Well yeah, if container ships wouldn't be as horribly efficient, manufacturing everything in China, or shipping various stages of garments halfway around the world, which leads to the finished product having traveled more than those that have worked on it will in their lifetime, wouldn't be possible. The problem with container ships is not just the CO2, but also that they burn the worst of the worst fuel (https://en.wikipedia.org/wiki/Fuel_oil#Environmental_issues).