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. Global ozone research and monitoring project report no. Second, the depletion of the stratospheric ozone layer and most notably the antarctic ozone hole has a signi. The main cause of ozone depletion and the ozone hole is manufactured chemicals. Some halocarbons ozone depleting substances, or odss deplete the ozone layer, while others greenhouse gases, or ghgs are thought to contribute to global warming. The emission of ozone depleting gases are threatening the earths ozone layer. The ozone layer is composed of 3 atoms of oxygen and is represented as o 3. National aeronautics and the ozone hole space administratio n. Cosmic ray theory for ozone hole effect of ozone layer depletion a. 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. The ozone layer is referred to as a specific region in the earths stratosphere that acts as a shield against the incoming ultraviolet rays of the sun. The thinning is most pronounced in the polar regions, especially over antarctica.
Research into ozone depletion has therefore focused largely,though not exclusively,on trends and processes within the stratosphere,the layer of stratified, relatively stable air that houses the ozone layer and. Experts blame ozone layer depletion on manmade chemicals containing chlorine and bromine that are emitted from a. The questions address the nature of atmospheric ozone, the chemicals that cause ozone depletion, how global and polar ozone depletion occur, and what could lie ahead for the ozone layer. The ozone layer resides in the stratospheric layer of the earths atmosphere. The ozone layer refers to the ozone within stratosphere, where over 90% of the.
Morgan richards, anna kathryn taylor, jarod green, and. Feb 12, 2021 ozone depletion, gradual thinning of earths ozone layer caused by the release of chemical compounds containing gaseous chlorine or bromine from industry and other human activities. The layers which occupy the lower part of the atmosphere removes the unwanted pollutants from the earths surface. In humans, a depleted ozone layer would likely mean high. Recent scientific data suggest that the ozone layer is decreasing at a faster pace than previ ously projected. Organization global ozone research and monitoring project report no. Protecting the ozone layer department of the environment. Ozone protects living organisms by absorbing harmful ultraviolet radiation uvb from the sun. It protects us from harmful uv rays that can have serious effects on animals, biodiversity and peoples health, including skin cancer and eye cataract.
All the while, surprised by the discovery of the ozone hole, government agencies scurried to better understand ozone depletion, and organized the national ozone experiment noze in 1986. The ozone layer, is made up of many molecules that contain three oxygen atoms. The european environment and health committee identified the need to assess these topics in 1997, as part of the leadup to the third ministerial conference on envi. Environmental assessment of ozone layer depletion due to the. Every year, since at least 1978, there is a sudden, rapid decrease in the stratospheric ozone levels at the end of the antarctic winter. The ozone hole is shown in purple above the antarctic on sept. Ozone depletion has fartherreaching affects than most people can realize. The thinning of the ozone layer has increased the risk that australians already face from overexposure to. He found that cfcs could lead to even more ozone destruction than the natural mechanisms did. Depletion is evaluated in the environmental impact category ozone layer depletion. The ozone layer protects us from excessive levels of harmful ultraviolet uv radiation. Analysis of stratospheric ozone depletion in the arctic using a data. Pollution is any undesirable change in physical, chemical or biological characteristics of air, land, water or soil.
The report is available at this url and the executive summary es is attached to this record as a pdf. Explore the causes, effects, and solutions to ozone. This project strengthened the understanding of how human emissions of cfcs were leading to unnaturallyhigh levels of chlorine in the stratosphere, leading to. The ozone layer, situated in the stratosphere about 15 to 30 km above the earths surface. A close look at the evolution at the life on earth reveals that initially the. Aug 28, 2015 ozone depletion describes two distinct but related phenomena observed since the late 1970s. The third body m absorbs the excess energy liberated by the above reaction and there by stabilise the o 3 ozone molecule. According to the environmental protection agency, this. Depletion of stratospheric ozone o3, as commonly known as the hole in the. Les diablerets, switzerland by jeanpierre pommereau, june 2010.
The affect of ozone depletion was studied by group 2. Global emissions of ozonedepleting substances have declined by more than. If increasing trends of odss had continued through to 2020, the wmo proje. Agents that bring about such an undesirable change are called as pollutants. Additional research has shown that ozone depletion occurs over every continent.
Protecting the ozone layer and reducing global warming. Protecting the ozone layer department of agriculture, water and. In the 1980s, scientists knew that the ozone layer was being damaged by ozone depleting substances odss, which were specific manufactured chemicals e. Ozone and uv changes the smaller ozone hole in the spring of 2002 should not be interpreted as a sign of early recovery of the ozone layer the extent of antarctic ozone depletion varies greatly from year to year depending on meteorological conditions. 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. Project ozone layer depletion pdf the stratospheric ozone layer forms a thin shield in the upper atmosphere, protecting life on earth from. Ozone layer depletion cause, effects, and solutions byjus. Depletion of the ozone layer increase in harmful ultraviolet light depletion of ozone layer chlorine reacts with o3 in the ozone depletion of the ozone layer impact on human body and ecosystems ozone layer depletion incoming harmful ultraviolet light depletion chain reaction q. In 1974, molina and rowland published a pivotal study that drew widespread attention to depletion of the stratospheric ozone layer due to emission of manmade. As our scientific knowledge about ozone depletion grew, so too did the response to the issue.
