Skip to main content

Thank you for visiting nature.com. 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.

Robust warming of the global upper ocean

Abstract

A large (1023 J) multi-decadal globally averaged warming signal in the upper 300 m of the world’s oceans was reported roughly a decade ago1 and is attributed to warming associated with anthropogenic greenhouse gases2,3. The majority of the Earth’s total energy uptake during recent decades has occurred in the upper ocean3, but the underlying uncertainties in ocean warming are unclear, limiting our ability to assess closure of sea-level budgets4,5,6,7, the global radiation imbalance8 and climate models5. For example, several teams have recently produced different multi-year estimates of the annually averaged global integral of upper-ocean heat content anomalies (hereafter OHCA curves) or, equivalently, the thermosteric sea-level rise5,9,10,11,12,13,14,15,16. Patterns of interannual variability, in particular, differ among methods. Here we examine several sources of uncertainty that contribute to differences among OHCA curves from 1993 to 2008, focusing on the difficulties of correcting biases in expendable bathythermograph (XBT) data. XBT data constitute the majority of the in situ measurements of upper-ocean heat content from 1967 to 2002, and we find that the uncertainty due to choice of XBT bias correction dominates among-method variability in OHCA curves during our 1993–2008 study period. Accounting for multiple sources of uncertainty, a composite of several OHCA curves using different XBT bias corrections still yields a statistically significant linear warming trend for 1993–2008 of 0.64 W m-2 (calculated for the Earth’s entire surface area), with a 90-per-cent confidence interval of 0.53–0.75 W m-2.

Your institute does not have access to this article

Relevant articles

Open Access articles citing this article.

Access options

Buy article

Get time limited or full article access on ReadCube.

$32.00

All prices are NET prices.

Figure 1: OHCA curves using published methods.
Figure 2: OHCA curves produced using the same mapping technique.
Figure 3: Uncertainties in OHCA.

References

  1. Levitus, S., Antonov, J., Boyer, T. P. & Stephens, C. Warming of the world ocean. Science 287, 2225–2229 (2000)

    ADS  CAS  Article  Google Scholar 

  2. Barnett, T. P. et al. Penetration of human-induced warming into the world’s oceans. Science 309, 284–287 (2005)

    ADS  CAS  Article  Google Scholar 

  3. Levitus, S. et al. Anthropogenic warming of Earth’s climate system. Science 292, 267–270 (2001)

    ADS  CAS  Article  Google Scholar 

  4. Willis, J. K., Chambers, D. P. & Nerem, R. S. Assessing the globally averaged sea level budget on seasonal to interannual timescales. J. Geophys. Res. 113, C06015 (2008)

    ADS  Article  Google Scholar 

  5. Domingues, C. M. et al. Improved estimates of upper-ocean warming and multi-decadal sea-level rise. Nature 453, 1090–1093 (2008)

    ADS  CAS  Article  Google Scholar 

  6. Cazenave, A. et al. Sea level budget over 2003–2008: a reevaluation from GRACE space gravimetry, satellite altimetry and Argo. Global Planet. Change 65, 83–88 (2009)

    ADS  Article  Google Scholar 

  7. Leuliette, E. W. & Miller, L. Closing the sea level rise budget with altimetry, Argo, and GRACE. Geophys. Res. Lett. 36, L04608 (2009)

    ADS  Article  Google Scholar 

  8. Murphy, D. M. et al. An observationally based energy balance for the Earth since 1950. J. Geophys. Res. 114, D17107 (2009)

    ADS  Article  Google Scholar 

  9. Ishii, M. & Kimoto, M. Revaluation of historical ocean heat content variations with time-varying XBT and MBT depth bias corrections. J. Oceanogr. 65, 287–299 (2009)

    Article  Google Scholar 

  10. Levitus, S. et al. Global ocean heat content 1955–2007 in light of recently revealed instrumentation problems. Geophys. Res. Lett. 36, L07608 (2009)

    ADS  Google Scholar 

  11. Lyman, J. M. & Johnson, G. C. Estimating annual global upper-ocean heat content anomalies despite irregular in situ ocean sampling. J. Clim. 21, 5629–5641 (2008)

    ADS  Article  Google Scholar 

  12. Palmer, M. D., Haines, K., Tett, S. F. B. & Ansell, T. J. Isolating the signal of ocean global warming. Geophys. Res. Lett. 34, L23610 (2007)

    ADS  Article  Google Scholar 

  13. Smith, D. M. & Murphy, J. M. An objective ocean temperature and salinity analysis using covariances from a global climate model. J. Geophys. Res. 112, C02022 (2007)

    ADS  Article  Google Scholar 

  14. Willis, J. K., Roemmich, D. & Cornuelle, B. Interannual variability in upper ocean heat content, temperature, and thermosteric expansion on global scales. J. Geophys. Res. 109, C12036 (2004)

    ADS  Article  Google Scholar 

  15. Gouretski, V. & Reseghetti, F. On depth and temperature biases in bathythermograph data: development of a new correction scheme based on the analysis of a global ocean database. Deep-Sea Res. I 10.1016/j.dsr.2010.03.011 (in the press)

