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Ruth,
I learned in Statistics 101 that
while correlation can provide a
basis for suspicion, it does not prove
a cause and effect relationship.
Again I ask, how do you know that if we had not
stopped using freon,
the depletion rate wouldn't have slowed
anyway? Jerry
PS- Please note Maury Siskel's message. Apparently freon usage
has not really stopped.
Rowland and Molina richly deserved that prize (I simply don't know Crutzen's work, but I do know Rowland's and Molina's). The ozone/CFC question differs considerably from the "greenhouse" cliamte change question. In 1979 or 1979, McElroy and colleagues published a paper in SCIENCE correlating depletion of the ozone layer with worldwide production and use of Freon aerosol sprays. It was a beautiful, unmistakeable positive correlation. When we stopped using Freon aerosols, the rate of depletion slowed. Freon aerosols put orders of magnitude more CFCs in the air, especially CF3Cl, than auto air conditioning systems, refrigerators, or any other closed but leaky system, and I think in controlling those we have gone overboard. Rowland and Molina's elucidation of the mechanism for ozone depletion is classic work. I use this example in our textbook, in fact, to pooint out the difference between the ozone depletion story and the greenhouse gas story. Ruth Weiner, Ph. D. ruthweiner@aol.com |