The natural distribution of ozone around the earth is. An international consensus about the causes and effects of ozone depletion has emerged. Find out what caused the ozone hole, and how the 1989 montreal protocol sought to put an end to ozone depletion. Following is the list of some of the main ozone depleting substances and the sources from where they are released. The ozone layer is important for blocking most of the harmful radiation that comes from the sun. Ppt ozone layer depletion powerpoint presentation free. Designation of amount of such depletion as an ozone hole is made when the detected amount of depletion. In the 199020 average profile, a broad minimum centered near 16 kilometers now occurs, with ozone values reduced by up to 90% of normal values. At the end of 20, 258 projects have been committed for an.
Ozone depletion refers to the wearing out or reduction of the amount of ozone in the stratosphere. Ozone layer depletion, its causes and its effects scribd. The vienna convention for protection of ozone layer was adopted by 43 nations in 1985. A polar vortex is a large pocket of very cold air, typically the coldest air in the northern hemisphere, which sits over the polar region during the winter season. It protects us from harmful uv rays that can have serious effects on animals, biodiversity and peoples health, including skin cancer and eye cataract. It was first identified in 1970s due to the advent of supersonic aircraft, which fly in the lower stratosphere and emit nitrogen oxides. Measurements from satellitebased instruments show that this area of very low ozone concentration has developed over antarctica every year since about 1975. The ozone layer refers to a region of earths stratosphere that absorbs most of the suns uv radiation. Ozone layer depletion causes and effects of ozone layer. Ozone is unstable and decomposes to molecular oxygen. The assessment may be reproduced or excerpted, without. Depletion of stratospheric ozone o3, as commonly known as the hole in the ozone layer, is an issue of international concern.
Global warming is caused by the greenhouse effect, which is essential to life as we know it on planet earth. The 1987 montreal protocol on substances that deplete the ozone layer began the phaseout of cfcs in 1993 and sought to achieve a 50 percent reduction in. Testing the hypothesis of ozone depletion 3 of 3 chlorine monoxide is one of the products of ozone destruction. The ozone layerthe ozone layer is a deep layer in thestratosphere, encircling the earth,that has large amounts of ozone in it. It addressed the im portance of conservation of ozone layer and established. Nearly 90% of earths ozone is in the stratosphere and referred to as the ozone layer. Presentation on ozone depletion linkedin slideshare. Mechanism of ozone depletion the reason for ozone depletion was earlier explained by various theories. The ozone layer is mainly found in the lower portion of the stratosphere, about 20 to 30 km 12 to 19 miles above the earth, though the thickness varies seasonally and geographically. The ozone layer has the capacity to absorb almost 9799% of the harmful ultraviolet radiations that sun emits and which can produce long term devastating effects on human beings as well as plants and animals coohill, t. This is the reason the ozone hole found over the polar region of earth. As controlled ozone depleting substances decline, the evolution of the ozone layer in the second half of the 21st century will largely depend on the atmospheric. Ozone depletion facts and information national geographic. Ozone depletion, gradual thinning of earth s ozone layer in the upper atmosphere caused by the release of chemical compounds containing gaseous chlorine or bromine from industry and other human activities.
The ozone layer is mainly found in the lower portion of the stratosphere. The ozone layer contains less than 10 parts per million of ozone the ozone layer absorbs 9799% of the suns mediumfrequency ultraviolet light from about 200 nm to 315 nm wavelength, which otherwise would potentially damage exposed life forms near the surface the ozone layer was discovered in 19 by the french physicists charles fabry and. Ozone depletion results in an increase of uvb radiation, but the shorter the wavelength, the stronger the increase within the uvb range. Ozone layer depletion, its causes and its effects free download as powerpoint presentation. This ozone layer sustains life on the earth by absorbing a great deal of uv ultra violet light radiating out of sun. Here we will study polar vortex circumpolar vortex which is a polar cyclone. Global warming and ozone layer depletion are two different problems see the sidebar misconceptions about global atmospheric change on page 95. How severe is the depletion of the antarctic ozone layer.
Ozone layer is also naturally broken down but there is a balance between its formation and natural depletion. The thinning is most pronounced in the polar regions, especially over antarctica. There are natural processes that create and destroy ozone in the stratosphere. What are the causes and effects of ozone depletion. Scribd is the worlds largest social reading and publishing site. It shields the entire earth frommuch of the harmful uv radiationthat comes from the sun 3. Apr 14, 2017 the ozone hole is an area where the amount of ozone in the upper atmosphere is much lower than normal. The ozone layer was discovered in 19 by the french physicists charles fabry and henri buisson. In response to this and additional fears about more widespread global ozone depletion, the montreal protocol on substances that deplete the ozone layer was implemented in 1987. Nasa provides daily images, data, and information from satellite instruments that monitor the ozone layer and the ozone hole ozone holea thinning break in the stratospheric ozone layer. Humans have introduced gases and chemicals into the atmosphere that have rapidly depleted the ozone layer in the last century. The the causes and effects of global ozone depletion have been illuminated in this paper. Above northern europe, the decrease is estimated to be about 3.
