Skip to main content

Thank you for visiting You are using a browser version with limited support for CSS. To obtain the best experience, we recommend you use a more up to date browser (or turn off compatibility mode in Internet Explorer). In the meantime, to ensure continued support, we are displaying the site without styles and JavaScript.

  • Letter
  • Published:

Obliquity pacing of the late Pleistocene glacial terminations


The 100,000-year timescale in the glacial/interglacial cycles of the late Pleistocene epoch (the past 700,000 years) is commonly attributed to control by variations in the Earth's orbit1. This hypothesis has inspired models that depend on the Earth's obliquity ( 40,000 yr; 40 kyr), orbital eccentricity ( 100 kyr) and precessional ( 20 kyr) fluctuations2,3,4,5, with the emphasis usually on eccentricity and precessional forcing. According to a contrasting hypothesis, the glacial cycles arise primarily because of random internal climate variability6,7,8. Taking these two perspectives together, there are currently more than thirty different models of the seven late-Pleistocene glacial cycles9. Here we present a statistical test of the orbital forcing hypothesis, focusing on the rapid deglaciation events known as terminations10,11. According to our analysis, the null hypothesis that glacial terminations are independent of obliquity can be rejected at the 5% significance level, whereas the corresponding null hypotheses for eccentricity and precession cannot be rejected. The simplest inference consistent with the test results is that the ice sheets terminated every second or third obliquity cycle at times of high obliquity, similar to the original proposal by Milankovitch12. We also present simple stochastic and deterministic models that describe the timing of the late-Pleistocene glacial terminations purely in terms of obliquity forcing.

This is a preview of subscription content, access via your institution

Access options

Buy this article

Prices may be subject to local taxes which are calculated during checkout

Figure 1: The Rayleigh test for phase directionality.
Figure 2: Deterministic and stochastic descriptions of the late-Pleistocene glacial variability.

Similar content being viewed by others


  1. Hays, J., Imbrie, J. & Shackleton, N. Variations in the earth's orbit: Pacemaker of the ice ages. Science 194, 1121–1132 (1976)

    Article  ADS  CAS  Google Scholar 

  2. Imbrie, J. & Imbrie, J. Modeling the climatic response to orbital variations. Science 207, 943–953 (1980)

    Article  ADS  CAS  Google Scholar 

  3. Paillard, D. The timing of Pleistocene glaciations from a simple multiple-state climate model. Nature 391, 378–391 (1998)

    Article  ADS  Google Scholar 

  4. Liu, H. Insolation changes caused by combination of amplitude and frequency modulation of the obliquity. J. Geophys. Res. 104, 25197–25206 (1999)

    Article  ADS  Google Scholar 

  5. Gildor, H. & Tziperman, E. Sea ice as the glacial cycles' climate switch: Role of seasonal and orbital forcing. Paleoceanography 15, 605–615 (2000)

    Article  ADS  Google Scholar 

  6. Saltzman, B. Stochastically-driven climatic fluctuations in the sea-ice, ocean temperature, CO2, feedback system. Tellus 34, 97–112 (1982)

    Article  ADS  CAS  Google Scholar 

  7. Pelletier, J. Coherence resonance and ice ages. J. Geophys. Res. 108, doi:10.1029/2002JD003120 (2003)

  8. Wunsch, C. The spectral description of climate change including the 100ky energy. Clim. Dyn. 20, 353–363 (2003)

    Article  Google Scholar 

  9. Saltzman, B. Dynamical Paleoclimatology: Generalised Theory of Global Climate Change (Academic, San Diego, 2002)

    Google Scholar 

  10. Broecker, W. Terminations. in Milankovitch and Climate (eds Berger, A. et al.) Part 2, 687–698 (D. Riedel, Hingham, 1984)

    Chapter  Google Scholar 

  11. Raymo, M. E. The timing of major climate terminations. Paleoceanography 12, 577–585 (1997)

    Article  ADS  Google Scholar 

  12. Milankovitch, M. Kanon der Erdbestrahlung und seine Andwendung auf das Eiszeiten-problem (Royal Serbian Academy, Belgrade, 1941)

    Google Scholar 

  13. Huybers, P. & Wunsch, C. A depth-derived Pleistocene age-model: Uncertainty estimates, sedimentation variability, and nonlinear climate change. Paleoceanography 19, doi:10.1029/2002PA000857 (2004)

    Article  ADS  Google Scholar 

  14. Imbrie, J. et al. in Milankovitch and Climate (eds Berger, A. et al.) Part 1, 269–305 (D. Riedel Publishing Company, 1984)

