This. As with most initiatives, extremism kills good ideas. Plans for carbon-free solutions that are so impractical to implement, or only in a far future, is a dead end. What we need now is to stop theorizing and take immediate measures to reduce the footprint of the current supply chain, mostly by rationalizing global exchanges (many raw materials are sent from A to B to be transformed/packaged only for the final product to be sent back home to be sold). Further decarbonization can also be reached in a reasonable future by retrofitting current ships with rotor sails to save fuel on windy days without impacting regular operations. The rest is science-fiction, and a waste of time and energy.