You say it all in the final sentence, Skippy. It's what RDH calls the "phoney bone of contention". We get drawn into the pointless argument over which is responsible and by doing so we automatically accept that CO2 is the culprit.
Once we accept that CO2 is to blame it becomes moot whether volcanoes or mankind produce the most. We can do bog all about volcanoes but even if man's contribution were the smaller, we can in theory reduce that, thereby helping to offset global warming.
Note that above I say "we automatically accept that CO2 is the culprit". That tends to suggest that I believe global warming is happening, which I do not. So it's a double phoney bone of contention in that you first believe the problem exists then you argue over how to cure it.
Next on the agenda is the sugar tax. How many recall, two years ago, the legend of the failing sugar crops of the world? This latest scam is simply to increase taxes. I even overheard two guys on ham radio debating the issue and coming to the conclusion that a sugar tax can only be a good thing, sugar being the root of all evil, destroying health etc.
And these are supposed to be clever people, capable of passing stringent exams!
If it were true, wouldn't the best course of action be to educate people, not to fine them for eating a bag of jelly beans?