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.
When up there, they can decompose and release chlorine and bromine atoms and destroy ozone. Although there are ozone-depleting gases everywhere in the atmosphere, the ozone hole forms in the Antarctic because of the special weather conditions there. The very cold temperatures in the Antarctic can form ice clouds called polar stratospheric clouds. Special chemical reactions can occur on these clouds and destroy ozone and form a hole in the Antarctic spring.
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.
But the whole world has worked together effectively to reduce the problem, and because of that, it is projected the ozone layer will recover and return to a healthy level by mid-century.
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