There are always extremists. As it is we can actually measure how much added CO2 is due to us, and it is about all of it. So we know we are causing the climate to destabilise.
Yes, and no. It makes plants grow bigger, but with slightly less nutrients. Plants are being hurt by climate change as many plants depend on the climate they come from.
Well the thing is what's important is weather or not [pun intended] CO2 actually has an impact on our climate. Do some deeper digging into some real data.... might piss you off
Yes, it does have a deeper impact. The world takes thousands of years to absorb added carbon. So the rate we add it is too much for the carbon slicks to absorb. I did dig.