Here's an argument that ought to put the one about a hole in the ozone layer at rest. Unfortunately, it hasn't been well documented. The last few decades have seen conservation advocates shout from the roof tops that the depletion in ozone levels is being compounded by an increased incidence in the use and subsequent release of chloro-fluoro carbons (CFC). The truth is, between 1962 and the early 1970s, the amount of global ozone rose 4-11%. This is because, in the stratosphere, 10-40 km above the Earth's surface, several tonnes of ozone is produced every second due to the interaction of ultraviolet radiation with oxygen molecules.