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.

Persistence of carbon release events through the peak of early Eocene global warmth


The Early Eocene Climatic Optimum (53–50 million years ago) was preceded by approximately six million years of progressive global warming1. This warming was punctuated by a series of rapid hyperthermal warming events triggered by the release of greenhouse gases1,2,3,4,5,6,7. Over these six million years, the carbon isotope record suggests that the events became more frequent but smaller in magnitude3,5,6,7. This pattern has been suggested to reflect a thermodynamic threshold for carbon release that was more easily crossed as global temperature rose, combined with a decrease in the size of carbon reservoirs during extremely warm conditions8,9,10,11. Here we present a continuous, 4.25-million-year-long record of the stable isotope composition of carbonate sediments from the equatorial Atlantic, spanning the peak of early Eocene global warmth. A composite of this and pre-existing7,12 records shows that the carbon isotope excursions that identify the hyperthermals exhibit continuity in magnitude and frequency throughout the approximately 10-million-year period covering the onset, peak and termination of the Early Eocene Climate Optimum. We suggest that the carbon cycle processes behind these events, excluding the largest event, the Palaeocene–Eocene Thermal Maximum (about 56 million years ago), were not exceptional. Instead, we argue that the hyperthermals may reflect orbital forcing of the carbon cycle analogous to the mechanisms proposed13,14 to operate in the cooler Oligocene and Miocene.

This is a preview of subscription content

Access options

Buy article

Get time limited or full article access on ReadCube.


All prices are NET prices.

Figure 1: Hyperthermals throughout the late Palaeocene to middle Eocene.
Figure 2: Coherence of bulk δ13C and δ18O across the Early Eocene Climate Optimum.
Figure 3: Conceptual threshold model results.


  1. Zachos, J. C., Dickens, G. R. & Zeebe, R. E. An early Cenozoic perspective on greenhouse warming and carbon-cycle dynamics. Nature 451, 279–283 (2008).

    Article  Google Scholar 

  2. Thomas, E., Zachos, J. C. & Bralower, T. J. in Warm Climates in Earth History (eds Huber, B., MacLeod, K. & Wing, S.) 132–160 (Cambridge Univ. Press, 2000).

    Google Scholar 

  3. Cramer, B. S., Wright, J. D., Kent, D. V. & Aubry, M. P. Orbital climate forcing of δ13C excursions in the late Paleocene–early Eocene (chrons C24n-C25n). Paleoceanography 18, 1097 (2003).

    Article  Google Scholar 

  4. Lourens, L. J. et al. Astronomical pacing of late Palaeocene to early Eocene global warming events. Nature 435, 1083–1087 (2005).

    Article  Google Scholar 

  5. Nicolo, M. J., Dickens, G. R., Hollis, C. J. & Zachos, J. C. Multiple early Eocene hyperthermals: Their sedimentary expression on the New Zealand continental margin and in the deep sea. Geology 35, 699–702 (2007).

    Article  Google Scholar 

  6. Galeotti, S. et al. Orbital chronology of Early Eocene hyperthermals from the Contessa Road section, central Italy. Earth Planet. Sci. Lett. 290, 192–200 (2010).

    Article  Google Scholar 

  7. Zachos, J. C., McCarren, H., Murphy, B., Rohl, U. & Westerhold, T. Tempo and scale of late Paleocene and early Eocene carbon isotope cycles: Implications for the origin of hyperthermals. Earth Planet. Sci. Lett. 299, 242–249 (2010).

    Article  Google Scholar 

  8. DeConto, R. M. et al. Past extreme warming events linked to massive carbon release from thawing permafrost. Nature 484, 87–91 (2012).

    Article  Google Scholar 

  9. Dickens, G. R. Rethinking the global carbon cycle with a large, dynamic and microbially mediated gas hydrate capacitor. Earth Planet. Sci. Lett. 213, 169–183 (2003).

    Article  Google Scholar 

  10. Komar, N., Zeebe, R. E. & Dickens, G. R. Understanding long-term carbon cycle trends: The late Paleocene through the early Eocene. Paleoceanography 28, 650–652 (2013).

    Article  Google Scholar 

  11. Lunt, D. J. et al. Orbital pacing of methane hydrate destabilization during the Paleogene. Nature Geosci. 4, 775–778 (2011).

    Article  Google Scholar 

  12. Sexton, P. F. et al. Eocene global warming events driven by ventilation of oceanic dissolved organic carbon. Nature 471, 349–352 (2011).

