Dark Magus... if I may put Monbiot's test to you (since you know so much about science and all)...
1. Does the atmosphere contain carbon dioxide?
(i.e. can it be shown to contain carbon dioxide experimentally?)
2. Does atmospheric carbon dioxide influence global temperatures?
(i.e. does the available empirical data demonstrate that sunlight, when converted to heat by atmospheric, land or sea absorption, is less likely to then escape the atmosphere if the atmosphere contains carbon dioxide or other so-called "greenhouse" gases?)
3. Will that influence be enhanced by the addition of more carbon dioxide?
(i.e. is there a proportional relationship between the amount of so-called "greenhouse" gases in the atmosphere and the amount of heat retained?)
4. Have human activities led to a net emission of carbon dioxide?
(i.e. has the combustion of extracted fossil fuels released carbon dioxide into the atmosphere which would not have been released had we not burnt the fuel?)
To which of those questions do you believe the answer is "no" or "undetermined"?