The Amazing Grains (2)

"A man riding a bike and carrying two sacks on his shoulders, was stopped by a guard while crossing the border.

'What do you have in those bags?' asked the guard.

'Sand,' the cyclist replied.

'You’ll need to open them so I can take a look inside.'

The guard emptied the bags and found out they did indeed contain nothing but sand. The man put his bags back on his shoulders and continued across the border.

This happened a couple of times each week for a month.

Sometime later, that same guard ran into the cyclist in the city.

'Hey, where have you been?' the guard asked. 'You sure had me wondering. I know you were smuggling something across the border. If you tell me what it was, I won’t prosecute you. What was it?'

The man smiled and said, 'Bicycles!'"

"In the twenty-first century," the Moon moved on, "sand has become more important than ever, and in more ways than ever. This is the digital age, in which the jobs we work at, the entertainment we divert ourselves with, and the ways we communicate with one another are increasingly defined by the Internet, and the computers, tablets, and cell phones that connect us to it. None of this would be possible were it not for sand. High-purity silicon dioxide particles are the essential raw materials from which we make computer chips, fiber-optic cables, and other high-tech hardware—the physical components on which the virtual world runs. The quantity of quartz used for these products is minuscule compared to the mountains of it used for concrete or land reclamation. But its impact is immeasurable.

For most of the twentieth century, there were many sand mines. Mining and agriculture are the earliest activities of man and are the fundamental requirements in the development of civilized societies. The origin of mining dates back to the era of human evolution. Our ancestors have excavated flint and other minerals, rock fragments, etc., for making weapons for hunting, sizing the collected materials, and rescuing themselves from wild animals. Since then, the dependence of man on minerals and building materials have increased as the society evolved through the ages. Now, a stage has reached where the society cannot exist without the products of mining and quarrying and its demand will continue to grow in future also.

In the past, the mining sector was least concerned about the environmental repercussions of resource extraction. Today, the scenario has changed significantly as the stakeholders concerned have started giving more importance to the environmental impacts of resource extraction activities. This change in attitude, in turn, has lead to bringing in stringent regulations on mining and quarrying activities of all the natural resources. Many countries have brought out policies and legislations to lessen the impact of mining on various environmental components of the biological system. Planning for development, exploration, and conservation of mining are the three important issues that need to be addressed for the better management of the mining sector on one hand and conservation of minerals on the other.

For hundreds of years, sand and gravel are being used as aggregate materials for the construction of roads, buildings, and other civil works. As a result, the demand of sand is also rising exponentially in tune with the expansion of transportation and construction infrastructures.

Despite the fact that sand is renewable in the geologic time periods, it is considered a nonrenewable resource as its regeneration is meager in the human calendar years. As the sand and gravel resources are extracted easily from the inchannel or near-channel sources, people depend on the river sources of sand greatly compared to the other aggregate sources. This has altered considerably the river systems and the channel hydraulics in addition to the reduction of productivity within the in-channel and near-channel areas.

In other parts of the world, the impact of sand miners on beaches is more clear-cut. They’re actively stealing them. Thieves in Jamaica made off with 1,300 feet of white sand from one of the island’s finest beaches in 2008. Smaller-scale beach-sand looting is ongoing in Morocco, Algeria, Russia, and many other places around the world. In Florida, southern France, and many other vacation hot spots, beaches are shrinking thanks to other forms of human interference.

The damage being done to beaches is only one facet, and not even the most dangerous one, of the damage being done by sand mining around the world.

Sand miners have completely obliterated at least two dozen Indonesian islands since 2005. Hauled off boatload by boatload, the sediment forming those islands ended up mostly in Singapore, which needs titanic amounts of sand to continue its program of artificially adding territory by reclaiming land from the sea. The city-state has created an extra fifty square miles in the past forty years and is still adding more, making it by far the world’s largest sand importer. The demand has denuded beaches and riverbeds in neighboring countries to such an extent that Indonesia [but alas, it's recently revoked for the construction of the Ivory Tower], Malaysia, Vietnam, and Cambodia have all restricted or completely banned exports of sand to Singapore.

