Cooking is art, baking is science.

Shipping? Shipping is about 2 % of global CO₂ emissions.

Large ships emit a lot of sulphur oxides (SO_x). E.g. cruise ships emit more than all cars of Europe. SO_x is not a greenhouse gas, but it’s a nasty pollutant nonetheless.

It’s cheaper. In Japan manga volumes are about 700 yen, which is about $5 currently. No budget for color printing there. Manga is often drawn by one person who is already massively overworked just to hit serialization deadlines, so no time (nor budget for assistants) for coloring.