Myth: Humans are not causing ozone depletion.
Fact: NASA has proved it beyond all reasonable doubt.
There is overwhelming scientific evidence that man-made chemicals are destroying the ozone layer -- Nobel prizes have already been awarded for the research. Rush Limbaugh argues that humans are safe, because volcanic chlorine has been working on the ozone layer longer than man-made chlorine, and yet we're still here. But this argument is false. Volcanic chlorine is water soluble, and rained harmlessly out of the atmosphere. Human CFCs are insoluble, and can therefore rise to the ozone layer where they can do their damage.
Do man-made chlorofluorocarbons (CFCs) destroy the ozone layer? There are no longer any skeptics left at NASA, the National Academy of Sciences, the National Center for Atmospheric Research, or the World Meteorological Organization. In fact, the three scientists who first sounded the alarm in the early 80s -- F. Sherwood Rowland, Paul Crutzen and Mario Molina -- received the 1995 Nobel Prize in chemistry for their work.
In 1991, NASA launched the Upper Atmosphere Research Satellite (UARS) in an attempt to determine once and for all if humans were responsible for causing this serious damage to the atmosphere. The data relayed back to NASA clinched the matter beyond all reasonable doubt. "There is a very clear link between man-made chlorofluorocarbons (CFCs) and destruction of the ozone layer," says Dr. Aidan Roche, the Lockheed scientist whose team analyzed the satellite data for years. (1)
In one paragraph, the process works this way. The ozone layer is a thin, protective layer of the stratosphere, which rises 12 to 15 miles high. It shields the earth from the sun's ultraviolet rays, which are deadly to most life forms. Unfortunately, ozone can be destroyed by chlorine radicals. The earth naturally produces chlorine radicals, especially from volcanic eruptions, but because they are water soluble they are safely rained out of the atmosphere. However, man-made CFCs are not water soluble. CFCs are free to rise all the way to the top of the stratosphere, where they break down, releasing their chlorine radicals. The reaction is complex, involving many different chemicals, but the result of these reactions is that the CFC is recreated, allowing it to continue wreaking havoc. Other processes are at work to remove CFCs from the ozone layer, so these reactions really can't continue indefinitely, but scientists expect the CFC's already present to remain there for the next century. In fact, recent measurements show that the level of CFCs is already declining, thanks to international treaties banning their production. (2)
The banning of CFCs is a triumph of both science and international diplomacy. In the early 80s, scientists working in the Antarctic noticed that there was a hole in the ozone layer over the South Pole. Preliminary research pointed to CFCs as the culprit. In October 1987, the world's nations signed the Montreal Protocol, pledging to cut CFC production in half over the next ten years. Subsequent scientific evidence suggested the threat was worse than realized, and the Protocol was strengthened twice - once in London in 1990, and again in Copenhagen in 1992. The Copenhagen agreement moved up the complete ban of CFCs to January 1996. Today, they are completely outlawed, although they can still be found on the black market.
And speaking of markets, one might presume that the chemical industry fought the ban tooth and nail. Actually, the industry's response was mixed. When the evidence was still preliminary and debatable, the chemicals companies furiously resisted any notion of a ban. But as the scientific evidence grew stronger, the industry reasonably concluded that it could not be seen defending profits from a product that threatened to destroy all life on the planet. In fact, Dupont proposed a global ban of CFCs before the governments of Europe and the United States did. (3) There was a self-interested motive in this, however; a global ban of CFC's would create a global need for a replacement, and Dupont was the best positioned to develop and market the first one. Even so, many find industry's rapid agreement to the ban heartening, although some watchdog groups, like Ralph Nader's Public Citizen, have chronicled many cases of industrial foot-dragging.
Interestingly, the greatest opposition to the scientific evidence came not from industry, but from the party of industry: the Republicans. During the 1992 presidential campaign, President George Bush contemptuously referred to Al Gore as "ozone man." Vice-president Dan Quayle called Al Gore's environmental bestseller, Earth in the Balance, a "strange manifesto." But perhaps no one has carried the ideological war to the atmospheric scientists quite like Rush Limbaugh. His is probably the most infamous factoid of the ozone debate: the volcanic eruption of Mount Pinatubo.
In The Way Things Ought to Be, Limbaugh wrote: