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.

  • Article
  • Published:

Human-induced changes to the global ocean water masses and their time of emergence

Nature Climate Change volume 10, pages 1030–1036 (2020)Cite this article

Subjects

This article has been updated

Abstract

The World Ocean is rapidly changing, with global and regional modification of temperature and salinity, resulting in widespread and irreversible impacts. While the most pronounced observed temperature and salinity changes are located in the upper ocean, changes in water masses at depth have been identified and will probably strengthen in the future. Here, using 11 climate models, we define when anthropogenic temperature and salinity changes are expected to emerge from natural variability in the ocean interior along density surfaces. The models predict that in 2020, 20–55% of the Atlantic, Pacific and Indian basins have an emergent anthropogenic signal; reaching 40–65% in 2050 and 55–80% in 2080. The well-ventilated Southern Ocean water masses emerge very rapidly, as early as the 1980–1990s, while the Northern Hemisphere water masses emerge in the 2010–2030s. Our results highlight the importance of maintaining and augmenting an ocean observing system capable of detecting and monitoring persistent anthropogenic changes.

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

Access options

Buy this article

  • Purchase on SpringerLink
  • Instant access to full article PDF
Buy now

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

Fig. 1: Observed and simulated salinity changes between 1950 and 2008, shown in patterns of 50-yr salinity changes, analysed on density surfaces.
Fig. 2: Anthropogenic salinity change along density surfaces.
Fig. 3: ToE and percentage of emergence in basin zonal means.
Fig. 4: Distribution of GSAT at emergence.

Similar content being viewed by others

Data availability

All CMIP5 model data used in this paper are available through the Earth System Grid and freely available for download (https://esgf-node.llnl.gov/search/cmip5/).

Code availability

The analysis code for this paper is written in Python and is available on GitHub (https://github.com/ysilvy/ocean_toe_2020)54. The density binning code and data are available upon request to the authors.

Change history

  • 28 August 2020

    In the PDF version of this Article originally published online, Figs. 3 and 4 appeared in reverse order; this has now been amended. The HTML version was unaffected.

References

  1. Barnett, T. P., Pierce, D. W. & Schnur, R. Detection of anthropogenic climate change in the world’s oceans. Science 292, 270–274 (2001).

    CAS  Google Scholar 

  2. Reichert, B. K., Schnur, R. & Bengtsson, L. Global ocean warming tied to anthropogenic forcing. Geophys. Res. Lett. 29, 20–4 (2002).

    Google Scholar 

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

    CAS  Google Scholar 

  4. Palmer, M. D., Good, S. A., Haines, K., Rayner, N. A. & Stott, P. A. A new perspective on warming of the global oceans. Geophys. Res. Lett. 36, L20709 (2009).

    Google Scholar 

  5. Pierce, D. W., Gleckler, P. J., Barnett, T. P., Santer, B. D. & Durack, P. J. The fingerprint of human-induced changes in the ocean’s salinity and temperature fields. Geophys. Res. Lett. 39, L21704 (2012).

    Google Scholar 

  6. Gleckler, P. J. et al. Human-induced global ocean warming on multidecadal timescales. Nat. Clim. Change 2, 524–529 (2012).

    Google Scholar 

  7. Tokarska, K. B., Hegerl, G. C., Schurer, A. P., Ribes, A. & Fasullo, J. T. Quantifying human contributions to past and future ocean warming and thermosteric sea level rise. Environ. Res. Lett. 14, 074020 (2019).

    CAS  Google Scholar 

  8. Bilbao, R. A. F., Gregory, J. M., Bouttes, N., Palmer, M. D. & Stott, P. Attribution of ocean temperature change to anthropogenic and natural forcings using the temporal, vertical and geographical structure. Clim. Dynam. 53, 5389–5413 (2019).

    Google Scholar 

  9. Terray, L. et al. Near-surface salinity as nature’s rain gauge to detect human influence on the tropical water cycle. J. Clim. 25, 958–977 (2012).

    Google Scholar 

  10. Stott, P. A., Sutton, R. T. & Smith, D. M. Detection and attribution of Atlantic salinity changes. Geophys. Res. Lett. 35, L21702 (2008).

