We are running out of sand. That sounds insane.
There are massive deserts all around the world that are just full of sand.
27.7% of the Earth's crust is just silicon,
a key component of silica sand. The problem is that not all sand is created equal
and we use a lot of it. Over 50 billion tons of sand and gravel
are used globally every year in paving and construction
but also in Windows, screens, silicon chips and photovoltaic cells.
And this massive sand demand has been going on for a long time.
A 2014 UN report estimated that sand was 85%
of all material mined globally by weight.
Sand is formed by the gradual erosion of rocks
into smaller and smaller grains. This is a process that takes thousands of years,
making sand a renewable resource only in a very technical sense.
Plus, that sand has different properties depending on how it was created.
Concrete typically uses water-weathered sand because the resulting grains are rough and angular,
which allows them to lock together. Wind-weathered desert sand, on the other hand,
tends to be too round and smooth. Therefore, Dubai, despite being built on a desert,
imports hundreds of millions of dollars of sand each year
to support its rapid growth. As for the screen in front of you
and the silicon chips inside your device, that's a slightly different story.
Glass needs to be made from near-pure silica sand,
sand that is at least 95% silicon dioxide,
or your window is going to look just awful. It also needs to be extremely fine
with grains between 0.075 millimeters and 1.18 millimeters,
and it also has to be the right color. For more sophisticated industrial purposes,
silica is extracted from rock quartz and quartz-rich sand,
then purified into 98% pure metallurgical-grade silicon.
Silicon for semiconductors needs to have a purity of 11 nines.
That's 99% a decimal and nine more nines.
The advantage of this process is that the geometry of the sand
doesn't actually matter all that much, so desert sand can be used.
That being said, natural sources of sand vary a lot in terms of composition,
and easily accessible quartz-rich sand sources are still a limited resource.
The global demand for sand is so intense
that the industry has attracted attention from organized crime,
and you know the situation is getting serious when a bunch of gangsters roll up and steal a beach.
Sure, it sounds funny, but illicit sand mining can cause serious problems.
Not only can intensive dredging of sand from rivers
and the ocean floor damage local ecosystems, but irresponsible sand mining can erode supports
from nearby structures and has resulted in multiple fatal bridge collapses.
Now, we could massively scale down our use of sand,
but we'd all still like to have buildings to live in,
roads to travel on, and TVs to watch, and so the spice must flow.
There are other options, though. We might be able to reduce the amount of sand we use
by shifting to other sources of aggregate and silica
like crushed rock, demolition material, and ore sand,
a byproduct of the mining industry. Some have even suggested replacing sand
with used, pyralized coffee grounds, which research has shown can even result
in 30% stronger concrete in the right proportions.
We also need to reuse what we've already extracted
as much as we can. The bright side is that many processed forms of sand
are basically infinitely recyclable. Around 80% of asphalt used in American roads
is already recycled back into new asphalt, and glass can be broken down, tumbled,
and turned back into sand. However, many forms of processed sand,
such as rubber-like silicone polymers, can only be downcycled a limited number of times
due to physical constraints, or they may be too contaminated to safely
and economically recycle at scale with current technology.
We also need to push for longer-lasting, repairable digital devices,
because even the very cheap ones are made from materials that are ultimately limited.
Life's a beach, and then you die. But first, you finish this video.
Nice job. Hey, thanks for watching. Like the video if you liked it. Dislike it if you disliked it.
Check out our other videos. We have many. And feel free to comment with video suggestions
down in the description or in the comments.
I need to go subscribe.