Ozone depletion

Starting in the late 1970's, an ozone hole was discovered over Antarctica.

These observations provided a correlation with the prediction from the hypothesis that CFC in the atmosphere can deplete the ozone layer.

Other hypotheses may also explain the depletion of the ozone layer:

These other hypotheses can be ruled out by measurements of CFC concentrations in the atmosphere and also concentrations of chlorine that is a product of the breakdown of CFC.