THE GOSAC PROJECT TO PREDICT THE EFFICIENCY OF OCEAN CO2 SEQUESTRATION USING 3-D OCEAN MODELS

• Main Authors: James C. Orr, Olivier Aumont, Andrew Yool, Gian-kasper Plattner, Fortunat Joos, Ernst Maier, Marie-france Weirig, Reiner Schlitzer, Ken Caldeira, Michael Wickett, Richard Matear, Bryan Mignone, Jorge Sarmiento, John Davison
• Other Authors: The Pennsylvania State University CiteSeerX Archives
• Format: Text
• Language: English
• Subjects: Southern Ocean
• Online Access: http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.467.868; http://www.climate.unibe.ch/~plattner/papers/orr03ghgt6_inpress.pdf

To evaluate the efficiency of the ocean in retaining purposefully sequestered CO2, eight ocean modeling groups made a set of standard injection simulations. Injection was made simultaneously at seven separate sites; separate 7-site simulations were made for injection at 800 m, 1500 m, and 3000 m. For injection at 3000 m, all models showed 85 % or greater global efficiency in year 2200, i.e., 100 years after the end of the specified 100-year injection period; at the same time, the 1500-m injection is 60-80 % efficient and 800-m injection is only 42-61 % efficient. Most of the CO2 injected at 3000 m was lost from the Southern Ocean (the principal region by which the deep ocean is ventilated); at shallower depths, relatively more was lost sooner, from the northern hemisphere and the tropics. The simulated global injection efficiency at 3000 m is correlated with both the simulated global mean CFC-11 inventory and deep-ocean natural 14C. Based on these correlations, the global observational constraints for these two tracers, and model diversity, it appears likely that the range of model-predicted efficiencies would bracket real ocean behavior under the same 3000-m injection scenario.