Ozone Hole at 2nd smallest in 20 years
Good news for those of us who’re so proud of our sunny weather in the southern hemisphere: Earth-watching satellites belonging to NASA and the National Oceanic and Atmospheric Administration (NOAA) have shown that the ozone hole is beginning to heal. So far this year, it’s covered an average area of 17.9 million square kilometers, with a peak reading on 22 September 2012 of 21.2 million square kilometers – a substantial reduction from the maximum size recorded in 2000 of 29.9 million square kilometers. For perspective, the current reduced size is approximately equivalent to the continent of North America.
The size of the ozone hole fluctuates from month to month, as changing temperatures and seasons affect the way chlorine-based pollutants like CFC’s react with the ozone in the upper atmosphere. Thanks to a number of international treaties, these pollutants are not being pumped into the air at the rate they were a few decades ago, but they are quite hardy compounds and take a very long time to break down. It is estimated that the decay of these pollutants is slow enough that the ozone layer won’t fully recover until some time after the year 2060.
To monitor the state of the ozone layer above Antarctica, visit: http://ozonewatch.gsfc.nasa.gov