  16. Palmer, M. et al. in Proc. OceanObs’09: Sustained Ocean Observations Inf. Soc. Vol. 2 (eds Hall, J., Harrison D. E. & Stammer, D.) (European Space Agency, 2010)

    Google Scholar 

  17. Knight, J. et al. Global oceans: do global temperature trends over the last decade falsify climate predictions? Bull. Am. Meteorol. Soc. 90, S56–S57 (2009)

    Google Scholar 

  18. Trenberth, K. E. An imperative for climate change planning: tracking Earth's global energy. Curr. Opin. Environ. Sustainability 1, 19–27 (2009)

    Article  Google Scholar 

  19. Trenberth, K. E. et al. in Proc. OceanObs’09: Sustained Ocean Observations Inf. Soc. Vol. 1 (eds Hall, J., Harrison D. E. & Stammer, D.) (European Space Agency, 2010)

    Google Scholar 

  20. Roemmich, D. et al. Argo: the challenge of continuing 10 years of progress. Oceanography 22, 46–55 (2009)

    Article  Google Scholar 

  21. Gouretski, V. & Koltermann, K. P. How much is the ocean really warming? Geophys. Res. Lett. 34, L01610 (2007)

    ADS  Article  Google Scholar 

  22. Wijffels, S. E. et al. Changing expendable bathythermograph fall rates and their impact on estimates of thermosteric sea level rise. J. Clim. 21, 5657–5672 (2008)

    ADS  Article  Google Scholar 

  23. Reseghetti, F., Borghini, M. & Manzella, G. M. R. Factors affecting the quality of XBT data – results of analyses on profiles from the Western Mediterranean Sea. Ocean Sci. 3, 59–75 (2007)

    ADS  Article  Google Scholar 

  24. Boyer, T. P. et al. World Ocean Database 2005 (ed. Levitus, S.) Ch. 1 (US Government Printing Office, 2006)

    Google Scholar 

  25. Ingleby, B. & Huddleston, M. Quality control of ocean temperature and salinity profiles – historical and real-time data. J. Mar. Syst. 65, 158–175 (2007)

    ADS  Article  Google Scholar 

  26. Gille, S. T. Warming of the Southern Ocean since the 1950s. Science 295, 1275–1277 (2002)

    ADS  CAS  Article  Google Scholar 

  27. Johnson, G. C. & Doney, S. C. Recent western South Atlantic bottom water warming. Geophys. Res. Lett. 33, L14614 (2006)

    ADS  Article  Google Scholar 

  28. Johnson, G. C., Purkey, S. G. & Bullister, J. L. Warming and freshening in the abyssal southeastern Indian Ocean. J. Clim. 21, 5351–5363 (2008)

    ADS  Article  Google Scholar 

  29. Johnson, G. C., Mecking, S., Sloyan, B. M. & Wijffels, S. E. Recent bottom water warming in the Pacific Ocean. J. Clim. 20, 5365–5375 (2007)

    ADS  Article  Google Scholar 

  30. AchutaRao, K. M. et al. Simulated and observed variability in ocean temperature and heat content. Proc. Natl Acad. Sci. USA 104, 10768–10773 (2007)

    ADS  CAS  Article  Google Scholar 

Download references

Acknowledgements

J.M.L. and G.C.J. were funded by the US National Oceanic and Atmospheric Administration (NOAA) Climate Program Office and NOAA Research. S.A.G., M.D.P. and D.M.S. were supported by the Joint DECC and Defra Integrated Climate Programme DECC/Defra (GA01101). C. Domingues, S. Levitus, T. Boyer, M. Ferrante and D. Trossman provided comments. C. Domingues, S. Levitus, and T. Boyer also provided corrected XBT profiles. This is Pacific Marine Environment Laboratory contribution number 3476 and Joint Institute for Marine and Atmospheric Research contribution number 09-372.

Author information

Authors and Affiliations

Authors

Contributions

J.M.L. led the writing and analysis, with writing contributions from G.C.J., J.K.W., M.D.P. and S.A.G., and analysis contributions from S.A.G., V.V.G., M.I., M.D.P., D.M.S. and J.K.W.

Corresponding author

Correspondence to John M. Lyman.

Ethics declarations

Competing interests

The authors declare no competing financial interests.

Supplementary information

Supplementary Information

This file contains Supplementary Methods, References, Supplementary Table S1 and Supplementary Figure S1 with legend. (PDF 215 kb)

PowerPoint slides

Rights and permissions

Reprints and Permissions

About this article

Cite this article

Lyman, J., Good, S., Gouretski, V. et al. Robust warming of the global upper ocean. Nature 465, 334–337 (2010). https://doi.org/10.1038/nature09043

Download citation

  • Received:

  • Accepted:

  • Issue Date:

  • DOI: https://doi.org/10.1038/nature09043

Further reading

Comments

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.

Search

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