Imagine being told that a group of engineers have just finished rebuilding a beach. And that the world is slowly running out of sand.

Former ‘Gadget Geeks’ presenter Tom Scott’s latest video examines this phenomenon, explaining that sand is, in fact, a non-renewable resource.

Scott takes his viewers to Cape May, New Jersey, where the US Army Corps of Engineers have been working on the beach, using multiple hopper dredges and miles of pipes, constructors, bulldozers and excavators to compensate for the depletion of sand and carry out beach-fill operations.

Scott explains that in beaches across the world, such as Miami Beach in America, the Gold Coast in Australia, or the beaches of Dubai, engineers dredge sand and pump it all back onto beaches.

It’s not just because of tourists. Beachers are also essential for protecting people from the ocean.

Note that every skyscraper, every building, in the world needs sand. Because concrete is basically a lot of sand glued together with cement. And the world is slowly running out of its sand supply.

If you’re wondering why don’t we simply look for sand in other places such as deserts and ocean floors, it’s because we can’t. Desert sand, for instance, is too fine, too smooth.

We need a particular kind of sand, the type that’s been created by water and waves over aeons.

“This is not a renewable resource, not on any timescale,” Scott warns.

As those familiar with the sand mafia in India know only too well, illegal sand-mining is an actual thing. “Hundreds of people have been killed over sand,” Scott says.