The 1987 Montreal Protocol has been very effective in resolving the Ozone layer Depletion. In the 1970s, scientists discovered that chlorofluorocarbons (CFCs) were destroying the ozone layer. This was causing a drastic thinning of the ozone layer over Antarctica known as the "ozone hole." In response, the 1987 Montreal Protocol established regulations to phase out ozone-depleting substances on a global scale. Since its implementation, research shows the ozone layer is beginning to recover and the effects of depletion have been mitigated by the Montreal Protocol.