Decadal variability of the ocean carbon sink

Timothy J DeVries, University of California Santa Barbara, Santa Barbara, CA, United States, Corinne Le Quere, University of East Anglia, School of Environmental Sciences, Norwich, United Kingdom, Oliver Andrews, University of Bristol, School of Geographical Sciences, Bristol, United Kingdom, Judith Hauck, Alfred Wegener Institute Helmholtz-Center for Polar and Marine Research, Bremerhaven, Germany, Tatiana Ilyina, Max Planck Institute for Meteorology, Hamburg, Germany, Peter Landschutzer, ETH Zurich, Zurich, Switzerland, Andrew Lenton, CSIRO Hobart, Hobart, TAS, Australia, Ivan D Lima, Woods Hole Oceanographic Inst, Woods Hole, MA, United States, Michael Nowicki, University of California, Santa Barbara, Geography, United States, Jorg Schwinger, NORCE Climate, Bergen, Norway and Roland Séférian, Meteo-France - CNRS, CNRM, CEN, Toulouse, France
Abstract:
In this study, we diagnose the interannual-to-decadal variability of ocean CO2 uptake from three independent methods: an ocean circulation inverse model (OCIM), global ocean biogeochemical models (GOBMs), and pCO2-based flux mapping products. We find that the ocean carbon sink could be responsible for up to 40% of the observed decadal variability in atmospheric CO2 accumulation. Data-based estimates of the ocean carbon sink from pCO2 mapping methods and decadal ocean inverse models generally agree on the magnitude and sign of decadal variability in the ocean CO2 sink at both global and regional scales. Simulations with ocean biogeochemical models confirm that climate variability drove the observed decadal trends in ocean CO2 uptake, but also demonstrate that the sensitivity of ocean CO2 uptake to climate variability may be too weak in models. Finally, we discuss the relative contribution of atmospheric pCO2, solubility, circulation, and biology to the decadal variability of the ocean CO2 sink.
Back to: The Evolving Ocean Carbon Sink: Processes and Impacts I