A Global Success Story
High above Earth, a layer of ozone gas blocks much of the Sun's harmful ultraviolet (UV) light. In the 1980s, scientists discovered that this ozone layer was getting dangerously thin, especially over Antarctica.
The cause was a group of chemicals called CFCs, which were used in fridges, air conditioners and spray cans. No single country could fix the problem alone, because the chemicals drifted around the whole planet.
In 1987, countries signed an agreement called the Montreal Protocol to phase out these chemicals. Over time, every member country of the United Nations joined. Companies had to invent new ways to make fridges and sprays, which took time and money.
Today, scientists report that the ozone layer is slowly healing and is expected to recover over the coming decades.