Emily Kwong

Remarkable loss of ozone that occurs over the Antarctic in October.

A lot of people call it the ozone hole, but it was really more of a thinning.

Scientists launched weather balloons to study its size, and they found something shocking.

High levels of two chemicals, chlorine and bromine, were breaking down ozone faster than it was being made, letting in the kind of radiation that causes cancer, crop failure.

And it was happening because of ozone-depleting substances made by us on Earth.

So the race was on to save the world.

Today on the show, how researchers mobilized on a global scale to close the ozone hole.

Plus, why the ozone layer is still recovering and what climate scientists can learn from this success.

You're listening to Shortwave, the science podcast from NPR.

So, Irina, I want to focus on how the ozone is operating over Antarctica because that's where the hole is.

And I know that the ozone layer over Antarctica naturally thins because things are a little different there, right?

And that's because sunlight triggers ozone formation, but also sunlight destroys ozone.

So the amount of ozone is always kind of fluctuating when the sun is present.

And during the Antarctic polar night in June, July, and August, when there's no sun, the ozone amounts are basically steady.

They don't really fluctuate.

And then in the spring, the sunlight comes back and these chemical reactions start happening again.

But isn't the Earth's atmosphere always moving and mixing?

So wouldn't the air from other parts of the world that have access to sunlight mix with Antarctica's air?

Oh, okay.

So the atmosphere of Antarctica is isolated because of this