OCEAN CO2 SEQUESTRATION EFFICIENCY 1 Ocean CO2 Sequestration E±ciency from 3-D Ocean Model Comparison

• Main Authors: James C. Orr A, Olivier Aumont A, Andrew Yool B, Gian-kasper Plattner C, Fortunat Joos C, Ernst Maier-reimer D, Marie-france Weirig E, Reiner Schlitzer E, Ken Caldeira F, Michael Wicket F, Richard Matear G
• Other Authors: The Pennsylvania State University CiteSeerX Archives
• Format: Text
• Language: English
• Subjects: Southern Ocean; North Atlantic
• Online Access: http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.569.157; http://www.climate.unibe.ch/~plattner/papers/orr01ghgt5_inpress.pdf

The e±ciency of sequestering CO2 arti¯cially in the deep ocean is not well known. To estimate uncertainties, we made standard simulations in a diverse group of seven ocean models. Each model discretizes the ocean into a 3-D array of grid cells, and each includes a standard description of the inorganic ocean carbon cycle. Injection simulations with seven injection sites per run were made separately for three di®erent depths. At 3,000m, all models retained at least 97 % of the total injected CO2 at the end of the 100-year injection period; after 500 years, retention e±ciency ranged from 48 to 82%. At 1,500m, retention e±ciency was less (82-96 % after 100 years; 28- 57 % after 500 years). At 800m, it was less still (73- 83% after 100 years; 15- 38 % after 500 years). For the 1,500-m injection, San Francisco is generally the most e±cient site, New York is the least e±cient. For the 3,000-m injection, di®erences between sites are smaller. Western boundary sites (New York and Tokyo) increased in e±ciency more than other sites. In the 1,500-m and 3,000-m simulations, injected CO2 is lost mostly from the Southern Ocean, except for CO2 injected at 1,500m at New York, which is lost mostly from the North Atlantic.