Here's a nifty experiment you can do at home that debunks the whole CO2 is a greenhouse gas mythology. The experiment shows that CO2 only reduces the temperature and it has to actually go well above the most dire of currently projected levels to do that. That much CO2 would make plants grow more thickly and spread more rapidly. An abundance of CO2 could theoretically turn deserts into grasslands and forest rather than the opposite thing.
But then, that probably wouldn't convince people to create a global collectivist state, give up their cars and move into hive cities where the central planners could more easily centrally plan.
So for now they'll likely stick to the CO2 is bad thing.