Bluntly: too late. You'd have to rewind to 2001 or so and go on the strictest measures worldwide. But we are utterly unequipped to deal with global issues, the Ozon layer success notwithstanding.

Get in a time machine. Go back to 1970. Make sure world starts phasing out all coal power by 2000, replacing with nuclear and what renewables are available then, and make sure modular scalable reactors are available for China so they use that instead of coal to power their rise. Convince everyone that late 20th century unscientific greens are full of shit and nuclear power is better than coal.

(Renewables were not fully competitive with fission until the 20teens, too late.)

It’s dialed in.

That’s not to mean replacing stuff with non carbon emitting sources today is worthless. It’s very important. Right now we are dialing in the next escalation of the problem, and we can still blunt that if we give a damn.

One thing you can do today is keep arguing against the romantic anti industrial unscientific greens. Degrowth and “abstinence based” policy will never work. People will never go for it, and we are never returning to pre industrial times. It’s a fantasy. If you try to force it people will elect anti environmental populists (as they have) and you will get the opposite of what we need.

Fantasies displace realistic solutions in the discourse, and “everyone needs to become poorer” gives anti environmental and fossil fuel industry shills a way to frame their case as “we are on the side of human development.” Don’t give them that argument. Stop it. It also won’t work with developing nations. “Hey Africa, we know we colonized you and all but can you do us a favor and stay poor to help fix the problem we mostly caused?” There is not enough “fuck you” in the universe for that one.

The solution is to replace fossil fuels with non carbon emitting sources, not to stop people from using energy.

Unironically the anti nuclear luddites killed the main chance to be divert climate change that we had over unfounded fearmongering