Is Stratospheric Ozone Decreasing on a Global Scale?
Beginning with a press conference by an ad-hoc “Ozone Trends Panel” in March 1988, the public has been subjected to a barrage of reports and press releases claiming that the ozone layer is being depleted at a rate that is “worse than expected.” [Since “expectations” must be based on theory, this begs the question as to whether the theory is wrong, or the observations are wrong, or if they are bow wrong.] There is doubt as to whether the data can be trusted, whether the calibration of the instruments has been maintained, and whether other gases, such as sulfur dioxide, have been interfering with the ozone measurements. Even if the data turned out to be sound, there is the question whether a long-term trend can be established with such a short record, in view of the large natural variations of ozone levels in the stratosphere. [One notes for example, that a March 1995 EPA pamphlet on “Stratospheric Ozone Depletion” presents no evidence for such a downward trend but merely states (on page
