Sand in short supply?

纵观人类历史,不起眼的沙粒公顷ve played a crucial role in how we have lived. But, not all sands are suitable for our purposes, and this is putting considerable pressure on environments in some parts of the world. We need better sand logistics, otherwise what has powered our past could be our future undoing, as Eva Higginbotham has been hearing...

Eva - Whether digging into it with our toes or hoovering it up in the car after a day at the beach, we all have a relationship with sand. Actually, we are all far more dependent on those tiny grains than you might've thought

Ian - We've used sand actually since the Dawn of civilization. Essentially it satisfies our basic needs because we build homes with it. It's absolutely a foundation for civilisation.

Eva - That's Ian Selby from the University of Plymouth who spends his time thinking about sand from what we do with it...

Ian - Once we blend it with a mud or cement.

Eva - To what it's made of...

Ian - Sand is often dominated by quartz because it's such a hard medium.

Eva - So, how it's created...

Ian - Sand is essentially a natural product. It's created by geological processes. Rocks are formed off minerals. The rocks then across time are subject to all sorts of processes, whether that's: wind, rain, snow ice, essentially climate driven processes, it could be hot or cold, that basically break down those rocks after their formation and they break them down into their component parts and it can take a very long time. We can talk about millions of years, tens of billions of years, even hundreds of millions of year to break down the rock into these small particles, which we call sand.

Eva - Sand is an absolutely integral part of modern life. Think of cement roads and concrete buildings and plaster and glass and even paint. The thing is, although pictures of the Sahara desert might make you think we have a never-ending supply...

Louise - The big one that people I guess are starting with is do we have enough sand.

Eva - That's Louise Gallagher from UNEP/GRID Geneva, she's been tracking how sand is used and raising the alarm about a potential future, where there is a scarcity of the right kind of sand in the right places because actually not all sand is created.

Louise - People really liked river sand because it's a certain type of shape, it's coarse, it's angular, it grips well together w when you want to use it to make things like concrete and it has no salt in it, that's very important and you don't have to wash it. Nature has done all the work for you in grading and sorting and cleaning that sand.

Eva - As the population continues to grow. And as we build more infrastructure, more sand is needed, particularly in the global south. To ensure that we globally have the resources to meet this demand means that we need to keep track of how much sand we actually need both now and projected into the future. I asked Louise, if we know how much sand we use each year and...

Louise - Best estimate that's out there right now is 50 billion tons of sand per year, which is just massive.

Eva - That's a lot of sand. The thing is the world actually has a lot of sand, but we need to be careful with how we use it. For example, although very plentiful the round grains of Sahara sand have little use in construction, and we currently sometimes use high quality sand where low quality sand would do. Partly thanks to the fact that historically sand has been seen as a never ending resource as opposed to a vital component of life that took, in some cases, hundreds of millions of years to be created.

Louise - I guess if you live in an area which hasn't been impacted by sand mining, it seems like there's loads and that it's not a problem. If you lived in an area where you've seen sand being taken out of your local rivers or off your local beaches, it doesn't feel like there's a lot of sand let, and your water availability can become a problem in some rivers, you can impact upon your land, your rivers start to erode more quickly, you can have banks of the rivers collapsing, including then bringing in buildings that are built on the banks of those rivers. Tqhat's like the direct impacts on the site level. Then finally, if we have overall much less than entering into the marine environment and making its way to the coast, making its way naturally to beaches, you can have increased coastal erosion, when the big storms come you have much worse effects, much worse impacts on land, you have loss of property, loss of life. If we don't manage sand properly at that kind of big systems level, you not only don't have the right type of sand for building what you need when you need it, you might also, on top of that, create a ton of problems.

Eva - It's clear that we need to pay closer attention to those tiny grains. This starts with more sensitive resource mapping and tracking of sand use globally. From a technical standpoint there are some substitutes in the works for some uses and Louise and others are hopeful that we'll move forward with making our own sand by crushing up waste rock produced by mining. Importantly though...

Louise - It's going to take a big change in how we think about building, how we think about the material, how we train our engineers, how we design building projects. It's going to be a big cultural shift. The technical challenges is going to be one challenge. The social and cultural and political aspects also are going to have to really be thought about very deeply as well.

Eva - Next time you're at the beach or walking along a river or looking up at a new building. It's worth thinking about the history of the grains involved in creating the scenes that we know and love and how we might best protect them.