Sand: is the world running out?
Sand is the world's favourite building material. Without it there would be no roads, railways, docks and harbours, highrise or family homes, because it's the main staple used to make concrete. It's also everywhere and widely regarded as a renewable resource that's available in abundance. But the reality is that the world is facing a sand shortage, and fighting over what is available is costing lives and destroying the environment, although no one really knows the true scale of the problem.
Since 1900 the rate at which the world is consuming building materials has increased 23-fold. Sand and gravel extraction accounts for over three quarters of this increase, making it the globe's most consumed material and exceeding the production even of fossil fuels and food.
Such is the demand for sand, says Aurora Torres of the German Centre for Integrative Biodiversity Research, in a Perspective article for the journal Science this week, that, in India, lives are being lost over at the hands of the "Sand Mafia" over who controls access to the stuff.
Describing sand exploitation as a tragedy of the commons, Torres points out that removal of sand is destabilising beaches, accelerating coastline and riverbank erosion, and promoting the spread of infectious diseases and invasive species. And, she and her colleagues point out, the price is usually paid by sand-rich, economically-poorer countries.
In Sri Lanka, the impact of the 2004 Boxing Day Tsunami was significantly worsened by sand erosion. Soil productivity in the country has also fallen as the removal of sand has encouraged saltwater incursion further inland, increasing soil salinity and hitting yields of food crops and rubber.
Elsewhere, deep water pools created by dredging operations in seasonal rivers are producing breeding grounds for disease-transmitting mosquitoes, increasing the burden of malaria. In West Africa, rates of the emerging disease called "Buruli ulcer", a severe skin infection caused by bacteria related to TB and linked to proximity to water, have increased significantly in heavily sand-extracted areas.
The dredging process itself is also potentially disasterous for the marine ecosystem. Seagrasses, seaweeds and coral beds can be decimated by mechanical sand extraction, and those that escape direct destruction are frequently compromised by tonnes of suspended sediments released into the water during the upheaval. This prevents light penetrating, bringing underwater photosynthesis to a standstill. The effect is a slowdown in marine productivity which reverberates up the food chain, ultimately impacting on fish yields and biodiversity. Meanwhile, the dredging vessels carting off the sand also take with them stowaways like the Asian clam, which become major invasive pests when they jump ship in remote geographies.
Clearly, with such a widescale and significant impact on the ecosystem, there must be global policies in place to track and control the process of sand recovery, use and recycling? You'd think so, but surprisingly, there aren't, which is why the true scale and impact of global sand extraction isn't know and isn't regulated.
"Achieving responsible consumption will require fostering coordination among multiple national and international policies; establishing controls on planning, permission, prospecting, extraction, and monitoring for the mining industry; developing payments for environmental and social damage; and building capacity for the sustainability of sand appropriation," says Torres.