Studies by NASA and the National Oceanic and Atmospheric Administration (NOAA) confirm that the Earth's ozone layer is mending.
The layer of ozone which lies mainly in the Earth's stratosphere protects humans from harmful rays of the sun. The amount of ozone in the atmosphere steadily decreased from 1979 to 1997 when it began to level off. Researchers have no doubt that the increase in ozone is because nations followed the 1987 Montreal Protocol on the Substances that Deplete the Ozone. The Montreal Protocols phased out many halogenated hydrocarbons that had played a role in ozone depletion.
The image on the left displays the largest hole in the ozone layer over Antactica on Sept. 10, 2000. Right is the ozone hole on Aug. 27, 2006. It can be tracked daily on the Ozone Hole Watch.