system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Is it true that the world is running out of sand to produce concrete, and if so, why is that?
gpt
Yeah, but no.  Yes the desert sands of Saudi and UAE etc are not great for concrete, but we do have a near infinite supply of material that can be made into sand.  Eg you can crush rocks down to a particle size / shape for use in concrete. 

Source: that’s what I’m doing now.

We are not running out of sand for concrete, but maybe cheap naturally occurring sand in the right shape? dunno, but whatever the issue, it’s localized.  It’s a big world.