By Devanshi Saxena
In the 1980s, scientists discovered a “hole” in the Earth’s ozone layer over Antarctica. Owing to the importance of ozone in protecting the life forms from the harmful ultraviolet rays of the sun, world communities banded together on a global platform with an aim to prevent the ozone hole from growing. As an outcome of the global initiative, the international treaty, known as the Montreal Protocol came into existence. It was specifically designed to phase out certain target chemicals like chlorofluorocarbons (CFC) and hydrofluorocarbons (HFC) which break down the ozone molecule. However, ozone level recovery at lower altitudes is not as per expectations even after a span of more than three decades. All the more alarming is the fact that scientists have no clue as to the reason behind these changes.
What is the ozone layer?
The ozone layer or ozone shield is a region of Earth’s stratosphere that absorbs most of the Sun’s ultraviolet radiation. The ozone layer is mainly found in the lower portion of the stratosphere, from approximately twenty to thirty kilometres above the Earth, although its thickness varies seasonally and geographically. The United Nations General Assembly has designated September 16 as the ‘International Day’ for the Preservation of the Ozone Layer to generate awareness regarding the harmful effects of ozone depletion and to mobilize the population towards the issues of environmental concern.
Heightening concern for ozone depletion
In 2013, after an extensive research, NASA concluded that the average size of the ozone hole fluctuates due to changes in heat and wind conditions in the Earth’s stratosphere. Recently, European Geosciences Union journal- Atmospheric Chemistry and Physics has reported that the ozone layer recovery in lower latitudes is not as per the standards set by the Montreal Protocol. However, the reason behind the unexpected decrease in the lower part of the stratospheric ozone layer still remains unclear.
Researchers have hypothesized that the fluctuations in the ozone level could be because of changes in the circulation of air in the stratosphere, which has caused the ozone to disperse in these areas. These changes could be attributed to the effects of climate change. Another plausible reason could be the release of new types of chlorine-based compounds which are used for industrial purposes. These chemicals have a short survival-span and are, therefore not covered under the Montreal Protocol but the stratospheric ozone has been adversely affected due to these chemicals.
Harmful effects of ozone layer decline
Ozone layer depletion increases the amount of ultraviolet radiation that reaches the Earth’s surface. Laboratory and epidemiological studies have demonstrated its adverse effects on humans as it leads to non-melanoma skin cancer and development of cataracts. UV radiation also interferes with the effective functioning of the food chain and biogeochemical cycles. It may lead to certain indirect changes in plants like an altered chain of nutrient distribution, the erratic timing of developmental phases and modified secondary metabolism which adversely affects the plant growth. Increase in UVB level also leads to the rapid disintegration of synthetic polymers, naturally occurring biopolymers, as well as some other materials of commercial interest.
Potential remedies to save the ozone
The most important aspect of control and prevention is to develop new alternatives to HFCs which do not degrade ozone. Another substantial method is to frame international regulations to prohibit any intended release of controlled refrigerants from motor vehicle air-conditioners or refrigeration equipment into the atmosphere. For enforcement and monitoring purposes, owners or operators of industrial/commercial refrigeration systems should be instructed to keep records on relevant repair services and the amount of consumed CFC-based refrigerants. Methods should be developed to conserve the controlled refrigerants through the use of approved recycling and recovery equipment.
Featured image source: Pixabay
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