Depletion is evaluated in the environmental impact category ozone layer depletion. In humans, a depleted ozone layer would likely mean higher rates of skin cancer, cataracts, and immune system problems. Twenty questions and answers about the ozone layer. Cosmic ray theory for ozone hole effect of ozone layer depletion a. Later amendments to the montreal protocol completely phased out production of cfcs. Technical report on stratospheric ozone depletion european. Questions and answers about the environmental effects of the ozone layer depletion and 4 climate change. The reason behind the ozone layer depletion is mainly due to the extensive use of ozone depleting substances ods. The world health organization was established in 1948 as a. The ozone layer protects earth from dangerous uv radiation fig. The montreal protocol on substances that deplete the ozone layer was adopted in 1987 to. Pdf file why has an ozone hole appeared over antarctica when ozone depleting substances are present. Halocarbon scenarios, ozone depletion potentials, and global warming potentials.
One example of ozone depletion is the annual ozone hole over antarctica that has occurred during the antarctic spring since the early 1980s. The present document contains key summaries from the scientific assessment of ozone depletion. A warming trend and stratospheric ozone depletion have been observed in europe over the last four decades. To the point where a seasonal hole in the ozone layer began to appear above the antarctic. 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. Experts blame ozone layer depletion on manmade chemicals containing chlorine and bromine that are emitted from a. The ozone layer is mainly found in the lower portion of the stratosphere, from approximately 15 to 35 kilometers 9. The montreal protocolthe regime designed to protect the stratospheric ozone layer has widely been hailed as the gold standard of global environmental governance and is one of few examples of international institutional cooperative arrangements successfully solving complex transnational problems. This is not really a hole through the ozone layer, but rather a large area of the stratosphere with extremely low amounts of ozone. The chlorine and bromine compounds that cause significant depletion of the ozone layer are cfcs, carbon tetrachloride ccl4, methyl chloroform ch3ccl3, hcfcs. The depletion of the ozone layer is a serious issue and various programmes have been launched by the government of various countries to prevent it. Pollution is any undesirable change in physical, chemical or biological characteristics of air, land, water or soil. Frequently asked questions about the ozone layer ozone.
Chlorofluorocarbons are not washed back to earth by. Aug 18, 2006 but the delayed recovery is a warning that we cannot take the ozone layer for granted and must maintain and accelerate our efforts to phase out harmful chemicals, said mr. 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. Aware that meaeures taken to protect the ozone layer from depletion ahould be baaed on relevant ecientific knowledge, taking into account teclmical and economic conaiderationa, deterained to protect the ozone layer by taking precautionary aea1ure1 to. Some halocarbons ozone depleting substances, or odss deplete the ozone layer, while others greenhouse gases, or ghgs are thought to contribute to global warming. When highenergy ultraviolet rays uvc strike an oxygen. Oct 23, 2020 one example of ozone depletion is the annual ozone hole over antarctica that has occurred during the antarctic spring since the early 1980s. The layers which occupy the lower part of the atmosphere removes the unwanted pollutants from the earths surface. At the end of 20, 258 projects have been committed for an amount of 299m. Protecting the ozone layer and reducing global warming.
The benchmarks for the recovery dates are the pre1980 stratospheric levels of chlorine, the chief ozone depleting gas. 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. Project report on ozone depletion environmental pollution. But, steps should be taken at the individual level as well. 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 depletion cause, effects, and solutions. Above northern europe, the decrease is estimated to be about 3. In humans, a depleted ozone layer would likely mean high. 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. The ozone layer, is made up of many molecules that contain three oxygen atoms. About depletion of the ozone layer is the anticipated increase in the amounts of. Ozone depletion ozone depletion ozone layer recovery.
Montreal protocol on substances that deplete the ozone layer, sept. 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 or ozone shield is a region of earths stratosphere that absorbs most of the suns ultraviolet radiation. This happens when the chlorine and bromine atoms in the atmosphere.
The ozone layer is a band of natural gas called ozone. Ozone layer depletion cause, effects, and solutions byjus. Ozone depletion and global warming an integrated approach. The ozone layer refers to the ozone within stratosphere, where over 90% of the. The stratospheric ozone layer forms a thin shield in the upper atmosphere, protecting life on earth from the suns ultraviolet uv rays. The third body m absorbs the excess energy liberated by the above reaction and there by stabilise the o 3 ozone molecule. Ozone layer depletion is the thinning of the ozone layer present in the upper atmosphere. Aug 28, 2015 ozone depletion describes two distinct but related phenomena observed since the late 1970s. The department of transportation dot had primary responsibility for another huge project the supersonic transport sst. Following is the list of some main ozone depleting substances and the sources from where they are released. Les diablerets, switzerland by jeanpierre pommereau, june 2010. The thinning of the ozone layer has increased the risk that australians already face from overexposure to uv radiation from an outdoor lifestyle.
Morgan richards, anna kathryn taylor, jarod green, and evan. The depletion of the stratospheric ozone layer, increases in troposphere ozone, higher levels of acidity in rain, rising carbon dioxide and methane concentrations, and changes in the radiative balance of the earthatmosphere energy system all reflects the increasing influence of human. Ozone depleting substances are the substances such as chlorofluorocarbons, halons, carbon tetrachloride, hydrofluorocarbons, etc. Recent scientific data suggest that the ozone layer is decreasing at a faster pace than previ ously projected. Chemistryclimate models that account for changes in ozone depleting substances odss and greenhouse gases are widely used to assess past ozone changes and project future values of ozone. Climate change, global warming, ozone layer depletion, acid rain and impacts on human communities and agriculture c. Concentrations of ozone depleting substances are expected to decline over the coming century. Ozone depletion, gradual thinning of earths ozone layer caused by the release of chemical compounds containing gaseous chlorine or. In the 1980s, scientists knew that the ozone layer was being damaged by ozone depleting substances odss, which were specific manufactured chemicals e. Satellite data indicate that the ozone hole in 2003 developed rapidly and. Agents that bring about such an undesirable change are called as pollutants.
