The discovery of the ozone hole in Antarctica in 1985 received global coverage as it was seen as one of the proofs that humans were ruining the world they live in. Scientists at the time blamed the gas chlorofluorocarbon (CFC-11) for causing the destruction of the ozone layer.
But a recent study by a group of scientists from MIT found that the ozone hole actually existed as early as 1957. At that time, scientists did not detect it due to technological constraints. The study was published in the journal Proceedings of the National Academy of Sciences with the hole being caused by the use of carbon tetrachloride. This chemical has been used as a degreaser and for dry cleaning since the 1930s.
The discovery of the large ozone hole in Antarctica worried scientists until the world's major countries signed the Montreal Protocol in 1989 to stop the use of CFC-11. CFCs are widely used in cooling devices such as refrigerators and air conditioners as well as in aerosol cans such as insecticides. After being replaced by HFCs and HFOs, scientists predict the ozone hole will recover by 2066.
