West Antarctic Ice Sheet retreat in the Amundsen Sea driven by decadal oceanic variability

Abstract

Mass loss from the Amundsen Sea sector of the West Antarctic Ice Sheet has increased in recent decades, suggestive of sustained ocean forcing or an ongoing, possibly unstable, response to a past climate anomaly. Lengthening satellite records appear to be incompatible with either process, however, revealing both periodic hiatuses in acceleration and intermittent episodes of thinning. Here we use ocean temperature, salinity, dissolved-oxygen and current measurements taken from 2000 to 2016 near the Dotson Ice Shelf to determine temporal changes in net basal melting. A decadal cycle dominates the ocean record, with melt changing by a factor of about four between cool and warm extremes via a nonlinear relationship with ocean temperature. A warm phase that peaked around 2009 coincided with ice-shelf thinning and retreat of the grounding line, which re-advanced during a post-2011 cool phase. These observations demonstrate how discontinuous ice retreat is linked with ocean variability, and that the strength and timing of decadal extremes is more influential than changes in the longer-term mean state. The nonlinear response of melting to temperature change heightens the sensitivity of Amundsen Sea ice shelves to such variability, possibly explaining the vulnerability of the ice sheet in that sector, where subsurface ocean temperatures are relatively high.

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Fig. 1: Locations of Amundsen Sea observations used in this study.
Fig. 2: Potential temperature and salinity at Dotson Ice Front.
Fig. 3: Cross-sections of potential temperature, meltwater fraction and current speed perpendicular to the ice front in different years.
Fig. 4: Meltwater flux and mean ocean temperature at Dotson Ice Front.
Fig. 5: Multi-decadal history of ocean forcing and outlet glacier response in the eastern Amundsen Sea.

References

  1. 1.

    Shepherd, A. et al. A reconciled estimate of ice-sheet mass balance. Science 338, 1183–1189 (2012).

    Google Scholar 

  2. 2.

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

    Google Scholar 

  3. 3.

    Schoof, C. Ice sheet grounding line dynamics: steady states, stability, and hysteresis. J. Geophys. Res. 112, F03S28 (2007).

    Google Scholar 

  4. 4.

    Goldberg, D., Holland, D. M. & Schoof, C. Grounding line movement and ice shelf buttressing in marine ice sheets. J. Geophys. Res. 114, F04026 (2009).

    Google Scholar 

  5. 5.

    Gudmundsson, G. H. Ice-shelf buttressing and the stability of marine ice sheets. Cryosphere 7, 47–655 (2013).

    Google Scholar 

  6. 6.

    Reese, R., Gudmundsson, G. H., Levermann, A. & Winkelmann, R. The far reach of ice-shelf thinning in Antarctica. Nat. Clim. Change 8, 53–57 (2018).

    Google Scholar 

  7. 7.

    Mouginot, J., Rignot, E. & Scheuchl, B. Sustained increase in ice discharge from the Amundsen Sea Embayment, West Antarctica, from 1973 to 2013. Geophys. Res. Lett. 41, 1576–1584 (2014).

    Google Scholar 

  8. 8.

    Scheuchl, B., Mouginot, J., Rignot, E., Morlighem, M. & Khazendar, A. Grounding line retreat of Pope, Smith, and Kohler Glaciers, West Antarctica, measured with Sentinel-1a radar interferometry data. Geophys. Res. Lett. 43, 8572–8579 (2016).

    Google Scholar 

  9. 9.

    Konrad, H. et al. Uneven onset and pace of ice-dynamical imbalance in the Amundsen Sea Embayment, West Antarctica. Geophys. Res. Lett. 44, 910–918 (2017).

    Google Scholar 

  10. 10.

    Thomas, R. H., Sanderson, T. J. O. & Rose, K. E. Effect of climatic warming on the West Antarctic ice sheet. Nature 277, 355–358 (1979).

    Google Scholar 

  11. 11.

    Jacobs, S. S., Hellmer, H. H. & Jenkins, A. Antarctic ice sheet melting in the southeast Pacific. Geophys. Res. Lett. 23, 957–960 (1996).

    Google Scholar 

  12. 12.

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

    Google Scholar 

  13. 13.

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

    Google Scholar 

  14. 14.

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

    Google Scholar 

  15. 15.

    Smith, J. A. et al. Sub-ice shelf sediments record 20th century retreat history of Pine Island Glacier. Nature 541, 77–80 (2017).

    Google Scholar 

  16. 16.

    Hillenbrand, C.-D. et al. West Antarctic Ice Sheet retreat driven by Holocene warm water incursions. Nature 547, 43–48 (2017).

    Google Scholar 

  17. 17.

