{"id":816,"date":"2009-06-02T08:55:38","date_gmt":"2009-06-02T08:55:38","guid":{"rendered":"http:\/\/astraea.net\/blog\/?p=816"},"modified":"2009-06-15T07:50:50","modified_gmt":"2009-06-15T07:50:50","slug":"20-years-on-the-ozone-hole-lingers","status":"publish","type":"post","link":"https:\/\/www.astraea.net\/blog\/20-years-on-the-ozone-hole-lingers\/","title":{"rendered":"20 years on, the ozone hole lingers"},"content":{"rendered":"

The global recognition of CFCs’ destructive potential led to the 1989 Montreal Protocol banning the production of ozone-depleting chemicals. Scientists estimate that about 80% of the chlorine (and bromine, which has a similar ozone-depleting effect) in the stratosphere over Antarctica today is from human, not natural, sources.<\/p>\n

Models suggest that the concentration of chlorine and other ozone-depleting substances in the stratosphere will not return to pre-1980 levels until the middle decades of this century. These same models predict that the Antarctic ozone layer will recover around 2040. On the other hand, because of the impact of greenhouse gas warming, the ozone layer over the tropics and mid-southern latitudes may not recover for more than a century, and perhaps not ever.<\/p>\n

The slide show linked here shows the ozone hole’s growth and stabilisation, but not reduction. (Blue and purple means thin ozone, ie bad; red means lots of ozone ie good.)<\/p>\n

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Antarctic Ozone Hole<\/h2>\n

September 1979
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October 2008<\/div>\n
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\"images\/ozone\/ozone_palette.png\"<\/div>\n
See the full sequence here<\/a>. <\/a><\/div>\n
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