But in the early 1970s, two chemists— Mario Molina and Sherwood Rowland— demonstrated that widely used chemicals called chlorofluorocarbons, or CFCs, could upset this balance.
Pero a principio de los 70s, dos químicos, Mario Molina y Sherwood Rowland, demostraron que unas substancias químicas muy utilizadas llamadas clorofluorocarbonos, o CFC, podían alterar este equilibrio.