Shipping is an extremely efficient way to move bulk goods around the planet, but it's responsible for around 3% of global man-made carbon emissions, and the unique energy requirements of long-haul cargo ships make them extremely difficult to decarbonize.There are all manner of technological solutions in the pipeline: hydrogen, green ammonia and methanol powerplants, flettner rotors, heaving oscillators... There's even been a return to giant sail-wings, as well as giant autonomous kites designed ...