Ozone hole prediction. Computer model showing Antarctic ozone levels from 1974 to 2054 if chlorofluorocarbons (CFCs), the chemicals widely blamed for destroying ozone, had not been banned worldwide in 1989. The image shows the ozone levels each summer, from most concentrated (red) through to the least (yellow, green, light blue and violet being near zero). The model increases emissions of CFCs each year by 3 percent. 1974 still represents a normal ozone level but by 1994 a large hole develops. By the year 2054, the ozone level is close to zero across most of the southern hemisphere. Stratospheric ozone prevents excess ultraviolet radiation reaching the surface and harming living organisms.