    Schmidtko, S., Heywood, K. J., Thompson, A. F. & Aoki, S. Multidecadal warming of Antarctic waters. Science 346, 1227–1231 (2014).

    Google Scholar 

  18. 18.

    Jacobs, S. S., Jenkins, A., Giulivi, C. F. & Dutrieux, P. Stronger ocean circulation and increased melting under Pine Island Glacier ice shelf. Nat. Geosci. 4, 519–523 (2011).

    Google Scholar 

  19. 19.

    Dutrieux, P. et al. Strong sensitivity of Pine Island ice-shelf melting to climatic variability. Science 343, 174–178 (2014).

    Google Scholar 

  20. 20.

    Webber, B. G. M. et al. Mechanisms driving variability in the ocean forcing of Pine Island Glacier. Nat. Commun. 7, 14507 (2017).

    Google Scholar 

  21. 21.

    Christianson, K. et al. Sensitivity of Pine Island Glacier to observed ocean forcing. Geophys. Res. Lett. 43, 10817–10825 (2016).

    Google Scholar 

  22. 22.

    Jenkins, A. et al. Decadal ocean forcing and Antarctic Ice Sheet response: lessons from the Amundsen Sea. Oceanography 29, 106–117 (2016).

    Google Scholar 

  23. 23.

    Jacobs, S. et al. Getz Ice Shelf melting response to changes in ocean forcing. J. Geophys. Res. Oceans 118, 4152–4168 (2013).

    Google Scholar 

  24. 24.

    Jacobs, S. et al. The Amundsen Sea and the Antarctic Ice Sheet. Oceanography 25, 154–163 (2012).

    Google Scholar 

  25. 25.

    Wåhlin, A. K., Yuan, X., Björk, G. & Nohr, C. Inflow of warm Circumpolar Deep Water in the central Amundsen shelf. J. Phys. Oceanogr. 40, 1427–1434 (2010).

    Google Scholar 

  26. 26.

    Ha, H. K. et al. Circulation and Modification of Warm Deep Water on the central Amundsen shelf. J. Phys. Oceanogr. 44, 1493–1501 (2014).

    Google Scholar 

  27. 27.

    Rignot, E., Jacobs, S., Mouginot, J. & Scheuchl, B. Ice-shelf melting around Antarctica. Science 341, 266–270 (2013).

    Google Scholar 

  28. 28.

    Gourmelen, N. et al. Channelized melting drives thinning under a rapidly melting Antarctic ice shelf. Geophys. Res. Lett. 44, 9796–9804 (2017).

    Google Scholar 

  29. 29.

    Paolo, F. S. et al. Response of Pacific-sector Antarctic ice shelves to the El Niño/Southern Oscillation. Nat. Geosci. 11, 121–126 (2018).

    Google Scholar 

  30. 30.

    Lilien, D. A., Joughin, I., Smith, B. & Shean, D. E. Changes in flow of Crosson and Dotson ice shelves, West Antarctica, in response to elevated melt. Cryosphere 12, 1415–1431 (2018).

    Google Scholar 

  31. 31.

    Khazendar, A. et al. Rapid submarine ice melting in the grounding zones of ice shelves in West Antarctica. Nat. Commun. 7, 13243 (2016).

    Google Scholar 

  32. 32.

    Payne, A. J., Vieli, A., Shepherd, A. P., Wingham, D. J. & Rignot, E. Recent dramatic thinning of largest West Antarctic ice stream triggered by oceans. Geophys. Res. Lett. 31, L23401 (2004).

    Google Scholar 

  33. 33.

    Scott, J. B. T. et al. Increased rate of acceleration on Pine Island Glacier strongly coupled to changes in gravitational driving stress. Cryosphere 3, 125–131 (2009).

    Google Scholar 

  34. 34.

    Holland, P. R., Jenkins, A. & Holland, D. M. The response of ice shelf basal melting to variations in ocean temperature. J. Climate 21, 2558–2572 (2008).

    Google Scholar 

  35. 35.

    Kimura, S. et al. Oceanographic controls on the variability of ice-shelf basal melting and circulation of glacial meltwater in the Amundsen Sea Embayment, Antarctica. J. Geophys. Res. Oceans 122, 10131–10155 (2017).

    Google Scholar 

  36. 36.

    Turner, J. et al. Atmosphere-ocean-ice interactions in the Amundsen Sea Embayment, West Antarctica. Rev. Geophys. 55, 235–276 (2017).

    Google Scholar 

  37. 37.

    Thoma, M., Jenkins, A., Holland, D. & Jacobs, S. Modelling Circumpolar Deep Water intrusions on the Amundsen Sea continental shelf, Antarctica. Geophys. Res. Lett. 35, L18602 (2008).

