What is the ozone hole? The "ozone hole" is a loss of
stratospheric ozone in springtime over Antarctica, peaking in
September. The ozone hole area is defined as the size of the
region with total ozone below 220 Dobson units (DU). Dobson
Units are a unit of measurement that refer to the thickness of
the ozone layer in a vertical column from the surface to the top
of the atmosphere, a quantity called the "total column ozone
amount." Prior to 1979, total column ozone values over
Antarctica never fell below 220 DU. The hole has been proven to
be a result of human activities--the release of huge quantities
of chlorofluorocarbons (CFCs) and other ozone depleting
substances into the atmosphere. Is the ozone hole related to
global warming? Global warming and the ozone hole are not
directly linked, and the relationship between the two is
complex. Global warming is primarily due to CO2, and ozone
depletion is due to CFCs. Even though there is some greenhouse
gas effect on stratospheric ozone, the main cause of the ozon