The Montreal Protocol on Substances that Deplete the Ozone Layer (MP) of 1987 is an international agreement to protect the stratospheric ozone layer from harmful synthetic chemical compounds. The targets of the MP are synthetic chemical substances that destroy an upper level protective ozone layer of the Earth and whose destructive behavior persists over decades if not centuries, depending on the chemical compound. The MP is considered an exemplary case of science-based policy making, adroit diplomacy, innovative treaty language, and regulatory collaboration, and is the most successfully implemented global environmental treaty in history. It is also the best example to date of global action based on the precautionary principle.

The Issue and Efforts Leading to the Montreal Protocol

Ozone is a bluish gas, harmful to breathe, that is composed of three atoms of oxygen. Nearly 90 percent of the planetary ozone is in the stratosphere, an atmospheric region...