Ozone is a colourless gas which is found in the stratosphere of our upper atmosphere. Ozone layer depletion cause, effects, and solutions. Causes of ozone layer depletion and its effects on human. The question is often asked why the world moved so quickly in dealing with ozone layer depletion, yet has moved so slowly in addressing the equally critical problem of climate change. Changes in co 2, n 2 o, and ch 4 will have an increasing influence on the ozone layer as odss decline. Les diablerets, switzerland by jeanpierre pommereau, june 2010. Protecting the ozone layer and reducing global warming. Frequently asked questions about the ozone layer ozone. It protects life on earth from the suns ultraviolet uv rays. This legally binding international treaty called for participating developed nations to reduce the use of cfcs and other ozone depleting substances. Ozone layer depletion is one of the most serious problems faced by our planet earth. However, the ozone layer is destroyed by manmade chemicals known as ozonedepleting substances ods. This is not really a hole through the ozone layer, but rather a large area of the stratosphere with extremely low amounts of ozone.
It is found largely in the stratosphere that extends from about 6 km at the poles and 17 km at the equator to about 50 km above the earths surface. A global thinning of the ozone layer results as ozone rich air from the remaining ozone layer flows into the ozone poor. Ozone o3 is a stratospheric layer that plays important role in providing support to humans for their survival. Cfcs get banned in 1974 scientists sherry rowland and mario molina discovered the link between the depletion of the ozone layer and cfcs. The layer of ozone gas is what which protects us from the harmful ultraviolet radiations of the sun. A free powerpoint ppt presentation displayed as a flash slide show on id. It is also one of the prime reasons which are leading to global warming. Pdf depletion of the ozone layer and its consequences. The main effect of ozone depletion is an increase in uvb rays reaching the earths surface causes. Ozone depletion is largely a result of manmade substances. Protecting the ozone layer department of the environment. Through that agreement and its subsequent amendments and adjustments, many nations of the world have carried out policies to.
Human activities that can damage or affect the ozone. It has been found that this protective ozone layer is getting depleted because of the presence of cfc chlorofluorocarbon compounds. There are many situations where human activities have. There is a corresponding hole over the arctic that similarly appears in the spring, although in some years warmer winters there do not result in a major depletion of the ozone layer. The latest ozone layer depletion news is included at the foot of the page. For nearly a billion years, ozonemolecules in the atmosphere haveprotected life on earth from theeffects of. Human activities and ozone layer free download as powerpoint presentation. Why the ozone layer is vital to life on earth the ozone layer is a protective shield that blocks the suns harmful ultraviolet rays from reaching the earths surface.
Ozone layer depletion is one of the major environmental issues which is getting thinner day by day as a. Apr 18, 2019 the ozone layer helps to protect life from harmful ultraviolet radiation. Once they get there they destroy ozone molecules and cause the ozone layer to become depleted or thinner. Why the hole in the atmospheric ozone layer above us. The ozone layer protects living things from harmful ultraviolet rays from the sun. This depletion makes humans more vulnerable to the uvb rays which are known to cause skin cancer as well as other genetic deformities.
Ozone depletion ozone depletion ozone layer recovery. In the 1960s, a normal ozone layer is clearly evident in the october average profile, with a peak near 16 kilometers altitude. As a result the total amount of ozone remains constant. Another most feared aspect of pollution is depletion of ozone layer of the stratosphere. Stratospheric ozone protection awards since 1990, epa has recognized outstanding achievement in ozone layer protection. Safeguarding earths protective ozone layer became a. Experts blame ozonelayer depletion on manmade chemicals containing chlorine and bromine that are emitted from a. Ozone depletion simple english wikipedia, the free encyclopedia. The ozone layer and its depletion linkedin slideshare. Progress report 2003 united nations environment programme, environmental e. In the upper atmosphere, atmospheric gases absorbs the suns radiation, get ionized, and release molecules. Ozone depleting substances are the substances such as chlorofluorocarbons, halons, carbon tetrachloride, hydrofluorocarbons, etc. There, it will absorb almost all ultraviolet light which is harmful to many organisms. Ozone depletion is primarily caused by human activities.
When highenergy ultraviolet rays uvc strike an oxygen. These compounds go tot the ozone layer through the air and reach the ozone then produce the halogens which ultimately produced oxygen o2 from the ozone o3 hence causing the depletion of ozone. Ozone layer depletion causes, effects and solutions 7. When cfc is released into the atmosphere, they mix with atmospheric. Ozone is a gas that is present in the ozone layer in the stratosphere of the earth. To the point where a seasonal hole in the ozone layer began to appear above the antarctic. Ozone absorbs a band of ultraviolet radiation called uvb. A dynamic equilibrium is maintained between the formation and decomposition of ozone. Nearly 500 organizations, teams, and individuals from 40 countries have received stratospheric ozone protection awards for their exceptional leadership, personal dedication, and technical achievements. Since about the 1970s, there has been a decrease in total volume of the ozone in the ozone. It is an essential factor for many global, biological and environmental phenomena. The ozone layer is a belt of naturally occurring ozone gas that sits 9. Within the stratosphere, the ozone layer is the portion that contains the highest.
