It wasn't all bad
Here's proof that when countries work together, good things happen.
In 1985, scientists discovered a huge hole in the ozone layer above the South Pole. The ozone layer absorbs most of the sun's ultraviolet radiation, which can cause skin cancer and damage crops. Man-made chemicals called chlorofluorocarbons (CFCs) eat at the ozone layer, and in the late 1980s, 180 countries signed the Montreal Protocol, agreeing to phase out CFCs in order to prevent additional holes from forming.
A new United Nations report says that the ozone layer is healing itself, and by the 2030s, the Northern Hemisphere could be fully repaired, with Antarctica following in the 2060s. The problem is not entirely solved — some parts of the ozone layer are not yet repaired, and scientists are concerned some unregulated chemicals that contain chlorine could slow down the healing process — but this is still "really good news," Paul Newman, the report's co-chairman and chief Earth scientist at NASA's Goddard Space Flight Center, told BBC News. "If ozone-depleting substances had continued to increase, we would have seen huge effects. We stopped that."