Emily Kwong

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

polar vortex, which results in this seasonal cycle that has its rhythms.

Now, let's go back in time when scientists really started noticing the ozone layer was changing over Antarctica beyond what was typical for the seasonal rhythm.

And these researchers went on an expedition to Antarctica to figure out why.

It's like their Achilles heel.