The ozone layer absorbs around 9799% of the mediumfrequency ultraviolet light emitted by the sun. Prolonged exposure to uvb radiation is linked to skin cancer, genetic damage and immune. Scientific assessment of ozone depletion ozone secretariat unep. The ozone layer is a band of natural gas called ozone. Ozone layer depletion can result in many negative effects on human beings, plant and animal life and the ecology as a whole. The report and executive summary highlight the key findings of the scientific assessment of ozone depletion. When highenergy ultraviolet rays uvc strike an oxygen. The protocol requests quadrennial reports from its scientific assessment panel that update the science of the ozone layer. Within the stratosphere, the ozone layer is the portion that contains the highest. If the ozone layer gets depleted, more uv rays enter the atmosphere. Montreal protocol on substances that deplete the ozone layer.
The earths ozone layer is mainly found in the lower portion of the stratosphere from approximately 20 to 30. The present document contains key summaries from the scientific assessment of ozone depletion. The reason behind the ozone layer depletion is mainly due to the extensive use of ozone depleting substances ods. Global emissions of ozone depleting substances have declined by more than. The ozone hole is not really a hole but a thinning of the ozone layer over the south polar region. The world health organization was established in 1948 as a. Depletion of the ozone layer occurs globally, however, the severe depletion of the ozone layer over the antarctic is often referred to as the ozone hole. There are natural processes that create and destroy ozone in the stratosphere.
Ozone depletion consists of two related events observed since the late 1970s. If increasing trends of odss had continued through to 2020, the wmo project. To the point where a seasonal hole in the ozone layer began to appear above the antarctic. In humans, a depleted ozone layer would likely mean higher rates of skin cancer, cataracts, and immune system problems. The ozone layer protects earth from dangerous uv radiation fig. A warming trend and stratospheric ozone depletion have been observed in europe over the last four decades. Testing the hypothesis of ozone depletion 3 of 3 chlorine monoxide is one of the products of ozone destruction. As a result, there has been a general thinning of the ozone layer over most of the globe, including between five to nine per cent depletion over australia since the 1960s. Following is the list of some main ozone depleting substances and the sources from where they are released. Ozone is formed by photochemical reaction, followed by three body reaction. Increased depletion has recently started occurring over the arctic as well. The stratospheric ozone layer forms a thin shield in the upper atmosphere, protecting life on earth from the suns ultraviolet uv rays. Ozone depletion and global warming overview page 1 of 5 halocarbons are chemical compounds containing carbon, one or more halogens, and sometimes hydrogen. The emission of ozonedepleting gases are threatening the earths ozone layer.
The full assessment report will be part of the information upon which the parties to the united nations montreal protocol will base their future decisions regarding protection of the earths stratospheric ozone layer. The maps were produced with data collected by statellite istruments, including the ozone monitoring instrument on the aura satellite. The atmosphere is a layer of air trapped by the earths gravity. This student paper was written as an assignment in. Ozone layer depletion is the thinning of the ozone layer that protects the earth from the harmful uv radiations. At the end of 20, 258 projects have been committed for an amount of 299m. Concentrations of ozone depleting substances are expected to decline over the coming century. When there was no ozone layer, life could only exist in the sea.
The ozone layer is being destroyed by cfcs and other substances. Like an infection that grows more and more virulent, the continentsize hole in earths ozone layer keeps getting bigger and bigger each year since the late 1970s, much of the protective layer of stratospheric ozone above antarctica has disappeared during september, creating what is popularly known as the ozone hole. Ozone depleting substances are the substances such as chlorofluorocarbons, halons, carbon tetrachloride, hydrofluorocarbons, etc. The word theory is used in this context because, we should remember, in the mid and late 1970s the notion of stratospheric ozone depletion was still just that a theory. The thinning of the ozone layer has increased the risk that australians already face from overexposure to uv radiation from an outdoor lifestyle. The ozone depletion phenomenon the ozone depletion. The ozone layer ozone in the stratosphere 1250 km above the surface of the earth absorbs ultraviolet radiation that can lead to skin cancer and other adverse effects 4. The antarctic hole now measures about 9 million square miles, nearly the. Ozone depletion progressing globally except in the tropical zone. Sounding the alarm the ozone layer protects earth from dangerous uv radiation fig. Pdf biology investigatory project project on ozone. When there was no ozone layer, life could only exist in. Ozone layer depletion cause, effects, and solutions. Newly detected ozone depleting substances in the atmosphere pdf.
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