That is assuming that CO2 actually is the cause of the latest
warming since the 1700s (really - it started back then with the
end of the mini ice age) and that humans are contributing to
this CO2 increase by more than a couple of percent.

This is one of the confusing points. The "Little Ice Age" (which was not
universal) ended roughly at the time industrialization began. Cause and
effect are not clear. However...

I'll keep saying this until someone listens. It doesn't matter whether or
not the rise in CO2 is the cause of warming. We need sources of renewable
energy that are either carbon-neutral, or emit zero carbon. If we focus on
this, the warming problem will probably take care of itself.