A huge hole in the ozone layer has appeared above the Arctic this year. It’s a record size hole for one in the northern hemisphere.
Since the 1980s, scientists have charted the size of the ozone hole above the Antarctic every summer. The holes have been so large some years that theyâ€™ve covered the whole continent and stretched all the way to South America.
Up to 70% of the ozone layer can be destroyed during extreme events, recovering several months later. This hole above the Arctic has always been smaller, up until March this year, when powerful wind patterns and extremely cold temperatures created conditions harsh enough to damage the layer.Â The findings have shown that the hole opened over northern Russia, Norway and parts of Greenland.
Human-made chemicals, particularly chlorofluorocarbons (CFCs) destroy the ozone layer once they are broken up into complex chemicals that negatively react with ozone. Most chemicals have been banned by a UN treaty, but it could be decades before all adverse chemicals are phased out of production.
Itâ€™s not normal for atmospheric conditions above the Arctic to trigger large ozone layer holes, but this past winter created such high winds and cold conditions for long periods of time, that high levels of ozone-destroying chemicals were able to reach it and do significant damage.
According to the authors of the report, published in Nature, this could become an annual event if weâ€™re not careful.
Image credit OMI/Aura/NASA: This chart shows the levels of ozone above the Arctic on 19 March 2010 (left) and 2011 (right). The 2011 chart reveals about a 50% drop.