Because water is essential to our survival, we are generally aware of the importance of saving this natural resource and of monitoring our day-to-day usage of it. But people are generally much less aware of the need to preserve sand, the second most exploited resource after water, and one that's also essential to withstanding climate change.
Some 50 billion tons of sand and gravel are used in the world every year. This amount of sand would be "enough to build a wall 27 meters wide and 27 meters high around planet Earth," estimates a new report from the United Nations Environment Program (UNEP). And, just like water, sand is not an infinitely renewable resource.
Why it's important to preserve sand
Sand is the second most exploited natural resource in the world. Its grains are mainly used as a raw material to make concrete, asphalt or glass in construction and related industries.
Desert sand is less attractive because of its wind-polished grains, which are thinner. It is therefore mainly the sand extracted from beaches and other coastal areas (lakes, estuaries, rivers) that is under threat. Indeed, the report states that most of the world's major rivers have lost between half and 95% of their natural sand and gravel delivery to oceans.
However, sea sand plays an essential geological role, since it limits soil erosion. The report's authors state that keeping sand on coasts may be the most cost-effective strategy for adapting to climate change because of how it helps protect against storm surges and impacts from sea level rise. These kinds of services, the authors argue, should be factored into its value.
Creating a circular economy for sand
Unlike water, few official regulations are in place to ensure a reasonable use of sand. This is a real social and environmental problem, since this resource is subject to major trafficking and illegal extraction, generating conflicts and causing insecurity for the inhabitants in some countries, as is the case in India or Morocco.
To fight against these "sand mafias" and preserve the environment of coastal landscapes, the UN report puts forward several solutions and draws up a list of specific measures. For example, setting an international standard to regulate the use of sand, establishing a fixed price for sand based on its real social and environmental value, creating a "circular economy for sand" by encouraging the reuse of this resource or banning the extraction of sand on beaches and the landfilling of mineral waste.