Paul Crutzen, Mario Molina and Sherwood Rowland were awarded the Nobel Prize in Chemistry in 1995 for helping us understand why the ozone layer, which protects us from harmful UV radiation, was disappearing. On this day, in 1987, nations signed the Montreal Protocol on Substances that Deplete the Ozone Layer in order to fix the problem. Thanks to the laureates' work we have managed to reverse this depletion and today the ozone layer is starting to recover. GIF: Ozone depletion occurs in cold tem

The reveal of chlorofluorocarbons' (CFCs) potential to destroy the ozone layer in the Earth’s stratosphere was a life-changing discovery. In 1974, atmospheric chemist and 1995 chemistry laureate Mario Molina and his co-laureate Sherwood Rowland demonstrated that CFC gases, freons, have a damaging effect on ozone in the atmosphere. Freons had many uses, including propellants in spray cans and refrigerants in refrigerators. By limiting the use of freons, the depletion of the ozone layer was slowed