But now comes word that it isn’t just wildlife that can go extinct. The element gallium is in very short supply and the world may well run out of it in just a few years. Indium is threatened too, says Armin Reller, a materials chemist at Germany’s University of Augsburg. He estimates that our planet’s stock of indium will last no more than another decade. All the hafnium will be gone by 2017 also, and another twenty years will see the extinction of zinc. Even copper is an endangered item, since worldwide demand for it is likely to exceed available supplies by the end of the present century.

Running out of oil, yes. We’ve all been concerned about that for many years and everyone anticipates a time when the world’s underground petroleum reserves will have been pumped dry. But oil is just an organic substance that was created by natural biological processes; we know that we have a lot of it, but we’re using it up very rapidly, no more is being created, and someday it’ll be gone. The disappearance of elements, though—that’s a different matter. I was taught long ago that the ninety-two elements found in nature are the essential building blocks of the universe. Take one away—or three, or six—and won’t the essential structure of things suffer a potent blow? Somehow I feel that there’s a powerful difference between running out of oil, or killing off all the dodos, and having elements go extinct.