Revision of global carbon fluxes based on a reassessment of oceanic and riverine carbon transport

Abstract

Measurements of atmospheric CO2 concentration provide a tight constraint on the sum of the land and ocean sinks. This constraint has been combined with estimates of ocean carbon flux and riverine transport of carbon from land to oceans to isolate the land sink. Uncertainties in the ocean and river fluxes therefore translate into uncertainties in the land sink. Here, we introduce a heat-based constraint on the latitudinal distribution of ocean and river carbon fluxes, and reassess the partition between ocean, river and land in the tropics, and in the southern and northern extra-tropics. We show that the ocean overturning circulation and biological pump tightly link the ocean transports of heat and carbon between hemispheres. Using this coupling between heat and carbon, we derive ocean and river carbon fluxes compatible with observational constraints on heat transport. This heat-based constraint requires a 20–100% stronger ocean and river carbon transport from the Northern Hemisphere to the Southern Hemisphere than existing estimates, and supports an upward revision of the global riverine carbon flux from 0.45 to 0.78 PgC yr−1. These systematic biases in existing ocean/river carbon fluxes redistribute up to 40% of the carbon sink between northern, tropical and southern land ecosystems. As a consequence, the magnitude of both the southern land source and the northern land sink may have to be substantially reduced.

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Fig. 1: Overturning circulation and biological pump link carbon and heat transport in ocean basins.
Fig. 2: Schematic of ocean transport asymmetries.
Fig. 3: Link between heat and carbon asymmetries.
Fig. 4: Observation-based estimates of carbon transport asymmetry AC.
Fig. 5: Impact of ocean/river carbon asymmetry on land sinks.
Fig. 6: Revised ocean/river flux is consistent with atmospheric CO2 data.

References

  1. 1.

    Tans, P. P., Fung, I. Y. & Takahashi, T. Observational contraints on the global atmospheric CO2 budget. Science 247, 1431–1438 (1990).

    Article  Google Scholar 

  2. 2.

    Peylin, P. et al. Global atmospheric carbon budget: results from an ensemble of atmospheric CO2 inversions. Biogeosciences 10, 6699–6720 (2013).

    Article  Google Scholar 

  3. 3.

    Pan, Y. et al. A large and persistent carbon sink in the world’s forests. Science 333, 988–993 (2011).

    Article  Google Scholar 

  4. 4.

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

    Article  Google Scholar 

  5. 5.

    Keeling, C. D., Piper, S. C., Whorf, T. P. & Keeling, R. F. Evolution of natural and anthropogenic fluxes of atmospheric CO2 from 1957 to 2003. Tellus B 63, 1–22 (2011).

    Article  Google Scholar 

  6. 6.

    Schimel, D., Stephens, B. B. & Fisher, J. B. Effect of increasing CO2 on the terrestrial carbon cycle. Proc. Natl Acad. Sci. USA 112, 436–441 (2015).

    Article  Google Scholar 

  7. 7.

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

    Article  Google Scholar 

  8. 8.

    Forkel, M. et al. Enhanced seasonal CO2 exchange caused by amplified plant productivity in northern ecosystems. Science 351, 696–699 (2016).

    Article  Google Scholar 

  9. 9.

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

    Article  Google Scholar 

  10. 10.

    Bousquet, P. et al. Regional changes in carbon dioxide fluxes of land and oceans since 1980. Science 290, 1342–1346 (2000).

    Article  Google Scholar 

  11. 11.

    Stephens, B. B. et al. Weak northern and strong tropical land carbon uptake from vertical profiles of atmospheric CO2. Science 316, 1732–1735 (2007).

    Article  Google Scholar 

  12. 12.

    Andres, R. J. et al. A synthesis of carbon dioxide emissions from fossil-fuel combustion. Biogeosciences 9, 1845–1871 (2012).

    Article  Google Scholar 

  13. 13.

    Denning, A. S., Fung, I. Y. & Randall, D. Latitudinal gradient of atmospheric CO2 due to seasonal exchange with land biota. Nature 376, 240–243 (1995).

