The ozone layer is an atmospheric barrier that protects living beings on Earth. It is located in the stratosphere, approximately 10 to 50 kilometers above the Earth's surface. Its main function is to filter ultraviolet (UV) rays, especially UV-B and UV-C rays, which are harmful to health and ecosystems. Without the ozone layer, life on the planet would be very different, and many species might be unable to survive.
In recent years, the ozone layer has been a cause for concern worldwide due to its progressive deterioration. This phenomenon has been intensified by human action, which has released chemical compounds, especially chlorofluorocarbons (CFCs), which have caused considerable deterioration of this important natural protection. Although there are natural factors that also affect the ozone layer, most of the damage is a direct consequence of industrial activities and the use of certain products.
Essential characteristics of the ozone layer
The ozone layer has a primary function within the Earth's atmosphere: filtering much of the ultraviolet (UV) radiation coming from the sun. Ozone, composed of three oxygen atoms (O3), absorbs most of the UV-C rays and a significant portion of the UV-B rays. These types of ultraviolet radiation can cause serious damage to living organisms, including humans, animals and plants.
The process of ozone layer formation is a natural, balanced cycle: solar radiation breaks oxygen molecules (O2) into oxygen atoms, which combine with other oxygen molecules to form ozone (O3). This cycle of formation and destruction is continuous and, under normal conditions, maintains a balance. However, chlorofluorocarbons (CFCs) and other chemicals have upset this balance, weakening the ozone layer and creating what is commonly called the “ozone hole.”
Causes of the destruction of the ozone layer
The deterioration of the ozone layer is mainly linked to artificial compounds released by human activities, including CFCs, halons, carbon tetrachloride and methyl bromide. These chemical compounds reach the stratosphere, where they are broken down by ultraviolet radiation, releasing chlorine and bromine atoms. A single chlorine atom, for example, can destroy thousands of ozone molecules.
The compounds mentioned above are found in products such as aerosol sprays, refrigeration systems, fire extinguishers and solvents. Once released into the atmosphere, they can take years to reach the stratosphere, but once there, their effects can persist for decades. This persistence and destructive capacity is what has caused the constant thinning of the layer in certain areas, especially over the poles.
Although the Montreal Protocol, signed in 1987, established the gradual elimination of ozone-depleting compounds, many of these chemicals are still present in the atmosphere. Despite the measures taken, the complete recovery of the ozone layer is a slow process that could take several decades.
Consequences of the weakening of the ozone layer
The destruction of the ozone layer has negative effects on both humans and natural ecosystems. Some of the main consequences are described below:
Impact on human health
UV-B rays that manage to penetrate the atmosphere due to the weakening of the ozone layer can cause serious health problems in humans. Some of the most important conditions are:
- Skin cancer: Prolonged exposure to UV-B rays can cause mutations in skin cells, increasing the risk of developing melanoma and other types of skin cancer.
- Immune system problems: UV-B radiation affects the DNA of cells, which weakens the immune system and makes it more vulnerable to infectious diseases.
- Visual disorders: Excessive exposure to UV rays can damage your eyes, causing cataracts and other vision problems.
- Respiratory problems: Increased tropospheric (ground-level) ozone can aggravate respiratory diseases such as asthma.
Effects on ecosystems
The weakening of the ozone layer also affects both terrestrial and marine ecosystems. In the oceans, the increase in UV-B radiation directly affects phytoplankton, which is the basis of many marine food chains. The decrease in phytoplankton affects the entire food chain, including the fish species that depend on it.
In terms of terrestrial ecosystems, many plants are sensitive to changes in UV radiation. This can alter their growth, flowering or the production of fruits and seeds. Some of the most affected species include crops of commercial interest, which could generate impacts on global agriculture.
Tips to protect the ozone layer
Although humanity has caused considerable damage to the ozone layer, it is still possible to reduce and mitigate the damage. There are several actions that individuals, governments and businesses can take to protect this vital layer of the atmosphere:
- Avoid products containing CFCs: Although many products have already been phased out, it is still possible to find refrigerants and aerosols containing CFCs, so it is crucial to opt for harmless alternatives.
- Minimize the use of private cars: Use public transport, bicycle or walk whenever possible. Cars are one of the main sources of polluting gases that also contribute to the weakening of the ozone layer.
- Save electricity: Electricity production generates a large amount of gas emissions that affect both the climate and the ozone layer. Choosing efficient appliances and reducing unnecessary energy consumption is a great help.
- Use light bulbs of low consumption: LED and other types of low-consumption light bulbs reduce energy needs and, therefore, emissions of polluting gases.
Small-scale actions by individuals can contribute to the recovery of the ozone layer. Although the road to full recovery is long, a global effort can achieve a faster and more effective recovery.
The ozone layer is essential for life on Earth. Without it, the sun's ultraviolet rays would reach the Earth's surface in much greater quantities, seriously affecting human, animal and plant health. The adoption of international measures such as the Montreal Protocol has begun to bear fruit, but it is imperative to continue implementing policies, technologies and behaviours that minimise the emission of ozone-depleting chemicals. With the right actions, the complete restoration of the ozone layer is a long-term goal that we can still achieve.