> For shipping this inevitably means to switch to green fuels (e.g., Ammonia). Once the production of such fuels has reached a certain scale, sails might not be

> For shipping this inevitably means to switch to green fuels (e.g., Ammonia). Once the production of such fuels has reached a certain scale, sails might not be necessary anymore. Green fuels will need to ramp up their production to meet the demand, better actual efficiency (not just financial) means that ramp up wouldn't need to be as steep as the demand won't be as high so we will have an easier time actually filling that demand. It's a bit like not changing to more energy efficient light-bulbs based on the assumption that in 20 years green fuels will make electricity so affordable, and emissions neutral, that it allegedly won't matter. One could do that, but if the cheap green energy doesn't end up materializing in that time then you did nothing to reduce to problem and end even further removed from an actual solution.