The all important question that rises above and before ALL other questions is the one of evidence.

Is there any evidence that carbon dioxide causes major warming?

In science, “evidence” has a very specific meaning and for a very good reason. In a court of law or a game of football, the label “evidence” can be plastered all over the place. If 500 footballers signed a petition to change a rule, that would be “evidence” the rule needed changing. But if 5 billion people signed a petition to make it rain in Mumbai on Thursday, that’s a waste of paper.

Science is only about the natural world. That’s why human opinions are irrelevant.