Thursday, July 13, 2017

Sand: The World Is Running Out of It

It seems our most important assets are often the most common things around us.  Water is an example.  It seems to be plentiful, so we do not assign a high price to it, but we use so much of it that it’s becoming in short supply in many parts of the world.  There is another common product that appears abundant to us but is also becoming difficult to find because consumption has dramatically increased.  That product goes by the generic name of aggregate.  In this context, the term refers to components that are used as strengtheners in composite materials such as cement and asphalt.  Sand and gravel are the components of most use for construction applications.  So how could we be running out of sand when it appears to be available in enormous quantities?  Like water, most of it is in a form that cannot be used effectively.

In March 2014, the United Nations Environment Programme (UNEP) felt compelled to issue a warning to an unsuspecting world in a document titled Sand, rarer than one thinks

“Sand and gravel represent the highest volume of raw material used on earth after water. Their use greatly exceeds natural renewal rates. Moreover, the amount being mined is increasing exponentially, mainly as a result of rapid economic growth in Asia.”

The report laments the fact that while aggregate use is widespread, little data is available on quantities being consumed.  Cement is one item for which data is available and it is one of the most common uses.

“One way to estimate the global use of aggregates indirectly is through the production of cement for concrete (concrete is made with cement, water, sand and gravel). The production of cement is reported by 150 countries and reached 3.7 billion tonnes in 2012….For each tonne of cement, the building industry needs about six to seven times more tonnes of sand and gravel….Thus, the world’s use of aggregates for concrete can be estimated at 25.9 billion to 29.6 billion tonnes a year for 2012 alone. This represents enough concrete to build a wall 27 metres high by 27 metres wide around the equator.”

Sand is defined by its particle size not by its material type.  The surface character of a grain of sand determines whether or not it would be useful as a construction material.  Sand moved about in water tends to retain multiple sharp edges and is valuable; sand moved by air tends to be smooth and rounded and of no value. 

“Sand was until recently extracted in land quarries and riverbeds; however, a shift to marine and coastal aggregates mining has occurred due to the decline of inland resources. River and marine aggregates remain the main sources for building and land reclamation. For concrete, in-stream gravel requires less processing and produces high-quality material….while marine aggregate needs to be thoroughly washed to remove salt. If the sodium is not removed from marine aggregate, a structure built with it might collapse after few decades due to corrosion of its metal structures….Most sand from deserts cannot be used for concrete and land reclaiming, as the wind erosion process forms round grains that do not bind well.”

Sand was once readily available from land-based quarries, but so much of it was used to create buildings that sites for additional quarries were either covered up by structures or the residents of the nearby structures refused to allow a messy quarry to exist in their neighborhood.  Water-based sand became the target, a move that generated availability and environmental issues.

“Negative effects on the environment are unequivocal and are occurring around the world. The problem is now so serious that the existence of river ecosystems is threatened in a number of locations….Damage is more severe in small river catchments. The same applies to threats to benthic [ocean floor] ecosystems from marine extraction.”

David Owen took this concern over the sand supply and generated an interesting tale for The New Yorker.  It was titled The End of Sand in the paper version, and The World Is Running Out of Sand online.  He provides some background information.

“Aggregate is the main constituent of concrete (eighty per cent) and asphalt (ninety-four per cent), and it’s also the primary base material that concrete and asphalt are placed on during the building of roads, buildings, parking lots, runways, and many other structures. A report published in 2004 by the American Geological Institute said that a typical American house requires more than a hundred tons of sand, gravel, and crushed stone for the foundation, basement, garage, and driveway, and more than two hundred tons if you include its share of the street that runs in front of it. A mile-long section of a single lane of an American interstate highway requires thirty-eight thousand tons.”

The US has certainly used its share of this commodity, but consumption now is driven by rapid development in Asia.  China is building roads and structures at a phenomenal rate; India will soon have a greater population than China and will wish to undergo its own phase of rapid building creating ever more demand.

“Pascal Peduzzi, a Swiss scientist and the director of one of the U.N.’s environmental groups, told the BBC last May that China’s swift development had consumed more sand in the previous four years than the United States used in the past century. In India, commercially useful sand is now so scarce that markets for it are dominated by ‘sand mafias’—criminal enterprises that sell material taken illegally from rivers and other sources, sometimes killing to safeguard their deposits.”

