Ozone concentrations over Antarctica in October 1979 and October 2008. The ozone hole is the large purple and blue area in the 2008 image. Click on image for full size (60 Kb) Image courtesy NASA.

The Ozone Hole is a major "thinning" of the ozone layer in Earth's atmosphere. It was first noticed in the late 1970s. The hole appears in the winter over the poles, especially the South Pole. Various chemicals that humans release into the atmosphere help cause the hole. Special weather patterns near the poles in winter also help cause the holes to form.

Ozone in the stratosphere protects us from ultraviolet radiation in sunlight. The ozone layer is sort of like sunscreen for planet Earth. That's why holes in the ozone layer are bad news.

Ozone is an unusual type of oxygen molecule. Normally, there are higher concentrations of ozone at various altitudes in the stratosphere. Sometimes, under the right conditions, chemical reactions in the ozone layer can destroy most of the ozone, creating an ozone "hole".

People from many countries have agreed to stop emitting most of the chemicals that destroy ozone. Scientists are hopeful that ozone holes will disappear sometime in the future if we continue to stop emissions of the problematic chemicals.