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Whether it’s your phone, laptop, or TV,
you’re watching this video on a miracle of technology.
As much as it might seem like it, these devices
aren’t made from literal magic,
but materials with unique and surprising properties.
But as special as they are, it shouldn’t surprise you to learn that they’re also hard to find enough of.
Today, we’re consuming them faster than
ever
and researchers are starting to worry that we may be running out.
This idea that we may exhaust our supply of
certain important elements is called criticality,
and it’s already starting to shape what
the technology of the future might look like.
We’re going to look at a bunch of reasons
why certain elements might become scarce,
but the obvious one is that there just wasn’t
a lot to begin with.
A great example of this is indium, which sits
two rows below aluminum on the periodic table.
Yet aluminum is more than a million times
more abundant in Earth’s crust.
As much as 75% of the world’s indium production
is used to make indium tin oxide,
which has the remarkable property of conducting electricity while remaining completely transparent.
It’s a key component in LCDs and touch screens,
so you’re probably looking at, or through, some indium right now!
It’s also used in solar panels and for the
ball bearings in Formula 1 race cars.
The world is planning on building a lot of
solar panels and LCDs in the coming years,
so we’re going to need a big supply of indium,
which is kind of a problem.
In fact, some estimates suggest our demand for the element may begin to exceed production by 2030.
Unfortunately, increasing that production
is easier said than done.
Indium is mined mainly as a byproduct of zinc
extraction, but even then it’s rare,
with abundances anywhere from 1 to 100 parts per
million in zinc ore.
So a big increase in indium production means
a glut of zinc,
whether we need more of that metal or not.
Instead of producing more indium, another
option is to simply use less of it.
Since we’re not likely to give up on televisions
and solar panels, that means finding an alternative.
For screens, that could mean antimony,
but the criticality of that element 
is even higher than that of indium.
So not a great substitute.
Manufacturers of solar panels could replace
indium with graphene or carbon nanotubes,
but these advanced materials are still experimental
and very expensive.
It’s not only very scarce elements that
face a supply risk, either.
Some materials have high abundance, but low
concentration.
The poster children for this problem are the
dubiously-named rare-earth elements,
which consist mainly of the elements in the lanthanide
series.
Scientists initially discovered them as trace
components of minerals that themselves were very rare.
This gave rise to the notion that they were
among the Earth’s scarcest elements.
Today, we know that that’s not actually
true.
Cerium, for example, is as abundant as copper,
and even the rarest of the rare-earths
is 200 times more common than gold!
What makes them “rare” is that, unlike
many other metals,
they didn’t end up in concentrated deposits in the Earth’s crust
that are easy to find and mine.
The rare-earths have the highest criticality
of any element
not just because they’re extremely difficult to extract,
but because
they’re also used in an incredible array of products.
Cerium is the only element other than iron
that produces sparks when struck.
If you’ve ever used a “flint” to start
a fire or a lighter instead of a match,
you’ve probably used an alloy of the two called ferrocerium.
Ferrocerium is valuable because it sparks
at a uniquely low temperature,
making things like lighters easier to use.
The unusual properties of rare-earths mean
they pop up in all sorts of modern technology.
Up to 50% of the glass in your smartphone
camera, for instance, is made of lanthanum.
Neodymium magnets are used in spinning hard
drives and DVD players,
while yttrium, europium, and terbium create the colors in your TV screen and LED lights.
A big part of why technology today is so different
from a century ago
is that we’ve learned to effectively extract and use these exotic materials.
Rarity isn’t the only reason an element
can have high criticality.
A material can be relatively abundant, yet
difficult to mine safely and ethically.
As governments around the world
become more concerned with the environmental and human impact of mining,
they may create regulations
that further diminish the supply of a critical element.
These broader limitations can mean that even
if a particular substance is safe,
it faces restrictions based on the byproducts of its
extraction.
A good example is monazite, a mineral rich
in rare-earth elements.
After processing, monazite can contain up
to 70% cerium and lanthanum,
enabling the creation of all the products we just talked
about.
But monazite also contains thorium, uranium, and radium, which are highly-regulated radioactive elements.
The cost and difficulty of dealing with these
toxic byproducts
led to the closure of America’s only rare-earth element processing facility in the early 2000s.
Another example is arsenic, which is a byproduct
of copper and gold mining.
In the form of gallium arsenide, it’s a
key component in the manufacturing of semiconductors,
which are the foundation for basically all
modern technology.
