A short item in
The Why Files explains the recent news that the
Antarctic ozone hole reached record size in 2006 despite being on the path to recovery. Scientists think that natural variation and weather patterns have more to do with the increase in size than any immediate change in atmospheric chemistry. As one expert explains, the record hole "Is not something to be overly alarmed about. It is part of the natural variability of the beast. Once you put the [ozone-destroying] chemicals in, you can't get rid of the natural variability, you have to get rid of the chemicals." And thanks to the Montreal Protocol, we are, with the result that scientists now expect atmospheric ozone levels over the poles to return to 1950 levels sometime around 2065. In the meantime, the ozone holes pose little direct threat to human life. Indirectly, however, the ozone hole may be causing significant environmental damage, as increased ultraviolet light appears to be killing phytoplankton, the base of the oceanic food chain.
2 Comments:
Let me get this straight - man-made chemicals are to blame for the ozone hole, but when it gets bigger despite the chemicals, its now natural variability? The thing lacking here is credibility.
Okay, let's think of something analogous, like say,... a forest fire. You've got a fire triggered by arson. There's your man-made culprit for the condition (wildfire), which in the absense of high winds can be expected to burn itself out in a few acres. But then the Santa Ana winds come up and suddenly you have a very large fire across hundreds of acres. There's your natural variable, which makes the fire spread despite all your firefighting efforts. The winds will eventually die down and the fire put out. But, in the meantime, does the fire chief lack credibility if he 'blames' the size of the fire on the winds?
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