Narrowing the uncertainty for deep-ocean injection efficiency

Orr, J. C., O. Aumont, A. Yool, G.-K. Plattner, F. Joos, E. Maier-Reimer, M.-F. Weirig, R. Schlitzer, K. Caldeira, M. E. Wickett, R. J. Matear, B. Mignone, and J. L. Sarmiento. In Greenhouse Gas Control Technologies, Proceedings of the Seventh International Conference on Greenhouse Gas Control Technologies, in press, Elsevier Science Ltd., Oxford, UK, 2005.

James C. Orr and Olivier Aumont, Laboratoire des Sciences du Climat et de l'Environnement, CEA-CNRS and IPSL, Gif-sur-Yvette, France

Andrew Yool, Southampton Oceanography Centre (SOC), Southampton, England, UK

Gian-Kasper Plattner and Fortunat Joos, Climate and Environmental Physics, Physics Institute, University of Bern (PIUB), Bern, Switzerland

Ernst Maier-Reimer, Max Planck Institut für Meteorologie (MPIM), Hamburg, Germany

Marie-France Weirig and Reiner Schlitzer, Alfred Wegener Institute for Polar and Marine Research (AWI), Bremerhaven, Germany

Ken Caldeira and Michael Wickett Lawrence Livermore National Laboratory (LLNL), Livermore, California, USA

Richard Matear, Commonwealth Science and Industrial Research Organization (CSIRO), Hobart, Australia

Brian Mignone and Jorge L. Sarmiento, AOS Program, Princeton University, Princeton NJ, USA


Only ocean models can predict how efficient the ocean is in sequestering CO2 by direct injection. Data is not available to directly evaluate model results in this regard, due to the century time scales required for the deep ocean waters to mix and be brought back to the surface. Ten ocean general circulation models (OGCM) have been compared within the framework of an international project to obtain site-specific efficiencies and corresponding uncertainties. Here we show that across the range of models there is a correlation between global injection efficiency and global metrics for CFC-11, natural 14C and bomb 14C. These correlations provide support for using these global tracer metrics to help narrow the uncertainty range for the 3000-m injection efficiency. After rejecting the models that do not meet these global tracer criteria, the range in efficiencies becomes four times narrower, dropping from 71±22% to 70±6% in year 2500.


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