Word: cfcs
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They were. In 1972 Rowland heard a report that trace amounts of CFCs had been found in the atmosphere in both the northern and southern hemispheres. What were they doing there? The answer, as Rowland and his colleague, Mario Molina, soon found, was that there was nowhere else for them to go but into the atmosphere. CFCs in aerosol cans are sprayed directly into the air, they escape from refrigerator coils, and they evaporate quickly from liquid cleaners and slowly from plastic foams...
...troposphere, CFCs are immune to destruction. But in the stratosphere, they break apart easily under the glare of ultraviolet light. The result: free chlorine atoms, which attack ozone to form chlorine monoxide (ClO) and O2. The ClO then combines with a free oxygen atom to form O2 and a chlorine atom. The chain then repeats itself. "For every chlorine atom you release," says Rowland, "100,000 molecules of ozone are removed from the atmosphere...
...Rowland and Molina announced their conclusion: CFCs were weakening the ozone layer enough to cause a marked increase in skin cancers, perhaps enough to perturb the planet's climate by rejuggling the stratosphere's temperature profile. In 1978 the U.S. banned their use in spray cans. "People assumed the problem had been solved," recalls Rowland. But the Europeans continued to use CFCs in aerosol cans; other uses of CFCs began to increase worldwide. Says Rowland: "All along, critics complained that ozone depletion was not based on real atmospheric measurements -- until, that is, the ozone hole appeared...
Still, the existence of an ozone hole did not necessarily mean CFCs were to blame, and a number of alternative explanations were proposed. Among them, says Dan Albritton, director of the Federal Government's Aeronomy Laboratory in Boulder, was the notion that the "hole did not signify an ozone loss at all, just a breakdown in the distribution system." An interruption in the movement of air from the tropics, where most ozone is created, to the poles could easily result in less ozone reaching the Antarctic. Another theory: perhaps the sunspot activity that peaked around 1980 created more ozone- destroying...
...cottage industry. There are dozens of them, and they are rivaling the effects of increasing CO2." In fact, by the year 2030 the earth will already face the equivalent of a doubling of CO2, thanks to these other rapidly increasing gases, including methane, nitrous oxide and all the CFCs. "These are the little guys," says Schneider. "But they nickel and dime you to the point where they add up to 50% of the problem...