'CO2 causes atmospheric warming. The underlying principles are simple and sound. We are emitting tons and tons of CO2 by burning vast quantities of fossil fuels.'. Yes, we know all this and there isn't a single skeptical scientist from Richard Lindzen onwards (and let's include the non-scientist Myron Ebell) who takes issue with that statement. The core question is a quantitative not qualitative one.

By the way, who are the groups 'pouring millions' and where do they state that they are 'trying to prove global warming is not happening'? It's probably best to keep to salient facts because 'None of their supposed "evidence" has withstood peer review or scrutiny' is a cheap, easy aside to make if we don't know who they are or to which evidence you're referring.