I dont.
Why do you think so?
My brother visited relatives in Hungary, and when returned brought a large indigo colored shopping bag, written on it: óriási zöld táska - by luminescent green.
On their own, no, but they do help in keeping plastic/paper bags out of the landfills, and if less plastic/paper bags are in demand, then less will be produced, which conserves energy.
No. not really. I've found that with the small green shopping bags that the Martians want them back - - - - Let's be sensible for once and get this recycling issue sorted - - - - FART IN A BOTTLE TO PRESERVE ENERGY !!