How Severe Is the Ozone Depletion Now?
Stratospheric ozone depletion, caused by increasing concentrations of human-produced chemicals, has increased since the 1980s. The springtime loss in Antarctica is the largest depletion. Currently, in non-polar regions, the ozone layer has been depleted up to several percent compared with that of two decades ago. As the figure below indicates, the magnitude of ozone depletion varies between the regions of the Earth. For example, there has been little or no ozone depletion in the tropics (about 20 degrees north and south of the equator). The magnitude of the depletion also depends on the season. From 1979 to 1997, the observed losses in the amount of ozone overhead have totaled about 5-6% for northern midlatitudes in winter and spring, about 3% for northern midlatitudes in summer and fall, and about 5% year round for southern midlatitudes. Since the early 1980s, the ozone hole has formed over Antarctica during every Southern Hemisphere spring (September to November), in which up to 60%
