By Donella Meadows
–September 1, 1993–
F. Sherwood Rowland was surprised by all the volcano questions. As a distinguished atmospheric chemist, the discoverer of the cause of the ozone hole, he gives regular public presentations on how the ozone layer works and why it is being depleted. Recently his audiences have been asking, sometimes with confusion, sometimes with hostility: Don’t volcanoes cause the ozone hole?
Finally he traced down the source of this question, and in a concerned speech last February (printed in the June 11 edition of Science magazine) Rowland explained why volcanoes cannot be the cause of the ozone hole, and why so many Americans think they are.
Volcanoes have been popping off for eons while the ozone layer has remained happily intact. Measurements of ozone concentration over Antarctica, conducted since 1956, showed no hole until about 1975, and an unmistakable and deepening hole since about 1980. No volcanic activity matches that pattern.
Volcanic eruptions do emit hydrogen chloride (chlorine is what breaks down the ozone layer — that was Sherwood Rowland’s discovery). But they also spew out huge amounts of water vapor. Hydrogen chloride dissolves in water. Most of the chlorine from an eruption never reaches the high stratosphere where the ozone layer is, because it washes down in rain. The massive eruptions of El Chichon in Mexico in 1982 and Pinatubo in the Philippines in 1991 produced only small increases in stratospheric chlorine.
Furthermore the chemical agents that DO eat up the ozone layer have been clearly detected. Their path of destruction is now so well demonstrated that even the companies that make those chemicals believe the evidence. Ozone depletion is caused by chlorine compounds called CFCs produced and emitted by human beings — Freons in our cooling systems, gases in our insulating foams, solvents in our electronics factories.
Some people just do not want to believe this. Some of these people are unwilling even to admit that there is an ozone hole, though it has been measured many times by scientists from many nations. And if there is a hole, then they refuse to allow the thought that people caused it. They would rather blame volcanoes.
Rowland described in his speech the sequence through which these people, reading science through a filter of denial, have popularized their volcano theory.
That theory rests upon one actual observation: after a 1976 eruption of Mount Augustine in Alaska the ashfall contained glassy lumps. Those lumps contained twice as much chlorine as did ash itself. One geologist wrote a paper in 1980 hypothesizing that the glassy stuff was the original magma thrown out by the volcano. If the ash contained less chlorine than the magma, then a huge amount of chlorine must have been lost — something like 100,000 tons. Some or all of that chlorine might have gone into the stratosphere.
The geologist then calculated, for the fun of it, how much chlorine might have been released, if all his assumptions were right, by another, much larger volcano, which erupted in what is now California 700,000 years ago. He guessed it might have been 289 million tons — 570 times the amount of CFCs produced in the world in 1975. This was an interesting conjecture, but based upon no actual measurement. The whole line of reasoning depends upon many assumptions, most of which have since been disproved.
That paper was out on the thin edge of science. Then it was seized by the ozone doubters and made even thinner. In 1989 a man named R.A. Maduro, with a bachelor’s degree in geology, who worked for a publication of the extreme left/right wing Lyndon LaRouche (LaRouche occupies the territory where the left and the right wing bend back to meet each other), wrote a book called The Holes in the Ozone Scare. He quoted the numbers about chlorine release from the Alaska and California volcanoes as fact, not hypothesis, and then claimed that the ozone scare was a plot hatched by the Du Pont Company, which was planning to make a bundle on CFC substitutes. (Since Du Pont was also the world’s largest maker of CFCs, Maduro’s accusation doesn’t make a whole lot of sense.)
Then Dixy Lee Ray, the former governor of Washington, once a zoologist, picked up the story, but garbled it further. In her book Trashing the Planet she mistakenly attributed the huge number for the volcano in California to the one in Alaska. She wrote: “The eruption of Mt. St. Augustine in 1976 injected 289 billion kilograms of hydrochloric acid directly into the stratosphere. That amount is 570 times the total world production of chlorine and fluorocarbon compounds in the year 1975…. So much is known.”
The mixed-up story was picked up from Ray’s book by the Wall Street Journal, the National Review, Omni, and the Washington Post, but the person who pounded the volcano theory into the public consciousness was none other than talk-show host Rush Limbaugh. In his best-selling book Limbaugh stretched the facts still further: “Mount Pinatubo in the Philippines spewed forth more than a thousand times the amount of ozone-depeting chemical in one eruption than all the fluorocarbons manufactured by wicked, diabolical, and insensitive corporations in history.” He claims he got this information from Dixy Lee Ray’s book, “the most footnoted, documented book I have ever read.” Limbaugh prefers to blame the ozone hoax not on Du Pont, but on “environmentalist wackos.”
So Sherwood Rowland and other atmospheric chemists are patiently answering volcano questions, though Rowland says, “it will be difficult for my message to catch up with their misstatements.”
“The world is a very complex system, the amount of information we have about it grows exceedingly rapidly, keeping up requires great effort,” says Rowland. “But I know of no easy way: you just have to do it. Meanwhile, the combination of some but not enough intelligence, plus considerable amounts of both ignorance and arrogance, can easily lead to being badly wrong in full voice and, worse yet, with a considerable following.”
Copyright Sustainability Institute 1993