Reduce Global Warming
Changes game start global warming to safe values, removes emissions from the economy priority and buffs the welfare effect of removing emissions to gigantic levels. Essentially this causes global emission levels to hover at or around safe levels so long as someone somewhere in the world is running some welfare priority.
This is done by editing values in the game templates to buff 2 environmental techs to insane levels and granting those techs at the start of the game, plus removing all emissions the game starts with. I have removed all other mentions of emissions in other techs and instead just let them have a bonus to economy/welfare.
This does mean that nuclear winter is easier to trigger since the planet is cooler already, I haven’t found a good way to edit values relating to stratospheric aerosols yet.