    Google Scholar 

  38. 38.

    St-Laurent, P., Klinck, J. M. & Dinniman, M. S. Impact of local winter cooling on the melt of Pine Island Glacier, Antarctica. J. Geophys. Res. Oceans 120, 6718–6732 (2015).

    Google Scholar 

  39. 39.

    Kim, C. S. et al. Is Ekman pumping responsible for the seasonal variation of warm circumpolar deep water in the Amundsen Sea? Cont. Shelf Res. 132, 38–48 (2017).

    Google Scholar 

  40. 40.

    Steig, E. J., Ding, Q., Battisti, D. S. & Jenkins, A. Tropical forcing of Circumpolar Deep Water inflow and outlet glacier thinning in the Amundsen Sea Embayment, West Antarctica. Ann. Glaciol. 53, 19–28 (2012).

    Google Scholar 

  41. 41.

    The IMBIE Team. Mass balance of the Antarctic Ice Sheet from 1992 to 2017. Nature 558, 219–222 (2018).

    Google Scholar 

  42. 42.

    Jenkins, A. The impact of melting ice on ocean waters. J. Phys. Oceanogr. 29, 2370–2381 (1999).

    Google Scholar 

  43. 43.

    Millan, R., Rignot, E., Bernier, V., Morlighem, M. & Dutrieux, P. Bathymetry of the Amundsen Sea Embayment sector of West Antarctica from Operation IceBridge gravity and other data. Geophys. Res. Lett. 44, 1360–1368 (2017).

    Google Scholar 

  44. 44.

    Jenkins, A. et al. Observations beneath Pine Island Glacier in West Antarctica and implications for its retreat. Nat. Geosci. 3, 468–472 (2010).

    Google Scholar 

  45. 45.

    Biddle, L. C., Heywood, K. J., Kaiser, J. & Jenkins, A. Glacial meltwater identification in the Amundsen Sea. J. Phys. Oceanogr. 47, 933–954 (2017).

    Google Scholar 

  46. 46.

    Nakayama, Y., Schröder, M. & Hellmer, H. H. From Circumpolar Deep Water to the glacial meltwater plume on the eastern Amundsen Shelf. Deep-Sea Res. I 77, 50–62 (2013).

    Google Scholar 

  47. 47.

    Jenkins, A. & Jacobs, S. S. Circulation and melting beneath George VI Ice Shelf, Antarctica. J. Geophys. Res. 113, C04013 (2008).

    Google Scholar 

  48. 48.

    Wunsch, C. The North Atlantic general circulation west of 50°W determined by inverse methods. Rev. Geophys. Space Phys. 16, 583–620 (1978).

    Google Scholar 

  49. 49.

    Jenkins, A. Convection-driven melting near the grounding lines of ice shelves and tidewater glaciers. J. Phys. Oceanogr. 41, 2279–2294 (2011).

    Google Scholar 

  50. 50.

    Jenkins, A. A simple model of the ice shelf–ocean boundary layer and current. J. Phys. Oceanogr. 46, 1785–1803 (2016).

    Google Scholar 

  51. 51.

    Little, C. M., Gnanadesikan, A. & Oppenheimer, M. How ice shelf morphology controls basal melting. J. Geophys. Res. 114, C12007 (2009).

    Google Scholar 

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Acknowledgements

We are grateful to all cruise participants who assisted in the collection of the data. A.J. and D.S. were supported by core funding from the UK Natural Environment Research Council (NERC) to the British Antarctic Survey’s Polar Oceans Program. P.D. was supported by funding from NERC’s iSTAR Programme through grant NE/J005770/11 and NSF grant 1643285. S.J.’s support included NSF grants ANT06-32282 and 16-44159. Support for S.H.L. and T.W.K. was provided by the Korea Polar Research Institute grant KOPRI PE17060. S.S. was supported by National Science Foundation Office of Polar Programs collaborative grants 0838975 and 1443569.

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A.J., D.S., P.D. and S.J. conceived the study. D.S., S.J., T.W.K., S.H.L., H.K.H. and S.S. planned and led the data collection. D.S., P.D. and T.W.K. processed the data. A.J., D.S. and P.D. undertook the data analyses and derivation of the final results. A.J. prepared the manuscript. All authors discussed the results and implications and commented on the manuscript at all stages.

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Correspondence to Adrian Jenkins.

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Jenkins, A., Shoosmith, D., Dutrieux, P. et al. West Antarctic Ice Sheet retreat in the Amundsen Sea driven by decadal oceanic variability. Nature Geosci 11, 733–738 (2018). https://doi.org/10.1038/s41561-018-0207-4

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