The causes of ozone layer depletion are not widespread but concentrated, and these causes of ozone layer depletion have been since the beginning of civilization.
There are multiple levels to the Earth’s atmosphere. The troposphere, the lowest layer, stretches from the Earth’s surface to about 6 miles (10 km) in altitude. Almost all human activities which are adding to the pollution of the atmosphere take place in the troposphere. Mt. Everest, the world’s highest peak, is just around 5.6 miles (9 kilometers) tall. The stratosphere, which extends from 6 miles (10 kilometers) to around 31 miles (50 kilometers), contains the ozone layer. Most commercial jets also fly in the stratosphere’s lower reaches.
Our major interest in this article is to look at the causes of ozone layer depletion and what can be done to protect our ozone layer from depleting.
What is the Ozone Layer?
The ozone layer is a region of the Earth’s atmosphere where ozone gas, an inorganic molecule with the chemical formula O3, is found in relatively high concentrations. The ozone layer is thicker across the poles than it is over the equator. In 1913, French physicists Charles Fabry and Henri Buisson discovered the ozone layer.
Ozone is a pale blue gas with a pungent (chlorine-like) odor. The majority of atmospheric ozone is localized in a stratospheric layer between 9 and 18 miles (15 and 30 kilometers) above the Earth’s surface. Despite its high concentration, this layer’s concentration is still low in contrast to other gases in the stratosphere.
Ozone is formed in the atmosphere when the sun’s rays divide oxygen molecules into single atoms. These single atoms interact with oxygen nearby to produce Ozone, a three-oxygen molecule. Ozone molecules are constantly generated and destroyed in the stratosphere at any one time. During the decades that it has been measured, the total amount has been rather steady.
Although there are only about three molecules for every ten million molecules of air, the ozone layer serves as Earth’s sunscreen, absorbing approximately 98 percent of harmful ultraviolet or UV rays. The stratosphere’s ozone layer absorbs a portion of the sun’s radiation, preventing it from reaching the planet’s surface.
UV rays would sterilize the earth if the ozone layer did not exist. There will be harmful effects like more sunburns, more skin cancer instances, higher cases of eye damage, wilting and death of trees and plants, and drastically reduced crop yields with a damaged but still present ozone layer. To summarize, ozone is really important.
Scientists have compiled data on average ozone levels over natural cycles that span several decades. Sunspots, seasons, and latitude all affect ozone concentrations in the atmosphere. These are well-understood and predictable processes. Each natural ozone decline has been followed by a recovery. However, beginning in the 1970s, scientific evidence revealed that the ozone shield was being depleted in ways that were not due to natural processes.
Importance of Ozone Layer
When ozone is detected in our lower atmosphere (known as the troposphere), it is classified as an air pollutant that is extremely detrimental to human health. We need it in the stratosphere, too, since even at a low concentration of 12 parts per million, ozone is so effective at absorbing the sun’s UV radiation that even a small amount is adequate to protect us on Earth.
UV radiation is emitted by the sun and harms living things. The radiations are absorbed by this layer, which prevents them from reaching the earth’s surface. Ozone shields the Earth from the Sun’s harmful ultraviolet (UV) rays. Life on Earth would be extremely difficult without the ozone layer in the atmosphere.
Plants, as well as the planktons that feed the majority of ocean life, are unable to thrive and grow in high levels of ultraviolet radiation. Humans would be more prone to skin cancer, cataracts, and immune system impairment if the Ozone Layer protection was weakened.
Causes of Ozone Depletion
The ozone layer has become thinner, owing to pollution, which has led the ozone layer to thin, exposing life on Earth to harmful radiation. Ozone holes are a common moniker for areas of ozone layer damage, although the term is deceptive. Damage to the ozone layer appears as a thin patch, with the thinnest parts near the poles
Since the mid-1980s, pollution has influenced the ozone layer above the Antarctic. The temperature in that location accelerates the conversion of CFCs to ozone-producing chlorine. CFCs were emitted by developed countries in the northern hemisphere for around 90% of the CFCs currently in the atmosphere.
The Montreal Protocol, signed in 1989, prohibited the manufacturing of ozone-depleting chemicals. The amount of chlorine and other ozone-depleting substances in the atmosphere has been steadily decreasing since then. Chlorine levels are expected to revert to their original form in around 50 years, according to scientists. The Antarctic ozone layers will have shrunk to less than eight million square miles by then.
Several key causes of ozone layer depletion have resulted in the ozone hole.
Natural Causes of Ozone Layer Depletion
Certain natural occurrences have been discovered to disrupt the ozone layer. However, it has been discovered that this causes just a 1-2 percent depletion of the ozone layer and that the consequences are only transient. The natural causes of ozone layer depletion include
The Sun’s energy output varies, particularly during the 11-year sunspot cycle. With more UV reaching Earth during the active portion of the 11-year sunspot cycle, more ozone is created. This process can increase average ozone concentrations by roughly 4% over the poles, but when this is averaged out over the entire globe, the global average ozone increase is only about 2%.
Total worldwide ozone levels have fallen by 1-2 percent from the maximum to the minimum of a normal cycle, according to observations dating back to the 1960s.
