During the Third Conference of Parties to the United Nations Framework Convention on Climate Change (COP-3) in Kyoto in December 1997 an international project on CO2 ocean sequestration was launched, under the auspices of the UNFCCC/OECD Climate Technology Initiative (CTI). The US, Japan and Norway agreed to support an initial field experiment on ocean CO2 sequestration by direct injection. Later Australia and Canada joined the team. At that time, some 25 years ago, ocean storage of CO2 by direct injection was actively considered along with subseabed geological storage of CO2 as options for Carbon Capture and Storage (CCS).The release experiment was originally planned to take place in Hawaii at 800 m depth in 2001. However, permitting prcoedures turned out to be difficult even if the experiment was to take place within an ocean research corridor. As a contingency plan it was decided to move the experiment to Norway in 2002. The project revised its scientific plan and submitted an application for a permit to release 5.4 tons of CO2 in 2002. The pure liquid CO2 would be released by remote control at 800 m water depth offshore mid-Norway from an array of CO2 in tanks mounted inside a cage on the seabed. During the experiment the greenhouse gas was to be released in limited amounts several times during the 10-day experiment period. The project team would subsequently measure and observe how CO2 dissolved in the ambient water.Shortly before the date of the experiment, permits were withdrawn. To cut short, the project ended after 5 years with its mission not completed due to opposition from private and public stakeholders claiming that the release experiment would pollute and disturb the ocean. This happened despite repeated findings of no significant impact.The ocean sequestration project was a direct follow-up of the UN Framework Convention on Climate Change. This convention encourages research on natural CO2 sinks, inclusive the ocean, and how these sinks may be stimulated for increased uptake. The London Convention and OSPAR both opened up for research on ocean sequestration and at that time (2002) were awaiting further findings in order to be able to conduct a balanced discussion on the issue. This seemed to contradict what actually happened. The paper will discuss what happened more than 20 years ago with this ocean CO2 storage project in relation to marine Carbon Dioxide Removal (mCDR) initiatives that are being considered today.