Arsenic is also used in the process 
of pressure-treating wood,
like what you might build a deck or mailbox post out of.
It’s also poisonous, and can cause cancer,
which means it hasn’t been mined in the United States since 1985.
That’s the tension in this class of criticality:
some of our most important technology relies on some pretty nasty stuff.
Right now, there are people and places willing
to do that dirty work,
but there’s no guarantee that this will always be true.
The last big cause of criticality is what
researchers call vulnerability to supply restriction.
It’s the idea that there are people and
politics behind everything we do,
and that those factors are inherently unpredictable.
For many elements, it’s not just that they’re
incredibly rare or dangerous to produce,
but that production happens in very few places.
Which, if you think about it, is a natural
consequence of our two previous factors.
If a resource is very rare, there are probably only a couple places in the world where it can be easily found.
And as more countries regulate the mining
industry,
there are fewer and fewer places willing to do the extraction.
If something happens to restrict production
in those few places, whether it’s deliberate or not,
the global supply of a critical element
could be threatened.
The world first started to understand this
about fifty years ago
when what’s today the Democratic Republic of the Congo underwent a period of severe civil unrest.
Back then, the DRC was the world’s chief
supplier of cobalt,
and the nation’s unrest led to a sharp drop in exports.
Today, the country still supplies about two-thirds
of the world’s cobalt.
It’s used in a bunch of things, but the most important by far is in the construction of lithium-ion batteries.
That’s the battery technology that powers
our phones and laptops,
but it’s also used in many modern electric cars.
If electric cars are going to be a big tool
in the fight against climate change,
that means the effort will hinge in part on the
stability of the DRC.
And cobalt isn’t the only example. Geology
and chemistry don’t care about national borders.
But because of how mineral deposits are often
concentrated,
one nation can end up controlling the lion’s share of a particular element.
The US, for instance, produces 73% of the
world’s helium,
which is critical for the use of MRI machines.
China provides 95% of the gallium used in
LED lights,
as well as around 70% of arsenic, antimony, and all the rare-earth elements.
In fact, of the 35 most critical elements
in the world, China is the leading producer of at least 20.
This is where geopolitics, technology, and
geology can overlap, sometimes uncomfortably.
Whether it’s China, the US, or somebody
else controlling most of one element,
that’s a lot of influence concentrated in one place.
That’s why some researchers believe the
key to overcoming this form of criticality
is to focus on finding more ways to make the
same stuff.
Another way might seem even more obvious:
we could just reuse the material we already have.
Recycling important elements from discarded
products
would help resolve all three factors that produce criticality.
Reusing material would slow the extraction of a finite resource and reduce the need for further mining,
which could have a big environmental
impact.
One study found that recovering metals at
a recycling plant produced 80% fewer emissions
than mining an equivalent quantity, which
is a win for stopping climate change.
And unlike extraction, which can only happen
where ore deposits are located,
stuff can be recycled anywhere.
That could reduce the market power of dominant
producers.
The challenge is that recycling individual
elements is a lot harder than, say,
recovering the plastic from a milk jug.
These materials often exist in only trace
amounts as part of a highly processed product
like a circuit board.
Worldwide, less than 1% of rare-earth elements
are recovered
and, in 2018, no arsenic was recycled 
anywhere in the world.
Instead, it ends up adding toxicity to your
local landfill.
Reversing this trend will require techniques
as innovative as the materials themselves.
One idea is phytomining, which uses specially-selected
plants to extract trace elements from recycled products.
The plants concentrate the metal in their
own structure,
which can then be destroyed to retrieve the substance.
Another option is bioleaching, which uses
engineered bacteria to dissolve
and extract metals like copper and cobalt.
It’s already used to produce more than 20%
of the world’s mined copper,
and researchers are investigating how to effectively use bioleaching in recycling programs.
Ultimately, we don’t really have much of
a choice when it comes to dealing with criticality.
Our modern forms of transportation, power
generation, and medicine
have come to rely on these nearly-magical materials.
To keep their benefits, we’ll need to learn
to deal with their scarcity.
But it’s not all bad news.
Criticality isn’t a single, static problem;
it’s a function of our ability to engineer and discover.
As we find new ways to solve problems and
more accessible, sustainable materials to use,
we can sidestep some of these challenges.
Others will require learning to live within
the constraints of what’s here on Earth,
but that research is already underway.
Still, the next time you buy a slick new phone,
make sure you don’t simply throw the old one away.
The elements inside could literally be priceless.
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