    Google Scholar 

  15. Shackleton, N. J., Berger, A. & Peltier, W. R. An alternative astronomical calibration of the lower Pleistocene timescale based on ODP site 677. Trans. R. Soc. Edinb. Earth Sci. 81, 251–261 (1990)

    Article  Google Scholar 

  16. Roe, G. & Allen, M. A comparison of competing explanations for the 100,000-yr ice age cycle. Geophys. Res. Lett. 26, 2259–2262 (1999)

    Article  ADS  Google Scholar 

  17. Blunier, T. & Brook, E. Timing of millennial-scale climate change in Antarctica and Greenland during the last glacial period. Science 291, 109–112 (2001)

    Article  ADS  CAS  Google Scholar 

  18. Wunsch, C. Greenland-Antarctic phase relations and millennial time-scale climate fluctuations in the Greenland cores. Quat. Sci. Rev. 22, 1631–1646 (2003)

    Article  ADS  Google Scholar 

  19. Marshall, S. & Clark, P. Basal temperature evolution of North American ice sheets and implications for the 100-kyr cycle. Geophys. Res. Lett. 29, doi:10.1029/2002GL015192 (2002)

  20. Zwally, H. et al. Surface melt-induced acceleration of greenland ice-sheet flow. Science 297, 218–222 (2002)

    Article  ADS  CAS  Google Scholar 

  21. Rubincam, D. Insolation in terms of earth's orbital parameters. Theor. Appl. Climatol. 48, 195–202 (1994)

    Article  ADS  Google Scholar 

  22. Huybers, P. & Wunsch, C. Rectification and precession-period signals in the climate system. Geophys. Res. Lett. 30, doi:10.1029/2003GL017875 (2003)

  23. Raymo, M. & Nisancioglu, K. The 41 kyr world: Milankovitch's other unsolved mystery. Paleoceanography 18, doi:10.1029/2002PA000791 (2003)

  24. Berger, A. & Loutre, M. F. Astronomical solutions for paleoclimate studies over the last 3 million years. Earth Planet. Sci. Lett. 111, 369–382 (1992)

    Article  ADS  Google Scholar 

  25. Huybers, P. On the Origins of the Ice Ages: Insolation Forcing, Age Models, and Nonlinear Climate Change. PhD thesis, MIT (2004)

    Google Scholar 

  26. Wunsch, C. Quantitative estimate of the Milankovitch-forced contribution to observed quaternary climate change. Quat. Sci. Rev. 23, 1001–1012 (2004)

    Article  ADS  Google Scholar 

  27. Ruddiman, W. F. Oribital insolation, ice volume, and greenhouse gases. Quat. Sci. Rev. 22, 1597–1622 (2003)

    Article  ADS  Google Scholar 

  28. Upton, G. & Fingleton, B. Spatial Data Analysis by Example Vol. 2 (John Wiley and Sons, Chichester, 1989)

    MATH  Google Scholar 

  29. Rosenblum, M. & Pikovsky, A. Synchronization: from pendulum clocks to chaotic lasers and chemical oscillators. Contemp. Phys. 44, 401–416 (2003)

    Article  ADS  CAS  Google Scholar 

  30. Schreiber, T. & Schmitz, A. Surrogate time series. Physica D 142, 346–382 (2000)

    Article  ADS  MathSciNet  Google Scholar 

Download references


Useful comments were provided by E. Boyle, W. Curry, T. Herbert, J. McManus, F. Ng, M. Tingley and G. Yang. P.H. is supported by the NOAA Postdoctoral Program in Climate and Global Change and C.W. is supported in part by the National Ocean Partnership Program (ECCO).

Author information

Authors and Affiliations


Corresponding author

Correspondence to Peter Huybers.

Ethics declarations

Competing interests

The authors declare that they have no competing financial interests.

Supplementary information

Supplementary Tables S1 and S2

This file contains data and statistics pertinent to testing the hypotheses of orbital control of the late Pleistocene glacial cycles. (PDF 18 kb)

Rights and permissions

Reprints and permissions

About this article

Cite this article

Huybers, P., Wunsch, C. Obliquity pacing of the late Pleistocene glacial terminations. Nature 434, 491–494 (2005).

Download citation

  • Received:

  • Accepted:

  • Issue Date:

  • DOI:

This article is cited by


By submitting a comment you agree to abide by our Terms and Community Guidelines. If you find something abusive or that does not comply with our terms or guidelines please flag it as inappropriate.


Quick links

Nature Briefing

Sign up for the Nature Briefing newsletter — what matters in science, free to your inbox daily.

Get the most important science stories of the day, free in your inbox. Sign up for Nature Briefing