IMO the main problem with cargo ships is that the bunker oil they use is super dirty (in terms of NOx, SOx, and particulate emissions), not that it’s inefficient in terms of CO2 per ton-kilometer. (That said, there’s still room for improvement on the latter, by using sails – either the traditional kind or the newfangled computer-controlled kite sails.)
IMO the main problem with cargo ships is that the bunker oil they use is super dirty (in terms of NOx, SOx, and particulate emissions), not that it’s inefficient in terms of CO2 per ton-kilometer. (That said, there’s still room for improvement on the latter, by using sails – either the traditional kind or the newfangled computer-controlled kite sails.)