How big was the 2003 ozone hole, and is it getting bigger?
Every four years, a team of many of the top scientists researching ozone depletion put together a comprehensive summary of the scientific knowledge on the subject, under the auspices of the World Meteorological Organization (WMO). According to their most recent assessment, (WMO, 2002), monthly total column ozone amounts in September and October have continued to be 40 to 50% below pre-ozone-hole values, with up to 70% decreases for periods of a week or so. During the last decade, the average ozone hole area in the spring has increased in size, but not as rapidly as during the 1980s. It is not yet possible to say whether the area of the ozone hole has maximized. However, chlorine in the stratosphere has reached nearly constant levels and is expected to start declining, so the ozone hole may have seen its maximum size. Annual variations in temperature will probably be the dominant factor in determining differences in size of the ozone hole in the near future, due to the importance of col
