In order to inform environmental and development policy-making processes, UNEP keeps under review the state of the world environment.
On 16 September 1987, the treaty known as the Montreal Protocol on Substances that Deplete the Ozone Layer was signed into existence by a group of concerned countries that felt compelled to take action to solve an alarming international environmental crisis: the depletion of the Earth’s protective ozone layer. Since that humble beginning 25 years ago, this treaty has taken root, grown and ﬁ nally blossomed into what has been described as “Perhaps the single most successful international environmental agreement to date”.
It has become an outstanding example of developing and developed country partnership, a clear demonstration of how global environmental problems can be managed when all countries make determined efforts to implement internationally-agreed frameworks. But why has it worked so well, how has it impacted our lives, what work lies before us, and what lessons we can learn from it?