Sand is an essential building block of human life (as a commodity used in infrastructure, electronics, etc.), of life support functions (ecosystem services) and for maintaining biodiversity. Achieving the SDGs will require the building of vast infrastructure, for which sand will be crucial. Silica sand is also essential in the building of the green economy, e.g., for the production of solar panels and renewable energy infrastructure, while climate change adaptation efforts also require infrastructure investment to protect against intensifying risks, like coastal erosion, and rebuilding will increase following severe weather events and relocation of people away from risk-prone areas. The need to build becomes even stronger in emerging COVID-19 recovery plans, which centre infrastructural investment as a cornerstone of national—and indeed global—economic revival.
How much sand is used annually?
Present estimates indicate that humans are using 40-50 billion metric tons of sand resources per year, an average of 18 kg per person per day. The building industry uses between 6-10 tonnes gravel for each tonne of cement used. China produces the most cement globally at an estimated 2.4 billion tonnes in 2017 (USGS, 2018), followed by India at 270 million tonnes and the USA at 86.3 million tonnes in the same year. In the USA, for every 1 ton of cement, 10 tons of aggregates are used. Using this ratio implies that as global annually cement production is expected to increase to 4.83 billion tonnes in 2030, aggregate use will likely reach close to 50 billion tonnes per year in 2030.
With the exception of marine sand, which requires expensive vessels, sand is principally extracted by large numbers of small- and medium-sized domestic enterprises who rely on sand for their livelihoods and in some cases, the trade falling into the hands of mafia. However, the immense scale of global sand extraction, and the historical neglect of this sector, makes this issue an important —and challenging—one for global sustainability.
Sand extraction from dynamic systems, such as riverine and active marine ecosystems, comes at a cost as it leads to significant environmental impacts, including coastal and river erosion, shrinking deltas, land-use changes, air pollution, salinisation of coastal aquifers and groundwater reserves, threats to freshwater and marine fisheries and biodiversity.
Future urbanisation and massive infrastructure development and maintenance will only further intensify the demand for sand, increasing sand market prices and the construction industry’s ecological footprint. Decisive actions are therefore urgent, particularly in the context of anticipating climate-change impacts, biodiversity loss and infrastructure-driven programmes to support critical industries after COVID-19.
According to UN report, China and India head the list of critical hotspots for sand extraction impacts in rivers, lakes and on coastlines, most likely because these countries also lead globally on infrastructure and construction. Aggregate extraction in rivers has led to pollution and changes in pH levels, instability of river banks leading to increased flood frequency and intensity, lowering of water aquifers exacerbating drought occurrence and severity. Damming and extraction have reduced sediment delivery from rivers to many coastal areas, leading to reduced deposits in river deltas and accelerated beach erosion. This adds to effects of direct extraction in onshore sand extraction in coastal dune systems and nearshore marine dredging of aggregates, which may locally lead to long-term erosion impacts.
While many countries have banned sand extraction from lakes, rivers or beaches, the legislation is either insufficient or not enforced adequately due to corruption, the absence of monitoring, or resources to prosecute offenders. Part of the challenge is that the sand industry is fragmented and significantly informal especially in India and in many other countries.
International trade in sand and gravel, which was unheard of till recently, is growing due to high demand in regions without local sand and gravel resources and is forecast to rise 5.5% a year with urbanisation and infrastructure development trends.
Using sand efficiently
There is scope for making more efficient use of sourced aggregates through land use planning, and pursuing alternative infrastructure and building design and construction methods. The goal of this strategy is reducing unnecessary construction. The second is avoided use of cement and concrete where possible, so that demand for natural sand is reduced to responsible levels. Substituting traditional concrete where possible in building design with traditional materials like timber, clay and local materials like laterite stones can also reduce our dependence on sand. Investing in infrastructure maintenance and retrofitting rather than demolishing old buildings to extend the lifetime of the current built environment is another simple way of reducing the use of sand. Some studies suggest adaptive reuse is attractive to investors and urban planners because it is profitable and effective at reducing abandoned or neglected urban areas.
Avoidance of irresponsible sand consumption in infrastructure projects may require crossing some new frontiers in infrastructure design and engineering. We can take leaf out of developed countries’ experience in land use and spatial planning and focusing more on green building design and construction. Where construction or traditional cement cannot be avoided, reduction of natural sand use can be achieved through manufacturing fine and coarse aggregates by recycling construction and demolition waste material.
So, there are several ways to get out of the mess we are in for which we need to take our first step. For this to happen, we must first acknowledge the scale of the issue as one of the major sustainability challenges of the century.