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Stable sea surface temperatures in the western Pacific warm pool over the past 1.75 million years


About 850,000 years ago, the period of the glacial cycles changed from 41,000 to 100,000 years. This mid-Pleistocene climate transition has been attributed to global cooling, possibly caused by a decrease in atmospheric carbon dioxide concentrations1,2. However, evidence for such cooling is currently restricted to the cool upwelling regions in the eastern equatorial oceans3,4, although the tropical warm pools on the western side of the ocean basins are particularly sensitive to changes in radiative forcing5,6. Here we present high-resolution records of sea surface temperatures spanning the past 1.75 million years, obtained from oxygen isotopes and Mg/Ca ratios in planktonic foraminifera from the western Pacific warm pool. In contrast with the eastern equatorial regions, sea surface temperatures in the western Pacific warm pool are relatively stable throughout the Pleistocene epoch, implying little long-term change in the tropical net radiation budget. Our results challenge the hypothesis of a gradual decrease in atmospheric carbon dioxide concentrations as a dominant trigger of the longer glacial cycles since 850,000 years ago. Instead, we infer that the temperature contrast across the equatorial Pacific Ocean increased, which might have had a significant influence on the mid-Pleistocene climate transition.

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Figure 1: Pleistocene reconstruction of surface water changes in the WPWP from the IMAGES core MD97-2140.
Figure 2: Comparison of spectral analysis of δ18O and Mg/Ca-derived SST records from MD97-2140 in the late and early Pleistocene.
Figure 3: Comparison of the WPWP Pleistocene climatic evolution with palaeoclimatic records from different regions.


  1. Berger, A., Li, X. S. & Loutre, M.-F. Modelling northern hemisphere ice volume over the last 3 Ma. Quat. Sci. Rev. 18, 1–11 (1999)

    ADS  Article  Google Scholar 

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

    ADS  Article  Google Scholar 

  3. Marlow, J. R., Lange, C. B., Wefer, G. & Rosell-Mele, A. Upwelling intensification as part of the Pliocene-Pleistocene climate transition. Science 290, 2288–2291 (2000)

    ADS  CAS  PubMed  Google Scholar 

  4. Liu, Z. & Herbert, T. D. High-latitude influence on the eastern equatorial Pacific climate in the early Pleistocene epoch. Nature 427, 720–723 (2004)

    ADS  CAS  Article  Google Scholar 

  5. Lea, D. W. The 100,000 year cycle in tropical SST, greenhouse forcing, and climate sensitivity. J. Clim. 17, 2170–2179 (2004)

    ADS  Article  Google Scholar 

  6. Broccoli, A. J. Tropical cooling at the last glacial maximum: an atmosphere-mixed layer ocean model simulation. J. Clim. 13, 951–976 (2000)

    ADS  Article  Google Scholar 

  7. Conkright, M. et al. World Ocean Atlas 1998 [CD-ROM] (Data Set Documentation 16, NODC, Silver Springs, Maryland, 1998)

    Google Scholar 

  8. Ropelewski, C. F. & Halpert, M. S. Global and regional scale precipitation patterns associated with the El Niño/Southern Oscillation. Mon. Weath. Rev. 115, 1606–1626 (1986)

    ADS  Article  Google Scholar 

  9. Halpert, M. S. & Ropelewski, C. F. Surface temperature patterns associated with the Southern Oscillation. J. Clim. 5, 577–593 (1992)

    ADS  Article  Google Scholar 

  10. Sun, D. Z. Possible effect of an increase in the warm-pool SST on the magnitude of El Nino warming. J. Clim. 16, 185–205 (2003)

    ADS  Article  Google Scholar 

  11. Yin, J. H. & Battisti, D. S. The importance of tropical sea surface temperature patterns in simulations of Last Glacial Maximum climate. J. Clim. 14, 565–581 (2001)

    ADS  Article  Google Scholar 

  12. Lea, D. W., Pak, D. K. & Spero, H. J. Climate impact of late quaternary equatorial Pacific sea surface temperature variations. Science 289, 1719–1724 (2000)

    ADS  CAS  Article  Google Scholar 

  13. 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 

  14. Visser, K., Thunell, R. C. & Stott, L. Magnitude and timing of temperature change in the Indo-Pacific warm pool during deglaciation. Nature 421, 152–155 (2003)

    ADS  CAS  Article  Google Scholar 

  15. Delcroix, T. Observed surface oceanic and atmospheric variability in the tropical Pacific at seasonal and ENSO timescales: a tentative overview. J. Geophys. Res. 103, 18611–18633 (1998)

    ADS  Article  Google Scholar 

  16. Ravelo, A. C., Andreasen, D. H., Lyle, M., Lyle, A. O. & Wara, M. W. Regional climate shifts caused by gradual global cooling in the Pliocene epoch. Nature 429, 263–267 (2004)

