Strengthening seasonal marine CO2 variations due to increasing atmospheric CO2


The increase of atmospheric CO2 (ref. 1) has been predicted to impact the seasonal cycle of inorganic carbon in the global ocean2,3, yet the observational evidence to verify this prediction has been missing. Here, using an observation-based product of the oceanic partial pressure of CO2 (pCO2) covering the past 34 years, we find that the winter-to-summer difference of the pCO2 has increased on average by 2.2 ± 0.4 μatm per decade from 1982 to 2015 poleward of 10° latitude. This is largely in agreement with the trend expected from thermodynamic considerations. Most of the increase stems from the seasonality of the drivers acting on an increasing oceanic pCO2 caused by the uptake of anthropogenic CO2 from the atmosphere. In the high latitudes, the concurrent ocean-acidification-induced changes in the buffer capacity of the ocean enhance this effect. This strengthening of the seasonal winter-to-summer difference pushes the global ocean towards critical thresholds earlier, inducing stress to ocean ecosystems and fisheries4. Our study provides observational evidence for this strengthening seasonal difference in the oceanic carbon cycle on a global scale, illustrating the inevitable consequences of anthropogenic CO2 emissions.

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Fig. 1: Trends in the seasonal difference of sea surface pCO2 1982–2015
Fig. 2: The changing seasonal sea surface pCO2 cycle
Fig. 3: Separation of the five-year mean seasonal cycle of pCO2 into its thermal and non-thermal components
Fig. 4: Regional and zonal mean trends in the winter-minus-summer difference.


  1. 1.

    Le Quéré, C. et al. Global carbon budget 2016. Earth Syst. Sci. Data 8, 605–649 (2016).

    Article  Google Scholar 

  2. 2.

    Rodgers, K. B. et al. A wintertime uptake window for anthropogenic CO2 in the North Pacific. Glob. Biochem. Cycles 22, GB2020 (2008).

    Google Scholar 

  3. 3.

    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, 1459–1464 (2015).

    CAS  Article  Google Scholar 

  4. 4.

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

    Article  Google Scholar 

  5. 5.

    Sarmiento, J. M. et al. Trends and regional distributions of land and ocean carbon sinks. Biogeosciences 7, 2351–2367 (2010).

    CAS  Article  Google Scholar 

  6. 6.

    Sarmiento, J. & Gruber, N. Ocean Biogeochemical Dynamics (Princeton Univ. Press, New Jersey, 2006).

  7. 7.

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

    CAS  Article  Google Scholar 

  8. 8.

    Delille, B. et al. Response of primary production and calcification to changes of p CO2 during experimental blooms of the coccolithophorid Emiliania huxleyi. Glob. Biogeochem. Cycles 19, GB2023 (2005).

  9. 9.

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

    CAS  Article  Google Scholar 

  10. 10.

    Sabine, C. L. et al. Surface Ocean CO2 Atlas (SOCAT) gridded data products. Earth Syst. Sci. Data 5, 145–153 (2013).

    Article  Google Scholar 

  11. 11.

    Bakker, D. C. E. et al. A multi-decade record of high-quality f CO2 data in version 3 of the Surface Ocean CO2 Atlas (SOCAT). Earth Syst. Sci. Data 8, 383–413 (2016).

    Article  Google Scholar 

  12. 12.

    Landschützer, P. et al. A neural network-based estimate of the seasonal to inter-annual variability of the Atlantic Ocean carbon sink. Biogeosciences 10, 7793–7815 (2013).

    Article  Google Scholar 

  13. 13.

    Landschützer, P., Gruber, N. & Bakker, D. C. E. Decadal variations and trends of the global ocean carbon sink. Glob. Biogeochem. Cycles 30, 1396–1417 (2016).

    Article  Google Scholar 

  14. 14.

    Dore, J. E., Lukas, R., Sadler, D. W., Church, M. J. & Karl, D. M. Physical and biogeochemical modulation of ocean acidification in the central North Pacific. Proc. Natl. Acad. Sci. USA 106, 12235–12240 (2009).

    CAS  Article  Google Scholar 

  15. 15.

    Gruber, N., Keeling, C. D. & Bates, N. R. Interannual variability in the North Atlantic Ocean carbon sink. Science 298, 2374–2378 (2002).

    CAS  Article  Google Scholar 

  16. 16.

    Bates, N. R. Multi-decadal uptake of carbon dioxide into subtropical mode water of the North Atlantic Ocean. Biogeosciences 9, 2649–2659 (2012).

    CAS  Article  Google Scholar 

  17. 17.

    Phillips, H. E. & Joyce, T. M. Bermuda’s tale of two time series: Hydrostation ‘S’ and BATS. J. Phys. Oceanogr. 37, 554–571 (2006).

    Article  Google Scholar 

  18. 18.

    Takahashi, T., Olafsson, J., Goddard, J., Chipman, D. & Sutherland, S. Seasonal variation of CO2 and nutrients in the high-latitude surface oceans: a comparative study. Glob. Biogeochem. Cycles 7, 843–878 (1993).

    CAS  Article  Google Scholar 

  19. 19.

    Takahashi, T. et al. Global sea-air CO2 flux based on climatological surface ocean p CO2, and seasonal biological and temperature effects. Deep.-Sea Res. II 49, 1601–1622 (2002).

    CAS  Article  Google Scholar 

  20. 20.

