By Donella Meadows

–April 18, 1991–

You may have seen the recent and ominous headlines: SCIENTISTS FIND OZONE DISAPPEARING FASTER THAN EXPECTED. OZONE LOSS RAISES RISK OF CANCER.

Is this news terrible, or simply bad? What does it mean?

Some of the more excitable environmentalists say it means they have been right all along. The human race is unravelling the earth’s systems. We must repent, reform, cease and desist.

Then there are the scoffers, who have been writing gleeful articles, as studies have shown that East Coast forests are not dying from acid rain as fast as some feared and dioxin may not be as toxic as we thought. Therefore, these folks are saying, there’s no environmental problem — full speed ahead. A little thin ozone is not enough to convince them they’re wrong. They’ll lay low and wait to pounce upon the next piece of environmental news that falls their direction.

With people using every tidbit of news to prove themselves right or to deny being wrong, it’s not easy to understand what really is happening up there in the ozone layer. Here, as far as I can tell and with no axes to grind, is what’s happening.

According to a NASA satellite that constantly circles the earth measuring atmospheric gases, the amount of ozone over the United States has been thinning twice as fast as scientists had projected. Ozone loss was already known to be severe over Antarctica and bad over the North Pole, but now the hole has hit highly populated latitudes. In the last few years the ozone layer has been depleted by 4-8 percent north of a line roughly through Philadelphia and by 4-6 percent south of there. Ozone depletion occurs mainly in the winter, but it’s now extending through April and May.

So what? According to the headlines, the major danger is skin cancer. For every one percent decline in ozone there is expected to be a 3-7 percent increase in skin cancer. Instead of roughly one in seven of us getting skin cancer sometime in our lives, the frequency will rise to one in five — more if ozone depletion gets worse, not so many if we stay out of the sun. (One in 100 of those cases of skin cancer is expected to be lethal.)

Many scientists are not so worried about the skin cancer as about the effects of ultraviolet light on nature as the ozone umbrella thins. Green plants are known to be hurt by UV light. So are the eyes and immune systems of animals. So are the tiny floating plankton that form the foundation of the food chain of the ocean. More UV light also means different atmospheric chemistry, more smog, and perhaps a changed climate. All these effects are less certain than skin cancer, but more worrisome.

Most worrisome of all is the knowledge that the chemicals that cause the ozone layer to thin — the CFCs — only reach the ozone layer after a delay of 5-15 years. The damage NASA is now detecting is coming from chemicals released years ago. More CFCs are on their way up, irretrievably. Their concentration will increase by 12-30 percent over the next decade no matter what we do, according to the old model, which has just been shown to be too conservative. Once a CFC molecule reaches the stratosphere, it stays there gobbling ozone molecules for 50-100 years.

It’s a frightening prospect, no doubt about it. No one knowledgeable about the ozone problem wants to hear that it’s worse than expected. Scientists thought this problem was fairly well understood. Now they have a hint that something is going faster, or more, or differently, than they thought.

There is some good news, however. The nations of the world have already worked out an agreement to phase out the use of CFCs. That agreement was strengthened just last year to speed up the phase-out. Perhaps it will have to be strengthened again, but many countries, including the whole European community, are in fact gearing down CFC production well ahead of schedule. The chemical, electronics, and refrigeration industries once threatened, as industries tend to do, that a phase-out would devastate them. But they’ve found ingenious ways to recycle or substitute for CFCs. No industrial disaster is forthcoming, even if this latest news shuts down CFC production faster than scheduled.

Whether there will be an ecological disaster is just not known. We’ve done a lot to prevent it. We don’t know whether we’ve done enough.

The message I hope the world will draw from this newest ozone development is not that the sceptics are wrong, nor that the alarmists are right, but that in spite of all we have learned about our earth, we are still tremendously ignorant. The environment still suprises us. It will go on surprising us. Its surprises will cut both ways. Some problems will turn out to be worse than we expect, some better.

Given how little we know, full speed ahead is the worst policy we could adopt. The second worst would be to stop in our tracks. The right way to go, when you’re going in ignorance, is slowly, with eyes and ears and satellites cocked for signs of trouble, always willing to learn and to try a new way forward.

Copyright Sustainability Institute 1991