    Article  Google Scholar 

  14. 14.

    Khatiwala, S., Primeau, F. & Hall, T. Reconstruction of the history of anthropogenic CO2 concentrations in the ocean. Nature 462, 346–349 (2009).

    Article  Google Scholar 

  15. 15.

    Broecker, W. S. & Peng, T.-H. Interhemispheric transport of carbon dioxide by ocean circulation. Nature 356, 587–589 (1992).

    Article  Google Scholar 

  16. 16.

    Sarmiento, J. L. & Sundquist, E. T. Revised budget for the oceanic uptake of anthropogenic carbon dioxide. Nature 356, 589–593 (1992).

    Article  Google Scholar 

  17. 17.

    Aumont, O. et al. Riverine-driven interhemispheric transport of carbon. Glob. Biogeochem. Cycles 15, 393–405 (2001).

    Article  Google Scholar 

  18. 18.

    Keeling, C. D., Piper, S. C. & Heimann, M. in Aspects of Climate Variability in the Pacific and the Western Americas (ed. Peterson, D. H.) 305–363 (American Geophysical Union, Washington, DC, 1989).

  19. 19.

    Gurney, K. R. et al. High resolution fossil fuel combustion CO2 emission fluxes for the United States. Environ. Sci. Technol. 43, 5535–5541 (2009).

    Article  Google Scholar 

  20. 20.

    Olivier, J. G. J., Janssens-Maenhout, G., Muntean, M. & Peters, J. A. H. W. Trends in Global CO 2 Emissions: 2016 Report (PBL Netherlands Environmental Assessment Agency, 2016); http://www.pbl.nl/en/publications/trends-in-global-co2-emissions-2016-report

  21. 21.

    Steinkamp, K. & Gruber, N. A joint atmosphere–ocean inversion for the estimation of seasonal carbon sources and sinks. Glob. Biogeochem. Cycles 27, 732–745 (2013).

    Article  Google Scholar 

  22. 22.

    Houghton, R. A. Why are estimates of the terrestrial carbon balance so different? Glob. Change Biol. 9, 500–509 (2003).

    Article  Google Scholar 

  23. 23.

    Houghton, R. A. et al. Carbon emissions from land use and land-cover change. Biogeosciences 9, 5125–5142 (2012).

    Article  Google Scholar 

  24. 24.

    Brewer, P. G., Goyet, C. & Dyrssen, D. Carbon dioxide transport by ocean currents at 25°N latitude in the Atlantic Ocean. Science 246, 477–479 (1989).

    Article  Google Scholar 

  25. 25.

    Keeling, R. F. & Peng, T.-H. Transport of heat, CO2 and O2 by the Atlantic's thermohaline circulation. Philos Trans. R. Soc. Lond. B 348, 133–142 (1995).

    Article  Google Scholar 

  26. 26.

    Large, W. G. & Yeager, S. G. The global climatology of an interannually varying air–sea flux data set. Clim. Dyn. 33, 341–364 (2009).

    Article  Google Scholar 

  27. 27.

    Resplandy, L. et al. Constraints on oceanic meridional heat transport from combined measurements of oxygen and carbon. Clim. Dyn. 47, 3335 (2016).

    Article  Google Scholar 

  28. 28.

    Ganachaud, A. & Wunsch, C. Large-scale ocean heat and freshwater transports during the World Ocean Circulation Experiment. J. Clim. 16, 696–705 (2003).

    Article  Google Scholar 

  29. 29.

    Schlitzer, R. in Inverse Methods in Global Biogeochemical Cycles (eds. Kasibhatla, P. et al.) 107–124 (American Geophysical Union, Washington, DC, 2000); https://doi.org/10.1029/GM114p0107

  30. 30.

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

    Article  Google Scholar 

  31. 31.

    Siegel, D. A. et al. Global assessment of ocean carbon export by combining satellite observations and food-web models. Glob. Biogeochem. Cycles 28, 181–196 (2014).

    Article  Google Scholar 

  32. 32.

