I don't know why the greens have such a down on CO2, it is a harmless plant food and so necessary for life on this planet.
They talk about it being a greenhouse gas - indeed it is used in many commercial greenhouses to increase crop yields, but there are other gases that are much more potent as a heat trapping blanket around the earth, the main one being water vapour.
The also talk about an 'ideal' average air temperature but ignore the fact the air temperature of the earth has changed from the ice ages to much hotter than the medieval warm period which was much warmer than now.
The fact that the atmosphere is a chaotic system implies that they, the climate scientists, will never totally understand it or make meaningful computer models of it.
The globe has cooled and warmed many times and by now man should be able to use technology to keep himself alive byt unfortunately the greens do want us to use technology, they want us back in some bohemian utopia which has never existed.