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Ozone Protection
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 Antarctica.
The ozone holes in 2000 and 2006 were the largest on record, measuring around 32.9 million square kilometres (more than three times the size of Australia) and, for the first time, extending over populated areas. However the size of the hole is also dependent on the meteorological conditions surrounding the Antarctic. The 2003 and 2007 ozone holes were much smaller, due in large part to the disruption of the hole by other weather conditions in the troposphere and stratosphere.
This is the first image of an animation. The animation shows the TOMS satellite data for all available years 1979-2007 inclusive (you can also view each image within the animation - one year's image per page). The data are the October 1-15 averages of the total column ozone amount, given in Dobson Units. The area extent of the ozone hole for each year is indicated by the red 220 DU line. For more information on the NASA TOMS (Total Ozone Mapping Spectrometer) instrument, see the TOMS home page:
The prospects for the long-term recovery of the ozone layer are good. Non-essential consumption of the major ozone depleting substances in the developed world slowed during the early 1990s and ceased in 1996, indicating that if the international community continues to comply with the Montreal Protocol the ozone layer should fully recover between 2050 and 2065.
An important factor in the recovery of the ozone layer is the impact of the enhanced greenhouse effect. One possible consequence of the continued build up of carbon dioxide and other greenhouse gases in the atmosphere is a cooling of the stratosphere, which can result in more ozone destruction in Antarctica.