Slow Recovery

This year marks the 20th anniversary of the discovery of the hole in the ozone layer in 1985. Soon afterward it was discovered, scientists tracked the cause of the disappearing ozone to a class of chemicals known as chlorofluorocarbons (CFCs) found in propellants and refrigerants. The good news is that the 1987 Montreal Protocols phased out most CFC production, and today the ozone hole is slowly mending. The bad news is that the process is taking longer than previously predicted. Full recovery of Earth's protective ozone layer is not expected until around 2065.