jan 1, 1974 - Roland and Molina (UCI) announce that CFC's are depleting the Ozone layer
Earth's atmosphere is starting to lose its most important layer. Aerosol cans sometimes contain ozone-depleting substances called chlorofluorocarbons, or CFC's. ... Such deterioration allows large amounts of ultraviolet B rays to reach Earth, which can cause skin cancer and cataracts in humans and harm animals as well.
Added to timeline:
APES- Block 4