Montreal, Canada. The international agreement banning hydrofluorocarbons is signed. The treaty is ratified by 197 countries. The ozone hole is shrinking, and it is estimated that it will close completely by the middle of the 21st century. UN Secretary-General Kofi Annan calls it “perhaps the single most successful international agreement to date.” Mario Molina and F. Sherwood Rowland, who explained the link between CFCs and the ozone hole in a 1974 article in Nature, will win the Nobel Prize in 1995.
