The Mekong River, near Si Phan Don, southern Laos. Photo by Basile Morin.
I don’t often think about it, but every time I look at the high-rises that are under construction in all directions around my condo, I am gazing at 500-foot-tall piles of sand.
It takes a lot of sand to make concrete – between six and seven tons of sand for each ton of cement. The world is consuming vast amounts of the stuff for construction projects from South Florida (where I live) to Singapore. And we don’t only use sand to make concrete. It is an essential component for glass, for the silicon chips that power our devices, for the slurry pumped into the ground in hydraulic fracturing to produce oil and gas, and even for enlarging existing islands and building entirely new ones.
Sand mining is likely the largest extractive industry on Earth. It represents 85% of all mineral extraction. As much as 50 billion tons are dredged each year. Yet most of us scarcely give sand a second thought in daily economic and political life.
This is beginning to change. Any extractive industry carries some environmental cost. Those costs are apt to be unjustifiably and intolerably severe when the extraction is carried out rapaciously, carelessly and corruptly. Amid a global construction boom that has sent demand for sand soaring in many places, conservationists are starting to get some traction in pointing out the consequences.
Coastal beaches and river beds are the main sources of the most-prized sand. The world’s deserts have plenty of the stuff, but eons of exposure to wind has rendered most of it too smooth and fine for commercial use. Some usable sand comes from ancient quarry deposits via so-called static extraction, but these supplies are limited. To make up the difference, the industry turns to “dynamic extraction.” This pushes much of the world’s sand extraction into environmentally sensitive marine and riparian environments.
Near the mouth of the Mekong River in Vietnam, sand dredging has lowered the riverbed by between two and three meters – nearly 10 feet at the top of that range – since 1990, the BBC recently reported. Since the supply of fresh water in the river is unaffected, the extra space is filled by an intrusion of salt water that injures wildlife and poisons croplands.
River sand is a renewable resource, up to a point. Left to their own devices, most rivers – including the Mekong – will bring substantial quantities of material downstream. A certain amount of extraction is sustainable and the environmental costs are tolerable, if the process is well managed. But this requires a level of governmental and commercial integrity that is not the rule in many places.
In Asia and Africa, violent gangs control and protect illegal extraction, often while authorities turn a blind eye. Exporting Mekong River sand has been against the law in Vietnam since 2009, and in Cambodia since 2017. Yet the BBC reports that Mekong sand is still easy to order online. Poor countries, including Caribbean locales like Jamaica and Haiti, are prone to damaging forms of extraction. In Britain, sand extraction has been pushed offshore into the waters east of England, where environmentalists say it is injuring important aquatic habitats.
There are some substitutes for industrial sand. Recycling glass and old building material can reduce demand for newly mined minerals. But given the open trade and light regulation of sand extraction in many places, recycling often can’t compete economically. Researchers are also exploring ways to make manufactured sand by crushing larger rocks. Manufactured sand is cheaper than the natural kind, but at least so far, its quality is lower.
Here in America, the last beachside sand mine – a facility near Monterey, California – is scheduled to close this year, according to the U.S. Geological Survey. Lower oil prices in recent years have curbed demand for sand in hydraulic fracturing, even as new mines opened in the Permian Basin region of Texas and New Mexico where much of the “fracking” boom has taken place. As a result, some older mines in Wisconsin have been forced to close. American fracking sand, meanwhile, is being shipped as far away as Argentina to find buyers in the oil fields.
The emerging attention to sand is a reminder that everything comes at a price. Sometimes the market price does not reflect the real costs associated with a carelessly produced commodity. We can’t afford to stop this sort of progress entirely. Too many people here and abroad need the sort of modern shelter that is rising all around my Florida home. But we can remember that our towers of concrete and glass are really castles made of sand, and we can be more careful about how we get the stuff from which we build them.