    DeVries, T. & Weber, T. The export and fate of organic matter in the ocean: new constraints from combining satellite and oceanographic tracer observations. Glob. Biogeochem. Cycles 31, 2016GB005551 (2017).

    Article  Google Scholar 

  33. 33.

    Yeager, S. & Danabasoglu, G. Sensitivity of Atlantic meridional overturning circulation variability to parameterized Nordic Sea overflows in CCSM4. J. Clim. 25, 2077–2103 (2011).

    Article  Google Scholar 

  34. 34.

    Wang, C., Zhang, L., Lee, S.-K., Wu, L. & Mechoso, C. R. A global perspective on CMIP5 climate model biases. Nat. Clim. Change 4, 201–205 (2014).

    Article  Google Scholar 

  35. 35.

    Ma, X. et al. Western boundary currents regulated by interaction between ocean eddies and the atmosphere. Nature 535, 533–537 (2016).

    Article  Google Scholar 

  36. 36.

    Doney, S. C. et al. Evaluating global ocean carbon models: the importance of realistic physics. Glob. Biogeochem. Cycles 18, GB3017 (2004).

    Article  Google Scholar 

  37. 37.

    Mikaloff Fletcher, S. E. et al. Inverse estimates of the oceanic sources and sinks of natural CO2 and the implied oceanic carbon transport. Glob. Biogeochem. Cycles 21, GB1010 (2007).

    Article  Google Scholar 

  38. 38.

    Jacobson, A. R., Mikaloff Fletcher, S. E., Gruber, N., Sarmiento, J. L. & Gloor, M. A joint atmosphere–ocean inversion for surface fluxes of carbon dioxide: 1. Methods and global-scale fluxes. Glob. Biogeochem. Cycles 21, GB1019 (2007).

    Google Scholar 

  39. 39.

    Gerber, M. & Joos, F. Carbon sources and sinks from an ensemble Kalman filter ocean data assimilation. Glob. Biogeochem. Cycles 24, GB3004 (2010).

    Google Scholar 

  40. 40.

    DeVries, T. The oceanic anthropogenic CO2 sink: storage, air–sea fluxes, and transports over the industrial era. Glob. Biogeochem. Cycles 28, 631–647 (2014).

    Article  Google Scholar 

  41. 41.

    Gruber, N. et al. Oceanic sources, sinks, and transport of atmospheric CO2. Glob. Biogeochem. Cycles 23, GB1005 (2009).

    Article  Google Scholar 

  42. 42.

    Sarmiento, J. L. et al. Sea–air CO2 fluxes and carbon transport: a comparison of three ocean general circulation models. Glob. Biogeochem. Cycles 14, 1267–1281 (2000).

    Article  Google Scholar 

  43. 43.

    Murnane, R. J., Sarmiento, J. L. & Le Quéré, C. Spatial distribution of air–sea CO2 fluxes and the interhemispheric transport of carbon by the oceans. Glob. Biogeochem. Cycles 13, 287–305 (1999).

    Article  Google Scholar 

  44. 44.

    Rödenbeck, C. et al. Global surface-ocean pCO2 and sea-air CO2 flux variability from an observation-driven ocean mixed-layer scheme. Ocean Sci. 9, 193–216 (2013).

    Article  Google Scholar 

  45. 45.

    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. Part II Top. Stud. Oceanogr. 56, 554–577 (2009).

    Article  Google Scholar 

  46. 46.

    Landschützer, P., Gruber, N., Bakker, D. C. E. & Schuster, U. Recent variability of the global ocean carbon sink. Glob. Biogeochem. Cycles 28, 927–949 (2014).

    Article  Google Scholar 

  47. 47.

    Wanninkhof, R. et al. Global ocean carbon uptake: magnitude, variability and trends. Biogeosciences 10, 1983–2000 (2013).

    Article  Google Scholar 

  48. 48.

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

    Article  Google Scholar 

  49. 49.

