Final answer:
The first major statement proposing the interaction of CFCs and stratospheric ozone was made in the 1970s. This led to the ban of CFCs in spray cans in 1978 and the ratification of the Montreal Protocol in 1987, which aimed to control the production and emission of chemicals damaging the ozone layer.
Step-by-step explanation:
The first major statement proposing the interaction of CFCs (chlorofluorocarbons) and stratospheric ozone was made in the 1970s. In 1973, scientists calculated that CFCs could reach the stratosphere and destroy ozone, leading to the ban of CFCs in spray cans in 1978 by the United States and most Scandinavian countries. Additional confirmation of CFCs breaking down ozone came in 1985 with the discovery of a 50% reduction in the ozone layer over Antarctica.
Two years later, in 1987, the Montreal Protocol agreement was ratified by nations worldwide. The protocol aimed to control the production and emission of chemicals that damage the ozone layer, including CFCs. Since 1995, the phase-out of CFCs has been largely successful, although some developing nations still used them until 2010.
The Montreal Protocol also requires wealthier nations to contribute financially to the development of technologies that will replace these harmful chemicals. This global cooperation and action have been crucial in addressing the depletion of the ozone layer.