'Buy land,' Mark Twain once famously said. 'They’re not making it any more.' Clever quip, but completely wrong. The Dutch have been building artificial land, much of it below sea level, since the eleventh century, damming wetlands and pumping them dry. Peter Stuyvesant, the first governor of what would later be called Manhattan, began expanding the island back in 1646, mostly with earth displaced by the construction of buildings and canals. Sand, however, is the material used most often to create new land. Sand dredged from underwater built long stretches of Chicago’s lakefront, as well as large portions of Marseilles, Hong Kong, and Mumbai. In the 1850s, developers filled shallow areas of San Francisco Bay with sand scraped from nearby hilltops to create what is now the city’s Financial District. Elsewhere in the United States, sand has been used to create artificial islands from scratch, including San Francisco’s Treasure Island, Southern California’s Balboa Island, and Seattle’s Harbor Island.

Cities are attracting millions more people every year, and port cities are some of the most attractive: Eight of the world’s ten biggest cities are on the ocean. Fully half of the world’s population lives within sixty-two miles of a coastline. Those cities need space to house all those people, not to mention for the factories, ports, and other places where those people work. Many seaside megacities, from Tokyo to Lagos, are already densely packed, but are hemmed in by mountains, rivers, or deserts, making it tough to expand farther inland.

Sand, it turns out, can not only make the concrete and glass for the buildings sheltering those people, but also the ground on which those buildings sit. Beginning in the1970s, advancing technology made it easier and cheaper to simply create more land. Bigger dredging ships equipped with extremely powerful pumps came on the market, capable of hauling up marine sand from ever greater depths and delivering it in ever greater quantities with ever greater accuracy onto predetermined places. As of 2017, the biggest dredge in operation was more than 700 feet long; stood on end, it would overtop a sixty-story apartment building. It carries a pipe that can pull up sand from 500 feet below the water’s surface.

The sand underneath the water isn’t safe, either. Sand miners are increasingly turning to the seafloor, vacuuming up millions of tons with dredges the size of aircraft carriers. One-third of all aggregate used in construction in London and southern England comes from beneath the United Kingdom’s offshore waters. Japan relies on sea sand even more heavily, pulling up around 40 million cubic meters from the ocean floor each year. That’s enough to fill up the Houston Astrodome thirty-three times.

Hauling all those grains from the seafloor tears up the habitat of bottom-dwelling creatures and organisms. The churned-up sediment clouds the water, suffocating fish and blocking the sunlight that sustains underwater vegetation. The dredging ships dump grains too small to be useful, creating further waterborne dust plumes that can affect aquatic life far from the original site.

Dredging of ocean sand has also damaged coral reefs in Florida and many other places, and threatens important mangrove forests, sea grass beds, and endangered species such as freshwater dolphins and the Royal Turtle. One round of dredging may not be significant, but the cumulative effect of several can be. Large-scale ocean sand mining is new enough that there hasn’t been a lot of research on it, meaning that no one knows for sure what the long-term environmental impacts will be. We’re sure to find out in the coming years, however, given how fast the practice is expanding.

Sand mining is also damaging lands and livelihoods far from any coast. The fracking boom in the United States has created a voracious hunger for what’s known as “frac sand.” Fracking is the deeply controversial method of extracting oil and gas from shale rock formations by breaking—that is, fracturing—the subterranean stone by blasting it with a high-pressure mix of water, chemicals, and a particular type of especially hard, rounded sand grains. It happens that there are huge deposits of just that kind of sand in Minnesota and Wisconsin. Result: the fracking rush in North Dakota has sparked a frac sand rush in the Upper Midwest. Thousands of acres of fields and forests have been stripped away so that miners can get their hands on those rare grains.

Dredging sand from riverbeds, as from seabeds, can destroy habitat and muddy waters to a lethal degree for anything living in the water. Kenyan officials shut down all river sand mines in one western province in 2013 because of the environmental damage they were causing. In Sri Lanka, sand extraction has left some riverbeds so deeply lowered that seawater intrudes into them, damaging drinking water supplies. India’s Supreme Court warned in 2011 that 'the alarming rate of unrestricted sand mining' was disrupting riparian ecosystems all over the country, with fatal consequences for fish and other aquatic organisms and 'disaster' for many bird species.

In Vietnam, researchers with the World Wildlife Federation believe sand mining on the Mekong River is a key reason the 15,000-square-mile Mekong Delta—home to 20 million people and source of half of all the country’s food and much of the rice that feeds the rest of Southeast Asia—is gradually disappearing. The ocean is overtaking the equivalent of one and a half football fields of this crucial region’s land every day. Already, thousands of acres of rice farms have been lost, and at least 1,200 families have had to be relocated from their coastal homes. All this is caused partly by climate-change-induced sea level rise, and partly by direct human intervention. For centuries, the delta has been replenished by sediment carried down from the mountains of Central Asia by the Mekong River. But in recent years, in each of the several countries along its course, miners have begun pulling huge quantities of sand from the riverbed to use for the construction of Southeast Asia’s surging cities.

