THE HOLE STORY : THE DAMAGE WE MEASURE NOW IS A RESULT OF WHAT WE DID YEARS AGO--AND YEARS’ WORTH OF CFC EMISSIONS ARE STILL ON THEIR WAY UP, IMPOSSIBLE TO STOP.
There’s bad news about the ozone layer. A new report shows a loss of stratospheric ozone over the Northern Hemisphere, about three times greater than scientists had expected.
There’s good news about the ozone layer. The U.S. Senate has just ratified an international treaty limiting the use of the chemicals that threaten it. E. I. Du Pont de Nemours and Co. has announced that it will stop manufacturing those chemicals altogether.
The ozone story has been breaking like that, bad news and good news, for three years now. One break makes you think the human race has unleashed a chemical disaster that is simply unstoppable. The next makes you think that life on this planet may have a future after all.
Ozone is a rare, unstable gas made of three oxygen atoms stuck together. In the lower atmosphere ozone breaks up quickly to form plain old two-atom oxygen. About 15 miles up, however, new ozone forms continuously as sunlight hits oxygen. The concentration of ozone up there is only about one molecule in every 100,000, but that’s enough to screen out much of the sun’s ultraviolet light. The ultraviolet light that does get through the ozone layer is what gives us sunburns and what burns our eyes when we look directly at the sun. It’s a sterilant. When I was a kid, the schools used to shine UV light on our heads to get rid of ringworm. UV light is a packet of energy just the right frequency to break up the chemical bonds that hold together all living things. Not until the ozone layer formed, 500 million years ago, could early life forms creep out onto the land. Until then they had to shelter under the sea--which gives you an idea of what the loss of the ozone layer could mean now.
You’ve probably heard that ozone depletion will cause human skin cancers. Possibly more important, however, could be the harm to human vision and immune systems. Every other form of life exposed to sunshine could be affected in some way, most especially green plants. The more the ozone layer is depleted, the greater the ecological disruption. If it goes far enough, there may be no land-based life at all.
Quite a price to pay for hairspray.
The depletion of the ozone layer is almost certainly due to pollution from chemicals called chlorofluorocarbons (CFCs). CFCs are used in aerosol sprays, refrigerants, fire extinguishers and a host of other products that some people consider essential to civilized life. The connection between CFCs and ozone was first postulated in 1974 by F. Sherwood Rowland and Mario J. Molina at UC Irvine. They calculated that CFCs could set off an insidious chain of ozone-destroying reactions.
When a CFC molecule reaches the stratosphere, sunlight splits it into, among other things, atoms of free chlorine. The chlorine reacts with ozone to form oxygen and chlorine oxide. The insidious part is that the chlorine oxide then breaks up to form chlorine again, which can bump off another ozone molecule. Each chlorine atom gobbles up ozone but remains itself unchanged, like a Pac-Man. Scientists estimate that a single atom of chlorine can destroy 100,000 molecules of ozone.
Another insidious fact: A CFC molecule released on the Earth’s surface can take as long as 15 years to wend its way up to the stratosphere. The damage we measure now is a result of what we did years ago-- and years’ worth of CFC emissions are still on their way, impossible to stop.
Environmentalists took Rowland and Molina’s warning seriously. They agitated until the United States banned the use of CFCs in aerosol sprays in 1979. That ban reduced world CFC output by 25%. Other uses of CFCs were increasing, however--for coolants in car air-conditioners, for solvents to clean electronic circuit boards, for blowing up the sort of plastic foams you find in hot-drink cups. Now about a million tons of CFCs are produced worldwide each year.
The United Nations Environment Programme (UNEP) held a meeting in March, 1985, to produce the Vienna Convention for the Protection of the Ozone Layer. “That was a dreadful piece of verbiage,” says Konrad von Moltke, an environmentalist in the thick of this battle. “It was an agreement to disagree.” The United States, Canada and Scandinavia, which already had aerosol bans, wanted other countries to adopt them, too. Some countries wanted strict limits on all CFC production. Others with major CFC industries, like France, West Germany, and Britain, were not convinced of the problem.
