, Volume 41, Issue 1, pp 23–33 | Cite as

Arctic Ice Cover, Ice Thickness and Tipping Points

  • Peter WadhamsEmail author


We summarize the latest results on the rapid changes that are occurring to Arctic sea ice thickness and extent, the reasons for them, and the methods being used to monitor the changing ice thickness. Arctic sea ice extent had been shrinking at a relatively modest rate of 3–4% per decade (annually averaged) but after 1996 this speeded up to 10% per decade and in summer 2007 there was a massive collapse of ice extent to a new record minimum of only 4.1 million km2. Thickness has been falling at a more rapid rate (43% in the 25 years from the early 1970s to late 1990s) with a specially rapid loss of mass from pressure ridges. The summer 2007 event may have arisen from an interaction between the long-term retreat and more rapid thinning rates. We review thickness monitoring techniques that show the greatest promise on different spatial and temporal scales, and for different purposes. We show results from some recent work from submarines, and speculate that the trends towards retreat and thinning will inevitably lead to an eventual loss of all ice in summer, which can be described as a ‘tipping point’ in that the former situation, of an Arctic covered with mainly multi-year ice, cannot be retrieved.


Ice cover Ice thickness Multi-year ice Ice loss 



This is a contribution to the Arctic Tipping Points project ( funded by FP7 of the European Union (contract #226248). The manuscript was improved by three anonymous reviewers.


