–1733 (2015)

  47. 47.

    et al. Long-term climate change commitment and reversibility: an EMIC intercomparison. J. Clim. 26, 5782–5809 (2013)

  48. 48.

    et al. Consistent evidence of increasing Antarctic accumulation with warming. Nature Clim. Change 5, 348–352 (2015)

  49. 49.

    , , & Dynamics of the Last Glacial Maximum Antarctic ice-sheet and its response to ocean forcing. Proc. Natl Acad. Sci. USA 109, 16052–16056 (2012)

  50. 50.

    et al. Antarctic contribution to meltwater pulse 1A from reduced Southern Ocean overturning. Nature Commun. 5, 1–10 (2014)

  51. 51.

    & A simple inverse method for the distribution of basal sliding coefficients under ice sheets, applied to Antarctica. Cryosphere 6, 953–971 (2012)

  52. 52.

    et al. Bedmap2: improved ice bed, surface and thickness datasets for Antarctica. Cryosphere 7, 375–393 (2013)

  53. 53.

    , , , & Full Stokes modeling of marine ice sheets: influence of the grid size. Ann. Glaciol. 50, 109–114 (2009)

  54. 54.

    et al. Grounding-line migration in plan-view marine ice-sheet models: results of the ice2sea MISMIP3d intercomparison. J. Glaciol. 59, 410–422 (2013)

  55. 55.

    et al. Pine Island glacier ice shelf melt distributed at kilometre scales. Cryosphere 7, 1543–1555 (2013)

  56. 56.

    & Palaeoclimate: looking back to the future. Nature Clim. Change 2, 317–318 (2012)

  57. 57.

    & Polar amplification in a coupled climate model with locked albedo. Clim. Dyn. 33, 629–643 (2009)

  58. 58.

    et al. in Climate Change 2013: The Physical Science Basis. Contribution of Working Group I to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change (eds . et al.) 383–464 (2013)

  59. 59.

    , & Ice flow of the Antarctic Ice Sheet. Science 333, 1427–1430 (2011)

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Acknowledgements

We thank the CMIP community for making their data openly available, and J. Lenaerts for providing present-day surface mass balance data. We are also grateful to K. Buckley (Victoria University high-performance computing cluster), C. Khroulev, T. Albrecht and the Parallel Ice Sheet Model groups at the University of Alaska, Fairbanks, and the Potsdam Institute for Climate Impact Research. This work was funded by contract VUW1203 of the Royal Society of New Zealand’s Marsden Fund, with support from the Antarctic Research Centre, Victoria University of Wellington, ANDRILL, GNS Science (NZ Ministry of Business Innovation and Employment contract C05X1001), National Science Foundation grant ANT-1043712, and the Australian Research Council (ARC). J. Renwick and D. Zwartz provided comments that improved the manuscript.

Author information

Affiliations

  1. Antarctic Research Centre, Victoria University of Wellington, Wellington 6140, New Zealand

    • N. R. Golledge
    •  & T. R. Naish
  2. GNS Science, Avalon, Lower Hutt 5011, New Zealand

    • N. R. Golledge
    • , T. R. Naish
    •  & R. H. Levy
  3. Department of Earth, Environment, and Physics, Worcester State University, Worcester, Massachusetts 01602, USA

    • D. E. Kowalewski
  4. Climate Change Research Centre, University of New South Wales, Sydney, New South Wales 2052, Australia

    • C. J. Fogwill
  5. Climate System Research Center, University of Massachusetts Amherst, Amherst, Massachusetts 01003, USA

    • E. G. W. Gasson

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Contributions

N.R.G. devised and carried out the ice-sheet modelling experiments and D.E.K. undertook climate model simulations to produce the present-day ocean temperature field. All authors contributed to the development of ideas and writing of the manuscript.

Competing interests

The authors declare no competing financial interests.

Corresponding author

Correspondence to N. R. Golledge.

Extended data

Supplementary information

Videos

  1. 1.

    Modelled ice sheet evolution under Antarctic-specific RCP 8.5 warming scenario

    Main graphic shows ice extent for 'low' simulations; blue lines show grounding-line locations for 'high' simulations. Pale blue shading shows grounded ice lost in 'high' simulations but present in the 'low' scenario. Grey shading denotes ice shelves. Note the increasing divergence between 'high' and 'low' beyond 2300 CE. Bold values and those in italics denote magnitudes and rates of sea-level contributions respectively. Leading values and those in parentheses relate to 'low' and 'high' scenarios respectively. WAIS: West Antarctic Ice Sheet; EAIS: East Antarctic Ice Sheet.

  2. 2.

    Modelled ice sheet evolution under Antarctic-specific RCP 8.5 warming scenario

    Main graphic shows ice extent for 'high' simulations. Warmer colours indicate areas of relatively faster-flowing ice. WAIS: West Antarctic Ice Sheet; EAIS: East Antarctic Ice Sheet. Graph shows the Antarctic contribution to global sea-level.

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