Just as the Vienna Convention was taking place, the news broke about the “ozone hole” over Antarctica. The British survey station at Halley Bay had recorded a steady loss of stratospheric ozone there since 1977, but the measurements were so unbelievable that they had been discounted. When similar losses were detected over Argentina, the findings were finally published. They were quickly confirmed by satellite data from the National Aeronautics and Space Administration. The NASA computer had been discarding low ozone readings on the assumption that they were errors. Ozone above Antarctica in October, the beginning of the Antarctic summer, was depleted by 40 to 60%.
Discovery of the hole shocked the scientific world and started a burst of research, environmental activism and international meetings.
The United States broke the ice in the international negotiations in November, 1986, when it stopped advocating an aerosol ban and suggested a 95% reduction in all CFC production. (In spite of Interior Secretary Donald P. Hodel’s ignorant remark about sunglasses as the answer to the ozone problem, the U.S. government, through the State Department, has taken a leadership role in the negotiations.) The World Resources Institute updated European environmental groups and got them involved. German environmentalists, including Von Moltke, used a national election to pressure all political parties to advocate a CFC production ban.
A breakthrough came in Geneva in March, 1987, when Mustafa Tolba, the director of UNEP, proposed a three-stage plan: First freeze CFC production at current levels; four years later reduce by 20%; four years after that reduce by another 30%. “No one expected a proposal that strong,” said Von Moltke, “but no one shot it down.”
The plan went back to national governments for consideration. The “good guys” in the White House--Secretary of State George P. Shultz and Lee M. Thomas of the Environmental Protection Agency--won out, perhaps aided by the fact that U.S. manufacturers such as Du Pont were developing CFC substitutes. The Freeze-20-30 plan was still afloat at a meeting in Brussels in June, and Von Moltke was rejoicing: “This goes beyond anything I could have imagined 12 months ago.”
Last September in Montreal, 24 nations and the European Economic Community finally signed an ozone agreement. It backed off freeze-20-30 but the agreed-upon CFC reductions will amount to about 40% worldwide over 10 years. This is the treaty the Senate just ratified.
The agreement may be too little, too late. Many Third World countries have not signed. Signing is no guarantee of action. The pact will have to be enforced, CFC production levels will have to be verified and sanctions against violators will have to be effective. Even if everyone abides perfectly, there are so many CFCs already in the environment and permitted by the agreement that atmospheric chlorine pollution may rise by 25% before it begins to turn down.
As the dignitaries were meeting in Canada, researchers taking the first measurements of the 1987 Antarctic spring were finding that the ozone depletion was worse than ever. Scientists have now been warned against working outside in the Antarctic sun because of the dangerous levels of UV radiation. And ozone depletion is now detectable in the north as well.
The ozone pact does set in place a mechanism that includes periodic reassessments and more stringent cutbacks if scientific findings require them. Though the news keeps breaking, bad and good, the agreement is a real achievement. For once nations have worked together to prevent an environmental catastrophe, instead of trying haplessly to repair one.
This great international breakthrough didn’t require a stroke of enlightenment causing everyone to become permanently virtuous. There was no world government forcing regulations onto stubborn, resisting nations. There was no environmental Gandhi leading the masses into action. What brought about agreement was dedicated people at many levels, with many skills, playing many different roles.
It’s worth listing some of the heroes of the ozone story, to acknowledge what kind of teamwork is necessary to make this fractious, interdependent world work:
--The world’s scientists, with their international networks that transcend politics, spotted the problem, learned a tremendous amount of atmospheric chemistry in a short time and steadily supplied crucial information to the political process.
--Citizen activists and environmental organizations in many countries mobilized pressure and educated politicians. Some of the organizations that deserve special mention are the Natural Resources Defense Fund, the World Resources Institute, Friends of the Earth U.K., and the Institute for European Environmental Policy.
--National governments, in particular those of the United States, Canada, the Scandinavian countries and eventually West Germany, led the way in the negotiations.
--Major corporations that manufacture CFCs played a generally constructive role.
--Finally, and most important, the United Nations Environmental Programme and its director, Tolba, provided skillful, untiring leadership in calling meetings and keeping the discussions going.
It’s easy to poke fun at environmentalists or argue that the United Nations is worthless or say that national governments are hopelessly self-seeking or believe nothing good about big corporations. But every one of those actors was essential to the ozone agreement. Given the changing news about ozone and other global environmental problems, we’ll probably need them all again.