    Google Scholar 

  11. Swart, N. C., Gille, S. T., Fyfe, J. C. & Gillett, N. P. Recent Southern Ocean warming and freshening driven by greenhouse gas emissions and ozone depletion. Nat. Geosci. 11, 836–841 (2018).

    CAS  Google Scholar 

  12. Mahlstein, I., Knutti, R., Solomon, S. & Portmann, R. W. Early onset of significant local warming in low latitude countries. Environ. Res. Lett. 6, 034009 (2011).

    Google Scholar 

  13. Diffenbaugh, N. S. & Scherer, M. Observational and model evidence of global emergence of permanent, unprecedented heat in the 20th and 21st centuries. Climatic Change 107, 615–624 (2011).

    Google Scholar 

  14. Hawkins, E. & Sutton, R. Time of emergence of climate signals. Geophys. Res. Lett. 39, L01702 (2012).

    Google Scholar 

  15. Mora, C. et al. The projected timing of climate departure from recent variability. Nature 502, 183–187 (2013).

    CAS  Google Scholar 

  16. Diffenbaugh, N. S. & Charland, A. Probability of emergence of novel temperature regimes at different levels of cumulative carbon emissions. Front. Ecol. Environ. 14, 418–423 (2016).

    Google Scholar 

  17. Lehner, F., Deser, C. & Terray, L. Toward a new estimate of ‘Time of Emergence’ of anthropogenic warming: insights from dynamical adjustment and a large initial-condition model ensemble. J. Clim. 30, 7739–7756 (2017).

    Google Scholar 

  18. Giorgi, F. & Bi, X. Time of emergence (TOE) of GHG-forced precipitation change hot-spots. Geophys. Res. Lett. 36, L06709 (2009).

    Google Scholar 

  19. Mahlstein, I., Portmann, R. W., Daniel, J. S., Solomon, S. & Knutti, R. Perceptible changes in regional precipitation in a future climate. Geophys. Res. Lett. 39, L05701 (2012).

    Google Scholar 

  20. Lyu, K., Zhang, X., Church, J. A., Slangen, A. B. A. & Hu, J. Time of emergence for regional sea-level change. Nat. Clim. Change 4, 1006–1010 (2014).

    Google Scholar 

  21. Keller, K. M., Joos, F. & Raible, C. C. Time of emergence of trends in ocean biogeochemistry. Biogeosciences 11, 3647–3659 (2014).

    Google Scholar 

  22. Rodgers, K. B., Lin, J. & Frölicher, T. L. Emergence of multiple ocean ecosystem drivers in a large ensemble suite with an Earth system model. Biogeosciences 12, 3301–3320 (2015).

    Google Scholar 

  23. Frölicher, T. L., Rodgers, K. B., Stock, C. A. & Cheung, W. W. L. Sources of uncertainties in 21st century projections of potential ocean ecosystem stressors. Glob. Biogeochem. Cycles 30, 1224–1243 (2016).

    Google Scholar 

  24. Henson, S. A. et al. Rapid emergence of climate change in environmental drivers of marine ecosystems. Nat. Commun. 8, 14682 (2017).

    Google Scholar 

  25. Turk, D. et al. Time of emergence of surface ocean carbon dioxide trends in the North American coastal margins in support of ocean acidification observing system design. Front. Mar. Sci. 6, 91 (2019).

    Google Scholar 

  26. Schlunegger, S. et al. Emergence of anthropogenic signals in the ocean carbon cycle. Nat. Clim. Change 9, 719–725 (2019).

    CAS  Google Scholar 

  27. Banks, H. & Wood, R. Where to look for anthropogenic climate change in the ocean. J. Clim. 15, 879–891 (2002).

    Google Scholar 

  28. Helm, K. P., Bindoff, N. L. & Church, J. A. Changes in the global hydrological-cycle inferred from ocean salinity. Geophys. Res. Lett. 37, L18701 (2010).

    Google Scholar 

  29. Durack, P. J. & Wijffels, S. E. Fifty-year trends in global ocean salinities and their relationship to broad-scale warming. J. Clim. 23, 4342–4362 (2010).

