An Ocean of Air (23 page)

Rowland is an impressive figure, six foot five, calm, imposing, and supremely scientific. He laid out the case in clear, concise terms. But the problems were always going to lie in the uncertainties. Many, perhaps even most, scientists believed that the ozone layer would suffer as a result of CFCs. The trouble was that nobody had any idea how much.

The CFC industries, led by Dupont, were determined to exploit every possible weakness in Molina and Rowland's argument. And one of their star witnesses was none other than Jim Lovelock.

Why was Lovelock on the "wrong" side? One reason is that he liked the CFC scientists he had met. Like Thomas Midgley, the people working for Dupont and the other CFC manufacturers weren't cartoon bad guys. Their companies all considered themselves to be highly reputable. Remember that CFCs had been invented only because Frigidaire—unprompted by government regulation—had decided to try and find a safer alternative to the refrigerants that were clearly dangerous. Dupont had even convened a conference in 1972 with other makers of CFCs to confirm that the chemicals weren't harmful. (Though unfortunately they confined themselves to direct health risks in the lower atmosphere, where at present levels CFCs will certainly do little harm.) Lovelock had warmed to the Dupont researchers who came to him for advice. "Some might say I was a bloody fool," he said later, "but I think I just did what came naturally. I liked the people [in the CFC industry], they seemed to be a very honorable, decent bunch of scientists."

Besides, even though he knew they had a vested interest in preserving the CFC industry, he also believed that they were right. Lovelock genuinely thought that CFCs would not do a significant amount of harm. According to his Gaia theory, living things had filled Earth with self-healing mechanisms. Nature, in Jim Lovelock's book, was too powerful to be disturbed by a few whiffs of CFCs. Even if some extra ultraviolet light slipped through the ozone layer, Lovelock thought that life would be able to cope. He also had a natural distaste for knee-jerk reactions, and despised
the weak-minded notion that anything "chemical" was bad and anything "natural" was good.

The hearing didn't achieve much, except to force the issue even farther into the open. All the scientists involved were now feeling the heat. Molina and Rowland were constantly under attack by the industry. Lovelock, meanwhile, became an environmental target. Spiteful newspaper reports in the United Kingdom began to say that he was "in the pockets of the aerosol industry." (It's ironic in view of all this that Lovelock's family was one of the first to give up aerosols using CFCs as a propellant. They had to—otherwise any spurt of hair spray or deodorant would have played havoc with his delicate measurements.)

Later, Lovelock would change his views. He eventually realized that even the Gaian self-healing mechanisms could be overwhelmed, and also that the loss of ozone was more serious than he—or anyone else—had thought. (He was also unafraid to say so.) But for now, he was still reacting against what he regarded as unscientific hysteria. "I respect Professor Rowland as a chemist," he told a newspaper reporter shortly after the Molina-Rowland story broke, "but I wish he wouldn't act like a missionary ... The Americans tend to get into a wonderful state of panic over things like this." What was really needed, according to Lovelock, was "a bit of British caution."

In April 1975, the U.S. National Academies of Sciences put together a twelve-person team of scientists to investigate the ozone issue. They were split into two groups. One was to review the science of Molina and Rowland's claims, while the job of the other was to make recommendations about what should be done. The teams began their laborious process of hearings and recommendations and arguments, and Molina and Rowland worried.

They were troubled because everything rested on their calculations. Apart from Lovelock's CFC measurements and a few balloons that had been sent up afterward, Molina and Rowland had no direct measurements from the stratosphere. They had to imagine what might be happening there and then set up artificial stratospheres in the lab to test their ideas. The stratosphere is a strange place; the air is thin, the temperature is warm,
and energetic ultraviolet rays abound, ripping apart the molecules that exist in more normal circumstances. Bizarre chemical species that wouldn't last a millisecond down near the ground are common in this maelstrom. And Rowland and Molina had to be sure they had included every one of the possibilities in their figures.

