Susan Solomon had an idea -- a really good one.

Because she was right, uncountable millions of young people around the world at risk for deadly skin cancer probably won't get it.

Uncountable bizarre mutations also won't appear among plants and animals in the world's wilderness and gardens.

Twenty years ago this week, Solomon, an atmospheric scientist, stepped onto the Antarctic snow, leading a team of scientists bent on checking out her idea about how to prove that human activity -- the manufacture and use of chlorine-based gases (CFCs or chlorofluorocarbons) -- was creating the frightening enormous holes that had appeared above the north and south poles in the ozone layer of Earth's upper atmosphere.

It seemed an outlandish idea at the time -- that mankind had become so dominant in the life of Earth that we could actually alter the atmosphere of the entire globe.

What child wants to think it has the power to hurt a nurturing parent?

It was real, though, and a close call.

Over the last couple of years, in the course of talking to climate scientists about the completely different problem of global warming, I have often enough seen them shake their heads in wonder and remark how lucky we all were that the ozone depletion and its causes were discovered in the nick of time.

They say the devastation to life on Earth -- if ozone depletion had gone unchecked -- would be hard to imagine.

Life had not evolved to live with a constant bath of the intense ultraviolet rays from the sun that the ozone layer blocked.

Overdose on UV and you're far more likely to get skin cancers.

Too much UV leaves wild plants and animals far more likely to suffer genetic mutation.

There is, however, a painful irony in what followed.

While the discoveries of Solomon and her team led to a true solution -- the world's nations banded together in the "Montreal Protocol" of 1989 to stop sending CFCs into the atmosphere -- that cure is now slowed by man-made global warming and even making that warming worse.

Within a year of Solomon's findings, leaders and manufacturers around the world were facing the new reality.

CFC gases used in cooling units of refrigerators, aerosol cans and many other products were quickly phased out and the ozone holes above each pole stopped growing.

Problem is, the gases that replaced them were strong greenhouse gases and were realized in the 1990s to be only adding to global warming.

And global warming, as professor Paul A. Newman, et al, have recently confirmed in a study published by the American Geophysical Union, slows the repair of the ozone holes.

The good news is that the ozone holes haven't grown any worse.

Without global warming, Newman suggests, the ozone holes would be starting to shrink soon and fully repaired by about 2050.

Now, he figures, those holes won't start shrinking for at least an additional 10 years and won't be completely closed, at the earliest, before 2070.

This ozone layer, high in the stratosphere, had long enveloped our Earth like a durable coat of clear polyurethane you might brush onto a wooden sun deck to protect it from the weather.

It was in the 1970s that scientists had confirmed giant holes in the ozone layer over each pole.

Solomon, whose smiling face next to a tabletop globe can be easily found here -- and who got fascinated by science as a kid growing up in Chicago -- has been richly honored around the world.

She's one of those scientists so widely recognized now by her peers that her bios usually have room to list only some of many top awards, including, for example, Japan's "Blue Planet Prize" of half-a-million dollars for having made a major contribution to solving a major global environmental problem.

There's some additional good news in this story, despite the fact that it has only added to the separate problem of global warming.

Once the grave global threat of ozone depletion was clearly understood, humankind proved capable of getting its act together and dealing with it.

Scientists often point out that the successful defeat of the CFC problem -- a problem we had created -- is a model, a geopolitical warm-up, for what humanity must now do to solve the greenhouse-gas problem, which we have also created.