Name: Why you don’t hear about the ozone layer anymore
Uploaded: 2021-09-26T05:01:06.000Z
Duration: 8 min 35 s
Description: VoiceTubeの動画で発音を聞きながら英語表現を覚えよう！学べる英語：

The 80s were all about  big hair, neon, MTV.

"Every October a hole appears in the  ozone layer over the south pole."

"...hole in the ozone shield is the size of the continental United States."

"The protective ozone layer is  being threatened as never before."

Scientists warned that humanity was on track to completely destroy the ozone layer by 2050.

and life as we knew it would cease to exist.

In an unprecedented act, the world came together to prevent an environmental catastrophe.

The ozone layer is a sort of “belt” around the Earth made up of gaseous molecules.

by absorbing two types of  ultraviolet radiation from the Sun.

It's a powerful shield, but  it's also fragile.

In 1985, scientists discovered a  massive loss of ozone here:

40% of the layer had dissipated, creating a “hole”.

Scientists realized the hole formed in the spring and every year it got worse.

It was now and way bigger  than anybody ever imagined.

That's Dr. Solomon, an atmospheric chemist.

In 1986, she flew to Antarctica,  along with other scientists

to investigate the cause of the ozone hole.

a young atmospheric chemist  from Boulder, Colorado."

You know once you step off the plane in Antarctica,

your main goal is to get out  without getting frostbite.

But what really our goal was to take measurements,

not just of ozone, but also of different chemicals that would help to show why it was going away.

Some scientists released balloons in the sky to take ozone measurements.

While others took measurements on the ground.

And they all came to the same conclusion.

The biggest problem was chlorine from a man-made compound called Chlorofluorocarbons, or CFCs.

But once they float up to the stratosphere the Sun breaks them down into chlorine.

They bind with ozone to make  oxygen and chlorine monoxide.

Then the loose oxygen atoms  bump the chlorine atom out,

freeing it to destroy more ozone molecules.

The long lifetime of the chlorofluorocarbons is a big part of the problem.

They live anywhere between 50 and 150 years in our atmosphere so...

what you use the year before  is almost entirely still there.

So it just builds up and builds up exponentially.

The US had already moved away  from CFCs in aerosol cans.

And they were still in everything from refrigerators and air conditioners and styrofoam.

The entire world needed to make a big change quickly or we'd face--

In 1987, ozone levels had dropped  by 50 percent.

This growing threat led to some of the fastest collective action on climate we've ever seen.

So I like to think of it as, there's three P's that when, they're met we do very well

It was perceptible and the solutions  were practical.

If you've been sunburned, you know that  skin cancer is not a good thing.

The personal nature of the threat is huge.

The perceptible was easy to do  with satellite measurements.

You can just watch it get  completely destroyed and go to zero

where there should have been a lot of ozone.

It was easy to find substitutes for  chlorofluorocarbons in spray cans that took,

And I think the main unifying factor  in all of that is the public.

Scientists like Dr. Solomon held  press conferences to inform the public.

"I think we will eventually see large scale depletions of the ozone layer in other latitudes."

The ozone hole started showing up  in TV shows and movies.

“It's those damn fluorocarbons, they've been kicking the hell out of the ozone.”

“Well so will the ozone, eventually.”

And all this public awareness put pressure on leaders around the world to act.

“We are here today because we recognize that urgent action is necessary.”

And the Montreal Protocol made it official.

It recognized “that world-wide emissions can significantly deplete the ozone layer

and result in adverse effects on human health and the environment."

It listed control measures to reduce ozone depleting substances in a series of steps.

who need alternative technology  and substituting products.

Every single country eventually  signed the protocol.

Making it the only universal treaty  to ever be ratified.

And the most successful environmental agreement in human history.

Soon after, the world's largest CFC producer began to phase them out.

Since the protocol went into effect  on January 1st, 1989

the consumption of ozone-depleting substances

Today, more than thirty years after  the Montreal Protocol was signed

the ozone hole has stopped growing  and is now shrinking.