Going to the beach today? Well, guess what: The world is running out of sand. Yes, sand. That seemingly infinite stuff covering beaches, riverbanks, and deltas around the world is in short supply as global demand increases year by year.

Sand is used to make glass, electronics, and aeronautics—but by far its biggest use is in construction. That’s because sand is an essential ingredient in the production of concrete. As cities grow larger and taller—think Dubai, Shanghai, and Mumbai—they use increasing amounts of sand to build skyscrapers, sidewalks, and all the other infrastructure that supports growth.

U.S. Geological Survey figures suggest sand and gravel use in construction alone accounts for about 30 billion tons a year globally. Combined with the sand and gravel used for land reclamation, embankments, concrete roadways, and industry, a conservative estimate for total annual consumption is around 44 billion tons.

According to the USGS, China, India, Brazil, the U.S., and Turkey are the world’s biggest concrete producers, with China and India together accounting for two-thirds of total production. But when it comes to sand consumption, there’s no contest: China gobbles the most by far as its megacities expand. In the past 20 years, cement demand in China has increased by an astronomical 437 percent compared to about 58 percent in the rest of the world, according to the United Nations Environment Program.

There seems to be plenty of sand in the world's deserts. Can't we use that? Not really. Desert sand is eroded predominantly by wind rather than water, and as a result it's too fine to be used in most construction materials. Until recently, most construction sand was mined from riverbanks and quarries. But with the dramatic increase in demand, marine and beach sand mining are increasingly common.

No matter where it occurs, sand mining has a tremendous impact on the environment. It causes flooding, leads to biodiversity and land loss, damages infrastructure like bridges and embankments, pollutes rivers and groundwater, and destroys beaches. Greenhouse gas emissions associated with sand extraction and transport take a significant toll as well.

As sea levels rise and development eats away at beaches, the impact of coastal and marine sand mining will intensify. River mining has already led to the destruction of entire ecosystems. Governments are responding with stronger regulations to monitor and control sand extraction in areas where it is likely to lead to costly environmental or infrastructure consequences.

But poorly enforced regulations in developing countries—particularly in parts of Africa and Asia—have created unintended consequences: a thriving black market in illegal sand mining, and sand mafias that exert control through threats, bribes, and violence. Yes, there are sand mafias. Some criminal syndicates deal sand now.

So far, no one has come up with a single replacement for natural sand that can keep pace with demand. But together, the alternatives may have some impact. Recycling concrete, quarry dust, and even glass bottles can help reduce demand. Replacing concrete with sustainable materials like straw and recycled materials in home and road construction is another partial solution.

Researchers are also developing natural sand alternatives. A team of engineers based in the UK are trying out a new concrete formula in India that replaces some sand with tiny plastic particles. And breakthroughs in self-healing bioconcretes are helping to extend the life of structures that would require a lot more sand to rebuild.