evidence: What’s going on with the hole in the ozone layer? There used to be a huge problem, and because of that, there was a hole, especially in the Antarctic, in the ozone layer. Ozone works as Earth’s natural sunscreen. It prevents harmful UV radiation to come down to the surface to cause skin cancer and damage vegetation. Man-made substances such as chlorofluorocarbons, because they were so safe, were used in a variety of applications, such as refrigerants or insulation foams. These gases have a very long atmospheric lifetime and can find their way into the stratosphere. [...] The ozone-depleting gases have been regulated by the Montreal Protocol, which is an international agreement signed by all countries around the world. And because of this, their levels in the atmosphere have been decreasing. As a result, in recent years, the ozone layer has shown first signs of recovery, although there are still large year-to-year variabilities in its size and strength.