They knew, for instance, of two chemicals that could turn out to be either heroes or villains. Hydrogen chloride (HCl) and chlorine nitrate (ClNO3) are "reservoirs" for chlorine. They are extremely stable even in the stratosphere, and once a chlorine atom gets tied up in one of these two, its destructive habits are over. Molina and Rowland had included both of these chemicals in their calculations. But had they got it right? Give the reservoirs too much credit for their ability to rein chlorine atoms in and you'll seriously underestimate the eventual ozone destruction. Give them too little credit, on the other hand, and your results will seem like fear-mongering. Until the first signs of ozone depletion showed up, nobody would know if Molina and Rowland had got it right.

Eventually, in September 1976, the reports were published. The first concluded that Molina and Rowland's calculations were justified. CFCs posed a threat to ozone. The second declared that, since it was not yet clear how serious the threat might be, it made sense to wait and see rather than to introduce immediate draconian regulations. Molina and Rowland later wrote that the two reports could have been shortened to one word each: "Yes," and "But." Confusion reigned. Newspapers took whichever message they preferred. "Scientists back new aerosol curbs to protect ozone in atmosphere," declared the
New York Times.
"Aerosol ban opposed by science unit," was how the
Washington Post
put it.

Still, a certain level of alarm had been raised. By 1978, America had at least banned the use of CFCs as a propellant. Canada, Norway, and Sweden followed suit. But then, in spite of the continued attempts of Molina and Rowland and many of their scientific colleagues to keep the issue alive, ozone and CFCs dropped quietly off the political agenda. Carter was out and Reagan was in; the green 1970s had given way to the greedy 1980s.

The problem was that even Molina and Rowland now thought it could be decades before the first incontrovertible signs of ozone loss appeared.
Until then, CFCs would gradually, imperceptibly nibble away at the ozone layer, and by the time we had concrete proof of a serious effect it would be too late. In summer 1984, Rowland gave a dispirited interview to the
New Yorker:

From what I've seen over the past 10 years, nothing will be done about this problem until there is further evidence that a significant loss of ozone has occurred. Unfortunately, this means that if there is a disaster in the making in the stratosphere, we are probably not going to avoid it.

Rowland was right that nothing much would happen without new evidence of ozone loss. But he had no idea how quickly and dramatically that would come. For in the autumn of that same year, a scientist who had spent several years adopting a bit of "British caution" decided to abandon his reticence and trumpet his findings to the world.

***

Antarctica in the 1950s was a rugged, macho place, and few stations were more rugged and macho than the British Antarctic Survey's remotest outpost at Halley Bay, which floats on a shelf of ice about a thousand miles from the South Pole. The temperature there never rose above freezing and in the winters plunged to 50 degrees below zero. An even worse problem was the wind, which howled over the flat ice shelf, whisking away any vestiges of bodily warmth as it whipped up snow into blizzard after blizzard and buried those first tough little wooden huts up to their necks.

The old traditions prevailed at Halley long after they had been overtaken in the rest of the world. There were men with beards, with their arcane Antarctic-only slang and coarse humor. There were dogs to pull sledges, and there was the flat white emptiness from horizon to horizon. No room there for softness, or comforts, or women.

Joe Farman, a quiet, pipe-smoking Briton of the old school, had been masterminding research at this bleak outpost since 1957. Every year, during the southern spring and summer, scientists from the British Antarctic Survey had trekked down to Halley to measure the amount of ozone overhead.

Why ozone? And why there? At first, it was an attempt to use movements of ozone to map upper atmospheric currents. Later, it was more out of habit. In the 1970s Molina and Rowland's findings about CFCs had given some extra impetus to this research, but Farman probably would have done it anyway. Long records of interesting atmospheric constituents usually prove useful in the end, for one reason or another. Compiling the records is often thankless, but after all, you never know. Farman didn't receive much money for his project, but it didn't cost that much to do and there were always plenty of volunteers to make the measurements.

Early in 1984, Farman received a visit from his boss at the funding agency, who asked him, yet again, why he was persisting with such an obscure record. "There is a big CFC industry," Farman replied. "And people are writing that ozone will change. And the only way you can tell if ozone has changed is to sit and keep measuring it." His boss's response: "You're making these measurements for posterity. Well tell me, what's posterity done for you?"