Meanwhile, the US has moved on to using sand to address another problem, one that will only grow and drive even greater consumption over time.

“In the United States, the fastest-growing uses include the fortification of shorelines eroded by rising sea levels and more and more powerful ocean storms—efforts that, like many attempts to address environmental challenges, create environmental challenges of their own.”

Owen has travelled the world in order to provide us with some interesting tales of sand usage.  He begins his article by describing the rigorous specifications for the sand required for those beach volleyball competitions that have become so popular.

“Ordinary beach sand tends to be too firm for volleyball: when players dive into it, they break fingers, tear hamstrings, and suffer other impact injuries.”

It has been necessary to develop very specific requirements for the sand used in volleyball competitions.  Owen discusses the issue with Todd Knapton a sand expert who helped develop the specifications.

“The specifications govern the shape, size, and hardness of the sand grains, and they disallow silt, clay, dirt, and other fine particles, which not only stick to perspiring players but also fill voids between larger grains, making the playing surface firmer. The result is sand that drains so well that building castles with it would be impossible.”

“Beach-volleyball promoters all over the world have to submit one-kilogram samples to Knapton for approval, and his office now contains hundreds of specimens. (He also vets beach-soccer sand for FIFA.)”

Knapton and colleagues also create courts for events and must search for the appropriate kind of sand—a task that can be difficult.

“The company’s biggest recent challenge was the first European Games, which were held in Baku, Azerbaijan, in 2015. Baku has beaches—it’s on a peninsula on the western shore of the Caspian Sea—but the sand is barely suitable for sunbathing, much less for volleyball. Knapton’s crew searched the region and found a large deposit with the ideal mixture of particle sizes, in a family-owned mine in the Nur Mountains, in southern Turkey, eight hundred miles to the west.”

“The mine is within shelling distance of the Syrian border. Knapton had planned to transport the sand across central Syria, through Iraq, around Armenia, and into Azerbaijan from the northwest, in two convoys of more than two hundred and fifty trucks each. But geopolitics intervened….Instead, Knapton and his crew bagged the sand in one-and-a-half-ton fabric totes, trucked it west to Iskenderun, and craned it onto ships. “We did five vessels, five separate trips,” Knapton said. “The route went across the Mediterranean, up the Aegean, through the Bosporus, across the Black Sea, and into Sochi.” From there, they took the sand by rail through Russia and Georgia, around Armenia, and across Azerbaijan.”

Clearly it is a mistake to think of sand as merely sand.  To further emphasize that point Owen provides some interesting insights into what is involved in building things in the Middle East. 

Apparently golf courses are easy to shape in sand-rich Dubai because sand is easier to move and rearrange than a grassy field, but, surprisingly, the local sand is unacceptable for use in sand traps and imported sand must be used.

“One day, I played golf with an Australian who worked for a major real-estate developer. The course, like Dubai itself, had been built on empty desert, and I commented that creating fairways and greens in such a forbidding environment must be difficult. ‘No,’ the Australian said. ‘Deserts are easy, because you can shape the sand into anything you like.’ The difficult parts, paradoxically, are the areas that are supposed to be sand: deserts make lousy sand traps. The wind-blown grains are so rounded that golf balls sink into them, so the sand in the bunkers on Dubai’s many golf courses is imported.”

The plentiful desert sand seems to be good only for participating in sand storms.

“Unfortunately for Dubai’s builders and real-estate developers, desert sand is also unsuitable for construction and, indeed, for almost any human use. The grains don’t have enough fractured faces for concrete and asphalt, and they’re too small and round for water-filtration systems. The high-compression concrete used in Dubai’s Burj Khalifa, the world’s tallest structure, was made with sand imported from Australia. William Langer told me that other desert countries face similar shortages.”

Real estate in Dubai was so expensive that it decided to create more of it offshore.  In that case land had to be created using sand dredged up from the sea—a lot of it.