  1. ACIA. 2005. Arctic climate impact assessment. Impacts of a warming Arctic. Cambridge: Cambridge University Press.Google Scholar
  2. Amundrud, T.L., H., Melling, R.G. Ingram, and S.E. Allen. 2006. The effect of structural porosity on the ablation of sea ice ridges. Journal of Geophysical Research 111: C06004. doi: 10.1029/2005JC002895.
  3. Atkinson, C.P., A.T. Wells, B. Shina, and V.O. Ivchenko. 2009. Rapid ocean wave teleconnections linking Antarctic salinity anomalies to the equatorial ocean-atmosphere system. Geophysical Research Letters 36: L08603. doi: 10.1029/2008GL036976.
  4. Brierley, A.S., N.W. Millard, S.D. McPhail, P. Stevenson, M. Pebody, J. Perrett, M. Squires, and G. Griffiths. 2002. Antarctic krill under sea ice: Elevated abundance in a narrow band just south of ice edge. Science 295: 1890–1892.CrossRefGoogle Scholar
  5. Comiso, J.C. 2002. A rapidly declining Arctic perennial ice cover. Geophysical Research Letters 29: 1956. doi: 10.1029/2002GL015650.CrossRefGoogle Scholar
  6. Comiso, J.C. 2003. Warming trends in the Arctic. Journal of Climate 16: 3498–3510.CrossRefGoogle Scholar
  7. Comiso, J.C., C.L. Parkinson, R. Gersten, and L. Stock. 2008. Accelerated decline in the Arctic sea ice cover. Geophysical Research Letters 35: L01703. doi: 10.1029/2007GL031972.CrossRefGoogle Scholar
  8. Comiso, J.C., P. Wadhams, W.B. Krabill, R.N. Swift, J.P. Crawford, and W.B. Tucker. 1991. Top/bottom multisensor remote sensing of Arctic sea ice. Journal of Geophysical Research 96: 2693–2709.CrossRefGoogle Scholar
  9. Francois, R.E., and W.K. Nodland 1972. Unmanned Arctic Research Submersible (UARS) system development and test report. Univ. Washington, Applied Physics Lab., Tech. Rept. APL-UW 7219.Google Scholar
  10. Giles, K.A., S.W. Laxon, and A.L. Ridout. 2008. Circumpolar thinning of Arctic sea ice following the 2007 record ice extent minimum. Geophysical Research Letters 35: L22502. doi: 10.1029/2008GL035710.CrossRefGoogle Scholar
  11. Guoliang, J., and P. Wadhams. 1989. Travel time changes in a tomography array caused by a sea ice cover. Progress in Oceanography 22: 249–275.CrossRefGoogle Scholar
  12. Haas, C., A. Pfaffling, S. Hendricks, L. Rabenstein, J.-L. Etienne, and I. Rigor. 2008. Reduced ice thickness in Arctic Transpolar Drift favors rapid ice retreat. Geophysical Research Letters 35: L17501. doi: 10.1029/2008GL034457.CrossRefGoogle Scholar
  13. Hautaniemi, H., M. Oksama, J. Multala, M. Leppäranta, K. Riska, and O. Salmela. 1994. Airborne electromagnetic mapping of ice thickness in the Baltic Sea. Proceedings IAHR Symposium, Trondheim, Norway. Google Scholar
  14. Jin, G., J.F. Lynch, R. Pawlowicz, and P. Wadhams. 1993. Effects of sea ice cover on acoustic ray travel times, with applications to the Greenland Sea Tomography Experiment. Journal of the Acoustic Society of America 94: 1044–1056.CrossRefGoogle Scholar
  15. Kerman, B., P. Wadhams, and J. Comiso. 1999. Informational equivalence between synthetic aperture radar imagery and the thickness of Arctic pack ice. Journal of Geophysical Research 104: 29721–29731.CrossRefGoogle Scholar
  16. Kwok, R. 2007. Near zero replenishment of the Arctic multiyear sea ice cover at the end of 2005 summer. Geophysical Research Letters 34: L05501. doi: 10.1029/2006GL028737.CrossRefGoogle Scholar
  17. Kwok, R., G.F. Cunningham, M. Wensnahan, I. Rigor, H.J. Zwally, and D. Yi. 2009. Thinning and volume loss of the Arctic Ocean sea ice cover: 2003–2008. Journal of Geophysical Research 114: C07005. doi: 10.1029/2009JC005312.CrossRefGoogle Scholar
  18. Kwok, R., H.J. Zwally, and D. Yi. 2004. ICES at observations of Arctic sea ice: A first look. Geophysical Research Letters 31: L16401. doi: 10.1029/2004GL020309.CrossRefGoogle Scholar
  19. Laxon, S., N. Peacock, and D. Smith. 2003. High interannual variability of sea ice thickness in the Arctic region. Nature 425: 947–949.CrossRefGoogle Scholar
  20. Martinson, D.G., and M. Steele. 2001. Future of the Arctic sea ice cover: Implications of an Antarctic analog. Geophysical Research Letters 28: 307–310.CrossRefGoogle Scholar
  21. Massom, R.A., J.C. Comiso, A.P. Worby, V.I. Lytle, and L. Stock. 1999. Regional classes of sea ice cover in the East Antarctic pack ice from satellite and in situ data during the winter time period. Remote Sensing Environment 68: 61–76.CrossRefGoogle Scholar
  22. Munk, W. 2003. Ocean freshening, sea level rising. Science 300: 2041–2043.CrossRefGoogle Scholar
  23. Parkinson, C.L., D.J. Cavalieri, P. Gloersen, H.J. Zwally, and J.C. Comiso. 1999. Arctic sea ice extents, areas, and trends, 1978–1996. Journal of Geophysical Research 104: 20837–20856.Google Scholar
  24. Perovich, D.K., J.A. Richter-Menge, K.F. Jones, and B. Light. 2008. Sunlight, water, ice: Extreme Arctic sea ice melt during the summer of 2007. Geophysical Research Letters 35: L11501. doi: 10.1029/2008GL034007.CrossRefGoogle Scholar
  25. Reimnitz, E., D. Dethleff, and D. Nürnberg. 1994. Contrasts in Arctic shelf sea-ice regimes and some implications: Beaufort Sea versus Laptev Sea. Marine Geology 119: 215–225.CrossRefGoogle Scholar
  26. Rossiter, J.R., and J.S. Holladay. 1994. Ice-thickness measurement. In Remote sensing of sea ice and icebergs, ed. S. Haykin, E.O. Lewis, R.K. Raney, and J.R. Rossiter, 141–176. New York: Wiley.Google Scholar
  27. Rothrock, D.A., Y. Yu, and G.A. Maykut. 1999. Thinning of the Arctic sea-ice cover. Geophysical Research Letters 26: 3469–3472.CrossRefGoogle Scholar
