I was eight years old when I was first taught about “the greenhouse effect”. What I remember is the fear. The teacher sketched a picture on the board: our planet, inside a greenhouse, with a little thermometer drawn so as to suggest it was about to explode with the rising heat. The Earth had beads of sweat on its face.

The grown-ups would fix it all, I thought. The people in charge wouldn’t let such a devastating future come to pass. I would grow up into a world where there were still ice caps and polar bears.

That childish belief finally perished around the time I discovered, on a visit to London Zoo, shortly after leaving school, that the Amazon rainforest – the lungs of our world – was being destroyed at a rate of 150 acres per minute.