I’m a sucker for chocolate cake. You put a piece in my view and I want it. What’s more, I’ll probably eat it. I’m one of those Dads who will hide behind a cupboard door to stop the kids seeing me snarfle a chocolate biscuit. The temptation is always too strong. I am weak.

That’s why I gazed with despair on the Earth Day headline that scientists have declared we must leave 75% of fossil fuel reserves unburnt to avoid catastrophic climate change. All those easy calories – doesn’t matter how many times we are told they are bad for us, while they are accessible, the temptation will always be there.

Many ‘greens’ act like food fascists, sneering at the contents of the shopping baskets of those ahead of them in the supermarket queues. It might make them feel better, but it won’t do anything to stop obesity.

You can blame politicians, but frankly, it takes a brave soul to stand up and say to the country we must sacrifice short-term gain for the sake of our grandchildren. Actually, it’s very easy to say, many do now say it, and many will support the words. The brave bit comes from putting words into action – and we must support them when they do, not the usual fusillades of ‘nowhere near good enough’ from those who have never had to make a big public decision in their lives.

The answer? I find I can drop the sugar hit if I get it out of my routine. Likewise we’ve got to get fossil fuels out of the routine of Joe and Josephine Public. We’ve got to make sustainability the new normal: easy, intuitive, reflexive, unthinking, desirable. Only then will we wean ourselves off fossil fuels.