    Article  Google Scholar 

  13. Pälike, H. et al. The heartbeat of the Oligocene climate system. Science 314, 1894–1898 (2006).

    Article  Google Scholar 

  14. Holbourn, A., Kuhnt, W., Schulz, M., Flores, J-A. & Andersen, N. Orbitally-paced climate evolution during the middle Miocene “Monterey” carbon isotope excursion. Earth Planet. Sci. Lett. 261, 534–550 (2007).

    Article  Google Scholar 

  15. Quillévéré, F., Norris, R. D., Kroon, D. & Wilson, P. A. Transient ocean warming and shifts in carbon reservoirs during the early Danian. Earth Planet. Sci. Lett. 265, 600–615 (2008).

    Article  Google Scholar 

  16. Sexton, P. F., Wilson, P. A. & Norris, R. D. Testing the Cenozoic multisite composite δ18O and δ13C curves: New monospecific Eocene records from a single locality, Demerara Rise (Ocean Drilling Program Leg 207). Paleoceanography 21, PA2019 (2006).

    Article  Google Scholar 

  17. Westerhold, T. et al. On the duration of magnetochrons C24r and C25n and the timing of early Eocene global warming events: Implications from the Ocean Drilling Program Leg 208 Walvis Ridge depth transect. Paleoceanography 22, PA2201 (2007).

    Article  Google Scholar 

  18. Agnini, C. et al. An early Eocene carbon cycle perturbation at 52.5 Ma in the Southern Alps: Chronology and biotic response. Paleoceanography 24, PA2209 (2009).

    Article  Google Scholar 

  19. Westerhold, T. & Röhl, U. High resolution cyclostratigraphy of the early Eocene —new insights into the origin of the Cenozoic cooling trend. Clim. Past 5, 309–327 (2009).

    Article  Google Scholar 

  20. Westerhold, T., Röhl, U. & Laskar, J. Time scale controversy: Accurate orbital calibration of the early Paleogene. Geochem. Geophys. Geosyst. 13, Q06015 (2012).

    Article  Google Scholar 

  21. Laskar, J., Fienga, A., Gastineau, M. & Manche, H. La2010: A new orbital solution for the long-term numerical solution for the long term motion of the Earth. Astron. Astrophys. 532, A89 (2011).

    Article  Google Scholar 

  22. Cramer, B. S., Toggweiler, J. R., Wright, J. D., Katz, M. E. & Miller, K. G. Ocean overturning since the Late Cretaceous: Inferences from a new benthic foraminiferal isotope compilation. Paleoceanography 24, PA4216 (2009).

    Article  Google Scholar 

  23. Dickens, G. R. Down the Rabbit Hole: Toward appropriate discussion of methane release from gas hydrate systems during the Paleocene–Eocene thermal maximum and other past hyperthermal events. Clim. Past 7, 831–846 (2011).

    Article  Google Scholar 

  24. Russon, T., Paillard, D. & Elliot, M. Potential origins of 400–500 kyr periodicities in the ocean carbon cycle: A box model approach. Global Biogeochem. Cycles 24, GB2013 (2010).

    Article  Google Scholar 

  25. Herbert, T. D. A long marine history of carbon cycle modulation by orbital-climatic changes. Proc. Natl Acad. Sci. USA 94, 8362–8369 (1997).

    Article  Google Scholar 

  26. Shipboard Scientific Party in Proc. ODP, Init. Repts. (eds Erbacher, J. et al.) Vol. 207 (Ocean Drilling Program, 2004).

    Google Scholar 

Download references


S.K.T. thanks D. Lunt for his generous help with setting up the threshold model. This research used samples and data provided by the ODP. ODP (now IODP) is sponsored by the US NSF and participating countries under the management of JOI, Inc. Financial support for this research was provided by a National Science Foundation International Research Fellowship (to S.K.T.).

Author information

Authors and Affiliations



S.K.T. developed the bulk carbonate stable isotope records with the assistance of C.D.C., designed and ran the threshold model experiments, and created the composite δ13C record and method for identifying hyperthermals. S.K.T. and P.F.S. wrote the manuscript. S.K.T. and R.D.N. developed Fig. 1. P.F.S. produced Supplementary Fig. 6. All authors contributed to the final text.

Corresponding author

Correspondence to Sandra Kirtland Turner.

Ethics declarations

Competing interests

The authors declare no competing financial interests.

Supplementary information

Supplementary Information

Supplementary Information (PDF 3105 kb)

Supplementary Information

Supplementary Information (XLSX 123 kb)

Rights and permissions

Reprints and Permissions

About this article

Verify currency and authenticity via CrossMark

Cite this article

Kirtland Turner, S., Sexton, P., Charles, C. et al. Persistence of carbon release events through the peak of early Eocene global warmth. Nature Geosci 7, 748–751 (2014).

Download citation

  • Received:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI:

Further reading


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