In the science fiction saga Dune, the action takes place on Arrakis, a desert planet enveloped in sand where powerful families vie for control of the mining of spice, the most valuable substance in the universe. On our planet, dominated by oceans, we mine the sand itself. In some ways sand is the most valuable solid substance in our world, as our buildings, infrastructure and much of our modern technology are literally constructed from its grains.
Melted sand was used to make the glass screen you’re looking at right now, not to mention the silicon chips that power your device. Sand is found in toothpaste, paint, cosmetics, ceramics, synthetic fibres and many other products. We use it to pave our roads and sidewalks, filter our water and clean up our oil spills. Huge quantities of sand are extracted for land reclamation projects (in Singapore and Dubai, for example), to extract shale gas (fracking) and in beach nourishment operations.
The ferocity and voraciousness with which our global civilization extracts and consumes sand and gravel (called aggregate) is raising fears that we are beginning to run out of this precious resource. The demand is expected to double in the coming decades, and current levels of consumption are already devastating ecosystems and fuelling organized crime and violence.
For humanity to reduce its global aggregate consumption—currently estimated at 50 billion tons per year, equivalent to the weight of 300 African elephants every second—to responsible levels and transition to a more sustainable sand system, the workings of that system will need to be better understood. Fortunately, researchers are studying the global sand system and seeking solutions to the growing crisis.
Unravelling the global sand system
Aurora Torres, a postdoctoral researcher at Michigan State University and the Catholic University of Louvain in Belgium, has devoted much time and effort to understanding the global sand system. She and her colleagues have recently published the paper Sustainability of the global sand system in the Anthropocene, which emphasises the need to have a wide-angle perspective. As Torres explained to OpenMind: “If we only focus on the sand mining sites we get an incomplete picture of the problem and our solutions might just lead to shifting the problem somewhere else. The mining of sand is driven by the demand for building materials in urban areas or for infrastructure projects. Looking at the entire sand-supply network allows us to gain a holistic understanding of the stresses on both nature and people across time and space and to identify the most efficient supply streams.”
As the UN Environment Programme 2019 Sand and Sustainability report notes: “Traceability of sand in supply chains within the construction sector is extremely weak. How can we have responsible consumption without tracing and differentiating responsible and irresponsible sand sources?” If sand can’t be traced, then “sustainable sand” can’t be certified, which explains why supply chain certification in the construction sector is still in its infancy.
A description of the opaque nature of sand mining in India was provided by journalist Rollo Romig in his 2017 New York Times article entitled How to Steal a River: “Sand mining is executed by an endless array of small, independent, often temporary players, largely working at night and in secret. And each step of the line of production is separated from the rest: The sand moves from diggers to truckers to dealers to builders with each link in the chain knowing as little as possible about where the sand they’re buying comes from or who mines it—for obvious reasons, they don’t want to know.”
Lack of information hinders sustainable management
Aggregates are dredged from the bottom of the sea, mined from beaches, dug out of quarries and produced from crushed rock, but the majority of material that feeds the construction industry in China, India, Bangladesh and other developing countries is extracted from rivers and lakes, and it is here that the lack of information is most evident. While satellite imagery can aid authorities in monitoring legal mining activity and detecting illegal extraction, what happens beneath the surface of the water is hidden from view, making it impossible to quantify the amount of resources illegally mined and regulate it effectively.
In China, much of the sand used to build the country’s megacities comes from Poyang Lake, the country’s largest freshwater lake and a national nature reserve. Millions of tonnes of sand have been dredged from the shores and bed of this shallow lake since 2001, drastically changing its appearance and devastating its ecosystem.
Many countries do have regulations to control sand mining, but they are often toothless and enforcement is lacking. Torres explains that the sand/aggregate industry is especially hard to regulate because it is “dominated by small and medium-sized companies, with the top ten producers combined representing less than 5% of global production. In fact, the sector is largely informal in many countries, where the sand has been traditionally extracted for construction projects without the need for a license and with the thinking that this is an infinite resource.” This Wild West mentality has attracted the interest of organized crime, which has come to dominate the sand mining industry in many countries, most notably India where sand mafias are able to circumvent the laws that do exist through corruption, intimidation and violence.
Avoiding unnecessary sand consumption
While a new legal framework to enable international cooperation in the global sand trade may eventually be put in place, in the meantime more active solutions are readily at hand. The UN Sand and Sustainability report puts avoiding unnecessary natural sand consumption in construction at the top of the list of available solutions and asserts that the “avoidance of irresponsible sand consumption must be designed into our infrastructure projects, construction projects and industrial products from the beginning.”
The measures listed in the report include avoiding surplus construction projects, such as those for speculation or prestige; planning more compact urban growth; designing lighter buildings that require less concrete; substituting concrete in buildings with traditional materials like timber or non-traditional options that emerge from innovation; employing green infrastructure (such as permeable pavement) instead of built infrastructure; retrofitting old buildings rather than demolishing them; and designing for the disassembly and reuse of building components.
Using recycled and alternative materials to replace natural sand in construction
Much research is being done to find waste by-products of other processes that can be safely added to concrete to reduce the quantity of natural sand required, from plastic waste and incinerator ash to volcanic ash, shredded rubber tires, treated palm oil fuel ash and even hemp. German researchers are studying whether desert sand—whose rounded shape makes it unsuitable for concrete—can be thermally treated to produce construction material, a promising though energy-intensive process. The obligatory recycling of construction and demolition waste material would also go a long way to providing a more sustainable source of aggregate and incentivise innovation in the reuse of such materials.
Ultimately, however, even if we successfully manage to reduce our use of sand by eliminating wasteful practices, embracing technological innovation and developing a robust recycling system in the construction industry, the fly in the ointment is that the projected increase in demand for aggregate in the coming decades due to our growing cities and the climate change mitigation measures that will be forced upon us is poised to eat up any improvements in efficiency. As Torres says, solving this problem will require “a societal transformation towards less material-intensive lifestyles, which swims against the tide of current global trends. The future of sand resources, nature and the human communities that directly or indirectly rely on them is inevitably tied to the direction that we as society take in the Anthropocene.”