write about ozone layer depletion its causes and effects
Answers
Explanation:
The main effect of ozone depletion is an increase in UV-B rays reaching the earth's surface. Causes : chlorofluorocarbon (CFCs), halons, and other compounds deplete the ozone layer. ... CFCs and halons break down into chlorine and bromine which in turn destroy the ozone layer
Answer:
Causes of Ozone Layer Depletion
There have been several concerns about ozone depletion. The problems and causes associated with ozone depletion arise from human activities. Unlike pollution which has several causes, there is one specific chemical compound that is responsible for the breakdown of the ozone layer.
These chemical compounds are present in many industrial manufactured products and aerosols. Nonetheless, since the discovery of ozone depletion, the Montreal Protocol was established to regulate the manufacture and use of these chemical compounds. Below is the detailed account of the chemicals responsible for the ozone layer depletion.
1. Chlorofluorocarbons (CFCs)
Chlorofluorocarbons (CFCs) are the primary cause for the ozone layer depletion. Industrial products including solvents, soaps, spray aerosols, insulating foams, ‘take-away’ containers and cooling utilities such as refrigerators and air conditioners use chlorofluorocarbons (CFCs). Over time, these substances accumulate in the atmosphere are carried by wind action into the stratosphere.
Once the chlorofluorocarbons (CFCs) are in the stratosphere, their molecules are broken up by the ultraviolet radiation from the sun which releases Chlorine atoms. The Chlorine atoms react with the Ozone, setting out a chemical cycle that destroys the good ozone. The U.S. Environmental Protection Agency (EPA) estimates that once Chlorine atom can break up more than 100,000 ozone molecules.
2. The ODS
There are also other chemical substances that are generally grouped as Ozone Depleting Substances (ODS). Examples are methyl bromide use in pesticides, methyl chloroform used on making industrial solvents, and halons used in fire extinguishers. Just like the chlorofluorocarbons (CFCs), these substances also chemically react with the ozone which starts a chemical cycle that break up the good ozone.
3. Other chemicals
Other chemicals that naturally present similar reactions with the good ozone include Clx, Hox and Noy which belong to the Chlorine, Hydrogen and Nitrogen families respectively.
Effects of Ozone Layer Depletion
Ozone layer depletion can have some serious consequences on effects of human health, plants, marine ecosystems, biogeochemical cycles and earth’s environment. Let us see each one of these in detail.
1. Effect on health of humans
With depletion in ozone’s layer, we humans are more prone to UV rays that reaches the Earth’s surface. Studies suggests that high levels of UV Rays cause non-melanoma skin cancer and plays a major role in malignant melanoma development. Direct exposure to UV rays can lead to development of cataracts which clouds the eye’s lens.
Permanent exposure to UV rays can also lead to weakening of the response of immune system and even permanent damage to immune system in some cases.
Aging of skin is yet another problem that will make you look older than what you really are. Extensive exposure to UV rays can lead to acceleration of the aging process of your skin.
2. Effect on plants
Plants become another casualty by radiation effects of UV rays. The physiological and developmental processes of plants are also severely affected apart from the growth. Some other changes that are caused by UV inlcude the way plants form, timing of development and growth, how nutrients are distributied within the plant and metabolism, etc.
3. Effect on marine ecosystems
UV rays also have adverse effect on the marine ecosystems. It badly affects the planktons that form the foundation of aquatic food webs. Phytoplankton grow close to the surface of the water and plays vital role in the food chain and oceanic carbon cycle. Changes in UV levels is know to affect both orientation and motility in phytoplankton. This reduces the survival and growth rate of these organisms.
UV rays are also known to affect the development stages of fish, shrimp, crab, amphibians, and other marine animals. When this happens it affects whole marine food chain as animals in the upper food chain that feed on these fishes are also affected.
4. Effect on biogeochemical cycles
Increases in UV radiation alters both sources and sinks of greenhouse gasses in the biosphere e.g.: e.g., carbon dioxide, carbon monoxide, carbonyl sulfide, ozone, and possibly other gases. Changes in UV levels would contribute to biosphere-atmosphere feedbacks that mitigate or amplify the atmospheric concentrations of these gases.
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