That's like saying "cooling a stationary house is littering". Operating a device for the comfort of the user is precisely why we make things like AC, whether it's in a car, a boat, or a house.
I assume (perhaps I should not) that by "littering" you are referring to the production of greenhouse gases. If this is so, I'd like to point out that if you are breathing, by your definition, you are littering with every breath.