You're listening to the inquiry with me Helena Merriman.

On the 30th of June this year a study was released in one of the world's top

scientific journals. It explained how a group of scientists who'd been measuring

the amount of ozone in the stratosphere

had made a startling observation. The hole in the ozone layer had shrunk.

Here, they said, was the first clear evidence that the ozone layer, the only thing protecting

humans and animals from deadly ultraviolet radiation, had begun to heal.

So how did this happen? Well, the scientists put it down to a groundbreaking treaty agreed in the late 80s that banned ozone-destroying chemicals.

It's been described as the most successful treaty ever created.

And behind it is an astonishing story that begins long before it was signed.

It involves Nobel Prize-winning scientists, ingenious campaigners, determined lawyers,

and of course the big chemical companies.

We've assembled four people at the heart of that story to help answer this

week's question. How did we save the ozone layer? the Ozone layer.

Part 1, the smoking gun. I got interested in science when I was a child, started playing with chemistry sets, microscopes, and so even at 11, 12 years old I became fascinated with science.

Our first expert witness Mario Molina, a Mexican scientist who won the Nobel Prize for his work on the ozone layer.

It all began when he was in his early 30s.

He was studying in the US and he and his supervisor, Professor

Sherry Rowland, decided to carry out research into a particular group of

chemicals called chlorofloricarbons or CFCs. One of many chemicals invented in the so-called

Age of Discovery in the early 20th century. The DuPont Company transforms natural

raw materials into articles that serve human needs and transforms natural

...