    ADS  CAS  Article  Google Scholar 

  17. Schefuß, E., Schouton, S., Fred Jansen, J. H. & Sinninghe Damste, J. S. African vegetation controlled by tropical sea surface temperatures in the mid-Pleistocene period. Nature 422, 418–421 (2003)

    ADS  Article  Google Scholar 

  18. Delcroix, T. & McPhaden, M. Interannual sea surface salinity and temperature changes in the western Pacific warm pool during 1992–2000. J. Geophys. Res. Oceans 107, 22135–22150 (2002)

    Google Scholar 

  19. Nürnberg, D., Mueller, A. & Schneider, R. R. Paleo-sea surface temperature calculations in the equatorial east Atlantic from Mg/Ca ratios in planktic foraminifers: A comparison to sea surface temperature estimates from Uk'37, oxygen isotopes, and foraminiferal transfer function. Paleoceanography 15, 124–134 (2000)

    ADS  Article  Google Scholar 

  20. Kiefer, T. & Kienast, M. Patterns of deglacial warming in the Pacific Ocean: a review with emphasis on the time interval of Heinrich event 1. Quat. Sci. Rev. (in the press)

  21. Imbrie, J. et al. On the structure and origin of major glaciation cycles. 2. The 100,000-year cycle. Paleoceanography 8, 699–735 (1993)

    ADS  Article  Google Scholar 

  22. Tziperman, E. & Gildor, H. On the mid-Pleistocene transition to 100- kyrr glacial cycles and the asymmetry between glaciation and deglaciation times. Paleoceanography 18, doi:10.1029/2001PA000627 (2003)

  23. Philander, S. G. & Fedorov, A. V. Role of tropics in changing the response to Milankovitch forcing some three million years ago. Paleoceanography 18, doi:10.129/2002PA000837 (2003)

  24. Rosenthal, Y., Field, F. & Sherrell, R. M. Precise determination of element/calcium ratios in calcareous samples using sector field inductively coupled plasma mass spectrometry. Anal. Chem. 71, 3248–3253 (1999)

    CAS  Article  Google Scholar 

  25. Boyle, E. A. & Keigwin, L. D. Comparison of Atlantic and Pacific paleochemical records for the last 250,000 years: changes in deep ocean circulation and chemical inventories. Earth Planet. Sci. Lett. 76, 135–150 (1985)

    ADS  CAS  Article  Google Scholar 

  26. Kawahata, H., Nishimura, A. & Gagan, M. K. Seasonal change in foraminiferal production in the western equatorial Pacific warm pool: evidence from sediment trap experiments. Deep-sea Res. II 49, 2783–2800 (2002)

    ADS  CAS  Article  Google Scholar 

  27. Carcaillet, J. T., Thouveny, N. & Bourles, D. L. Geomagnetic moment instability between 0.6 and 1.3 Ma from cosmonuclide evidence. Geophys. Res. Lett. 30, doi:10.1029/2003GL017550 (2003)

  28. Mix, A. C. et al. Benthic foraminiferal stable isotope stratigraphy of Site 846; 0–1.8 Ma. Proc. ODP Sci. Res. 138, 839–854 (1995)

    Google Scholar 

  29. Rosenthal, Y. & Lohmann, G. P. Accurate estimation of sea surface temperatures using dissolution-corrected calibrations for Mg/Ca paleothermometry. Paleoceanography 17, doi: 1029/2001PA000749 (2002)

  30. Bemis, B. E., Spero, H. J., Bijma, J. & Lea, D. W. Reevaluation of the oxygen isotopic composition of planktonic foraminifera: experimental results and revised paleotemperature equations. Paleoceanography 13, 150–160 (1998)

    ADS  Article  Google Scholar 

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The support of French MENRT, TAAF, CNRS/INSU and IPEV to the Marion-Dufresne and the IMAGES Program was necessary to perform this work. We are grateful to N. Buchet, B. Le Coat, P. Field and S. Perron-Cushman for technical help, and to A. Broccoli, A. C. Ravelo, D. Andreasen and C. Lévi for comments. This study was partially supported by Rutgers' post-doctoral fellowship to T.d.G.-T. and by the National Science Foundation to Y.R.

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Correspondence to Thibault de Garidel-Thoron.

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Supplementary information

Supplementary Figure S1

This figure displays the location of the sites discussed in the text, on a map of annual mean sea surface temperatures. (DOC 233 kb)

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de Garidel-Thoron, T., Rosenthal, Y., Bassinot, F. et al. Stable sea surface temperatures in the western Pacific warm pool over the past 1.75 million years. Nature 433, 294–298 (2005).

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