Is time running out for sand?

Geoscientist Tom Bide from the British Geological Survey makes a case for urgent sustainable extraction practices and management of sand resources so as not to destabilise ecosystems.

Sand is one of the most important raw materials on the planet. The geological process of sand creation can take thousands or even millions of years, as large rocks are pummelled and ground down into tiny grains. The trouble is that we are now extracting far more material from the Earth than can be replenished.

Rapid urbanisation, driven by large-scale population migration into cities, has fuelled a growing need for sand as a building material. Demand for sand and gravel increased 23-fold between 1900 and 2010 and is projected to reach around 82 billion tonnes per year by 2060 – around 300 kilograms of it is needed for every tonne of concrete made.

It is not hard to understand why illegal or unregulated sand extraction is booming. On a local scale, sand mining can provide employment for communities and the raw materials needed for urban development in lower GDP countries. According to figures adapted from the Global Financial Integrity Ranking 2020, illegal sand extraction and trade is the third largest transnational crime, with an estimated annual value of up to $350bn.

Unregulated mining has considerable negative environmental, social and economic impacts. The sand found on beaches and in deserts is largely too fine-grained and smooth to be used in construction, so manufacturers search out riverine or marine sands, the grains of which have rough edges far more suited for use as a binding agent in materials such as concrete. In areas with the correct geological environment to produce riverine sand, extraction has become a huge problem. Rivers such as the Mekong in Vietnam and the Yangtze in China are facing catastrophic changes along their banks, often changing the flow of water. This poses risks to local communities and livelihoods that rely on the rivers.

To protect sand deposits, in areas where sand extraction is unregulated we must team up with local stakeholders to work towards being robust and legal; this will secure long-term material availability while adhering to the UN’s sustainable goals and protecting the natural environment.

Sustainable practices

The British Geological Survey has extensive experience in monitoring, planning and managing sand resources around the world. It works collaboratively across the globe on geoscience-led solutions, including mapping reserves and mines and investigating alternative materials.

Currently, areas of high-risk sand extraction are being mapped and monitored using satellite surveys, ensuring that authorities are aware of the scale of the risk as well as current and projected extraction rates. Monitoring capacity will need to be expanded to ensure unregulated mining is properly understood and the environmental impacts of extraction are better mitigated.

From a materials perspective, it is worth considering the viability of manufactured sand, which can be more sustainable and cost effective in the longer term. Alternatives such as construction, demolition and excavation waste, crushed glass or ore sands provide suitable substitutes, and promote a circular economy.

Reducing sand use in urban development requires monitoring, geoscience, regulation, recycling, better planning and a fundamental rethink of how we design and construct buildings to meet modern needs. Sand resources are under pressure, but there is still time to manage them more responsibly.

Image credit | iStock