Yet another thing we are running out of.
For years on TreeHugger, we have talked about Peak Everything, having started with Peak Oil. So it seems really odd to talk about Peak Sand, but in fact, we appear to be running out of the stuff. The problem is that concrete is 26 percent sand, and we are still making huge amounts of concrete; according to Neil Tweedie in the Guardian, about 2 cubic meters every year for every man, woman and child on the planet.
China leads the charge in today’s sand-fuelled construction boom, consuming half the world’s supply of concrete. Between 2011 and 2014 it used more concrete than the United States did in the entire 20th century. Aggregate is the main ingredient for roads, and China laid down 146,000 km [91,000 miles] of new highway in a single year.
You would think that we had as much sand as we could possibly use, huge deserts of it. But as noted in our earlier post on this subject, "desert sand has been wind-blown and eroded and evidently smoothed out so that it doesn’t make good concrete." There has been some research into making concrete with desert sand, but it's still in the labs at Imperial College London.
In fact, even in the middle of the desert, they have to import sand. Tweedie writes :
A textbook example is the Burj Khalifa in Dubai, the world’s tallest skyscraper. Despite being surrounded by sand, it was constructed with concrete incorporating the “right kind of sand” from Australia. Riverbed sand is prized, being of the correct gritty texture and purity, washed clean by running fresh water. Marine sand from the seabed is also used in increasing quantities, but it must be cleansed of salt to avoid metal corrosion in buildings. It all comes at a cost.
The problem now is the demand for sand so huge that it is being dug up everywhere, legally and illegally.
Why buy expensive sand, sourced from licensed mines, when you can anchor your dredger in some remote estuary, blast the sand out of the riverbed with a water jet and suck it up? Or steal a beach? Or dismantle an entire island? Or whole groups of islands? This is what the “sand mafias” do.
And if the Chinese and Indians need it for buildings and highways, Americans need it for fracking; the grains of sand hold open the fractures that let the gas flow.
What's to be done? Tweedie suggests adding plastic to concrete instead of sand and aggregate. "Research suggests small particles of plastic waste – 'plastic sand' – can replace 10% of the natural sand in concrete, saving at least 800m tonnes per year." My suggestion might be to simply use a lot less of the stuff, because the carbon footprint of concrete is a bigger problem than the footprint in the sand. Replace it in buildings with wood, and just stop building highways and parking garages for cars, promoting rail, surface transit (no concrete subway tunnels) and bikes. And electrify everything so that we don't need fracking. Then we can all ride our bikes to the beach.