By Donella Meadows
–May 18, 1989–
A fat lady in apron and snow boots is out on her porch earnestly spraying an aerosol can out into space. The caption says, “Mrs. Alice Snood of East Icicle, Vermont, is doing what she can to get rid of the silly ozone layer. She says a global warming trend would be a darn good idear … especially up at her place in the middle of February.”
When Danziger penned that cartoon for the Christian Science Monitor, I suppose he purposely mixed up the atmospheric facts to make Mrs. Snood funnier. But even if his confusions were intentional, I’m not sure most readers caught them — did you?
There are three errors in that one short caption:
1. In the United States aerosol cans no longer contain the chlorofluorocarbons (CFCs) that destroy the ozone layer. CFC-based aerosol sprays were banned here ten years ago. They are still used in other countries, but by international agreement they are now being phased out everywhere.
2. Ozone depletion is not what causes global warming. CFC pollutants do two unrelated things when they get into the stratosphere — they destroy ozone, and they are among several gases that cause greenhouse warming. (They account for about 25% of the warming potential at the moment.) So Mrs. Snood COULD speed up global warming by spraying CFCs, but not by spraying aerosol cans, and not by depleting the ozone layer.
3. Alas, a global warming does not necessarily mean a warmer February in Vermont. No one is sure what the changed climate will be like, if we go on letting it change, but it won’t be a simple matter of shifting all zones northward. Vermont might have hotter summers and colder winters, or vice versa. It might have less rain, or more. What is sure is that weather would be different everywhere. Sea, lake, river, and groundwater levels would change. Forests, farms, and ecosystems would have to move somehow or die. Mrs. Snood better get off her porch and start preventing global warming instead of trying to enhance it.
Her confusion, or Danziger’s, or our own, is not surprising. We are disrupting so many gases in the earth’s atmosphere that they are getting all jumbled together in media accounts and in public understanding. We’d better get them straight; every one of them has the potential to change our lives. For starters, there are four important kinds of gases to keep our eyes on: high up ozone, low down ozone, acid rain makers, and greenhouse gases.
HIGH UP OZONE is a natural thin layer in the stratosphere, twice as high as jet planes fly. It absorbs ultraviolet light, which, if it reaches the earth’s surface, can damage many things, including human eyes and skin. High up ozone is being depleted (as in the ozone hole over the South Pole) because of human release of CFCs — not so much from aerosol cans as from refrigerators, air conditioners, and many industrial uses.
High up ozone is good and we’re destroying it. LOW DOWN OZONE is bad and we’re creating it. It’s one of the most irritating ingredients in urban smog — and now it’s found in rural areas too. Ozone is a strong oxidant; it delivers the equivalent of a slow burn to vegetation and to lungs. It’s building up down here where we can breathe it because of the action of sunlight on hydrocarbon pollutants, mostly from the tailpipes of cars and trucks. No, unfortunately, it doesn’t percolate up to the stratosphere, where we need it. Too much ozone down low does not help the problem of too little ozone up high.
ACID-MAKING GASES also come out of tailpipes and smokestacks. They are mainly sulfur and nitrogen oxides; when they dissolve in rain, snow, or fog, they make sulfuric and nitric acids. They eat into lungs, they acidify streams and pickle aquatic life, and they seem to be conspiring with low-down ozone to sicken the forests.
GREENHOUSE GASES are the ones that are warming the earth, changing the climate, and making the seas rise. There are a bunch of them — carbon dioxide from fossil-fuel burning, nitrogen oxides, CFCs, and methane. They all block the release of heat from the earth’s surface, the way the windows trap the sun’s heat in your car. Because some greenhouse gases are there naturally, our earth stays warm and welcoming to life. Too few and we freeze, too many and we roast. Concentrations of greenhouse gases in the atmosphere are now rising rapidly. We human beings are putting them there.
The fragile mixture of gases that envelops our beautiful planet is constantly changing as living creatures in their billions and trillions take them in and give them out. In its normal dynamic balance the atmosphere moderates the earth’s temperature, mediates the weather, and permits the existence of all life. That balance is being deranged because one species is suddenly pumping hundreds of millions of tons of junk into the air every year. That’s the species that calls itself Homo sapiens — “man the wise.”
Copyright Sustainability Institute 1989