A WHILE AGO I went to a lecture on geothermal power. Afterwards I got talking to the man sitting next to me, a retired professor of physics. When I told him I was a writer, his face lit up. A writer? Ah, you’re the people the planet needs! You must get the message out – it’s simple, just four words – coal is too cheap! Get that into every newspaper and magazine! Oh, well, I mumbled, I’m not that sort of writer. He peered at me. Uh, actually, I blurted out, I’m a fiction writer. His face fell. Fiction? You mean you write…novels?

Coal is too cheap. That was the message that was going to save the planet, and I was not the person who was going to deliver it. My new acquaintance was right: as far as I know, the cheapness of coal has never been the subject of a novel. Stung by his dismissal, I toyed with the idea of writing the great coal-is-too-cheap novel.