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Convergence of atmospheric and North Atlantic carbon dioxide trends on multidecadal timescales


Oceanic uptake of carbon dioxide substantially reduces the rate at which anthropogenic carbon accumulates in the atmosphere1, slowing global climate change. Some studies suggest that the rate at which the oceans take up carbon has significantly decreased in recent years2,3,4,5,6,7,8. Others suggest that decadal variability confounds the detection of long-term trends9,10,11. Here, we examine trends in the partial pressure of carbon dioxide in the surface waters of three large biogeographic regions in the North Atlantic, using observational data collected between 1981 and 2009. We compare these oceanic observations with trends in atmospheric carbon dioxide levels, taken from a global observational network. We show that trends in oceanic carbon dioxide concentrations are variable on a decadal timescale, often diverging from trends in atmospheric carbon dioxide. However, when the entire 29-year period is considered, oceanic trends converge with atmospheric trends in all three regions; it takes 25 years for this long-term trend to emerge and overcome the influence of decadal-scale variability. Furthermore, in the southernmost biome, the data suggest that warming—driven by a multidecadal climate oscillation and anthropogenic forcing12,13—has started to reduce oceanic uptake of carbon in recent years.

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Figure 1: Trend in oceanic pCO2 compared to atmospheric pCO2 trend20 for a multidecadal and a decadal period.
Figure 2: Trend in oceanic pCO2 versus atmospheric pCO2, variable years.

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  1. Denman, K. L. et al. in IPCC Climate Change 2007: The Physical Science Basis (eds Solomon, S. et al.) 499–587 (Cambridge Univ. Press, 2007).

    Google Scholar 

  2. Schuster, U. et al. Trends in North Atlantic sea-surface fCO2 from 1990 to 2006. Deep-Sea Res. II 56, 620–629 (2009).

    Article  Google Scholar 

  3. Watson, A. J. et al. Tracking the variable North Atlantic sink for atmospheric CO2 . Science 326, 1391–1393 (2009).

    Article  Google Scholar 

  4. Le Quéré, C. et al. Trends in the sources and sinks of carbon dioxide. Nature Geosci. 2, 831–836 (2009).

    Article  Google Scholar 

  5. Corbiere, A., Metzl, N., Reverdin, G., Brunet, C. & Takahashi, T. Interannual and decadal variability of the oceanic carbon sink in the North Atlantic subpolar gyre. Tellus B 59, 168–178 (2007).

    Article  Google Scholar 

  6. Metzl, N. et al. Recent acceleration of the sea surface fCO2 growth rate in the North Atlantic subpolar gyre (1993–2008) revealed by winter observations. Glob. Biogeochem. Cycles 24, GB4004 (2010).

    Article  Google Scholar 

  7. Le Quéré, C., Takahashi, T., Buitenhuis, E. T., Rödenbeck, C. & Sutherland, S. C. Impact of climate change on the global oceanic sink of CO2 . Glob. Biogeochem. Cycles 24, GB4007 (2010).

    Article  Google Scholar 

  8. Canadell, J. et al. Contributions to accelerating atmospheric CO2 growth from economic activity, carbon intensity, and efficiency of natural sinks. Proc. Natl Acad. Sci. USA 104, 18886–18870 (2007).

    Article  Google Scholar 

  9. Thomas, H. et al. Changes in the North Atlantic Oscillation influence CO2 uptake in the North Atlantic over the past 2 decades. Glob. Biogeochem. Cycles 22, GB4027 (2008).

    Article  Google Scholar 

  10. Ullman, D. J., McKinley, G. A., Bennington, V. & Dutkiewicz, S. Trends in the North Atlantic carbon sink: 1992–2006. Glob. Biogeochem. Cycles 23, GB4011 (2009).

    Article  Google Scholar 

  11. Gruber, N. Fickle trends in the ocean. Nature 458, 155–156 (2009).

    Article  Google Scholar 

  12. Ting, M-F., Kushnir, Y., Seager, R. & Li, C-H. Forced and internal twentieth-century SST trends in the North Atlantic. J. Clim. 22, 1469–1481 (2009).

    Article  Google Scholar 

  13. Löptien, U. & Eden, C. Multidecadal CO2 uptake variability of the North Atlantic. J. Geophys. Res. 115, D12113 (2010).

    Article  Google Scholar 

  14. Takahashi, T. et al. Climatological mean and decadal change in surface ocean pCO2, and net sea–air CO2 flux over the global oceans. Deep-Sea Res. II 56, 554–577 (2009).

