Now why do you suppose nobody believes them?
Years ago I decorated an American Express committee that reviewed their financial services marketing. Fortunately for them someone far wiser was also involved - Lester Wunderman.
I always recall him commenting on constant discounting, "You are training your prospects to expect bribes".
This came to mind when I saw that despite the endless propaganda of those who run things, most British people think Global Warming is a load of old bollocks.
The reason is perfectly clear.
Gordon Brown, the Bliar, Cameron - and many of the others - are habitual, incessant, condescending, unrepentant, bare-faced liars. So any sane person must assume whatever they say is untrue. They lie about everything else. Why not this?
Anyhow, actions speak louder than words. If a smarmy oaf like Al Gore or a tax-dodger like Bono flies round the world in a private jet to tell you carbon emissions are killing the universe you have to assume they're as full of shit as Christmas turkeys.