Ozone still declining in the lower stratosphere
The reason for the continuing drop in ozone levels is a mystery
An unexplained decrease in stratospheric ozone – revealed by satellite measurements – appears to have been offsetting the ozone layer’s overall recovery over the past 20 years. The finding flies in the face of atmospheric models, which predict ozone levels in all parts of the atmosphere should be recovering in the years following the Montreal Protocol agreement which banned the use of ozone-depleting chemicals such as chlorofluorocarbons (CFCs) in 1987.