Sand extraction from rivers has also caused untold millions of dollars worth of damage to infrastructure around the world. The stirred-up sediment clogs up water supply equipment, and all the earth removed from riverbanks leaves the foundations of bridges exposed and unsupported. A 1998 study found that each ton of aggregate mined from the San Benito River on California’s central coast caused $11 million in infrastructure damage—costs that are borne by taxpayers.35 In many countries, sand miners have dug up so much ground that they have dangerously exposed the foundations of bridges and hillside buildings, putting them at risk of collapse.

Sand extraction from rivers has also caused untold millions of dollars worth of damage to infrastructure around the world. The stirred-up sediment clogs up water supply equipment, and all the earth removed from riverbanks leaves the foundations of bridges exposed and unsupported. A 1998 study found that each ton of aggregate mined from the San Benito River on California’s central coast caused $11 million in infrastructure damage—costs that are borne by taxpayers. In many countries, sand miners have dug up so much ground that they have dangerously exposed the foundations of bridges and hillside buildings, putting them at risk of collapse.

Sand mining can also directly harm people and their communities. Unprotected miners have died when sandpit walls collapsed on them. Fisherfolk from Cambodia to Sierra Leone are losing their livelihoods as sand mining decimates the populations of fish and other aquatic creatures they rely on. In some places, mining has made riverbanks collapse, taking out agricultural land and causing floods that have displaced whole families. In Vietnam in 2017 alone, so much soil slid into heavily mined rivers, taking with it the crops and homes of hundreds of families, that the government shut down sand extraction completely in two provinces.

Even after the sand miners are done, the battered landscape they leave behind can be startlingly dangerous. In Sri Lanka and India, sand mining has destroyed crocodile habitats, sending the beasts closer to river shores, where they have killed at least half a dozen people.

In response to all this destruction, governments around the world have tried, with varying levels of commitment, to regulate sand mining and to restrict the places and manner in which it is done. That in turn has spawned a booming worldwide black market in sand.

Illegal sand mining runs a wide gamut. At one end, it includes legitimate businesses overstepping the boundaries of their permits. At the other extreme are outright criminals, from petty thieves to well-organized gangs willing to kill to protect their sand business. Like any big-money black market, sand also generates violence. People have been shot, stabbed, beaten, tortured, and imprisoned over sand mining in countries around the world—some for trying to stop the environmental damage, some in battles over control of the land, and some caught in the cross fire. In Cambodia, police have jailed environmental activists who boarded river dredges to protest against illegal mining. In Ghana, security forces have opened fire on rowdy demonstrations against local sand miners. In China, a dozen members of a sand mining gang were sent to prison in 2015 after battling with knives in front of a police station. In Indonesia in 2016, an activist was beaten into a coma, and another tortured and stabbed to death, by the sand miners they were trying to stop. In Kenya, at least nine people have been killed—including a policeman hacked to death with machetes—in battles between farmers and sand miners.

So what is to be done?

Stronger government regulations can prevent, or at least mitigate, much of the harm caused by sand mining. They do in most of the developed world. Most restrictions on sand mining are relatively recent, however.

Activism can make a big difference, too. Aggrieved citizens living near existing or proposed mines can and do lobby to keep them smaller, quieter, cleaner, and safer—or to keep them out of their backyard altogether. All of us have to recognize, though, that there is a price to be paid for protecting the environment and local residents’ aesthetic sensibilities."

"Finally, " the Moon intended to close discussion. "Sandman,  as what Metallica sang, has cradled our dreams, made us throw sand away for an Ivory Tower. Indeed, the Ivory Tower has its momentum, but wait, for whom the Ivory Tower's bell tolls? For the general public? Or, perhaps, simply to quench Mr. So-and-so's ambition? Isn't it more appropriate to build a Water Tower, which will transmit knowledge to all fields of ricefields, which will bring literacy to the whole society, in order to lead to a just and civilized society, as well as to fulfill the requirements of a democratic society? And Allah knows best."

The river began to recede, reflection of the moon's light scattered on its surface. She left while singing Metallica's Enter Sandman,

Exit light, enter night, take my hand!

