Simulation of 50 Mton CO2 injection per year into the ocean using an ocean general circulation model

To evaluate whether chronic impacts on biota are caused by continuous 50 Mton CO₂ injection per year into the ocean, we simulated transport and dilution of the injected CO₂ using an offline ocean general circulation model (OGCM) with a horizontal resolution of 0.1 by 0.1 degrees. Carbon dioxide is continuously injected during 30 years into a site with one degree in longitude and three degrees in latitude. Since most of CO₂ dissolved water is transported in the longitudinal direction, its broad latitudinal width is effective to decrease CO₂ concentration in order to reduce/avoid biological impacts. CO₂ concentration increases in the first several to 10 years, but it has an upper limit after the initial increase. Since the simulated maximum CO₂ concentration is 80 percents of the "predicted no effect concentration" (PNEC), an index to estimate concentration causing no effects on biota, we can expect that continuous 50 Mton/year CO₂ injection causes no chronic impacts.