Ozone Layer Depletion: Effects of ozone depletion

The main concern of ozone depletion is the increase in the amount of UVB rays reaching Earth, which can have many effects on humans, our environment, animals, plants as well as materials.

The most known effect of ozone depletion on humans is skin cancer. Reduction in ozone levels will lead to higher levels of UVB reaching the Earth's surface. Less ozone means less protection for the Earth from the Sun's UV rays and thus, more UV rays will enter the Earth. An increase in exposure to UVB rays will lead to more absorption of UVB radiation. This will in fact cause DNA in humans to produce transcription errors when replicating, which causes nonmelanoma cancer.

There are two kinds of cancer involved, nonmelanoma cancer and malignent melanoma. The first is relatively mild and can be treated but the latter is much less common and much more dangerous, being lethal in about 15%-20% of the cases diagnosed. UVB rays are known to play a significant role in the development of malignent melanoma.

Research has shown that UV radiation increases the likelihood of certain cataracts.
Cataracts are a form of eye damage in which a loss of transparency in the lens of the eye clouds vision. If left untreated, cataracts can lead to blindness.

The increase in the amount of UV radiation reaching the Earth can cause adverse health risks, such as respiratory problems and weaking of the immune system. The body's immune system is its first line of defense against invading germs. Recent research has shown that the some viruses can be activated by increased exposure to UV.

However, ozone depletion has one possible beneficial effect. The inceased UV radiation entering the Earth also represents the increase in Vitamin D capacity in the sunlight reaching Earth. UVB and/or Vitamin D has been found to be associated with reduced risk over a dozen forms of cancer.

Ozone depletion also causes a disruption in the marine ecosystem. Studies have shown that UV rays can affect phytoplankton, the foundation of the marine food chain. The UV rays affect the orientation mechanisms and mobility of microorganisms as such and reduce their survival rates.

Solar UVB radiation has also been found to cause damage to the early developmental stages of fish, shrimp, crab, amphibians and other animals. The most severe effects are a decreased reproductive capacity as well as impaired larval development. Hence, an increase in exposure to UVB rays can cause a significant reduction in the marine population for animals which feed on these small animals.

Ozone depletion also affects plants. A number of economically important species of plants, such as rice, depends on cyanobacteria residing on their roots for them to absorb and utilise nitrogen properly. Cyanobacteria are sensitive to UV light and they would be affected by its increase.

Plant growth will also be affected by the increase in UV rays. Physiological and developmental processes of plants are affected by UVB radiation, despite mechanisms to reduce or repair these effects and a limited ability to adapt to increased levels of UVB.

Synthetic polymers, naturally occurring biopolymers, as well as some other materials of commercial interest are adversely affected by solar UV radiation. Today's materials are somewhat protected from UVB by special additives. Therefore, any increase in solar UVB levels will accelerate their breakdown, limiting the length of time for which they are useful.

The increasing concern for the causes and effects of ozone depletion led to the adoption of the Montreal Protocol, in the year 1987, in order to reduce and control the industrial emission of chlorofluorocarbons. 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.

This is a simple graph to illustrate the effects of ozone depletion.