We're off to Never-never Land! *)

Citations & References:
- Vince Beiser, The World in a Grain: The Story of Sand and How It Transformed Civilization, 2018, Riverhead Books
- Pettijohn, Potter, Siever, Sand and Sandstone, 1972, Springer-Verlag
- D. Padmalal & K. Maya, Sand Mining: Environmental Impacts and Selected Case Studies, 2014, Springer
*) "Enter Sandman" written by Lars Ulrich, James Hetfield & Kirk Hammett

Bahasa

The Amazing Grains (1)

"A riverboat captain, wanting to put his passengers at ease, said, 'I’ve sailed boats on this river for so long, I know where each sandbar is.'But suddenly, the boat struck a sandbar so hard, it shook the boat and all the passengers. 'Look,' he said, 'there’s one of them now!' the Moon began to talk when her light was reflected by the tide at downstream, after previously greeting with Basmalah and Salaam.

"Sand," the Moon continued, "something that seems as trivial as it is ubiquitous, the humblest materials but a solid substance on Earth, the main material by way of modern cities are made as well as the literal foundation of modern civilization.

Perhaps the only place where most people really appreciate sand—or even think about it—is the beach. But not only that, in fact, sand has been important to us for centuries, even millennia. People have used it for construction since at least the time of the ancient Egyptians. In the fifteenth century, an Italian artisan figured out how to turn sand into fully transparent glass, which made possible the microscopes, telescopes, and other technologies that helped drive the Renaissance’s scientific revolution.

Sand is at the core of our daily lives. Look around you right now. Is there a floor beneath you, walls around, a roof overhead? Chances are excellent they are made at least partly out of concrete. And what is concrete? It’s essentially just sand and gravel glued together with cement.

Take a glance out the window. All those other buildings you see are also made from sand. So is the glass in that window. So are the miles of asphalt roads that connect all those buildings. So are the silicon chips that are the brains of your laptop and smartphone. The very ground beneath you is likely artificial, manufactured with sand dredged up from underwater. We humans bind together countless trillions of grains of sand to build towering structures, and we break apart the molecules of individual grains to make tiny computer chips.

Sand lies deep in our cultural consciousness. It suffuses our language. We draw lines in it, build castles in it, hide our heads in it. In medieval Europe (and a classic Metallica song), the Sandman, a cosmic being who controls all dreams, helped ease us into sleep. In our modern mythologies, the Sandman is a DC superhero and a Marvel supervillain. In the creation myths of indigenous cultures from West Africa to North America, sand is portrayed as the element that gives birth to the land. Buddhist monks and Navajo artisans have painted with it for centuries. Sand is both minuscule and infinite, a means of measurement and a substance beyond measuring.

All of this, happened when the advent of the modern industrialized world exist, in the decades just before and after the turn of the twentieth century, that people really began to harness the full potential of sand and begin making use of it on a colossal scale. It was during this period that sand went from being a resource used for widespread but artisanal purposes to becoming the essential building block of civilization, the key material used to create mass-manufactured structures and products demanded by a fast-growing population.

What is sand, anyway? F. J. Pettijohn, Paul Edwin Potter, Raymond Siever, all of then are Professors of Geology, say that Sand is loose, non-cohesive granular material, the grains or framework elements of which must by definition be sand-sized. Various attempts have been made to define sand more precisely. These attempts are largely directed toward expressing grain size in terms of grain 'diameter' of some specified magnitude.

In as much as sand grains are non-regular solids, it is first necessary to define the term 'diameter' as applied to such solids. Attempts to codify the meaning of 'sand' as a size-term are many. The effort to do so is usually part ofa larger effort to codify all size terms and to construct a 'grade scale'. The various choices made for the size class 'sand' in some of these grade scales. We shall here adopt the diameter limits 0.0625 (1/16) and 2.0 mm for 'sand'—limits which have become generally accepted among sedimentologists.

The Udden-Wentworth scale, defined the most commonly used geologic standard, the term sand encompasses loose grains of any hard material with a diameter between 2 and 0.0625 millimeters. That means the average grain of sand is a tad larger than the width of a human hair. Those grains can be made by glaciers grinding up stones, by oceans degrading seashells and corals—many Caribbean beaches are made of decomposed shells, even by volcanic lava chilling and shattering upon contact with air or water—that’s where Hawaii’s black sand beaches come from.

Nearly 70 percent of all sand grains on Earth, however, are quartz. These are the ones that matter most to us. Quartz is a form of silicon dioxide, or SiO2, also known as silica. Its components, silicon and oxygen, are the most abundant elements in the Earth’s crust, so it’s no surprise that quartz is one of the most common minerals on Earth.14 It is found abundantly in the granite and other rocks that form the world’s mountains and other geologic features. Most of the quartz grains we use were formed by erosion.