2. Stratospheric winds
Very strong winds in the stratosphere transport nitrogen gas from solar storms further into the atmosphere where they get mixed with and attack the ozone layer.
3. Volcanic eruptions
The chemical conversion of chlorine into more reactive forms that destroy ozone is aided by explosive volcanic eruptions that inject significant amounts of sulfur dioxide into the stratosphere. Major volcanic eruptions (most notably El Chichon in 1983 and Mt. Pinatubo in 1991) are also thought to have contributed to ozone depletion.
Man-made Causes of Ozone Layer Depletion
There are also man-made causes of ozone layer depletion and these are the main causes of ozone layer depletion and include
1. The Use of Chlorofluorocarbons
One of the man-made causes of ozone layer depletion is the use of chlorofluorocarbons but it is also one of the major causes of ozone layer depletion.
Refrigerators of the early 1900s used poisonous gases such as ammonia and methyl chloride as refrigerants. Unfortunately, as hazardous gases seeped from the appliances, this resulted in fatalities. As a result, the hunt for a non-toxic, non-flammable chemical to use as a refrigerant began. As a result, the CFC was born. CFCs come in a variety of forms, but the two most common are CFC-11 and CFC-12.
CFC manufacturing and usage began to increase in the 1930s. Each year, nearly 300 million pounds of CFC-11 were emitted into the atmosphere by the early 1980s. Then, in 1985, a British researcher named Joe Farman and his colleagues released a study on huge seasonal ozone losses over Antarctica.
The Montreal Protocol, which limits the manufacture and use of CFCs, was signed in 1987 thanks to the combined efforts of the quick-acting scientific community, industry, and legislators.
The Montreal Protocol has now been signed by every country on the planet. Although CFCs have been outlawed, the ozone layer continues to deplete. This is because CFCs have a life span of 50 to 100 years, and it takes time for the number of CFCs in the environment to substantially decrease. Furthermore, CFCs are still being emitted into the atmosphere.
CFCs are slowly released as an old refrigerator or air conditioning unit deteriorates in a landfill, for example. It takes around 5 years for the influence of CFCs discharged into the air to be felt over Antarctica, where depletion occurs. CFCs generated at the ground level eventually make their way into the stratosphere.
Because most of the sun’s UV radiation is blocked by ozone in the stratosphere, CFCs must rise beyond the ozone layer before sunlight can break them down. Solar radiation, once high enough, releases chlorine, the majority of which is converted to ozone in the form of hydrochloric acid and chlorine nitrate.
Because these reactions are unique to the polar areas, due to their extraordinarily low temperatures in the stratosphere, which generate a distinct type of cloud, when these substances make their way to Antarctica, those chemical reactions begin (Polar stratospheric clouds). During the winter, the polar vortex originates in the stratosphere of the southern hemisphere when temperatures decrease.
Temperatures are still frigid enough to generate polar stratospheric clouds as sunlight returns to Antarctica in late winter and early spring. There is also sunlight now. On the cloud particle surfaces, chemical reactions occur, transforming non-reactive chlorine and bromine into reactive compounds.
The vortex serves as a container, containing the contents of the Antarctic stratospheric inside its confines and allowing reactive chlorine and bromine compounds to destroy ozone molecules. These reactions will continue as long as ozone molecules are present until the ozone is nearly depleted. The ozone hole is what it’s called.
However, atmospheric experts have discovered that the rate of this reaction is not as high as originally thought, therefore CFCs are no longer the primary driver of ozone depletion.
2. Global Warming
Global warming though resulting in climate change is also one of the man-made causes of ozone layer depletion. Most of the heat is trapped in the troposphere, which is the layer underneath the stratosphere, as a result of global warming and the greenhouse effect.
Because ozone is present in the stratosphere, heat does not reach the troposphere, causing it to remain chilly. Because the recovery of the ozone layer necessitates the maximum amount of sunlight and heat, the ozone layer is depleted.
3. Unregulated Rocket Launches
Rocket launches are also one of the major man-made causes of ozone depletion. According to studies, the unregulated launch of rockets depletes the ozone layer far more than CFCs do. If not addressed, this might result in a significant depletion of the ozone layer by 2050.
4. Nitrogenous Compounds
Small amounts of nitrogenous compounds emitted by human activities, such as NO, N2O, and NO2, are thought to be one of the causes of ozone layer depletion.
Ozone Depleting Substances (ODS)
“Ozone-depleting substances are the substances such as chlorofluorocarbons, halons, carbon tetrachloride, hydrofluorocarbons, etc. that are responsible for the depletion of the ozone layer.”
Ozone-Depleting In the atmosphere below, substances are eco-friendly, relatively stable, and non-toxic. This is why they have become increasingly popular over time. Their stability, however, comes at a cost: they can float and remain stationary in the stratosphere.
When ODS are broken down by the powerful UV radiation up there, the resultant chemical is chlorine and bromine. The ozone layer is known to be depleted at supersonic speeds by chlorine and bromine. They accomplish this by removing an atom from the ozone molecule. A single molecule of chlorine has the power to degrade thousands of ozone molecules.