It was slightly disingenuous of Joe Farman to say this about CFCs, because he was already nursing a secret. He had been nursing it for three years, but later that same year he decided to divulge it. Something had shown up in this long, repetitive series of measurements that at first Farman didn't quite believe. Ozone always changed a bit at Halley, between the dark winter months and the return of the sun. But in 1977 something different had begun to happen. In October each year, at the onset of spring, the ozone had begun to plummet. Each year the drop was a little worse. In 1983, where Farman would normally expect about three hundred units of ozone, he was seeing less than two hundred.

At first, Farman and his two colleagues kept mum. Above all, they didn't want to look foolish. A NASA satellite had been measuring ozone over the whole of Antarctica for the past five years and had noticed nothing amiss. Perhaps there was something funny about the instruments Farman and his group were using. Perhaps there was something funny about Halley itself. So in the season of 1983-84, Farman sent a new instrument down to Halley. He also took a look at the record from another British station, Argentine Islands, which was more than a thousand miles farther
north. Both stations confirmed what Halley had already shown. Now 40 percent of the ozone was disappearing each austral spring. There was a hole in the sky.

When he saw this, Farman threw his British caution to the winds. The paper that he and his two colleagues wrote landed in the offices of
Nature
on Christmas Eve and was published in May 1985. Molina and Rowland's paper had had little immediate effect, but Farman's caused an uproar. Among the most astonished was Donald Heath's research group at the NASA Goddard Space Flight Center, whose job was to coordinate the ozone measurements made by NASA's Nimbus-7 satellite. They had no hole in their data. What was Farman's group talking about?

Hastily, Heath's group pulled their data out to check it again. They were mortified. The data recovery program had been designed to throw out spurious numbers before the researchers even saw the results; that way they wouldn't have to be bothered by irritating measuring glitches. Any measurement of ozone values that fell below 180 units was obviously ridiculous and had simply been ditched. The satellite had seen Farman's ozone hole all right, but thanks to their overeager program the researchers themselves hadn't seen a thing. Now, using the correct data from 1979 to 1983, they watched a hole the size of the continental United States gradually appear over Antarctica. In some cases, the ozone dropped to less than 150 units.

Heath's group had learned an important lesson about Earth's atmosphere. Even if you are sure you understand the way our ocean of air works, it is still always wise to expect the unexpected.

Meanwhile, the rest of the ozone community was in disarray. Even Molina and Rowland's worst scenarios hadn't predicted something as extreme as this, and so soon. There was no sign of a hole like this anywhere else on Earth, so it must have something to do with the extreme Antarctic conditions. But what?

In research labs and coffee rooms at universities throughout the world, attention began to focus on the first, most obvious characteristic of the Antarctic stratosphere: It is the most isolated air on Earth. Every winter, winds whip up around the edge of the entire ice-covered continent until they form a giant vortex whose walls separate the air from warmer breezes farther north. Trapped inside this vast whirlwind, Antarctic air grows steadily colder, and colder. And then, a new kind of cloud appears in the Antarctic skies.

Normal clouds are formed of liquid water drops, and they can occur at almost all levels in the troposphere—the lower part of the atmosphere—which is the place where we live and experience our wind and weather. As you progress upward through this layer of air, the temperature drops steadily until, at the top of the troposphere, it reaches a minimum. Immediately above this point, the stratosphere begins. Now there are ozone molecules to catch sunlight and warm the air, and the temperature starts to rise. The cold point between these two layers traps any water vapor by turning it into clouds and sending the rain falling back down to Earth. It is a water-tight barrier, stretching around the world like a giant tarpaulin, keeping the lower atmosphere wet and the upper atmosphere bone-dry. That's why the stratosphere almost never has clouds.

But the stratosphere still contains just a little water that has leaked through from below, and—if the temperatures are low enough—this can freeze solid into tiny flecks of ice. That is what happens in the Antarctic stratosphere, in winter.