    Google Scholar 

  30. Durack, P. J., Wijffels, S. E. & Matear, R. J. Ocean salinities reveal strong global water cycle intensification during 1950 to 2000. Science 336, 455–458 (2012).

    CAS  Google Scholar 

  31. Lago, V. et al. Simulating the role of surface forcing on observed multidecadal upper-ocean salinity changes. J. Clim. 29, 5575–5588 (2016).

    Google Scholar 

  32. Zika, J. D. et al. Improved estimates of water cycle change from ocean salinity: the key role of ocean warming. Environ. Res. Lett. 13, 074036 (2018).

    Google Scholar 

  33. Sallee, J.-B. et al. Assessment of Southern Ocean water mass circulation and characteristics in CMIP5 models: historical bias and forcing response. J. Geophys. Res. Oceans 118, 1830–1844 (2013).

    Google Scholar 

  34. Heuzé, C. North Atlantic deep water formation and AMOC in CMIP5 models. Ocean Sci. 13, 609–622 (2017).

    Google Scholar 

  35. Good, S. A., Martin, M. J. & Rayner, N. A. EN4: quality controlled ocean temperature and salinity profiles and monthly objective analyses with uncertainty estimates. J. Geophys. Res. Oceans 118, 6704–6716 (2013).

    Google Scholar 

  36. Sallée, J.-B., Speer, K., Rintoul, S. & Wijffels, S. Southern Ocean thermocline ventilation. J. Phys. Oceanogr. 40, 509–529 (2010).

    Google Scholar 

  37. de Lavergne, C., Palter, J. B., Galbraith, E. D., Bernardello, R. & Marinov, I. Cessation of deep convection in the open Southern Ocean under anthropogenic climate change. Nat. Clim. Change 4, 278–282 (2014).

    Google Scholar 

  38. Heuzé, C., Ridley, J. K., Calvert, D., Stevens, D. P. & Heywood, K. J. Increasing vertical mixing to reduce Southern Ocean deep convection in NEMO3.4. Geosci. Model Dev. 8, 3119–3130 (2015).

    Google Scholar 

  39. Dufour, C. O. et al. Preconditioning of the Weddell Sea polynya by the ocean mesoscale and dense water overflows. J. Clim. 30, 7719–7737 (2017).

    Google Scholar 

  40. IPCC Special Report on Global Warming of 1.5 °C (eds Masson-Delmotte, V. et al.) (WMO, 2018).

  41. Yamaguchi, R. & Suga, T. Trend and variability in global upper‐ocean stratification since the 1960s. J. Geophys. Res. Oceans 124, 8933–8948 (2019).

    Google Scholar 

  42. Gregory, J. M. et al. The flux-anomaly-forced model intercomparison project (FAFMIP) contribution to CMIP6: investigation of sea-level and ocean climate change in response to CO2 forcing. Geosci. Model Dev. 9, 3993–4017 (2016).

    CAS  Google Scholar 

  43. Todd, A. et al. Ocean-only FAFMIP: understanding regional patterns of ocean heat content and dynamic sea level change. J. Adv. Model Earth. Syst. https://doi.org/10.1002/essoar.10501557.1 (2020).

  44. Gille, S. T. Decadal-scale temperature trends in the southern hemisphere ocean. J. Clim. 21, 4749–4765 (2008).

    Google Scholar 

  45. Khatiwala, S. P. et al. Global ocean storage of anthropogenic carbon. Biogeosciences 10, 2169–2191 (2013).

    CAS  Google Scholar 

  46. Frölicher, T. L. et al. Dominance of the Southern Ocean in anthropogenic carbon and heat uptake in CMIP5 models. J. Clim. 28, 862–886 (2015).

    Google Scholar 

  47. Roemmich, D. et al. Unabated planetary warming and its ocean structure since 2006. Nat. Clim. Change 5, 240–245 (2015).

    Google Scholar 

  48. Durack, P. J., Gleckler, P. J., Landerer, F. W. & Taylor, K. E. Quantifying underestimates of long-term upper-ocean warming. Nat. Clim. Change 4, 999–1005 (2014).

