In scores of countries across the globe, a crisis is building around the world's most important and yet most overlooked commodity: sand.
We use more of this humble natural resource than any other except water and air. Sand is the thing modern cities are made of. Every apartment block, office tower and shopping mall from Beijing to Lagos is made at least partly with concrete, which is basically just sand and gravel stuck together with cement. Every yard of asphalt road that connects all those buildings is also made with sand. So is every window in every one of those buildings.
Sand is the essential ingredient that makes modern life possible. And, incredibly, we are starting to run out.
That's mainly because the number and size of cities is exploding, especially in the developing world. Since 1950, the world's urban population has ballooned to over 3.9 billion from 746 million. To build those cities, people are pulling unprecedented amounts of sand out of the ground.
There's so much demand that riverbeds and beaches are being stripped bare, ocean beds denuded, and landscapes devastated. (Desert sand, shaped more by wind than by water, generally doesn't work for construction.) Governments are cracking down in response—which in turn has spawned a worldwide black market in sand. In a shocking number of countries, people are being imprisoned, tortured and murdered over sand. Still, the amount of sand being mined worldwide is increasing—at terrible costs to people and the planet.