Environment Counts | Arctic ozone loss comparable to the Antarctic for the first time in recorded history
Author: Geoff Zeiss – Published At: 2011-10-02 20:02 – (807 Reads)
In the Antarctic, complete removal of lower-stratospheric ozone ascribed to chlorine compounds such as chlorofluorocarbons (CFCs) results in an ozone hole every year. In the Arctic, ozone loss until now has been much more limited. This article reports that for the first time in recorded history chemical ozone destruction over the Arctic is comparable to that in the Antarctic ozone hole.
Antarctic ozone hole
Chemical ozone destruction occurs over both polar regions in late winter/early spring. In the Antarctic, complete removal of lower-stratospheric ozone has resulted in an ozone hole every year since the late 1970s. In 1986 the National Ozone Expedition (NOZE I) went to Antarctica and took measurements of various trace gases and physical properties of the atmosphere. The following year NOZE II collected additional data. The data showed conclusively that human-produced trace gases that contain chlorine and bromine, such as chlorofluorocarbons, were causing the ozone hole.
Arctic ozone hole
In the Arctic, ozone loss is highly variable and has until now been much more limited. Significant depletion occurs in the Arctic ozone layer during the late winter and spring period (January – April). However, the maximum depletion is generally less severe than that observed in the Antarctic, with no large and recurrent ozone hole taking place in the Arctic. However, in early 2011 unusually extended cold conditions in the Arctic lower stratosphere led to persistent enhancement in ozone-destroying forms of chlorine and to unprecedented ozone loss. The loss exceeded 80 per cent over 18â€“20 km in altitude.