You can think of sand sort of like a colossal army, or a group of related armies, made up of quintillions of tiny soldiers. Only these armies are deployed not to kill, but to create. Rather than destroy, these soldiers build structures and products and perform services for us.

At first glance, sand grains, like uniformed troops, all look pretty much the same. In fact, though, there are many different types, with different attributes, strengths, and weaknesses, which in turn determine the uses to which they can be put. Some are prized for their hardness, some for their pliancy; some for their roundness, some for their angularity; some for their color, some for their purity. Some sands, like specially chosen commandos, are put through elaborate physical or chemical processes to alter their capabilities, or are combined with other materials to perform tasks they could not in their original state.

Construction sand—the hard, angular grains used primarily to make concrete—are the infantry of this army. This kind of sand is abundant, easily found, and not especially pure. Construction sand can be found in virtually every country, often mixed with its indispensable partner, gravel.

Silica sands are purer—at least 95 percent17 silica—and are found in fewer places than construction or marine sand. Also called industrial sands, they’re the Special Forces of the sand army, capable of being put to more sophisticated purposes than the average foot soldier. These are the sands you need to make glass.

For the most part, we don’t draft desert sands into our service. The grains found in deserts are mostly too round to use for construction. The reason is that wind is harsher than water. In a river, water cushions the impact of the grains tumbling against one another. In a desert, they just bang full force into one another, rounding off their corners and angles.

At the dawn of the twentieth century, almost all of the world’s large structures—apartment blocks, office buildings, churches, palaces, fortresses—were made with stone, brick, clay, or wood. The tallest buildings on Earth stood fewer than ten stories high. Roads were mostly paved with broken stone, or more likely, not paved at all. Glass in the form of windows or tableware was a relatively rare and expensive luxury. The mass manufacture and deployment of concrete and glass changed all that, reshaping how and where people lived in the industrialized world.

Concrete is an invention as transformative as fire or electricity. It has changed where and how billions of people live, work, and move around. Concrete is the skeleton of the modern world, the scaffold on which so much else is built. It gives us the power to dam enormous rivers, erect buildings of Olympian height, and travel to all but the remotest corners of the world with an ease that would astonish our ancestors. Measured by the number of lives it touches, concrete is easily the most important man-made material ever invented.

This world-transforming substance is composed mainly of the simplest, most commonplace ingredients: gravel and sand. Concrete, in fact, is the primary driver of the global sand crisis; we use far more sand to make concrete than for any other purpose. Billions of tons of sand and gravel are unearthed every year and pressed into service to form shopping malls, freeways, dams, and airports. The whole substrate of the world we live in rests on the shoulders of that vast infantry of miniature stones.

All of which is even more amazing when you consider that only a little over a century ago, we barely used concrete at all.

Let’s clear up one thing right away: Cement is not the same thing as concrete. Cement is an ingredient of concrete. It’s the glue that binds the gravel and sand together. Cements (there are many forms) are typically made by crushing up clay, lime, and other minerals, firing them in a kiln at temperatures up to 2,700 degrees, then milling the result into a silky-fine gray powder. Mix that powder with water and you get a paste. The paste doesn’t simply dry, like mud; it “cures,” meaning the powder’s molecules bond together via a process called hydration, its chemical components gripping each other ever tighter, making the resulting substance extremely strong. Reinforced with a platoon of sand, that paste thickens into mortar, the stuff used to hold bricks together.

Though concrete is the quintessential modern building material, people in several places over the centuries have stumbled on the trick of making it. The Mayans, who flourished 2,000 years ago in what is now southern Mexico, Guatemala, and Belize, made crude concrete beams to support some of their buildings. The Greeks used cement mortars. (Some scholars believe the ancient Egyptians used a form of concrete in the building of pyramids, though most disagree. The Egyptians almost certainly did use sand, though, to help their bronze saws cut through stone for their monuments, likely including the pyramids. Sand, in fact, has been used for construction since at least 7000 BCE, by ancient peoples who mixed it with mud to make crude bricks.) But by far the most enthusiastic and technically sophisticated users of concrete in the ancient world were the Romans. But it’s not clear exactly when or how the Romans figured out the secret of concrete making.

