CO2 - Causing Hot Cold Ozone Destroying Arctic Death
Weather eye: destruction of Arctic ozone | The Times
April 2 2011
Spring is here, but in the Arctic the arrival of sunshine after the long winter darkness has caused a serious problem. During the past few weeks, about half the ozone in the stratosphere 20km (12 miles) above the Arctic has been destroyed. The combination of sunlight and man-made pollution from chlorofluorocarbons slashed ozone levels for March close to the lowest recorded levels.
Each winter a giant vortex of cold air whirls around the polar region, virtually sealed off from the rest of the global atmosphere. In this freezing vortex, the stratosphere grows intensely cold and this winter it reached very low temperatures, down to minus 83C (-117F) on March 10. In these conditions strange iridescent clouds of ice form in the stratosphere, glowing with the surreal colours of mother-of-pearl.
But when the spring sunshine reappears, those stratospheric clouds act as a springboard for the sunlight and chlorine pollution to destroy ozone.....
Despite the ban on ozone-depleting chemicals, the ozone layer will remain vulnerable for many years, because chlorine already in the stratosphere takes a long time to disappear. Added to that, the lower stratosphere globe has been growing steadily colder over recent decades thanks to carbon dioxide. Although CO2 warms the lower atmosphere, it has the opposite effect in the upper atmosphere, radiating heat back into space. And in a further twist, the lack of ozone also adds to the cooling of the stratosphere, helping to destroy more ozone at the poles.