    Rödenbeck, C., Houweling, S., Gloor, M. & Heimann, M. CO2 flux history 1982–2001 inferred from atmospheric data using a global inversion of atmospheric transport. Atmos. Chem. Phys. 3, 1919–1964 (2003).

    Article  Google Scholar 

  50. 50.

    Grace, J., Mitchard, E. & Gloor, E. Perturbations in the carbon budget of the tropics. Glob. Change Biol. 20, 3238–3255 (2014).

    Article  Google Scholar 

  51. 51.

    Conway, T. J. & Tans, P. P. Development of the CO2 latitude gradient in recent decades. Glob. Biogeochem. Cycles 13, 821–826 (1999).

    Article  Google Scholar 

  52. 52.

    Fan, S. et al. A large terrestrial carbon sink in North America implied by atmospheric and oceanic carbon dioxide data and models. Science 282, 442–446 (1998).

    Article  Google Scholar 

  53. 53.

    Regnier, P. et al. Anthropogenic perturbation of the carbon fluxes from land to ocean. Nat. Geosci. 6, 597–607 (2013).

    Article  Google Scholar 

  54. 54.

    Bauer, J. E. et al. The changing carbon cycle of the coastal ocean. Nature 504, 61–70 (2013).

    Article  Google Scholar 

  55. 55.

    Clark, E. A., Sheffield, J., van Vliet, M. T. H., Nijssen, B. & Lettenmaier, D. P. Continental runoff into the oceans (1950–2008). J. Hydrometeorol. 16, 1502–1520 (2015).

    Article  Google Scholar 

  56. 56.

    Bianchi, T. S. et al. Enhanced transfer of terrestrially derived carbon to the atmosphere in a flooding event. Geophys. Res. Lett. 40, 116–122 (2013).

    Article  Google Scholar 

  57. 57.

    Kwon, E. Y. et al. Global estimate of submarine groundwater discharge based on an observationally constrained radium isotope model. Geophys. Res. Lett. 41, 8438–8444 (2014).

    Article  Google Scholar 

  58. 58.

    Le Gland, G., Mémery, L., Aumont, O. & Resplandy, L. Improving the inverse modeling of a trace isotope: how precisely can radium-228 fluxes toward the ocean and submarine groundwater discharge be estimated? Biogeosciences 14, 3171–3189 (2017).

    Article  Google Scholar 

  59. 59.

    Woolf, D. K., Land, P. E., Shutler, J. D., Goddijn-Murphy, L. M. & Donlon, C. J. On the calculation of air-sea fluxes of CO2 in the presence of temperature and salinity gradients: air-sea CO2 fluxes. J. Geophys. Res. Oceans 121, 1229–1248 (2016).

    Article  Google Scholar 

  60. 60.

    Rödenbeck, C. et al. Data-based estimates of the ocean carbon sink variability – first results of the Surface Ocean pCO2 Mapping intercomparison (SOCOM). Biogeosciences 12, 7251–7278 (2015).

    Article  Google Scholar 

  61. 61.

    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 

  62. 62.

    Dunne, J. P. et al. GFDLas ESM2 Global Coupled Climate-Carbon Earth System Models. Part I: physical formulation and baseline simulation characteristics. J. Clim. 25, 6646–6665 (2012).

    Article  Google Scholar 

  63. 63.

    Dunne, J. P. et al. GFDLas ESM2 Global Coupled Climate-Carbon Earth System Models. Part II: carbon system formulation and baseline simulation characteristics. J. Clim. 26, 2247–2267 (2013).

    Article  Google Scholar 

  64. 64.

    Séférian, R., Iudicone, D., Bopp, L., Roy, T. & Madec, G. Water mass analysis of effect of climate change on air–sea CO2 fluxes: the southern ocean. J. Clim. 25, 3894–3908 (2012).

    Article  Google Scholar 

  65. 65.

    Ilyina, T. et al. Global ocean biogeochemistry model HAMOCC: model architecture and performance as component of the MPI-Earth system model in different CMIP5 experimental realizations. J. Adv. Model. Earth Syst. 5, 287–315 (2013).

