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Observations beneath Pine Island Glacier in West Antarctica and implications for its retreat

Abstract

Thinning ice in West Antarctica, resulting from acceleration in the flow of outlet glaciers, is at present contributing about 10% of the observed rise in global sea level1. Pine Island Glacier in particular has shown nearly continuous acceleration2,3 and thinning4,5, throughout the short observational record. The floating ice shelf that forms where the glacier reaches the coast has been thinning rapidly6, driven by changes in ocean heat transport beneath it. As a result, the line that separates grounded and floating ice has retreated inland7. These events have been postulated as the cause for the inland thinning and acceleration8,9. Here we report evidence gathered by an autonomous underwater vehicle operating beneath the ice shelf that Pine Island Glacier was recently grounded on a transverse ridge in the sea floor. Warm sea water now flows through a widening gap above the submarine ridge, rapidly melting the thick ice of the newly formed upstream half of the ice shelf. The present evolution of Pine Island Glacier is thus part of a longer-term trend that has moved the downstream limit of grounded ice inland by 30 km, into water that is 300 m deeper than over the ridge crest. The pace and ultimate extent of such potentially unstable retreat10 are central to the debate over the possibility of widespread ice-sheet collapse triggered by climate change11,12.

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Figure 1: Map and satellite imagery of the study area.
Figure 2: Configuration of the ocean cavity beneath the PIG ice shelf.
Figure 3: Multi-beam echosounder imagery of the seabed ridge beneath the PIG ice shelf.
Figure 4: Seawater properties observed in the ocean cavity beneath the PIG ice shelf.

References

  1. 1

    Rignot, E. et al. Recent Antarctic ice mass loss from radar interferometry and regional climate modelling. Nature Geosci. 1, 106–110 (2008).

    Article  Google Scholar 

  2. 2

    Joughin, I., Rignot, E., Rosanova, C. E., Lucchitta, B. K. & Bohlander, J. Timing of recent accelerations of Pine Island Glacier, Antarctica. Geophys. Res. Lett. 30, 1706 (2003).

    Google Scholar 

  3. 3

    Rignot, E. Changes in West Antarctic ice stream dynamics observed with ALOS PALSAR data. Geophys. Res. Lett. 35, L12505 (2008).

    Google Scholar 

  4. 4

    Shepherd, A., Wingham, D. J., Mansley, J. A. D. & Corr, H. F. J. Inland thinning of Pine Island Glacier, West Antarctica. Science 291, 862–864 (2001).

    Article  Google Scholar 

  5. 5

    Wingham, D. J., Wallis, D. W. & Shepherd, A. Spatial and temporal evolution of Pine Island Glacier thinning, 1995–2006. Geophys. Res. Lett. 36, L17501 (2009).

    Article  Google Scholar 

  6. 6

    Shepherd, A., Wingham, D. & Rignot, E. Warm ocean is eroding West Antarctic ice sheet. Geophys. Res. Lett. 31, L23402 (2004).

    Article  Google Scholar 

  7. 7

    Rignot, E. J. Fast recession of a West Antarctic glacier. Science 281, 549–551 (1998).

    Article  Google Scholar 

  8. 8

    Thomas, R. H., Rignot, E., Kanagaratnam, P., Krabill, W. & Casassa, G. Force-perturbation analysis of Pine Island Glacier, Antarctica, suggests cause for recent acceleration. Ann. Glaciol. 39, 133–138 (2004).

    Article  Google Scholar 

  9. 9

    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).

    Article  Google Scholar 

  10. 10

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

    Article  Google Scholar 

  11. 11

    Mercer, J. H. West Antarctic ice sheet and CO2 greenhouse effect: A threat of disaster. Nature 271, 321–325 (1978).

    Article  Google Scholar 

  12. 12

    Oppenheimer, M. Global warming and the stability of the West Antarctic ice sheet. Nature 393, 325–332 (1998).

    Article  Google Scholar 

  13. 13

    Nitsche, F. O., Jacobs, S. S., Larter, R. D. & Gohl, K. Bathymetry of the Amundsen Sea continental shelf: implications for geology, oceanography, and glaciology. Geochem. Geophys. Geosyst. 8, Q10009 (2007).

    Article  Google Scholar 

  14. 14

    Walker, D. P. et al. Oceanic heat transport onto the Amundsen Sea shelf through a submarine glacial trough. Geophys. Res. Lett. 34, L02602 (2007).

