40 years ago scientists sounded the alarm on nuclear winter and it changed the

world. Once you've saved the world from nuclear weapons what do you do with the rest of your life?

It's Monday, November 6th, but you guessed it, it's actually Science Friday.

I'm Cyfry producer Rasha Iridi.

In honor of this 40 year anniversary, Ira talks with someone whose work on nuclear winter went on to influence nuclear policy,

and it changed the course of nuclear warfare forever.

This week holds anniversaries for two important milestones in nuclear warfare.

In November 1952, 71 years ago, the U.S. detonated a terrible new weapon, a massive hydrogen bomb in the Marshall Islands.

It vaporized a whole island, leaving behind a mile-wide crater where the island once

was. It was around 700 times more powerful than the bomb dropped on

Hiroshima. Fast forward to almost 40 years ago today. On October 30, 1983, millions of Americans flipped open the Sunday paper to find a shadowy,

gray, very apocalyptic photo with the words, would nuclear war be the end of the world? It introduced the world to nuclear

winter, the terrifying climate changes that might be brought on by nuclear war.

And it was the iconic scientist, Carl Sagan,

that introduced the term.

He was an author of the first research on nuclear winter,

spent years warning politicians, world leaders, and the general public.

The idea that more nuclear weapons make you safer is an illusion beyond a certain point.

More nuclear weapons make you less farm. The threat of nuclear

winter has reduced since then but with thousands of nuclear weapons still in

existence that risk is not zero. My next guest is also a pioneer in nuclear winter research.

Dr. Alan Roebuck, climate scientist and distinguished professor at Rutgers

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