The hole develops each year between late August and early October. Regions with higher levels of ozone are shown in yellow, lower levels in blue. Click to enlarge. Scientists expect the hole to peak in the next few weeks, possibly making 1999 the worst year ever recorded for the destruction of the ozone layer. The ozone hole above the Antarctic develops each year between late August and early October.
Ozone protects Earth's inhabitants by absorbing dangerous ultraviolet radiation from the sun.
A more urgent sign of the ozone's destruction this year, NASA says, is the development of a secondary hole of an unusually large size over the frozen continent. In the image, lower concentrations of ozone are shown in purple, with higher ones in yellow and red. But a hole in the layer wasn't spotted until the 1980s. In cold weather, ice crystals form and serve as a kind of perch for the chlorine which rises through the atmosphere as part of the CFCs, which are emitted from some aerosol containers and refrigerants. Chlorine serves as a catalyst for a process that destroys ozone, turning it into breathable oxygen.