You posted a link to a rabbithole of fascist-cheering, bone-stupid argumentation, and conspiracy theory. Setting aside their fairly obvious attempts at political astroturfing, the depths to which those people are lying with regards to AGW to people who lack the scientific literacy to evaluate the arguments being made is appalling. So are their race-baiting shithead politics, but this more bluntly--I mean, this is math.

I make this post assuming you're not in on it.

Plants are often limited by resources other than CO2. Also, high temperatures reduce crop yields in most places.

Wait, you think that we should triple the CO2 levels? Humanity's well-being on this earth is not exactly bottle-necked by our current ability to produce plant matter, and at 1200ppm I'm pretty sure we'll discover lots of new and exciting (not-good exciting) ways that our survival is bottle-necked.