The stratospheric ozone layer and the Montreal Protocol

The destruction of the stratospheric ozone layer from the early 1980's by halogen compounds originated from the chemical industry is considered the first global damage to the Earth's atmosphere by human activities. Likewise, the Montreal Protocol signed in 1987 in order to regulate ozone depleting substances is a pioneering agreement in the field of environmental regulation for the protection of the environment on the global scale. It has inspired the Kyoto Protocol for the reduction of greenhouse gases emission. More than twenty years after the Montreal Protocol, this article reviews the state of the ozone layer at global scale, the reduction of ozone depleting substances in the atmosphere, the previsions for the ozone recovery and the influence of global atmospheric change due to increased greenhouse gases emissions on this recovery. The double benefit of the Montreal Protocol on the emission of greenhouse gases is also described. (author)