IntroductionOzone Layer Statistics: The ozone layer, a fragile protective shield of gas high in the Earth’s stratosphere, has a pretty incredible job. Initial Ozone Loss By the mid-1980s, the Antarctic ozone layer was about 50% thinner. Ozone Hole Size Trend The average area of the Antarctic ozone hole has been trending smaller since the early 2000s. The ozone layer is a part of the Earth’s atmosphere with a high concentration of ozone gas. It’s a region over Antarctica where the ozone layer has become severely thinned, with ozone levels dropping by more than 50%.