Rhoda, scientists don't have a monopoly on spreading alarm. Sceptics like to cry the 'end of civilization as we know it' if we stop digging things up and burning them.

I'm sure there are plenty of people studying feedback, but research results don't come to order. And there are suggestions of tipping points beyond which positive feedback might take over (eg arctic gas hydrates) but discussion of those is according to Martin a demonstration of ill-will; why should that be?