    Article  Google Scholar 

  66. 66.

    Tjiputra, J. F. et al. Evaluation of the carbon cycle components in the Norwegian Earth System Model (NorESM). Geosci. Model Dev. 6, 301–325 (2013).

    Article  Google Scholar 

  67. 67.

    Long, M. C., Deutsch, C. & Ito, T. Finding forced trends in oceanic oxygen. Glob. Biogeochem. Cycles 30, 2015GB005310 (2016).

    Article  Google Scholar 

  68. 68.

    Kay, J. E. et al. The Community Earth System Model (CESM) Large Ensemble Project: a community resource for studying climate change in the presence of internal climate variability. Bull. Am. Meteorol. Soc. 96, 1333–1349 (2014).

    Article  Google Scholar 

  69. 69.

    Aumont, O., Ethé, C., Tagliabue, A., Bopp, L. & Gehlen, M. PISCES-v2: an ocean biogeochemical model for carbon and ecosystem studies. Geosci. Model Dev. 8, 2465–2513 (2015).

    Article  Google Scholar 

  70. 70.

    Hobbs, W., Palmer, M. D. & Monselesan, D. An energy conservation analysis of ocean drift in the CMIP5 global coupled models. J. Clim. 29, 1639–1653 (2015).

    Article  Google Scholar 

  71. 71.

    Séférian, R. et al. Inconsistent strategies to spin up models in CMIP5: implications for ocean biogeochemical model performance assessment. Geosci. Model Dev. 9, 1827–1851 (2016).

    Article  Google Scholar 

  72. 72.

    Lundberg, L. & Haugan, P. M. A Nordic seas–Arctic Ocean carbon budget from volume flows and inorganic carbon data. Glob. Biogeochem. Cycles 10, 493–510 (1996).

    Article  Google Scholar 

  73. 73.

    Macdonald, A. M., Baringer, M. O., Wanninkhof, R., Lee, K. & Wallace, D. W. R. A 1998–1992 comparison of inorganic carbon and its transport across 24.5°N in the Atlantic. Deep Sea Res. Part II Top. Stud. Oceanogr. 50, 3041–3064 (2003).

    Article  Google Scholar 

  74. 74.

    Holfort, J., Johnson, K. M., Schneider, B., Siedler, G. & Wallace, D. W. R. Meridional transport of dissolved inorganic carbon in the South Atlantic Ocean. Glob. Biogeochem. Cycles 12, 479–499 (1998).

    Article  Google Scholar 

  75. 75.

    Álvarez, M., Ríos, A. F., Pérez, F. F., Bryden, H. L. & Rosón, G. Transports and budgets of total inorganic carbon in the subpolar and temperate North Atlantic. Glob. Biogeochem. Cycles 17, 1002 (2003).

    Article  Google Scholar 

  76. 76.

    Johns, W. E. et al. Continuous, array-based estimates of Atlantic Ocean heat transport at 26.5°N. J. Clim. 24, 2429–2449 (2011).

    Article  Google Scholar 

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Acknowledgements

L.R. was granted support by the Climate Program Office of the National Oceanic and Atmospheric Administration grant NA13OAR4310219. S.K. was supported by US National Science Foundation (NSF) grant OCE 10-60804. K.B.R. was supported by NASA award NNX14AL85G. N.C.A.R. is sponsored by the NSF. The authors also thank the groups developing MOM, MITgcm, NEMO and CMIP5 models for providing their model results.

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L.R. directed the analysis of the several data sets used here and shared responsibility for writing the manuscript. R.F.K. and B.B.S. shared responsibility for writing the manuscript. C.R. computed the land sinks. L.B., M.C.L. and K.B.R. provided model results. All authors contributed to the final version of the manuscript.

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Correspondence to L. Resplandy.

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Resplandy, L., Keeling, R.F., Rödenbeck, C. et al. Revision of global carbon fluxes based on a reassessment of oceanic and riverine carbon transport. Nature Geosci 11, 504–509 (2018). https://doi.org/10.1038/s41561-018-0151-3

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