To live, we need air and we need water. To live our comfortable 21st century lives, we need sand. We use it to construct our homes and our roads, our computers and our glass, and even the tires on our cars. If it disappears, it won’t come back for millennia.
We take sand for granted, assuming that it’s a renewable resource, and even if it’s not, surely the deserts have enough sand to supply even the most voracious building boom?
No, they don’t. Desert sand is created by wind erosion, making the molecules too round to be useful for construction aggregates.
The coastal areas of Earth’s continents consist of rock and sand in the form of beaches, caused by the action of water on rock. These beaches are attractive places to live and to visit, meaning that the planet’s population gravitates to coastal areas. The pressure on the world’s beaches grows every year, with hotels, condos, and housing encroaching further and further on the sandy shores.
Beaches are living things, and they need room to breathe. When those attractive, and expensive, waterfront highrises are built, closer and closer to the water line, the sand has nowhere to go and the area runs the risk of erosion because the sand will be carried away by the action of the waves. Even the billionaire residents of Malibu, California, can’t stem the tide of erosion despite their plans to dredge the ocean and relocate the sand to their front yards.
Further away from the shore, damming rivers for hydroelectric projects also prevents new sand from reaching the beach: a river that has been dammed will not flow fast enough to wear down the rocks that eventually become sand, and even if it does, the sand will be trapped by the dam. Furthermore, river sand is ideal for construction, so harvesting it deprives the coastal beaches of even more replenishing material.
Encroachment and the inability to replenish themselves are not the only threats to the world’s beaches. Sand has become an incredibly valuable commodity, and harvesting it, both legally and illegally, has become a huge issue for coastal conservation. Seventy per cent of the world’s beaches are disappearing, fast. We use 40 billion tons of sand every year, for construction and industry.
And the saddest thing about this is that although it is often stolen to be re-sold to developers for construction, saltwater sand is entirely unsuitable for building because its high salt content will corrode the rebar. From Antigua to Zanzibar, building with beach sand has been made illegal because the structures will collapse after about 30 years. Only freshwater river sand can be used untreated in construction. To be used legally, sand harvested from ocean beaches must be treated with desalinating processes, which adds to its cost. Concrete made with sea sand aggregate is illegal in many places, although this doesn’t stop unscrupulous builders.
In India, organized crime controls the sand business: hundreds of people have died because they got in the way of Indian developers’ voracious appetite for sand. Speculators have built thousands of condo units, for example, that will sit empty for decades while India’s poor are confined to slums because of the lack of affordable housing.
In the Chinese city of Shenzhen, the Ping ‘An building, meant to be the world’s tallest after the Burj in Dubai, has had to halt construction because authorities discovered substandard sea sand in its construction. And several other buildings in Shanzhan alone have suffered from this problem.
Ironically, the presence of sand causes just as much conflict in some places as its absence. The city state of Singapore, for example, is “reclaiming” acres of territory in the body of water that separates it from its neighbour, Indonesia. The three-mile limit of a nation’s territory can be expanded by some judicious sand deposits and disputes are raging all over the world as countries dredge sand from one place and use it to build usable landmass in another. The famous palm tree and earth-shaped developments in Dubai, for example, are built on sand. And in China, “reclaimed” land created by blowing sand onto living coral reefs and covering it with concrete, is being used to establish military bases in previously inaccessible areas.
No matter how noble the reason, dredging sand from the bottom of the ocean to rebuild the coastline is environmentally dangerous as well: a dredger sucks up everything in its path—sand, marine life, coral, and archaeological materials—and grinds it up before spewing it onto the shore.
As with all of our other resources, we have squandered sand and now we are paying for it. Rocky shorelines are undoubtedly beautiful, but only when they are the result of natural forces. When our sandy beaches disappear into the concrete jungle, we will be very sorry.