Earth's elements in danger of being used upS

It's one thing to use up the world's supply of a complex substance like oil. It's another to extract and deplete Earth's entire stock of a chemical element. We'll be out of gallium in less than a decade, warns science fiction author Robert Silverberg, thanks to its use in flat-panel TV and computer displays. Not far behind is zinc, with an estimated 30 years to depletion. Copper, too. There's only one proper capitalist response to the situation: Clear those three spots on the periodic table, and replace them with ads.