The annual thinning of the ozone layer over Antarctica is an artifact of the polar winter. Although it is claimed that the ozone hole didn’t exist prior to the 1980’s… It has occurred during every Antarctic spring in which anyone was trying to measure it.
Ozone in the upper atmosphere is created when UV radiation from the Sun strikes oxygen molecules. This leads to the creation of ozone. The ozone layer doesn’t so much act as sunscreen as it acts like reactive armor. During the Antarctic winter very little sunlight hits the upper atmosphere over Antarctica and the Antarctic polar vortex prevents much in the way of atmospheric mixing between the polar and higher latitude air masses. This leads to an annual depletion of Antarctic ozone from mid-August through mid-October (late winter to mid spring). As the Antarctic spring transitions to summer, there is more exposure to sunlight and the ozone layer is replenished.
This process has occurred since the dawn of continuous ozone measurements in 1986. NOAA’s Earth System Research Laboratory / Global Monitoring Division features a very disingenuous chart on their ozone page.
The NOAA ESRL/GMD chart implies that the annual ozone hole did not exist during an earlier period of measurements from 1967-1971. This is wrong. The actual data from 1967-1971 clearly show that the annual ozone hole did exist. It may have been less pronounced at higher altitudes and it may have bottomed out in September rather than October; but it did exist. At low altitude (200 MB and 400 MB) it was nearly identical to the present-day…
There are a lot of reasons why earlier measurements differ from the modern data:
1. The older data were sparsely sampled (1/4 the number of profiles) and the earlier ozonesonde balloons rarely, if ever, reached higher altitudes (40 MB and 25 MB).
2. The error bars of the two data sets almost overlap.
3. Natural climate oscillations. 1967-1971 was during a period of global cooling. 1986-1991 was during a period of global warming. Without having a continuous series of profiles across a full wavelength of the ~60-yr PDO/ENSO cycle, it’s impossible to know if the annual ozone depletion has a cyclical nature.
4. Chlorofluorocarbons (CFC’s). It is possible that CFC’s did exaggerate the Antarctic ozone hole. However, the data clearly show that CFC’s did not create it.
The ozone hole scare cost many people a lot of money. Refrigerating fluids, particularly in automobile air conditioners, had to be replaced. If you were the owner of a 1980’s motor vehicle in need of air conditioner repairs in the 1990’s, you may as well have traded your vehicle in; because the cost of repairs became almost prohibitive due to new environmental regulations related to CFC’s.
The economic cost of this particular chapter of environmental junk science was minuscule in comparison to that of the current environmental swindle (anthropogenic global warming)… But this should serve as one more reminder that no one ever bothered to check the work of these Enviromarxist con men prior to Steve McIntyre’s debunking of Mann’s Hockey Stick.
Oltmans, S. J.; Hofmann, D. J.; Komhyr, W. D.; Lathrop, J. A. Ozone vertical profile changes over South Pole. NASA. Goddard Space Flight Center, Ozone in the Troposphere and Stratosphere, Part 2, p 578-581