NASA | A Story of Ozone: The Earth’s Natural Sunscreen

In this talk, Dr. Paul Newman tells the story of how scientists and policy-makers safeguarded the Earth’s ozone layer and the world we avoided by by regulating chlorofluorocarbons (CFCs) . Back in the 60s, we used chlorofluorocarbons, a chlorine-containing chemical, in everything from hairsprays and deodorants to foam products and air conditioners. But in 1974, chemists Sherwood Rowland and Mario Molina published a paper claiming CFCs were destroying the ozone layer. The Molina-Rowland paper launched a debate in the scientific community that ultimately led to the halls of the United Nations. Today, more than 191 countries have signed the Montreal Protocol— a treaty that regulates the use of chlorofluorocarbons—and the ozone layer is on the mend. But the story has taken a new and unpredictable turn as the class of compounds that replaced CFCs act as greenhouse gases.