The human industrial complex requires enormous inputs of natural resources to build and extend itself. If you rank these raw materials by volume used, number one will be water. Number two will be sand.

Hard to accept? Go anywhere in the world and look around. If you’re in a city looking at a high-rise building, it’s probably mostly concrete (sand), just like the streets, sidewalks, bridges, and the freeways with their interchanges and ramps. The windows in the skyscrapers and storefronts are glass (sand). Some buildings are made of brick (sand) or block (sand). And some of the highways are asphalt (sand). Out in the country most houses may be framed with wood, but they rest on foundations and basements of concrete and block, and many of them are roofed with asphalt shingles. I’m finding this out, and telling you about it, using computer chips made of sand.

The world uses a lot of sand; 50-60 billion tons a year, according to the United Nations Environment Programme, and the demand curve continues to climb precipitously in Asia. China poured more concrete in two years, 2011-13, than the United States poured in the entire 20th Century. The fracking revolution that recently gripped the US oil industry is built of sand, as well; by 2012 frackers were using 30 million tons of sand a year, nearly overwhelming the existing supply chain.

Of course, we are running out of sand. Like fossil fuel, it takes thousands of years to produce, and we are using it far faster than the world can replace it. As with everything else, our response to this rapidly approaching existential crisis is to use the stuff faster.

One additional supply-limiting factor is that desert sand, rounded and smoothed by wind, cannot be used for most purposes, only water-shaped sand, which retains its jagged edges and binds well with others. All over the globe, sand is being dredged from the ocean floor, scooped up from river beds and scraped off beaches; it’s a 70-billion-dollar-a-year industry, most of which is either unregulated or flatly illegal.

The environmental damage being done is immeasurable. The thousands of large dredge boats working the coastal oceans of the world are disrupting ecosystems, killing marine life and altering the ocean’s currents and tides. Sand in the ocean doesn’t just lie there, it moves constantly, coming off one beach and fetching up on another, moving off shore and then into shore and along the shore. Always it tries to stay in equilibrium as it reacts to storms, construction — and dredging.

Sand dredging off the Florida coast, to provide raw material for more tourist hotels and residences, is the main reason Miami’s beaches “erode” so much every year that they have to be replenished with dredged sand — so the tourists in their sand buildings will have sand to walk on as they contemplate the timelessness of the ocean and the majesty of unspoiled nature.

The sand industry (setting aside ocean dredging) is unusually accessible to poor people, and can be practiced on a small scale that is difficult to detect and regulate. But the easily accessible deposits, on land and along stream beds, are almost all gone now and the competition for what remains is fierce. In the coastal countries of Africa, such as Morocco and Sierra Leone, “sand mafias” have sprung up that fight each other for their sand the way the real Mafia fights for its drug territories.

The good thing about these sand wars is that although they will get worse toward the end of the human industrial complex, they will expire with it. We will not have need of skyscrapers and superhighways after the crash. We will be fully occupied seeing about food and water.

The Bible calls us foolish if we build our house upon sand. What do you call people who build a global economy made of sand?