“Creating so much artificial land required enormous shipments of quarried stone, from across the Emirates, as well as hundreds of millions of tons of sand, which foreign contractors dredged from the floor of the Gulf and heaped into piles. According to a U.N. report, the dredging ‘exhausted all of the marine sand resources in Dubai,’ and also did extensive environmental damage. Seafloor dredging creates the undersea equivalent of choking sandstorms, killing organisms, destroying coral reefs and other habitats, and altering patterns of water circulation.”

Creating land to build upon by dredging of marine sand to is one aspect of a growing environmental problem.  Concerns about coastal sea incursion are generating a need for enormous amounts of sand to build protective berms.  The sand will, of course, have to be dredged from the sea.  A particularly vexing situation arises when people choose to live on fragile barrier islands.  These are islands of sand that accumulate due to the action of tides and waves offshore from the mainland coast.  Houses built on these islands might have excellent ocean views, but they are at constant risk of damage from storms and rising seawaters.

“Robert S. Young, a geology professor at Western Carolina University, in North Carolina, told me recently, ‘When people first settled this country, nobody built on the barrier islands. They were too stormy, and they weren’t good places to live.’ Today, however, many barrier islands are densely covered with houses—the biggest and the most expensive of which often have the greatest exposure to ocean storms, since they’re the ones with the best water views. The rapid growth in construction has been driven by lax land-use ordinances, below-market flood-insurance rates, the indomitability of the human spirit, and, mainly, the willingness of Congress to cover much of the cost when the inevitable occurs.  ‘The Feds have poured in money over and over,’ Young continued. ‘Folks will say to me, “Gosh, Robert, people must be crazy to rebuild their roads and homes again and again, after all the storms,” and my answer is ‘No, they’re making a perfectly rational economic decision. We’re the crazy ones, because we’re paying for it.’ ”

Congress would occasionally allocate funds for protecting homes by piling ridges of ocean sand along shorelines, but the effort always ended up being prohibitively expensive.  With the attempt to respond to Hurricane Sandy that suddenly changed.

“Congress responded to Sandy by passing the Disaster Relief Appropriations Act of 2013, also known as the Hurricane Sandy Supplemental bill. It allocated a little more than forty-nine billion dollars for a long list of relief efforts, including more than five billion for the Army Corps of Engineers. Much of the Corps’s money has been spent on dredging sand from the seafloor and piling it up on shorelines between oceanfront real estate and the water.”

This fiscal response reinforces a perverse logic.

“Building houses and creating artificial dunes to protect them are mutually reinforcing interventions, because the houses turn the dunes into necessities and the dunes make the houses seem rational.”

And there are the inevitable environmental consequences.

“As in Dubai, the seafloor suffers. Offshore sand dredging has been described as “submerged, open-pit strip mining.” It directly kills organisms that live or feed on the seafloor, including sea turtles, and it stirs up clouds of fine particles, which can suffocate fish by clogging their gills.”

The pure folly of the activity becomes clear when one realizes that building the artificial barriers is a never ending process.  Owen describes one effort to protect Long Beach Island located off the New Jersey coast.

“The island is a little more than twenty miles long, and for most of that length it’s no wider than two or three residential blocks. The crew I watched was working on a beach in Harvey Cedars, a town near the island’s northern end. Two red-hulled dredging ships were anchored offshore—one in federal waters, three miles out, the other much closer. The far ship vacuumed sand from the ocean floor, fifty feet down, and when its hold was full it switched places with the near ship, which had pumped its own load into a submerged steel pipe that ran all the way to the beach. As the far ship filled, its hull slowly sank from view; as the near ship emptied, its hull slowly rose.”

“The company’s dredges operate around the clock, seven days a week, all year long; they are expensive to run and leaving them idle is uneconomical. And the job is open-ended, since the artificial dune isn’t meant to be permanent: its purpose is to neutralize big waves by allowing them to consume it. The Corps expects to rebuild the entire system, from end to end, on a four-to-six-year cycle. The dredges I was watching were scheduled to move south, to Delaware, as soon as they’d finished on Long Beach Island, and then to begin working their way up the coast again. And then again, and then again after that—until either the money has run out or the ocean has risen too high to be held back by sand.”

Welcome to the Anthropocene where humans seem determined to plunder valuable resources until they are gone.  Perhaps a hope is harbored that some new technology will come to the rescue. 

More likely, suffering on a Biblical scale will ensue.

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