In the 1980s, scientists found evidence that the ozone layer was being depleted. How the ozone hole forms the ozone hole is not really a hole but a thinning of the ozone layer over the south polar region. The 2010 report found, over the past decade, global ozone and ozone in the arctic and antarctic regions is no longer decreasing but is not yet increasing. These are released by solvents, spray aerosols, refrigerators, airconditioners. But the area has significantly lessas much as twothirds less protective ozone to. Protecting the ozone layer and reducing global warming undp. Schonbein in the year 1840 confirmed its existence and jacqueslouis soret rooted the chemical formula of ozone as o 3 and proved that ozone is an allotropic form of oxygen. The new halon free systems have been used successfully in iraq. The ozone hole has been starting to heal 30 years after the global effort to. The antarctic hole now measures about 9 million square miles, nearly the size of north america.
Stratospheric ozone depletion noaa earth system research. There are natural processes that create and destroy ozone in the stratosphere. This layer protects the earth from the suns harmful uv radiation. The destruction continues rapidly until all the available ozone is depleted. Concerns about the ozone layer led to the 1987 montreal protocol to phase out cfcs. Reactions in experimental chambers are one thing the free atmosphere is something. By the middle of this century, scientists expect it will be fully restored. The richness of the ozone layer that makes the hole so significant and the science behind the hole is far less popular. That unusually large ozone hole over the arctic has closed. The ozone layer depletion is a major concern and is associated with a number of factors. Chemical manufacturers were able and willing, after some initial resistance, to produce cfc substitutes. However, the ozone layer is destroyed by manmade chemicals known as ozone depleting substances ods.
Due to the depletion of the ozone layer by cfcs ozone hole is formed in that region. May 24, 2020 despite popular beliefs, the ozone hole is not actually a hole in the ozone layer, but a region of depleted ozone in the stratosphere over the antarctic, which occurs at the beginning of spring in the southern hemisphere, sometime between august and october. A large ozone hole has occurred each year since the early 1990s as shown in figure q102. Closing the gap transcript every day, as the sun shines on the earth, it sends ultraviolet rays that can cause sunburn and sometimes damage our dna. Scientists pinpointed the emissions of certain gases containing ozone depleting substances as the main source of the problem. The ozone layer or ozone shield is a region of earths stratosphere that absorbs most of the suns ultraviolet radiation. Although the stratospheric ozone layer still bears the impacts of ozone depleting substances.
But the area has significantly lessas much as twothirds less protective ozone to shield the earths surface. Pdf ozone in the stratosphere is constantly being produced and destroyed by different types of uv radiations coming from the sun. May 05, 2020 the hole in the ozone layer a portion of earths atmosphere that shields the planet from ultraviolet radiationfirst opened over the arctic in late march when. 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. Uv rays can cause sunburn and damage the dna, the ozone layer absorbs most of the harmful radiations and protects us. However, when a chlorine monoxide molecule encounters a free atom of oxygen, the oxygen atom breaks up the. 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. The ozone layer is on track to completely repair itself in. Powerpoint is the worlds most popular presentation software which can let you create professional depletion of ozone layer powerpoint presentation easily and in no time.
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. Apr 01, 2021 view all of the antarctic hemisphere daily maps of total ozone for march 2021. Prolonged exposure to uvb radiation is linked to skin cancer, genetic damage and immune system suppression in humans and animals, and lower. Protecting the ozone layer department of the environment. This helps you give your presentation on depletion of ozone layer in a conference, a school lecture, a business proposal, in a webinar and business and professional representati. Together, they describe what ozone, the ozone layer, ozone depletion and the ozone hole are, how ozone depletion occurs, mankinds influence, its impacts, and the international agreements put in place to control it. Ozone layer research and technical resources us epa. When it comes to the ozone hole, chlorine is the enemy. The ozone hole area is usually defined as the geographical area within the 220du contour see white line on total ozone maps. Like a sunscreen for our planet, the ozone layer absorbs most of this harmful radiation and protects us.
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. It is a layer in the earths stratosphere that contains high levels of ozone. The ozone layer or ozone shield is a region of the earths stratosphere that absorbs most of the suns ultraviolet uv radiation. Oct 23, 2020 national aeronautics and space administration nasa ozone hole watch. Every year, since at least 1978, there is a sudden, rapid decrease in the stratospheric ozone levels at the end of the antarctic winter. Over time, the hole grew smaller and smaller, and the ozone layer began to heal.
It takes years for cfcs and other ozone depleting compounds to reach the stratosphere. Canadas involvement in ozone research and monitoring reflects our special concern as a northern polar nation over the fate of the arctic ozone layer. Uv rays can cause sunburn and damage the dna, the ozone layer absorbs most. Sep 11, 2017 ozone measurements from halley research station, that have been recorded since the international geophysical year igy in 195758, led to the discovery of the hole in the ozone layer in 1985.
Ozone hole is created in the region where ozone layer has been depleted. There is a substantial time lag between the time when ods emissions begin to decline and the point at which the ozone layer begins to recover. It absorbs 97 99% of the uv radiation from the sun. Ozone can be bad every spring a hole in the layer of harmless ozone as big as the usa opens over antarctica, a smaller one develops over the arctic at the north pole this is the first signs that the ozone layer is. The stratospheric ozone layer forms a thin shield in the upper atmosphere, protecting life on earth from.