    Gorgues, T., Aumont, O. & Rodgers, K. B. A mechanistic account of increasing seasonal variations in the rate of ocean uptake of anthropogenic carbon. Biogeosciences 7, 2581–2589 (2010).

    CAS  Article  Google Scholar 

  21. 21.

    Le Quéré, C. et al. Saturation of the Southern Ocean CO2 sink due to recent climate change. Science 316, 1735–1738 (2007).

    Article  Google Scholar 

  22. 22.

    Landschützer, P. et al. The reinvigoration of the Southern Ocean carbon sink. Science 349, 1221–1224 (2015).

    Article  Google Scholar 

  23. 23.

    DeVries, T., Holzer, M. & Primeau, F. Recent increase in oceanic carbon uptake driven by weaker upper-ocean overturning. Nature 542, 215–218 (2017).

    CAS  Article  Google Scholar 

  24. 24.

    Monteiro, P. M. S. et al. Intraseasonal variability linked to sampling alias in air-sea CO2 fluxes in the Southern Ocean. Geophys. Res. Lett. 42, 8507–8514 (2015).

    CAS  Article  Google Scholar 

  25. 25.

    Rödenbeck, C. et al Data-based estimates of the ocean carbon sink variability—first results of the Surface Ocean p CO2 Mapping intercomparison (SOCOM). Biogeosciences 12, 7251–7278 (2015).

    Article  Google Scholar 

  26. 26.

    Bates, N. et al. A time-series view of changing ocean chemistry due to ocean uptake of anthropogenic CO2 and ocean acidification. Oceanography 27, 126–141 (2014).

    Article  Google Scholar 

  27. 27.

    Lauvset, S. K., Gruber, N., Landschützer, P., Olsen, A. & Tjiputra, J. Trends and drivers in global surface ocean pH over the past 3 decades. Biogeosciences 12, 1285–1298 (2015).

    CAS  Article  Google Scholar 

  28. 28.

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

    CAS  Article  Google Scholar 

  29. 29.

    McKinley, G. A. et al. Timescales for detection of trends in the ocean carbon sink. Nature 530, 469–472 (2016).

    Article  Google Scholar 

  30. 30.

    Graven, H. D. et al. Enhanced seasonal exchange of CO2 by northern ecosystems since 1960. Science 341, 1085–1089 (2013).

    CAS  Article  Google Scholar 

  31. 31.

    Lovenduski, N. S., Gruber, N., Doney, S. C. & Lima, D. I. Enhanced CO2 outgassing in the Southern Ocean from a positive phase of the Southern Annular Mode. Glob. Biogeochem. Cycles 21, GB2026 (2007).

    Article  Google Scholar 

  32. 32.

    Zeebe, P. E. & Wolf-Gladrow, D. CO 2 in Seawater: Equilibrium, Kinetics, Isotopes (Elsevier, Amsterdam, 2001).

  33. 33.

    Lee, K. et al. Global relationships of total alkalinity with salinity and temperature in surface waters of the world’s oceans. Geophys. Res. Lett. 33, L19605 (2006).

    Article  Google Scholar 

  34. 34.

    Reynolds, R. W., Rayner, N. A., Smith, T. M., Stokes, D. C. & Wang, W. An improved in situ and satellite SST analysis for climate. J. Clim. 15, 1609–1625 (2002).

    Article  Google Scholar 

  35. 35.

    Lauvset, S. K. et al. A new global interior ocean mapped climatology: the 1°×1° GLODAP version 2. Earth Syst. Sci. Data 8, 325–340 (2016).

    Google Scholar 

  36. 36.

    Olsen, A. et al. The Global Ocean Data Analysis Project version 2 (GLODAPv2)—an internally consistent data product for the world ocean. Earth Syst. Sci. Data 8, 297–323 (2016).

    Article  Google Scholar 

  37. 37.

    Key, R. et al. Global Ocean Data Analysis Project version 2 (GLODAPv2), ORNL/CDIAC-162, ND-P093 (Carbon Dioxide Information Analysis Center, 2015),

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We thank J. Marotzke and H. Li from the Max Planck Institute for Meteorology in Hamburg for their comments. P.L. was supported by the Max Planck Society for the Advancement of Science. N.G. was supported by ETH Zürich (Swiss Federal Institute of Technology in Zürich) and by European Union grant 283080 (GEOCARBON). D.C.E.B. was supported by the United Kingdom Shelf Sea Biogeochemistry Blue Carbon project (NE/K00168X/1; funded by the Natural Environment Research Council, the Department for Energy and Climate Change and the Department for Environment, Food and Rural Affairs). K.D.S. was partly supported through the Cluster of Excellence ‘CliSAP’ (EXC177), University of Hamburg, funded through the German Research Foundation (DFG).

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P.L. and N.G. designed the study with input from D.C.E.B. N.G. and P.L. developed the theoretical framework and wrote the paper together with D.C.E.B., I.S. and K.D.S. P.L. developed the neural network method and performed the analysis, assisted by N.G., I.S. and K.D.S. D.C.E.B. led the SOCAT synthesis effort that underlies this work. All authors discussed the results and implications and commented on the manuscript at all stages.

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Correspondence to Peter Landschützer.

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Supplementary Notes, Supplementary Table 1, Supplementary Figures 1–9 and Supplementary References

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Landschützer, P., Gruber, N., Bakker, D.C.E. et al. Strengthening seasonal marine CO2 variations due to increasing atmospheric CO2. Nature Clim Change 8, 146–150 (2018).

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