It is present in traces less than 1 ppm in the atmosphere. Ozone present in the stratosphere forms a protective layer and known as ozone layer, ozonosphere or ozone umbrella its concentration in atmosphere is about 10 ppm. The severe depletion of the antarctic ozone layer known as the ozone hole occurs because of the special meteorological and chemical conditions that exist there when the very low winter temperatures in the antarctic stratosphere cause polar stratospheric clouds pscs to form which are isolated from stratospheric air in the polar vortex. Ozone depleting substances are those substances which deplete the ozone layer. Since there is no other known source of chlorine monoxide, finding this chemical in the upper atmosphere would strongly support the idea that chlorine is destroying ozone. It contains high concentrations of ozone o3 relative to other parts of the atmosphere. The recognition of the dangers presented by chlorine and bromine to the ozone layer spawned an international effort to restrict the production and the use of cfcs and other halocarbons. Ozone layer research and technical resources us epa. Most ozone is found in the stratosphere upper part of the atmosphere, more than 10 to 16 kms from the surface of the earth. These chemicals are found in cleaning agents, aerosols, insulating foam, and refrigerants. The ozone layer is made up of ozone molecules, like ozzy ozone, and forms a thin shield high up in the sky. The earths ozone layer is mainly found in the lower portion of the stratosphere from approximately 20 to 30. Within the stratosphere, the ozone layer is the portion that contains the highest proportion of. The term ozone depletion can refer to a number of distinct, but related phenomena.
The layer shields the entire earthfrom much of the harmful ultravioletradiation that comes from the sun. Cfcs, hcfcs, halons, methyl bromide, carbon tetrachloride, and methyl chloroform. Mar 21, 2020 ozone depletion, gradual thinning of earth s ozone layer in the upper atmosphere caused by the release of chemical compounds containing gaseous chlorine or bromine from industry and other human activities. An international agreement known as the montreal protocol on substances that deplete the ozone layer was reached in 1987. The ozone layer is a belt of the naturallyoccuring gas ozone that sits at an altitude of between 15 and 30 kilometers above the earth. Ozone depletion over india with so much worry about the rapid ozone depletion taking place in various parts of the earth, indian scientists are closely monitoring the ozone layer over india for possible depletion trends. Ozone and environment ozone o3 a gas composed of three atoms of oxygen bluish gas that is harmful to breathe nearly 90% of the earths ozone is in the stratosphere and is referred to as the ozone layer ozone absorbs a band of ultraviolet radiation called uvb ozone depleting substances ods.
One example of ozone depletion is the annual ozone hole over antarctica that has occurred during the antarctic spring since the early 1980s. Ozone depletion biology science fair project ideas. More recently, fears have emerged about significant ozone depletion over the arctic, closer to the more populous regions of the northern hemisphere. Project ozone layer depletion pdf the stratospheric ozone layer forms a thin shield in the upper atmosphere, protecting life on earth from. Polar vortex in the previous posts, we have studied about tropical cyclones and extra tropical cyclones temperate cyclone. Ozone depletion is the process of destruction of the ozone layer which can cause adverse effects on the living forms by many pollutants releases out from the vehicles, industries etc. Effects and measures to protect ozone layer depletion. The proteins cells in plants undergo harmful mutations, all due to ultraviolet radiations. List of books and articles about ozone layer online. This timeline highlights the average area of the ozone hole between september 7th and october th as observed by nasa spacedbased instruments see colored bars and scale. Environmental studies ozone depletion tutorialspoint. Quantifying contributions of chlorofluorocarbon banks to.
In the 1980s, scientists began finding clues that the ozone layer was being depleted. Unfortunately, cfcs can eventually find their way into the earths atmosphere and the ozone layer. Its consequences, the causal debate, and international cooperation number 6 february 8, 1988 since the announcement of a thinning of the ozone layer over the antarctic by uk scientists in 1985, world attention has been focusing on the causes of this phenomenon. Unlike oxygen o2, ozone has a strong scent and is blue in color.
Ozone layer is a thin, fragileshield that contains relatively highconcentrations of ozone. The rate of degradation of ozone layer is estimated to be around 1% per 10 years. The evaporation of surface water through the stomata of leaves increases, which results in the decreased moisture content of the soil. Is there a difference in ozone coverage between different hemispheres. Ozone layer the ozone layer is basically naturally occurring gas in the region of stratosphere where ozone particles are accumulated 2. There is a burgeoning need to reduce the production of industrial products causing ozone depletion and global warming. The increased use of humanproduced gases such as chlorofluorocarbons cfcs has led to a magnified springtime depletion of the protective ozone layer at both earths poles, especially over antarctica, a phenomenon well known as the ozone hole. You can find maps of the ozone layer and compare different regions of the globe for ozone coverage. Pdf causes of ozone layer depletion and its effects on. My teaching and textbook1 have always covered many physicsrelated social issues, including stratospheric ozone depletion and global warming. It is formed slowly over the period of 2500 million years.
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