    Google Scholar 

  49. McDougall, T. J. & Jackett, D. R. The material derivative of neutral density. J. Mar. Res. 63, 159–185 (2005).

    Google Scholar 

  50. Häkkinen, S., Rhines, P. B. & Worthen, D. L. Warming of the global ocean: spatial structure and water-mass trends. J. Clim. 29, 4949–4963 (2016).

    Google Scholar 

  51. Desbruyères, D., McDonagh, E. L., King, B. A. & Thierry, V. Global and full-depth ocean temperature trends during the early twenty-first century from argo and repeat hydrography. J. Clim. 30, 1985–1997 (2017).

    Google Scholar 

  52. Iudicone, D. et al. Water masses as a unifying framework for understanding the Southern Ocean carbon cycle. Biogeosciences 8, 1031–1052 (2011).

    CAS  Google Scholar 

  53. Hawkins, E. et al. Uncertainties in the timing of unprecedented climates. Nature 511, E3–E5 (2014).

    CAS  Google Scholar 

  54. Silvy, Y. ocean_toe_2020 v1.0.0. Github repository (2020); https://doi.org/10.5281/zenodo.3944613

Download references

Acknowledgements

We thank C. de Lavergne, A. Fedorov, P. Gleckler, J. Gregory, E. Hawkins, G. Madec, H. Mercier, J. Mignot, B. Santer and L. Terray for helpful discussions. We acknowledge the support from the Make Our Planet Great Again project ARCHANGE (Agence Nationale pour la Recherche project no. ANR-18-MPGA-0001) from the European Research Council under the European Union’s Horizon 2020 research and innovation programme (grant no. 637770) and from the Centre National de la Recherche Scientifique. We also acknowledge the CMIP5 modelling groups, the ESGF and IPSL/ESPRI-MOD data distribution systems. The work of P.J.D. was prepared by Lawrence Livermore National Laboratory (LLNL) under contract no. DE-AC52-07NA27344 and is a contribution to the US Department of Energy, Office of Science, Climate and Environmental Sciences Division, Regional and Global Modeling and Analysis Program (LLNL release no. LLNL-JRNL-794900).

Author information

Authors and Affiliations

  1. LOCEAN-IPSL, Laboratoire d’Océanographie et du Climat: Expérimentation et Approches Numériques, Sorbonne Université/CNRS/IRD/MNHN, Paris, France

    Yona Silvy, Eric Guilyardi & Jean-Baptiste Sallée

  2. NCAS-Climate, University of Reading, Reading, UK

    Eric Guilyardi

  3. Program for Climate Model Diagnosis and Intercomparison, Lawrence Livermore National Laboratory, Livermore, CA, USA

    Paul J. Durack

Authors
  1. Yona Silvy
    View author publications

    You can also search for this author in PubMed Google Scholar

  2. Eric Guilyardi
    View author publications

    You can also search for this author in PubMed Google Scholar

  3. Jean-Baptiste Sallée
    View author publications

    You can also search for this author in PubMed Google Scholar

  4. Paul J. Durack
    View author publications

    You can also search for this author in PubMed Google Scholar

Contributions

The density binning of CMIP5 data was designed and performed by E.G. and P.J.D. All subsequent analysis for this paper was performed by Y.S. and supervised by E.G and J.-B.S. Observational data were provided by P.J.D. All authors contributed to interpreting the results and writing the manuscript.

Corresponding author

Correspondence to Yona Silvy.

Ethics declarations

Competing interests

The authors declare no competing interests.

Additional information

Peer review information Nature Climate Change thanks Veronique Lago, Nadya Vinogradova-Shiffer and the other, anonymous, reviewer(s) for their contribution to the peer review of this work.

Publisher’s note Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Supplementary information

Supplementary Information

Supplementary discussion, Figs. 1–14 and Table 1.

Rights and permissions

Reprints and permissions

About this article

Check for updates. Verify currency and authenticity via CrossMark

Cite this article

Silvy, Y., Guilyardi, E., Sallée, JB. et al. Human-induced changes to the global ocean water masses and their time of emergence. Nat. Clim. Chang. 10, 1030–1036 (2020). https://doi.org/10.1038/s41558-020-0878-x

Download citation

  • Received:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI: https://doi.org/10.1038/s41558-020-0878-x

This article is cited by

Search

Advanced 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