Consider there is no opposition but physics.
That makes it seem doable.
First, I’d ban the use of all fossil fuels. Next, the use of chemicals (like pesticides and weed killers) which harm the environment. Forests could no longer be destroyed to create grazing land for animals. People would have to become completely vegetarian, or only eat meat very rarely. Fishing would need to be brought down to sustainable levels. Factories would be required to either completely reduce their damage to the atmosphere or shut down. Microplastics would need to be eliminated, which would affect countless things. Lastly, we’d focus on cleaning up messes we’ve already made.
Basically, businesses, governments, and individuals would have to put environmental impact first every time a decision is made.
I’m sure I missed a few things. I can’t go into detail as you asked, because I am not educated enough on any of these topics.