The Romans built houses, shops, public buildings, and baths from concrete. The breakwaters, towers, and other structures that made up the colossal man-made harbor of Caesarea, in what is now Israel, were built with concrete, as was the foundation of the Colosseum, along with countless bridges and aqueducts across the empire. Most famously, Rome’s Pantheon, built nearly 2,000 years ago, is roofed with a spectacular concrete dome—still the biggest concrete structure without reinforcing steel in the world.

Then in the years leading up to the twenty-first century, the use of sand expanded tremendously again, to fill needs both old and unprecedented. Concrete and glass began rapidly expanding their dominion from wealthy Western nations to the entire world. At roughly the same time, digital technology, powered by silicon chips and other sophisticated hardware made with sand, began reshaping the global economy in ways gargantuan and quotidian.

Today, your life depends on sand. You may not realize it, but sand is there, making the way you live possible, in almost every minute of your day. We live in it, travel on it, communicate with it, surround ourselves with it.

Wherever you woke up this morning, chances are good it was in a building made at least partly out of sand. Even if the walls are made of brick or wood, the foundation is most likely concrete. Maybe it’s also plastered with stucco, which is mostly sand. The paint on your walls likely contains finely ground silica sand to make it more durable, and may include other forms of high-purity sands to increase its brightness, oil absorption, and color consistency.

You flicked on the light, provided by a glass bulb made from melted sand. You meandered to the bathroom, where you brushed your teeth over a sink made of sand-based porcelain, using water filtered through sand at your local purification plant. Your toothpaste likely contained hydrated silica, a form of sand that acts as a mild abrasive to help remove plaque and stains.

Your underwear snapped into place thanks to an elastic made with silicone, a synthetic compound also derived from sand. [Silicone also helps shampoo make your hair shinier, makes shirts less wrinkle-prone, and reinforced the boot sole with which Neil Armstrong made the first footprint on the moon. And yes, most famously, it has been used to enhance women’s busts for more than fifty years].

Dressed and ready, you drove to work on roads made of concrete or asphalt. At the office, the screen of your computer, the chips that run it, and the fiber-optic cables that connect it to the Internet are all made from sand. The paper you print your memos on is probably coated with a sand-based film that helps it absorb printer ink. Even the glue that makes your sticky notes stick, to tell your subordinate, who arrived late, that 'I'm here,' is derived from sand.

At day’s end, you flopped down with a cup of tea, or maybe, a glass of wine. Guess what? Sand was used to make the bottle, the glass, and even the wine. Wine is sometimes made with a dash of colloidal silica, a gel form of silicon dioxide used as a “fining” agent to improve the beverage’s clarity, color stability, and shelf life.

Sand, in short, is the essential ingredient that makes modern life possible. Without sand, we couldn’t have contemporary civilization.

And believe it or not, we are starting to RUN OUT of sands.

Though the supply might seem endless, usable sand is a finite resource like any other. (Desert sand generally doesn’t work for construction; shaped by wind rather than water, desert grains are too round to bind together well.) We use more of this natural resource than of any other except air and water. Humans are estimated to consume nearly 50 billion tons of sand and gravel every year. That’s enough to blanket the entire state of California. It’s also twice as much as we were using just a decade ago.

Today, there is so much demand for sand that riverbeds and beaches around the world are being stripped bare of their precious grains. Farmlands and forests are being torn up. And people are being imprisoned, tortured, and murdered. All over SAND.

The key factor driving our world’s unprecedented consumption of this humblest of materials is this: the number and size of cities is exploding. Every year there are more and more people on the planet, and every year more and more of them move to cities, especially in the developing world.

The scale of this migration is staggering. In 1950, some 746 million people—less than one-third of the world’s population—lived in cities. Today, the number is almost 4 billion, more than half of all the people on Earth. The United Nations predicts that another 2.5 billion will join them in the next three decades. The global urban population is rising by about 65 million people annually; that’s the equivalent of adding eight New York Citys to the planet every single year.

To build these cities of concrete, asphalt, and glass, humans are pulling sand out of the ground in exponentially increasing amounts. The overwhelming bulk of it goes to make concrete, by far the world’s most important building material. In a typical year, according to the United Nations Environment Programme, the world uses enough concrete to build a wall 88 feet high and 88 feet wide right around the equator. China alone used more cement between 2011 and 2013 than the United States used in the entire twentieth century.

Armies of sand have built our cities, paved our roads, shown us distant stars and subatomic particles, spawned the Internet, and made our way of life possible. But extracting and deploying them on the immense scale of the twenty-first century has also brought destruction and death. On the next session, we'll talk about how sand mining develops. Bi idhnillah."

[Session 2]

Bahasa