....In 1979 (click here) —when scientists were just coming to understand that atmospheric ozone could be depleted—the area of ozone depletion over Antarctica grew to 1.1 million square kilometers, with a minimum ozone concentration of 194 Dobson Units. In 1987, as the Montreal Protocol was being signed, the area of the hole reached 22.4 million square kilometers and ozone concentrations dropped to 109 DU. By 2006, the worst year for ozone depletion to date, the numbers were 29.6 million square kilometers and just 84 DU. By 2011, the most recent year with a complete data set, the hole stretched 26 million square kilometers and dropped to 95 DU.
According to NASA scientist Pawan Bhartia, “The Antarctic hole is stabilizing and may be slowly recovering. Our focus now is to make sure that it is healing as expected.” The amount of ozone-depleting substances (ODS) in the atmosphere has stopped rising in recent years, and may actually be decreasing. The yearly ozone hole should continue for a while, though, as CFCs and other ODSs can last for decades in the air. Scientists found in a 2009 study that without the Montreal Protocol, global ozone depletion (not just Antarctic) would be at least 10 times worse than current levels by 2050....