  28. Rothrock, D.A., J. Zhang, and Y. Yu. 2003. The arctic ice thickness anomaly of the 1990s: A consistent view from observations and models. Journal of Geophysical Research 108: 3083. doi: 10.1029/2001JC001208.CrossRefGoogle Scholar
  29. Sear, C.B., and P. Wadhams. 1992. Statistical properties of Arctic sea ice morphology derived from sidescan sonar images. Progress in Oceanography 29: 133–160.CrossRefGoogle Scholar
  30. Shakhova, N., I. Semiletov, A. Salyuk, V. Yusupov, D. Kosmach, and Ö. Gustafsson. 2010. Extensive methane venting to the atmosphere from sediments of the East Siberian Arctic Shelf. Science 327: 1246–1249.CrossRefGoogle Scholar
  31. Stroeve, J., M.M. Holland, W. Meier, T. Scambos, and M. Serreze. 2007. Arctic sea ice decline: Faster than forecast. Geophysical Research Letters 34: L09501. doi: 10.1029/2007GL029703.CrossRefGoogle Scholar
  32. Stroeve, J.C., M.C. Serreze, F. Fetterer, T. Arbetter, W. Meier, J. Maslanik, and K. Knowles. 2005. Tracking the Arctic’s shrinking ice cover: Another extreme September minimum in 2004. Geophysical Research Letters 32: L04501. doi: 10.1029/2004GL021810.CrossRefGoogle Scholar
  33. Tietsche, S., D. Notz, J.H. Jungclaus, and J. Marotzke. 2011. Recovery mechanisms of Arctic summer sea ice. Geophysical Research Letters 38: L02707. doi: 10.1029/2010GL045698.CrossRefGoogle Scholar
  34. Timco, G.W., and R.M.W. Frederking. 1996. A review of sea ice density. Cold Regions Research and Technology 24: 1–6.CrossRefGoogle Scholar
  35. Tonge, E.M. 1992. An incremental approach to AUVs. Proceedings Oceanology International’92, Brighton, 10–13 March 1992. Spearhead Exhibitions 1.Google Scholar
  36. Wadhams, P. 1988. The underside of Arctic sea ice imaged by sidescan sonar. Nature 333: 161–164.CrossRefGoogle Scholar
  37. Wadhams, P. 1990. Evidence for thinning of the Arctic ice cover north of Greenland. Nature 345: 795–797.CrossRefGoogle Scholar
  38. Wadhams, P., and J.C. Comiso. 1992. The ice thickness distribution inferred using remote sensing techniques. In Microwave remote sensing of sea ice. ed. F. Carsey, Geophysical Monograph 68, American Geophysical Union, Washington, 375–383.Google Scholar
  39. Wadhams, P. 1997a. Ice thickness in the Arctic Ocean: The statistical reliability of experimental data. Journal of Geophysical Research 102: 27951–27959.CrossRefGoogle Scholar
  40. Wadhams, P. 1997b. Variability of Arctic sea ice thickness—statistical significance and its relationship to heat flux. In Operational oceanography, The challenge for European co-operation, 368–384. Elsevier.Google Scholar
  41. Wadhams, P. 2008. Arctic sea ice changes under global warming. Proceedings ICETECH 2008, International Conference on Performance of Ships and Structures in Ice, Banff, July 20–23 2008. Society of Naval Architects and Marine Engineers, ISBN 978-0-9780896-1.Google Scholar
  42. Wadhams, P., N. Hughes, and J. Rodrigues. 2011. Arctic sea ice thickness characteristics in winter 2004 and 2007 from submarine sonar transects. Journal of Geophysical Research 116: C00E02. doi: 10.1029/2011JC006982.
  43. Wadhams, P., and N.R. Davis. 2000. Further evidence of ice thinning in the Arctic Ocean. Geophysical Research Letters 27: 3973–3975.CrossRefGoogle Scholar
  44. Wadhams, P., and N.R. Davis. 2001. Arctic sea-ice morphological characteristics in summer 1996. Annales of Glaciology 33: 165–170.CrossRefGoogle Scholar
  45. Wadhams, P., and M. Doble. 2008. Digital terrain mapping of the underside of sea ice from a small AUV. Geophysical Research Letters 35: L01501. doi: 10.1029/2007GL031921.CrossRefGoogle Scholar
  46. Wadhams, P., and M.J. Doble. 2009. Sea ice thickness measurement using episodic infragravity waves from distant storms. Cold Regions Science and Technology 56: 98–101.CrossRefGoogle Scholar
  47. Wadhams, P., and W. Munk. 2004. Ocean freshening, sea level rising, sea ice melting. Geophysical Research Letters 31: L11311. doi: 10.1029/2004GL020039.CrossRefGoogle Scholar
  48. Wadhams, P., F. Parmiggiani, G. de Carolis, D. Desiderio, and M.J. Doble. 2004a. SAR imaging of wave dispersion in Antarctic pancake ice and its use in measuring ice thickness. Geophysical Research Letters 31: L15305. doi: 10.1029/2004GL020340.CrossRefGoogle Scholar
  49. Wadhams, P., W.B. Tucker III, W. Krabill, R. Swift, J.C. Comiso, and N.R. Davis. 1991. Relationship between sea ice freeboard and draft in the Arctic Basin, and implications for ice thickness monitoring. Journal of Geophysical Research 97: 20325–20334.CrossRefGoogle Scholar
  50. Wadhams, P., J.P. Wilkinson, and A. Kaletzky. 2004b. Sidescan sonar imagery of the winter marginal ice zone obtained from an AUV. Journal of Atmospheric and Oceanic Technology 21: 1462–1470.CrossRefGoogle Scholar
  51. Wadhams, P., J.P. Wilkinson, and S.D. McPhail. 2006. A new view of the underside of Arctic sea ice. Geophysical Research Letters 33: L04501. doi: 10.1029/2005GL025131.CrossRefGoogle Scholar
  52. Wang, M., and J. Overland. 2009. A sea ice free summer Arctic within 30 years? Geophysical Research Letters 36: L07502. doi: 10.1029/2009GL037820.CrossRefGoogle Scholar
  53. Yu, Y., G.A. Maykut, and D.A. Rothrock. 2004. Changes in the thickness distribution of Arctic sea ice between 1958–1970 and 1993–1997. Journal of Geophysical Research 109: C08004. doi: 10.1029/2003JC001982.CrossRefGoogle Scholar

Copyright information

© Royal Swedish Academy of Sciences 2012

Authors and Affiliations

  1. 1.Department of Applied Mathematics and Theoretical PhysicsCentre for Mathematical Sciences, University of CambridgeCambridgeUK

Personalised recommendations