Measurements at Halley Bay in Antarctica reveal that October ozone concentrations are now less than half what they were during the 1960s. Ozone damage has not been restricted to Antarctica. The ozone layer over sub-tropical parts of Australia has thinned, which means that levels of harmful ultraviolet radiation reaching the ground are far greater than in the past. Signatories to the Montreal Protocol to protect the ozone layer are meeting this week in Beijing to discuss funding to help developing countries eliminate ozone-depleting chemicals. DNA damaging radiation is ultraviolet radiation that is most likely responsible for skin cancer.
Ultraviolet radiation is greatest on cloudless days.
Anticipated global warming next century will cool the stratosphere, further increasing the rate of ozone destruction, according to Dr Fraser. Based on the maximum predicted emissions of ozone depleting chemicals allowed under the Montreal Protocol, it will be at least the year 2050 before the ozone layer recovers. Chlorine and bromine atoms released from CFCs and halons respectively, cause the depletion of the ozone. CFCs are industrial chemicals used in the past as refrigerants, solvents, pressure packs and foaming agents. Halons were used as fire fighting chemicals.