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. Agreement in comparisons of model results with observations increases confidence in the model projec. It protects us from harmful uv rays that can have serious effects on animals, biodiversity and peoples health, including skin cancer and eye cataract. 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. Ozone depletion has fartherreaching affects than most people can realize.
Global emissions of ozonedepleting substances have declined by more than. The ozone layer contains less than 10 parts per million of ozone, while the average ozone concentration in earth. 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 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 rate of degradation of ozone layer is estimated to be around 1% per 10 years. National aeronautics and the ozone hole space administratio n. The odp for halon 1 is 16, this value has been widely accepted. The thinning is most pronounced in the polar regions, especially over antarctica.
He found that cfcs could lead to even more ozone destruction than the natural mechanisms did. However, these do not cause more than 1 2% of the ozone depletion. The ozone layer in the 21st century greg bodeker and darryn w. Nasa sees first direct proof of ozone hole recovery. It has been suggested that bromine is more damaging to the ozone layer than previously believed.
There are natural processes that create and destroy ozone in the stratosphere. Control measures of urban and industrial waste, special reference ewaste, biomedical waste. 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. Rhode island ozone attainment demonstration submitted on april 30, 2008. The longer the atmospheric lifetime of a compound the more of it can enter the stratosphere and contribute to ozone depletion. Extinguishing concept lowering ozone depletion and green house effect ecolog project objective project initiated coordinated founded by airbus. A close look at the evolution at the life on earth reveals that initially the. According to the environmental protection agency, this.
Within the stratosphere, the ozone layer is the portion that contains the highest. 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. In 1987, the united states, along with other countries, signed an international agreement the montreal protocolto protect strato spheric ozone. Mechanism of ozone depletion the reason for ozone depletion was earlier explained by various theories. Pdf biology investigatory project project on ozone. Two years after the discovery of the antarctic ozone hole in 1985, nations of the world signed the montreal protocol on substances that deplete the ozone layer, which regulated ozone depleting compounds. However, this idea was not taken seriously until the discovery of the ozone hole over antarctica in 1985. Every year, since at least 1978, there is a sudden, rapid decrease in the stratospheric ozone levels at the end of the antarctic winter. Protecting the ozone layer department of the environment. Semester i compulsory course aecc environment studies b. If increasing trends of odss had continued through to 2020, the wmo proje. Scientific assessment of ozone depletion ozone secretariat unep.
Substances that deplete the ozone layerthat action was necessary. 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. Increased depletion has recently started occurring over the arctic as well. 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. Prolonged exposure to uvb radiation is linked to skin cancer, genetic damage and immune. There are different types of air pollutants, such as gases such as ammonia, carbon monoxide, sulfur dioxide, nitrous oxides, methane and chlorofluorocarbons, particulates both organic and inorganic, and biological. The situation then reached an alarming scale in 1987 when an international expedition found that half of the antarcticas ozone have disappeared over a region twice the size of the united states, creating an enormous hole in the ozone layer. The ozone layer resides in the stratospheric layer of the earths atmosphere. Ozone is formed by photochemical reaction, followed by three body reaction. Nuclear hazards and human health risks chernobyl, 3 mile island, daiichi fukushima d.
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. Environmental assessment of ozone layer depletion due to the. Halon depletes the ozone layer and is a great contributor to the green house effect. Ozone layer protection environmental protection department. 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. During the long winter months of darkness over the antarctic, atmospheric temperatures drop. Although the stratospheric ozone layer still bears the impacts of ozone depleting. Nasa and the environment the case of ozone depletion 3 stage 1awareness when ozone depletion first became an issue in the late 1960s, nasa was preoccupied with apollo and landing a man on the moon. Ozone depletion and global warming overview page 1 of 5 halocarbons are chemical compounds containing carbon, one or more halogens, and sometimes hydrogen. Testing the hypothesis of ozone depletion 3 of 3 chlorine monoxide is one of the products of ozone destruction. The ozone hole is not really a hole but a thinning of the ozone layer over the south polar region. The affect of ozone depletion was studied by group 2. Ozone control strategies groundlevel ozone new england.
It contains a high concentration of ozone o 3 in relation to other parts of the atmosphere, although still small in relation to other gases in the stratosphere. Depletion of stratospheric ozone o3, as commonly known as the hole in the. Update on ozone depleting substances odss and other gases of. Projectscampaignszonalmeans and the merged satellite column ozone. The thinning of the ozone layer has increased the risk that australians already face from overexposure to. Air pollution is the presence of substances in the atmosphere that are harmful to the health of humans and other living beings, or cause damage to the climate or to materials. See kerr, ozone hole bodes ill for the globe, 241 science 785 1988. Ecolog extinguishing co lowering ozone depletion and. Since about 1975, scientists have detected a severe drop in ozone concentration in the layer over the antarctica each spring. The ozone layer contains less than 10 parts per million of ozone, while the average ozone concentration in earths atmosphere as a whole is about 0. The emission of ozonedepleting gases are threatening the earths ozone layer. Protecting the ozone layer department of the environment and.
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