    Article  Google Scholar 

  15. Bates, N. R. Interannual variability of the oceanic CO2 sink in the subtropical gyre of the North Atlantic Ocean over the last 2 decades. J. Geophys. Res. 112, C09013 (2007).

    Article  Google Scholar 

  16. Rödenbeck, C. Estimating COSources and Sinks from Atmospheric Mixing Ratio Measurements using a Global Inversion of Atmospheric Transport (Tech. Rep. 6, Max-Planck-Inst. for Biogeochem. Jena, 2005) available via:

  17. Sarmiento, J. L. et al. Response of ocean ecosystems to climate warming. Glob. Biogeochem. Cycles 18, GB3003 (2004).

    Article  Google Scholar 

  18. Takahashi, T., Sutherland, S. C. & Kozyr, A. Global Ocean Surface Water Partial Pressure of CO2 Database: Measurements Performed during 1957-2009 (Version 2009). (ORNL/CDIAC-152, NDP-088r. CDIAC, ORNL, US DOE, Oak Ridge, Tennessee, 10.3334/CDIAC/otg.ndp088r, 2010).

  19. Follows, M., Ito, T. & Dutkiewicz, S. On the solution of the carbonate chemistry system in ocean biogeochemistry models. Ocean Model. 12, 290–301 (2006).

    Article  Google Scholar 

  20. GLOBALVIEW-CO2: Cooperative Atmospheric Data Integration Project—Carbon Dioxide, Reference Matrix. (CD-ROM,, Path: ccg/co2/GLOBALVIEW, NOAA ESRL, Boulder, CO, 2010).

  21. Takahashi, T. et al. Global sea–air CO2 flux based on climatological surface ocean pCO2, and seasonal biological and temperature effects. Deep-Sea Res. II 49, 1601–1622 (2002).

    Article  Google Scholar 

  22. Reverdin, G. North Atlantic subpolar gyre surface variability (1895–2009). J. Clim. 23, JCLI3493.1 (2010).

    Article  Google Scholar 

  23. Skjelvan, I., Falck, E., Rey, F. & Kringstad, S. B. Inorganic carbon time series at Ocean Weather Station M in the Norwegian Sea. Biogeosci. 5, 549–560 (2008).

    Article  Google Scholar 

  24. Häkkinen, S. & Rhines, P. B. Shifting surface currents in the northern North Atlantic Ocean. J. Geophys. Res. 114, C04005 (2009).

    Article  Google Scholar 

  25. Lozier, M. S. et al. The spatial pattern and mechanisms of heat-content change in the North Atlantic. Science 319, 800–803 (2008).

    Article  Google Scholar 

  26. Knorr, W. Is the airborne fraction of anthropogenic CO2 emissions increasing? Geophys. Res. Lett. 36, L21710 (2009).

    Article  Google Scholar 

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

    Article  Google Scholar 

  28. Reynolds, R. W. et al. Daily high-resolution-blended analyses for sea surface temperature. J. Clim. 20, 5473–5496 (2007).

    Article  Google Scholar 

  29. Levitus, S. (ed.) World Ocean Atlas 2005, Volume 1 and 2 (NOAA Atlas NESDIS 61, US Government Printing Office, 2005).

  30. Key, R. et al. A global ocean carbon climatology: Results from Global Data Analysis Project (GLODAP). Glob. Biogeochem. Cycles 18, GB4031 (2004).

    Article  Google Scholar 

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G.A.M. and A.R.F. acknowledge funding from NASA (07-NIP07-0036). The SURATLANT Project is supported by Institut National des Sciences de l’Univers (INSU, as contribution of the ORE SSS) and Institut Paul Emile Victor (IPEV) in France. This work was also supported by French program LEFE/FlamenCO2, a component of SOLAS-France and European Integrated Project CARBOOCEAN (511176). T.T. is supported by a NOAA grant (NA080AR4320754).

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G.A.M designed the study and wrote the manuscript. A.R.F. did the data analysis. T.T. developed the oceanic pCO2 database. N.M. synthesized the SURATLANT data. All authors discussed and revised the manuscript.

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Correspondence to Galen A. McKinley.

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The authors declare no competing financial interests.

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McKinley, G., Fay, A., Takahashi, T. et al. Convergence of atmospheric and North Atlantic carbon dioxide trends on multidecadal timescales. Nature Geosci 4, 606–610 (2011).

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