ozone
...ave doubled in the northern hemisphere mid-latitudes and quadrupled in the southern mid-latitudes, resulting in an estimated 19 million additional cases of non-melanoma skin cancer, 1.5 million cases of melanoma and 129 million more cases of eye cataracts. What is Ozone? Ozone is a naturally occurring molecule containing three atoms of oxygen. The ozone layer occurs in the upper atmosphere (the stratosphere) 15-30 km above the surface of the earth, and protects life on earth by absorbing ultra-violet (UV) radiation from the sun. Ozone layer depletion - causes and effects Concerns about the depletion of the ozone layer exist because the ozone layer reduces the amount of harmful ultraviolet radiation that reaches the earth's surface. The ozone layer is also an important part of the global atmosphere-climate system in which present day living organisms, including humans, have evolved. Any significant change to this layer can have far-reaching consequences for human health. CFCs, halons, methyl chloroform, carbon tetrachloride, HCFCs, hydrobromofluorocarbons and methyl bromide are directly implicated in the depletion of the ozone layer. These and other ozone depleting substances also contribute to varying extents to the enhanced greenhouse effect. Data collected in the upper atmosphere has shown that there has been a general thinning of the ozone layer over most of the globe. This includes a five to nine percent depletion over Australia since the 1960s. In addition to this general thinning, more dramatic damage occurs over Antarctica each spring when the ozone hole forms. This damage is due not only to the availability of ozone depleting substances in the stratosphere, but also specific metrological conditions that facilitate the destruction of ozone over Antartica. The ozone hole in 2000 was the largest on record, me...