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:

Diverging seasonal extremes for ocean acidification during the twenty-first century


How ocean acidification will affect marine organisms depends on changes in both the long-term mean and the short-term temporal variability of carbonate chemistry1,2,3,4,5,6,7,8. Although the decadal-to-centennial response to atmospheric CO2 and climate change is constrained by observations and models1, 9, little is known about corresponding changes in seasonality10,11,12, particularly for pH. Here we assess the latter by analysing nine earth system models (ESMs) forced with a business-as-usual emissions scenario13. During the twenty-first century, the seasonal cycle of surface-ocean pH was attenuated by 16 ± 7%, on average, whereas that for hydrogen ion concentration [H+] was amplified by 81 ± 16%. Simultaneously, the seasonal amplitude of the aragonite saturation state (Ωarag) was attenuated except in the subtropics, where it was amplified. These contrasting changes derive from regionally varying sensitivities of these variables to atmospheric CO2 and climate change and to diverging trends in seasonal extremes in the primary controlling variables (temperature, dissolved inorganic carbon and alkalinity). Projected seasonality changes will tend to exacerbate the impacts of increasing [H+] on marine organisms during the summer and ameliorate the impacts during the winter, although the opposite holds in the high latitudes. Similarly, over most of the ocean, impacts from declining Ωarag are likely to be intensified during the summer and dampened during the winter.

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

Fig. 1: Changing seasonal cycles of carbonate chemistry variables.
Fig. 2: Relative change in the seasonal amplitude of carbonate chemistry variables with increasing atmospheric CO2.
Fig. 3: The twenty-first century changes in seasonal amplitudes.
Fig. 4: Partitioning of the geochemical and radiative effects of atmospheric CO2 on seasonality change.

Similar content being viewed by others


  1. Orr, J. C. et al. Anthropogenic ocean acidification over the twenty-first century and its impact on calcifying organisms. Nature 437, 681–686 (2005).

    Article  CAS  Google Scholar 

  2. Wootton, J. T., Pfister, C. A. & Forester, J. D. Dynamic patterns and ecological impacts of declining ocean pH in a high-resolution multi-year dataset. Proc. Natl Acad. Sci. USA 105, 18848–18853 (2008).

    Article  CAS  Google Scholar 

  3. Albright, R. et al. Reversal of ocean acidification enhances net coral reef calcification. Nature 531, 362–365 (2016).

    Article  CAS  Google Scholar 

  4. Kwiatkowski, L. et al. Nighttime dissolution in a temperate coastal ocean ecosystem increases under acidification. Sci. Rep. 6, 22984 (2016).

    Article  CAS  Google Scholar 

  5. Shaw, E. C., McNeil, B. I., Tilbrook, B., Matear, R. & Bates, M. L. Anthropogenic changes to seawater buffer capacity combined with natural reef metabolism induce extreme future coral reef CO2 conditions. Glob. Chang. Biol. 19, 1632–1641 (2013).

    Article  Google Scholar 

  6. Takahashi, T. et al. Climatological distributions of pH, pCO2, total CO2, alkalinity, and CaCO3 saturation in the global surface ocean, and temporal changes at selected locations. Mar. Chem. 164, 95–125 (2014).

    Article  CAS  Google Scholar 

  7. Hagens, M. & Middelburg, J. J. Attributing seasonal pH variability in surface ocean waters to governing factors. Geophys. Res. Lett. 43, 12528–12537 (2016).

    Article  CAS  Google Scholar 

  8. Takeshita, Y. et al. Including high-frequency variability in coastal ocean acidification projections. Biogeosciences 12, 5853–5870 (2015).

    Article  Google Scholar 

  9. Bopp, L. et al. Multiple stressors of ocean ecosystems in the 21st century: projections with CMIP5 models. Biogeosciences 10, 6225–6245 (2013).

    Article  Google Scholar 

  10. McNeil, B. I. & Matear, R. J. Southern Ocean acidification: a tipping point at 450-ppm atmospheric CO2. Proc. Natl Acad. Sci. USA 105, 18860–18864 (2008).