Ozone-depleting compounds have remained in the atmosphere for many years and will continue to do so in the future. This effectively means that many of the ozone-depleting compounds that humans have permitted to enter the atmosphere over the past 90 years are still on their way into the atmosphere, contributing to ozone depletion.
The following is a list of some of the most common ozone-depleting compounds and their sources of release:
- Chlorofluorocarbons (CFCs)
- Hydrofluorocarbons (HCFCs)
- Carbon Tetrachloride
- Methyl Chloroform
1. Chlorofluorocarbons (CFCs)
It is referred to as the most widely used ozone-depleting compound because it accounts for more than 80% of total ozone depletion. Before 1995, it was used as a coolant in home appliances such as freezers, refrigerators, and air conditioners in both buildings and cars. Dry cleaning products, hospital sterilants, and industrial solvents all include this chemical. It’s also used in foam items like mattresses and pillows, as well as in-home insulation.
2. Hydrofluorocarbons (HCFCs)
Over time, hydrofluorocarbons have taken the position of chlorofluorocarbons. They are not as detrimental to the ozone layer as CFCs.
It’s utilized in specific fire extinguishers in situations when water or extinguisher chemicals could damage the equipment or substance.
4. Carbon Tetrachloride
It’s also found in several solvents and fire extinguishers.
5. Methyl Chloroform
Cold cleaning, vapor degreasing, chemical processing, adhesives, and certain aerosols are all common uses in industry.
The causes of ozone layer depletion can be grouped into two and there are the natural and man-made causes of ozone layer depletion.
How to Protect the Ozone Layer
Some actions have been taken globally to reduce ozone layer depletion hence, protecting the ozone layer.
The Montreal Protocol
The Montreal Protocol on ozone-depleting compounds was developed in 1987 by the international community to address the loss of the ozone layer. It was the first international treaty to be signed by all countries in the world, and it is often regarded as the UN’s greatest environmental success story.
The Montreal Protocol’s goal is to minimize ozone-depleting substance production and consumption to reduce their presence in the atmosphere and thereby safeguard the Earth’s ozone layer.
The EU’s ozone-depleting substance regulations are among the most stringent and advanced in the world. The EU has not only implemented the Montreal Protocol through a series of legislation but has also phased out harmful substances faster than needed.
A variety of measures are included in the present EU “Ozone Regulation” (Regulation (EC) 1005/2009) to assure a higher degree of ambition. While the Montreal Protocol governs the manufacturing and bulk sale of these chemicals, the Ozone Regulation restricts their use in the majority of circumstances (certain uses are still permitted in the EU). Furthermore, it governs not just bulk compounds, but also those found in products and equipment.
The EU Ozone Regulation further establishes licensing requirements for all ozone-depleting substance exports and imports, as well as regulating and monitoring substances not covered by the Montreal Protocol (over 90 chemicals), as well as five more chemicals known as “new substances.”
Actions required globally to continue the recovery of the ozone layer are:
- Ensure that existing ozone-depleting substance limitations are appropriately implemented, and that worldwide ozone-depleting substance consumption continues to decline.
- Ensure that ozone-depleting compounds (both in storage and in existing equipment) are handled in an ecologically favorable manner and that they are replaced with climate-friendly alternatives.
- Assuring that ozone-depleting chemicals are not diverted from their legal usage.
- Reducing the use of ozone-depleting compounds in non-consumption uses, as defined by the Montreal Protocol.
- Ensure that no new chemicals or technologies arise that could endanger the ozone layer (e.g. very short-lived substances).
Actions required by individuals to protect the ozone layer.
- Avoid inhaling gases that are harmful to the ozone layer owing to their composition or manufacturing method. CFCs (chlorofluorocarbons), halogenated hydrocarbons, methyl bromide, and nitrous oxide are among the most harmful gases.
- Reduce the use of automobiles. Urban, biking, or walking are the best modes of transportation. If you must go by automobile, attempt to carpool with others to reduce the number of cars on the road, thus reducing pollution and saving money.
- Avoid using cleaning items that are damaging to both the environment and ourselves. Many cleaning products contain solvents and caustic compounds, however, these can be replaced with non-toxic alternatives such as vinegar or bicarbonate.
- Purchase things made in your area. You not only receive fresh things this way, but you also avoid eating food that has traveled large distances. Because of the medium utilized to carry that product, more nitrous oxide is produced as the distance traveled increases.
- Keep air conditioners in good working order, as failures cause CFCs to seep into the atmosphere.
Causes of Ozone Layer Depletion – FAQs
What does the ozone layer do?
The stratosphere’s ozone layer absorbs a portion of the sun’s radiation, preventing it from reaching the planet’s surface. Most notably, it absorbs the UVB portion of the spectrum. UVB is a type of ultraviolet light that comes from the sun (and sun lamps) and has many negative consequences.
What is the ozone layer made of?
The stratospheric ozone layer is made up of ozone gas (90 percent of the total ozone in the atmosphere). The action of Ultra Violet (UV) light on oxygen molecules made of two oxygen atoms produces ozone, which comprises three oxygen atoms.