EGU General Assembly 2021
© Author(s) 2023. This work is distributed under
the Creative Commons Attribution 4.0 License.

Quantifying the ocean carbon sink for 1994-2007: Combined evidence from multiple methods

Galen A. McKinley1, Jessica Cross2, Timothy DeVries3, Judith Hauck4, Amanda Fay1, Peter Landschützer5, Goulven G. Laruelle6, Nicole Lovenduski7, Pedro Monteiro8, Ray Najjar9, Laure Resplandy10, Christian Rödenbeck15, Christopher Sabine12, Rik Wanninkhof13, and Nancy Williams14
Galen A. McKinley et al.
  • 1Columbia University, Lamont Doherty Earth Observatory, New York, USA (
  • 2NOAA PMEL, Seattle, USA
  • 3University of California - Santa Barbara, USA
  • 4Alfred Wegener Institute, Bremerhaven, Germany
  • 5Max Planck Institute for Meteorology, Hamburg, Germany
  • 6Université Libre de Bruxelles, Belgium
  • 7University of Colorado - Boulder, USA
  • 8CSIR, Cape Town, South Africa
  • 9Pennsylvania State University, University Park, USA
  • 10Princeton University, Princeton, USA
  • 12University of Hawaii, Honolulu, USA
  • 13NOAA AOML, Miami, USA
  • 14University of South Florida, St. Petersburg, USA
  • 15Max Planck Institute for Biogeochemistry, Jena, Germany

By means of a variety of international observing and modeling efforts, the ocean carbon community has developed numerous estimates for ocean carbon uptake. In this presentation, we report on the synthesis effort we are undertaking under the auspices of an Ocean Carbon and Biogeochemistry Working Group.  Our initial goal for this working group is to determine the best estimate for the net and anthropogenic carbon sink from 1994-2007 based on three approaches that independently use interior data, surface data or hindcast ocean models. Combining two approaches that use interior ocean data to estimate anthropogenic carbon, Fant = -2.40+-0.21 PgC/yr (2 sigma uncertainty). Estimates for the net, or contemporary, ocean carbon uptake come from 6 products that interpolate surface ocean pCO2 data to global coverage: Fnet = -1.58+-0.19  PgC/yr for 1994-2007. Uncertain closure terms for naturally-outgassed river-derived carbon and non-steady state natural carbon fluxes in the open ocean are then added to derive Fant from surface observation-based Fnet. Ocean models do not include river-derived carbon, but do include non-steady state natural carbon fluxes, and thus a third estimate for Fant is derived. The combined best-estimate is Fant = -2.35+-0.53 PgC/yr.  We detail the uncertainties and assumptions made in deriving these estimates, and suggest paths forward to further reduce uncertainties.

How to cite: McKinley, G. A., Cross, J., DeVries, T., Hauck, J., Fay, A., Landschützer, P., Laruelle, G. G., Lovenduski, N., Monteiro, P., Najjar, R., Resplandy, L., Rödenbeck, C., Sabine, C., Wanninkhof, R., and Williams, N.: Quantifying the ocean carbon sink for 1994-2007: Combined evidence from multiple methods, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-6704,, 2021.

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