We cant do it now thats true. But isnt the process you described called photosynthesis? Using Sunlight (heat in form of UV Waves) to turn Smoke (CO2 and bunch of other stuff that isnt used) with Water into sugars which build the structure of plants?
Luckily it isnt that easy to burn down every server as burning carpets in south america or books in other places
Yes. And stop the criminalization of being a drug addict/user so it can be easier to end the viscious circle. Help the people to get off of it and dont punish them for using it.