The sub-seabed disposal of CO2 is safer than the disposal of CO2 in inland aquifers. Even if small amounts of CO2 seeped out of sea floor, CO2 would disperse and dissolve into sea water. On the surface of the sea, there exist no depressions where CO2 may concentrate. Sediments under deep sea floor are very cool because the deep oceanic water is usually at a few degrees centigrade. CO2 hydrate is formed in sediments under wide areas of ocean floor deeper than about 300m. Virtually complete isolation of huge amounts of CO2 is possible by the deep sub-seabed disposal. Liquid CO2 with heavy suspension intrudes laterally under light unconsolidated sediments at sea floor deeper than about 3700m. Lateral intrusion technique for the super-deep sub-seabed disposal of CO2 can protect the ecology on the sea floor.