James Delingpole describes the global warming ideology in terms of groupthink rather than conspiracy:
Rule Two. Because their common view/belief cannot be subjected to external proof they have to reinforce its authority by claiming ‘consensus.’ The idea is to emphasize that all right-thinking people hold this view and that it is no longer open to challenge.
Accreditationism fulfills these three rules also. It may have started as a conspiracy to keep factory inspectors employed but it continues through groupthink in the organisations that fall for the cartel’s sales pitch.