September 16th marks International Day for the Preservation of the Ozone Layer. Although there would be no life without sunlight, the energy emanating from the sun would be too much for life on Earth to thrive without the protection afforded by the ozone-layer. Scientists raised the alarm when they discovered in the 1970s that human actions had created a hole in this protective ozone shield. The hole was caused by ozone-depleting gases (ODGs), which were used in aerosols, refrigerators, and air-conditioning coolants. The thinning ozone layer caused increases in the risks of skin cancer, cataracts, and other negative consequences. Additionally, without the ozone layer, solar energy would damage plants, crops, and ecosystems. As a reaction to this threat, in 1985, the world’s governments adopted the Vienna Convention for the Protection of the Ozone Layer.
Under the Convention’s Montreal Protocol, governments, scientists, and industry worked together to cut out 99 percent of all ozone-depleting substances. Thanks to the Montreal Protocol, the ozone layer is regenerating and it is expected to return to pre-1980 values by mid-century.
World Ozone Day celebrates this achievement. It shows that collective decisions and united action, supported and guided by science, are the only way to solve major and global challenges.