Sand and gravel (also referred to as aggregates) are the most extracted material in the world by weight and the 2nd most consumed resource after water. According to UNEP, the world’s use of aggregates exceeds 40 billion tons annually. Even so, due to the prevalence of official under-reporting around the world, these numbers may still underestimate global sand extraction and use.
The trouble is that over-exploitation of sand is damaging to national assets. Intensive excavation has already depleted most land quarries, which were historically the easiest sources to exploit. Since desert sand is not suitable to be used in construction – its round, polished shape prevents the binding of grains – operators gradually shifted to river, coastal and marine sands. It turned out that extracting aggregates from riverbeds induces more intense and more frequent floods and threatens the water supply by lowering the water table. Consequently, several countries took measures to forbid it or strengthened regulation frameworks.
Oceanic extraction appeared at first less damaging to local economies, yet it also brings its share of problems. The use of huge dredgers inevitably destroys seabed habitats and ecosystems, which in turn, impacts submarine organisms of the upper water layer. This eventually threatens the livelihood of coastal communities and islanders that rely on fishing activities. Another issue that should have been anticipated is that removing offshore sand disturbs a natural equilibrium: these newly depleted spaces refill with coastal sand that logically relocates from the shorelines. Therefore, submarine extraction accelerates coastal erosion, depletion of beaches and disappearance of small islands. It is estimated that already 75 to 90% of the planet’s beaches have started to retreat.
Beaches serve as geological barriers that protect the inlands, including houses and infrastructure. Thus, their absence triggers a decline of protection against extreme events such as floods, droughts and storm surges, leading to increasing costs in disaster prevention and response. There are also serious economic stakes: for instance, half of Florida’s GDP depends directly on beach-related tourism, thus coastal erosion directly threatens these incomes. Beach nourishment is often used as a solution; however, such intervention is extremely costly and mostly inefficient since the sand artificially put in place usually lasts less than 2 years.
The impact is also geopolitical. The contraction of shorelines modifies international frontiers and compels local populations to migrate to already highly stressed locations demographically speaking. In Indonesia for instance, at least two dozen islands have already disappeared since 2005 and Bali is becoming dangerously crowded. Singapore is also a good example of sand-related dispute. The city-state has become by far the world’s largest sand importer to sustain its massive development, so much so that the neighboring countries of Cambodia, Vietnam, Malaysia and Indonesia, all of which directly suffer the consequences of over-extraction, decided to ban sand exchanges with Singapore.
International sand exchanges represent each year a net value of 70bn dollars. Over-exploitation, depletion, growing demand and swelling prices have unleashed mafias that conduct illegal trade in soil and sand. All over the world, illegal sand mining operations have become widespread due to weak governance and corruption. Criminal gangs steal beach and river sand to sell to the construction industry. The worst may be that a significant trigger for the current construction boom – which uses up huge proportions of sand – is mere property speculation. In many countries, slums continue to grow while most new apartments are still deserted and much too expensive for the poorest population to afford. In China for instance, 65 million apartments are uninhabited. In Spain, 30% of accommodations constructed after 1996 are still vacant.
So, what can be done? Sand is almost free, which makes it the most interesting material in terms of economic realism. Yet with such dire consequences, sand also has a hidden cost that should be accounted for. Alternatives exist: in construction, other materials can be used such as hay or wood, and industrialists are increasingly encouraged to operate with part-recycled materials. It is also proven that ground glass retains the same mechanical properties as sand and could be used as a substitute. Although more expensive, sand extraction could be organized from dams, which trap massive amounts of sand that will never reach the coasts.
Authorities have both stakes and leverages in addressing the sand issue. From a national strategy approach, these alternatives could be encouraged, even incentivized, to get over the current short-termism and stop the exploitation of such a precious resource. Regulations can also be strengthened at national to supranational level – few exist outside of the European Union – and some actions are duly needed to resorb weak governance, corruption and sand-related illegal mining and smuggling. From an environmental point of view, better monitoring of aggregate extraction should be set up, including impact assessments. But perhaps a very first step for us would be, this summer whilst lying on the sand and enjoying a nice vacation, to take a moment to contemplate how much more this sand can do and how serious the need is for its protection.
Claire Hugo, Climate Analyst – Sources: Beyond Ratings, Denis Delestrac; United Nations Environment Program (UNEP)