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

An assessment of CO2 storage and sea-air fluxes for the Atlantic Ocean and Mediterranean Sea between 1985 and 2018  

Fiz F. Perez1, Marion Gehlen2, Jerry Tjiputra3, Are Olsen4, Meike Becker4, Marta Lopez-Mozos1, Jens D. Müller5, Nadine Goris3, and Judith Hauck6
Fiz F. Perez et al.
  • 1Instituto Investigaciones Marinas (IIM, CSIC), Eduardo Cabello, 6, 36208, Vigo, Spain (
  • 2LSCE/IPSL, Laboratoire des Sciences du Climat et de l’Environnement, Orme des Merisiers, CEA/Saclay 91198 Gif-sur-Yvette Cedex, France
  • 3NORCE Norwegian Research Centre, Bjerknes Centre for Climate Research, Bergen, Norway
  • 4University of Bergen, Bjerknes Centre for Climate Research, Bergen, Norway
  • 5Environmental Physics, Institute of Biogeochemistry and Pollutant Dynamics, ETZ, Zurich, Switzerland
  • 6Alfred-Wegener-Institute, Bremerhaven, Germany

The dynamic and thermohaline characteristics of the Atlantic Ocean linked to the Atlantic Meridional Overturning Circulation (AMOC) give it a specific role in the accumulation of heat and CO2, either of natural or anthropogenic origin (Cant), from the surface layer to the deep waters, significantly mitigating the impacts of anthropogenic climate change. Here, we evaluate the annual mean, long-term trends, seasonal cycle and interannual variability of net sea-air CO2 fluxes (FCO2) between 1985 and 2018 based on observation products (pCO2-products) and global ocean biogeochemical models (GOBMs) for the Atlantic from 30ºS to the Nordic Seas (~79ºN) and the Mediterranean. The mean contemporary FCO(sum of anthropogenic and natural components) is estimated to be 0.362 ± 0.067 and 0.47 ± 0.15 Pg C yr-1 using pCO2-products and GOBMs, respectively. The GOBMs show consistent growth trends in CO2 uptake with rates similar to the atmospheric CO2 growth, however trends obtained from CO2-products show a sharp increase from the pre-2000 period to the post-2000 period. There is overall agreement between pCO2-products and GOBMs results for mean values, seasonal cycle and interannual variability in all biomes, except for the North Atlantic subpolar biome, where pCO2-products show lower mean values, larger trends, and a different seasonal cycle than GOBMs. The GOBMs and pCO2-products show very concordant values in equatorial and subtropical regions, where CO2 variability is strongly determined by temperature. For the period 1994-2007, GOBMs show concordant values in annual Cant storage rate with carbonate marine system observations (Gruber et al., 2019) with values of 0.506 ± 0.106 Pg C yr-1 vs 0.673 ± 0.066 Pg C yr-1, respectively. The Cant storage rate agreement between GOBMs and observations are also registered in the different biomes, although in both permanently stratified subtropical in North and South Atlantic biomes, the storage rates in GOBMs show a larger spread with their mean values 30 and 40% lower than those estimated from observations. In general, the Atlantic accumulates more Cant than that inferred from the cumulative FCO2 changes, partly due to a significant lateral Cant transport from the Southern Ocean (about 30%).

How to cite: Perez, F. F., Gehlen, M., Tjiputra, J., Olsen, A., Becker, M., Lopez-Mozos, M., Müller, J. D., Goris, N., and Hauck, J.: An assessment of CO2 storage and sea-air fluxes for the Atlantic Ocean and Mediterranean Sea between 1985 and 2018  , EGU General Assembly 2023, Vienna, Austria, 24–28 Apr 2023, EGU23-13759,, 2023.