Final answer:
The Montreal Protocol, agreed upon in 1987, is the international treaty that stipulated the phase-out of chlorofluorocarbons and other ozone depleting chemicals. It is a key example of global cooperation to protect the ozone layer, with phased reductions of harmful substances and recovery being observed as a result.
Step-by-step explanation:
The phase-out of chlorofluorocarbons (CFCs) and other ozone-depleting chemicals was a major stipulation of the Montreal Protocol on Substances that Deplete the Ozone Layer. This international treaty, agreed upon in 1987, marks a significant example of global cooperation against the environmental challenge of ozone layer depletion.
The Montreal Protocol committed signatory nations to phase out the production and use of CFCs and 95 other chemicals known to harm the ozone layer. Due to these efforts, scientists have observed signs of recovery in the ozone layer. The protocol's success is evident in the way CFCs have been mostly phased out since 1995; less hazardous substances are scheduled for phase-out by 2030.
Furthermore, the protocol established a framework for developed nations to financially contribute towards developing alternative technologies that will replace these harmful chemicals, ensuring even wider global participation in these environmental protection efforts.