In the mid-1970s, scientists realised that the ozone layer was threatened by the accumulation of gases containing halogens (chlorine and bromine) in the atmosphere. Then, in the mid-1980s, scientists discovered a “hole” in the ozone layer above Antarctica, the region of the, Earth’s atmosphere with severe depletion.
International Day for the Preservation of the Ozone Layer 2023 celebrates the achievements of the Montreal Protocol on substances that deplete the ozone layer, in fixing the ozone layer and reducing climate change.
The principal aim of the Montreal Protocol is to protect the ozone layer by taking measures to control total global production and consumption of substances that deplete it, with the ultimate objective of their elimination on the basis of developments in scientific knowledge and technological information. It is structured around several groups of ozone-depleting substances. Implementation of the Montreal Protocol progressed well in developed and developing countries. All phase-out schedules were adhered to in most cases, some even ahead of schedule. The production and consumption of controlled ozone-depleting substances have been phased out up to 99%, thanks to the Montreal Protocol and its amendments.
Without the Montreal Protocol, large-scale depletion of the ozone layer would have occurred with major consequences.
Consequences of Ozone Depletion
- Skin Cancer
There are strong links between over-exposure to Ultraviolet (UV) radiation and the development of the three most common forms of skin cancer (malignant melanoma, basal cell carcinoma and squamous cell carcinoma).
- Eye Disease
Exposure to high levels of UV radiation leads to an increased risk of cataracts. Cataracts are responsible for around half of blindness world-wide.
- Other Health Matters
UV radiation can have other health effects. These effects include the production of vitamin D in the skin that is beneficial to health.
- Food Security
Over the course of evolution, animals, plants, and microbes have developed mechanisms that allow them to cope with the variation in UV-B radiation that they experience in their normal environments, protected by the intact ozone layer. This includes the plants and animals that we all rely on for food.
Just as uncontrolled ozone depletion threatens food production, it also threatens plants, animals, and microbes in natural ecosystems. Those ecosystems provide the “ecosystem services” that we all rely on for clean air and clean water, and to absorb carbon dioxide for the atmosphere.
For nearly four decades, the Montreal Protocol has been instrumental, and will continue to be instrumental, in protecting human health, nature and the climate. Thanks to the Montreal Protocol, the ozone layer is healing and expected to return to pre-1980 values by mid-century.