Site selection in CO2 ocean sequestration: Dependence of CO2 injection rate on eddy activity distribution

Site selection in CO2 ocean sequestration is examined based on the idea that a site where injected CO2 is efficiently diluted is favourable in reducing/avoiding biological impacts. Simulations of CO2 injection into several sites by an eddy-resolving oceanic general circulation model (OGCM) show that the maximum CO2 concentration differs by a factor of 10 among sites. The distribution of eddy activity is the most important causative factor producing the geographical differences in CO2 dilution. Based on the relationship between the maximum CO2 concentration and eddy activity, we estimated the distribution of the maximum CO2 injection rate by a proposed method, which does not cause chronic impacts on biota. Around Japan, extensive ocean volume has the potential to dilute 20 million tonnes per year without chronic impacts, and some areas can be injected with 80 million tonnes per year.