    Article  CAS  Google Scholar 

  11. Sasse, T. P., McNeil, B. I., Matear, R. J. & Lenton, A. Quantifying the influence of CO2 seasonality on future aragonite undersaturation onset. Biogeosciences 12, 6017–6031 (2015).

    Article  Google Scholar 

  12. McNeil, B. I. & Sasse, T. P. Future ocean hypercapnia driven by anthropogenic amplification of the natural CO2 cycle. Nature 529, 383–386 (2016).

    Article  CAS  Google Scholar 

  13. Riahi, K. et al. RCP 8.5—a scenario of comparatively high greenhouse gas emissions. Climatic Change 109, 33–57 (2011).

    Article  CAS  Google Scholar 

  14. Doney, S. C., Fabry, V. J., Feely, R. A. & Kleypas, J. A. Ocean acidification: the other CO2 problem. Annu. Rev. Mar. Sci. 1, 169–192 (2009).

    Article  Google Scholar 

  15. Kroeker, K. J., Kordas, R. L., Crim, R. N. & Singh, G. G. Meta-analysis reveals negative yet variable effects of ocean acidification on marine organisms. Ecol. Lett. 13, 1419–1434 (2010).

    Article  Google Scholar 

  16. Mangan, S., Urbina, M. A., Findlay, H. S., Wilson, R. W. & Lewis, C. Fluctuating seawater pH/pCO2 regimes are more energetically expensive than static pH/pCO2 levels in the mussel Mytilus edulis. Proc. R. Soc. B 284, 20171642 (2017).

    Article  Google Scholar 

  17. Pörtner, H.-O. Ecosystem effects of ocean acidification in times of ocean warming: a physiologists view. Mar. Ecol. Prog. Ser. 373, 203–217 (2008).

    Article  Google Scholar 

  18. Munday, P. L. et al. Ocean acidification impairs olfactory discrimination and homing ability of a marine fish. Proc. Natl Acad. Sci. USA 106, 1848–1852 (2009).

    Article  CAS  Google Scholar 

  19. Watson, S.-A., Fields, J. B. & Munday, P. L. Ocean acidification alters predator behaviour and reduces predation rate. Biol. Lett. 13, 20160797 (2017).

    Article  Google Scholar 

  20. Gruber, N. et al. Rapid progression of ocean acidification in the California current system. Science 337, 220–223 (2012).

    Article  CAS  Google Scholar 

  21. Kwiatkowski, L. et al. Emergent constraints on projections of declining primary production in the tropical oceans. Nat. Clim. Chang. 7, 355–358 (2017).

    Article  CAS  Google Scholar 

  22. Ishii, M. et al. Air–sea CO2 flux in the Pacific Ocean for the period 1990–2009. Biogeosciences 11, 709–734 (2014).

    Article  Google Scholar 

  23. Schuster, U. et al. An assessment of the Atlantic and Arctic sea–air CO2 fluxes, 1990–2009. Biogeosciences 10, 607–627 (2013).

    Article  Google Scholar 

  24. Sarma, V. V. S. S. et al. Sea–air CO2 fluxes in the Indian Ocean between 1990 and 2009. Biogeosciences 10, 7035–7052 (2013).

    Article  CAS  Google Scholar 

  25. Lenton, A. et al. Sea–air CO2 fluxes in the Southern Ocean for the period 1990–2009. Biogeosciences 10, 4037–4054 (2013).

    Article  Google Scholar 

  26. Mongwe, N. P., Chang, N. & Monteiro, P. M. S. The seasonal cycle as a mode to diagnose biases in modelled CO2 fluxes in the Southern Ocean. Ocean. Model. 106, 90–103 (2016).

    Article  Google Scholar 

  27. Taylor, K. E., Stouffer, R. J. & Meehl, G. A. An Overview of CMIP5 and the experiment design. Bull. Am. Meteorol. Soc. 93, 485–498 (2011).

