- [Narrator] The early 80s were a very different time.
Crazy hair, crazy clothes,
we didn't know we were headed toward a planet-wide disaster.
Oh yeah, that's right, we were headed towards
a planet-wide disaster.
And if nothing had been done about it,
this is what the world would have become in 2065.
Crops failing, livestock farming failing,
aquaculture failing, and cancer rates through the roof.
Step outdoors in Washington DC,
and you'll get a severe sunburn in five minutes.
Lucky for us, NASA had our backs.
NASA might be famous for exploring space,
but that's not its only job.
The agency studies Earth too.
They help track how our environment works,
and catch if something goes wrong.
And in 1985, things indeed had gone terribly wrong.
Teams of scientists
from NASA and the British Antarctic Survey
discovered a severely damaged section of Earth's ozone layer
over Antarctica.
Here's why that's a problem.
The ozone layer is a region in the stratosphere
that absorbs harmful UV light from the sun.
It's basically our planet's natural sunscreen.
And it had grown extremely thin over Antarctica.
So the ozone hole, as it became known,
was absorbing less UV light than normal.
In fact, from September through November of that year,
the ozone levels in the hole dropped by up to 67%.
That's like if you only used a third of the sunscreen
you were supposed to before going to the beach.
Thankfully, NASA had a pretty good idea
of what was happening.
For years prior, scientists had been sounding the alarm
on chemicals called chloro-fluoro carbons,
or CFCs for short.
They were common in products
like aerosol sprays and refrigerators,
and were chosen specifically
because they were non toxic to humans.
But scientists soon discovered that that just didn't matter
because these molecules were extremely toxic
to the ozone layer.
Turns out, when UV light hits a CFC molecule,
it releases a chlorine atom,
which basically goes on a killing spree to celebrate,
turning ozone molecules into oxygen,
which are basically worthless
when it comes to protecting your planet from UV radiation.
One chlorine atom, for instance,
can destroy over 100,000 ozone molecules
before it finally binds with another molecule
and becomes inert.
And the worst part is that chlorine atoms
are especially destructive to the ozone
in cold temperatures.
You know what else is cold?
Antarctica.
But if CFCs continued to go on unchecked,
cold regions wouldn't be the only casualty.
By 2020, 17% would be gone worldwide,
and a similar ozone hole would form over the Arctic.
By 2040, 70% would be gone.
By 2050, after the poles,
the tropics begin to lose their ozone layer completely.
And by 2065, we're doomed!
UV radiation levels on Earth's surface double,
which sparks all sorts of problems.
- If that UV were coming all the way to the surface,
we would get skin cancer,
we would have cataracts on our eyes,
animals would get cataracts, our crops would die.
So life on Earth as we know it,
and life for humans really wouldn't be possible.
It sounds like some kind of
a horrible Hollywood disaster movie, I think.
But yeah, we would have been in for,
I mean, it sounds very extreme, apocalyptic consequences,
but really, we might have been.
- [Narrator] Obviously, none of that happened.
That's because scientists across the world
banded together.
The Montreal Protocol was signed in 1987,
lowering production of harmful CFCs.
- The policy-makers listened to science,
they were informed by science,
and they made a great decision.
They said, we care, we're going to try
to come up with a treaty that solves these problems,
and it worked.
- [Narrator] By 1996, CFCs were banned completely
in developed countries.
Now there are signs that the ozone is recovering,
and could be completely healed by the end of the century.
So it looks like the world won't crumble by 2065 anymore.
Well, at least not from a depleted ozone layer.