    Article  Google Scholar 

  15. 15

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

    Article  Google Scholar 

  16. 16

    Hellmer, H. H., Jacobs, S. S. & Jenkins, A. Oceanic erosion of a floating Antarctic glacier in the Amundsen Sea. Antarct. Res. Ser. 75, 83–99 (1998).

    Article  Google Scholar 

  17. 17

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

    Article  Google Scholar 

  18. 18

    Jenkins, A., Vaughan, D. G., Jacobs, S. S., Hellmer, H. H. & Keys, J. R. Glaciological and oceanographic evidence of high melt rates beneath Pine Island Glacier, West Antarctica. J. Glaciol. 43, 114–121 (1997).

    Article  Google Scholar 

  19. 19

    Dupont, T. K. & Alley, R. Assessment of the importance of ice-shelf buttressing to ice-sheet flow. Geophys. Res. Lett. 32, L04503 (2005).

    Article  Google Scholar 

  20. 20

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

    Article  Google Scholar 

  21. 21

    Lowe, A. L. & Anderson, J. B. Evidence for abundant subglacial meltwater beneath the paleo-ice sheet in Pine Island Bay, Antarctica. J. Glaciol. 49, 125–138 (2003).

    Article  Google Scholar 

  22. 22

    Swithinbank, C. et al. Coastal-change and Glaciological Map of the Eights Coast Area, Antarctica: 1972–2001 (Geol. Invest. Ser. Map I-2600-E, USGS, 2004).

    Google Scholar 

  23. 23

    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).

    Article  Google Scholar 

  24. 24

    Alley, R. B., Anandakrishnan, S., Dupont, T. K., Parizek, B. R. & Pollard, D. Effect of sedimentation on ice-sheet grounding-line stability. Science 315, 1838–1841 (2007).

    Article  Google Scholar 

  25. 25

    Shepherd, A., Wingham, D. J. & Mansley, J. A. D. Inland thinning of the Amundsen Sea sector, West Antarctica. Geophys. Res. Lett. 29, 1364 (2002).

    Article  Google Scholar 

  26. 26

    Kellogg, T. B. & Kellogg, D. E. Recent glacial history and rapid ice stream retreat in the Amundsen Sea. J.Geophys. Res. 92, 8859–8864 (1987).

    Article  Google Scholar 

  27. 27

    Pritchard, H. D., Arthern, R. J., Vaughan, D. G. & Edwards, L. A. Extensive dynamic thinning on the margins of the Greenland and Antarctic ice sheets. Nature 461, 971–975 (2009).

    Article  Google Scholar 

  28. 28

    McPhail, S. D. et al. Exploring Beneath the PIG Ice Shelf with the Autosub3 AUV. Oceans 09 (IEEE, 2009).

    Google Scholar 

  29. 29

    Holt, J. W. et al. New boundary conditions for the West Antarctic ice sheet: Subglacial topography of the Thwaites and Smith glacier catchments. Geophys. Res. Lett. 33, L09502 (2006).

    Article  Google Scholar 

  30. 30

    Vaughan, D. G. et al. New boundary conditions for the West Antarctic ice sheet: Subglacial topography beneath Pine Island Glacier. Geophys. Res. Lett. 33, L09501 (2006).

    Google Scholar 

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Acknowledgements

We thank the Captain and crew of Nathaniel B Palmer and NBP09-01 cruise participants for assistance with the AUV operations. This work was financially supported by the UK Natural Environment Research Council (NE/G001367/1) and the US National Science Foundation (ANT0632282). R. Howlett, G. Griffiths, K. Nicholls and S. Jenkins commented on the manuscript.

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A.J. and S.S.J. proposed the research. A.J., P.D. and S.D.M. planned the AUV missions. S.D.M., J.R.P., A.T.W. and D.W. prepared and programmed the AUV. P.D., S.D.M. and J.R.P. processed the data. A.J., P.D. and S.S.J. analysed the results. A.J. wrote the text. A.J. and P.D. prepared the figures. All authors read and commented on the paper.

Corresponding author

Correspondence to Adrian Jenkins.

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The authors declare no competing financial interests.

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Jenkins, A., Dutrieux, P., Jacobs, S. et al. Observations beneath Pine Island Glacier in West Antarctica and implications for its retreat. Nature Geosci 3, 468–472 (2010). https://doi.org/10.1038/ngeo890

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