    Article  Google Scholar 

  28. Egleston, E. S., Sabine, C. L. & Morel, F. M. M. Revelle revisited: buffer factors that quantify the response of ocean chemistry to changes in DIC and alkalinity. Glob. Biogeochem. Cycles 24, GB1002 (2010).

    Article  Google Scholar 

  29. Hauck, J. & Völker, C. Rising atmospheric CO2 leads to large impact of biology on Southern Ocean CO2 uptake via changes of the Revelle factor. Geophys. Res. Lett. 42, 2015GL063070 (2015).

    Article  Google Scholar 

  30. Orr, J. C. in Ocean Acidification (eds Gattuso, J.-P. & Hansson, L.) 41–66 (Oxford Univ. Press, Oxford, 2011).

  31. Kerrison, P., Hall-Spencer, J. M., Suggett, D. J., Hepburn, L. J. & Steinke, M. Assessment of pH variability at a coastal CO2 vent for ocean acidification studies. Estuar. Coast. Shelf Sci. 94, 129–137 (2011).

    Article  CAS  Google Scholar 

  32. Schulz, K. G. & Riebesell, U. Diurnal changes in seawater carbonate chemistry speciation at increasing atmospheric carbon dioxide. Mar. Biol. 160, 1889–1899 (2013).

    Article  CAS  Google Scholar 

  33. Jury, C. P., Thomas, F. I. M., Atkinson, M. J. & Toonen, R. J. Buffer capacity, ecosystem feedbacks, and seawater chemistry under global change. Water 5, 1303–1325 (2013).

    Article  CAS  Google Scholar 

  34. Orr, J. C. & Epitalon, J.-M. Improved routines to model the ocean carbonate system: mocsy 2.0. Geosci. Model Dev. 8, 485–499 (2015).

  35. Dickson, A. G., Sabine, C. L. & Christian, J. R. Guide to Best Practices for Ocean CO 2 Measurements (North Pacific Marine Science Organization, 2007).

  36. Sellers, P. J. et al. Comparison of radiative and physiological effects of doubled atmospheric CO2 on climate. Science 271, 1402–1406 (1996).

    Article  CAS  Google Scholar 

Download references


This study was funded by the H2020 CRESCENDO grant (no. 641816), the ERC IMBALANCE-P synergy grant (no. 610028) and the MTES/FRB Acidoscope project. We acknowledge the World Climate Research Programme’s Working Group on Coupled Modelling, which is responsible for the Coupled Model Intercomparison Project (CMIP). For CMIP, the US Department of Energy’s Program for Climate Model Diagnosis and Intercomparison provided coordinating support and led the development of software infrastructure in partnership with the Global Organization for Earth System Science Portals. To analyse the CMIP5 data, this study benefited from the IPSL Prodiguer-Ciclad facility, which is supported by the National Centre for Scientific Research, the University of Pierre et Marie Curie and Labex L-IPSL, which is funded by the French National Research Agency (no. ANR-10-LABX-0018) and by the European FP7 IS-ENES2 project (no. 312979). We thank B. Le Vu for preliminary discussions.

Author information

Authors and Affiliations



Both authors conceived this study, J.O. produced the derived variables and both authors performed the analysis and wrote the manuscript, with L.K. leading the process.

Corresponding author

Correspondence to Lester Kwiatkowski.

Ethics declarations

Competing interests

The authors declare no competing financial interests.

Additional information

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

Supplementary information

Supplementary Information

Model Evaluation, Supplementary Tables 1–2, Supplementary Figures 1–13 and Supplementary References

Rights and permissions

Reprints and permissions

About this article

Check for updates. Verify currency and authenticity via CrossMark

Cite this article

Kwiatkowski, L., Orr, J. Diverging seasonal extremes for ocean acidification during the twenty-first century. Nature Clim Change 8, 141–145 (2018).

Download citation

  • Received:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI:

This article is cited by


Quick links

Nature Briefing Microbiology

Sign up for the Nature Briefing: Microbiology newsletter — what matters in microbiology research, free to your inbox weekly.

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