Speaking to a meeting of the American Geophysical Union, NASA atmospheric scientist Natalya Kramarova said that it should take until 2070 for Earth’s shield against harmful ultraviolet radiation to fully recover from the widespread use of Freon and other damaging chlorofluorocarbons.
They have been phased out since the 1989 Montreal Protocol agreement.
Shifts in weather around Antarctica can cause wide swings in the size of the ozone hole, making it difficult to tell if it is steadily becoming smaller. It reached its largest size in 2006.
Kramarova estimates that it should become apparent by 2025 whether the ozone hole is truly recovering.
Graphic Data: Ozone Hole Watch