The Ozone layer saves the Earth from the ultraviolet rays coming down from the sun. The sun rays are absorbed by the ozone in the atmosphere and thus do not reach the earth. If ozone depletion occurs, the effects on the planet could be catastrophic.
Formation of Ozone:-
Ozone is a bluish gas that is formed by three atoms of oxygen O3. The form of oxygen that humans breathe in comprises two oxygen atoms O2. When found on the surface of the planet, ozone is considered a dangerous pollutant and is one substance responsible for producing the greenhouse effect.
Presence of ozone in the atmosphere:-
The atmosphere is made up of different layers, Ozone is present in the stratosphere. The stratosphere reaches 30 miles above the Earth, and at the very top, it contains ozone. The highest regions of the stratosphere contain about 90% of all the ozone.
Discovery of ozone-depleting substances:-
In recent years, the ozone layer has been the subject of much discussion. And rightly so, because the ozone layer protects both plant and animal life on the planet.
The fact that the ozone layer was being depleted was discovered in the mid-1980s. The main cause of this is the release of CFCs chlorofluorocarbons. Scientists were concerned when they discovered in1970s that chemicals called chlorofluorocarbons or CFCs-long used as refrigerants and as aerosol spray propellants posed a possible threat to the ozone layer. Released into the atmosphere, these chlorine-containing chemicals rise and are broken down by sunlight, whereupon the chlorine reacts with and destroys ozone molecules_upto 100,000 per CFC molecule.
For this reason, the use of CFCs in aerosols has been banned in the United States and elsewhere. Other chemicals, such as bromine halocarbons, as well as nitrous oxides from fertilizers, may also attack the ozone layer. Destruction of the ozone layer is predicted to cause an increase in skin cancer and cataracts, damage to certain crops and to plankton and the marine food web, and an increase in carbon dioxide due to the decrease in plants and plankton.
Victim of ozone depletion:-
Antarctica was an early victim of ozone destruction. A massive hole in the ozone layer right above Antarctica now threatens not only that continent, but many others that could be the victims of Antarctica’s melting icecaps. In the future, the ozone problem will have to be solved so that the protective layer could be conserved.
Effects of ozone depletion:-
Stratospheric ozone filters out most of the sun’s potentially harmful shortwave ultraviolet (UV) radiation. If this ozone becomes depleted, then more UV rays will reach the earth. Exposure to higher amounts of UV radiation could have serious impacts on human beings, animals, and plants.
1. Harm to human health:
- More skin cancers, sunburns, and premature aging of the skin.
- More cataracts, blindness, and other eye diseases: UV radiation can damage several parts of the eye, including the lens, cornea, retina, and conjunctiva.
- Cataracts(a clouding of the lens) are the major cause of blindness in the world. A sustained 10% thinning of the ozone layer is expected to result in almost two million new cases of cataracts per year, globally(Environment Canada,1993).
- Weakening of the human immune system(immunosuppression). Early findings suggest that too much UV radiation can suppress the human immune system, which may play a role in the development of skin cancer.
2. Adverse impacts on agriculture, forestry, and natural ecosystem:
- Several of the world’s major crop species are particularly vulnerable to increased UV, resulting in reduced growth, photosynthesis, and flowering. These species include wheat, rice, barley, oats, corn, soybeans, peas, tomatoes, cucumbers, cauliflower, broccoli, and carrots.
- The effect of ozone depletion on the Canadian agricultural sector could be significant.
- Only a few commercially important trees have been tested for UV (UV-B) sensitivity, but early results suggest that plant growth, especially in seedlings, is harmed by more intense UV radiation.
3. Damage to marine life:
- In particular, plankton (tiny organisms in the surface layer of oceans) are threatened by increased UV radiation. Plankton is the first vital step in aquatic food chains.
- Decreases in plankton could disrupt the fresh and saltwater food chains, and lead to a species shift in Canadian waters.
- Loss of biodiversity in our oceans, rivers, and lakes could reduce fish yields for commercial sport fisheries.
How to protect the ozone layer:-
Growing concern for ozone depletion led to the adoption of the Monitorial Protocol in 1987, in order to reduce and control industrial emission of chlorofluorocarbons (CFCs). Such international agreements have succeeded to a great extent in reducing the emission of these compounds.
However, more cooperation and understanding among all the countries of the world is required to mitigate the problem. You too can do your bit to save the ozone. Use/buy more recycled products, save energy, take public transport, and most importantly, spread awareness. Our individual efforts can go a long way in saving the Earth’s blanket.