O_{3 -} ozone - it's in the stratosphere, starting from 6 to 10 miles up from earth, and extending to about 30 miles. One of its functions is to protect us from radiation by absorbing most UV-B sunrays. Those are the ultraviolet rays that burn our skin. One by-product of this protection is that because it absorbs radiation, it becomes hot. So hot, that it gives off heat, thus creating, in effect, its own source of heat. You can see that the stratospheric ozone layer is a major player in the overall temperatures of our planet. When people talk about the ozone layer, they are usually referring to this.

So far so good. But ozone's evil twin exists right here at ground level, in an atmospheric layer called the troposphere. This is often called surface-level ozone.

What's the difference? Stratospheric ozone protects us from frying, helps regulate earth's temperatures, and keeps our food crops from sizzling to a crisp before we have a chance to put them in a pan.

Surface-level ozone gives us smog. And it's toxic to plants and animals.

Here's where the situation gets unnerving. We talk a lot about the "hole in the ozone layer." Well, it's not just talk - there are holes in the stratospheric ozone layer.

Both above Antarctica and above the Arctic polar regions, we've got holes. The size of these holes varies depending on the season, but overall, the Antarctic hole is larger.

We need our ozone layers intact. They are our radiation security blankets.

There's bad news and good news. First the bad: the ozone holes are being caused mainly by human-created chemicals that, until recently, we used with abandon: in our air conditioners, refrigerator coolants, and aerosol propellants.

Here's the good news. We humans have taken this ozone hole situation seriously. No one argues or debates or denies it. Planet-wide, people are doing what they can. Industry has created "ozone-friendly" products. Governments have regulated the use of ozone-destroying substances.

NOAA scientists predict that if we continue to behave, the ozone layer will recover within the next 50 years.¹

We can do this - and it shows that when we unite on the planet for a good cause (like, um, survival), humans can work together effectively.

∞

Nov. 19, 2006

^1. Stratospheric Ozone. Science: Ozone Basics. Updated by Karin L. Gleason, from NOAA.