How high can it go? Petrol that is

Then there’s the well-funded greenhouse denialist think-tanks on the lookout for any evidence, argument or anecdote that might raise public doubts - legitimate or otherwise - about the growing strength of the scientific consensus. Mr Ehrlich’s ridiculous predictions furnish them with excellent examples of how irresponsibly some environmentalists have prosecuted their case. (Some friend to the environment he turned out to be.)

So lots of uncertainty remains. As ever, in the long run, our luck will turn on the underlying logic of the situation.

Some people think our climate has natural inbuilt stabilisers. As CO2 concentrations and temperatures rise, greater plant growth could absorb lots of our CO2 emissions, neutralising the problem.

But as well as benign, stabilising “negative feedback” - like thermostat or the supply and demand of resources I discussed above - there’s also the destabilising kind of feedback.

That’s “positive feedback” like a microphone that’s held too close to a speaker or a hyper-inflation spinning out of control. As warming melts polar ice-caps, their smaller size reflects progressively less of the sun’s warmth back into space and so contributes to further warming and things go from bad to worse. You get the picture.

Who knows which kind of effect will dominate? But in the long term, though the pain you’re feeling at the petrol bowser might feel like a problem, it’s actually part of the solution - for our economy and very probably our planet.