Understand the difference between groundlevel and stratospheric ozone 2. Protecting the ozone layer and reducing global warming. The stratospheric ozone layer forms a thin shield in the upper atmosphere, protecting life on earth from the suns ultraviolet uv rays. Satellite instruments monitor the ozone layer, and we use their data to create the images that depict the amount of ozone.
In 1970 ozone holes are first discovered in antarctica. No one knows for certain how much more ozone depletion will occur. Soon after the discovery of the antarctic ozone hole. It is clear that under cloudfree skies there is a strong correlation between ground level erythemal uv radiation and levels of atmospheric ozone 4. When highenergy ultraviolet rays uvc strike an oxygen. In the 1970s, no ozone hole was observed, as defined by a significant region with total ozone values less than 220 du dark blue and purple colors. This blanket of ozone, or o3, blocks most of the suns highfrequency ultraviolet rays. This is not really a hole through the ozone layer, but rather a large area of the stratosphere with extremely low amounts of ozone. Causes of ozone layer depletion and its effects on human. The severe depletion of stratospheric ozone in late winter and early spring in the antarctic is known as the ozone hole see q10.
The ozone layer and ultraviolet radiation one earth, one. The main causes responsible for the depletion of the ozone layer are listed below. Oct 18, 2018 these measurements gave the first clues that there was trouble in the ozone layer. But in the early 1980s, scientists discovered that the ozone layer was. Ozone deppypyg y ygletion typically begins in late july and early august with an observed ozone hole size of 10 million square kilometers by mid august. Shanklin published in the journal nature the first paper on observations of springtime losses of ozone over antarctica. This has focussed their concern on various environmental issues and steps.
The latter phenomenon is referred to as the ozone hole. National aeronautics and the ozone hole space administratio n. In the past 19years, parts of the ozone layer have. Skeptics vs ozone hole lunar and planetary laboratory. Over the arctic, similar processes occur, but ozone. Why has an ozone hole appeared q9 the stratosphere. There are also springtime polar tropospheric ozone depletion. In fact, the ozone depletion was far worse than molina and roland had predicted.
Ozone layer how the arctic ozone layer is responding to. The 2007 report showed that the hole in the ozone layer was recovering and the smallest it had been for about a decade. The hole in the ozone layer blue over antarctica results from chemicals such as cfcs. It was one of the latest forming ozone holes observed and it was one of the longest lasting ozone holes observed.
Mar 28, 2020 a large hole in the ozone layer is continuing to heal, helping weather systems in the southern hemisphere to go back to normal, according to a study from the university of colorado boulder. In late spring or early summer novemberdecember the ozone hole disappears in satellite images as ozone depleted air is displaced and mixed with ozone rich air transported toward the pole from outside the ozone. The chlorine comes from chlorofluorocarbons cfcs, for short, which were. In recent years, the ozone depletion has also been noted in the northern polar region. Nov 10, 2020 the hole formed at the south pole due to the regions unique meteorological and chemical conditions. The ozone layer is a region in the earths stratosphere that contains high concentrations of ozone and protects the earth from the harmful ultraviolet. Depletion of the ozone layer results in increased uv. The ozone layer contains less than 10 parts per million of ozone, while the average ozone concentration in earth. The ozone layer helps in absorbing the ultraviolet uv rays of the sun which are harmful to human beings. Chlorofluorocarbons or cfcs are the main cause of ozone layer depletion. The chlorine becomes actively involved in the process of. Download free powerpoint presentation of depletion of ozone layer which is used for giving presentation of different topics eg. Chemistry of the ozone layer until the hole was discovered, scientists were fairly sure that they understood the chemical processes at work in the ozone layer.
The new halonfree systems have been used successfu. 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. The ozone layer can be depleted by free radical catalysts, including nitric oxide no, nitrous oxide n 2 o, hydroxyl oh, atomic chlorine cl, and atomic bromine br. The worlds ozone layer is on track to be completely healed by the 2060s, according to modelling by the uns environmental agency unep. Ozone is a naturally occurring molecule made up of three oxygen atoms. Explain the greenhouse effect and its potential harmful effects.
Increased depletion has recently started occurring over the arctic as well. The ozone layer, cfcs and global warming objectives subjects. Unlike the hole that developed over the arctic, the antarctic ozone hole in the southern. The term ozone hole is applied when the depletion level is below 200 dobson unit d. The ozone layer is a protective shield that blocks the suns harmful ultraviolet rays from reaching the earths surface. The ozone hole appears over antarctica because meteorological and chemical conditions unique to this region increase the effectiveness of ozone destruction by reactive halogen gases see q7 and q8. However, when a chlorine monoxide molecule encounters a free atom of oxygen, the oxygen atom breaks up the chlorine monoxide, stealing the oxygen atom and releasing the chlorine atom back into the stratosphere to destroy more ozone. The discovery of the ozone hole undoubtedly helped to seal those negotiations, but there were sev eral other important drivers to international accord.
Ozone hole pdf the thinning of the ozone oracle 10g grid architecture pdf layer is caused by a chemical reaction where man. While there are natural sources for all of these species, the concentrations of chlorine and bromine increased markedly in recent decades because of the release of large quantities of manmade organohalogen compounds. Ozone layer depletion cause, effects, and solutions. 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.
When the concentration of ozone in a region becomes low than 200 du then the term ozone hole is applied in that region. Many of them can persist in the stratosphere for centuries. No one had imagined that ozone depletions like the 50% losses. The chlorine comes from chlorofluorocarbons cfcs, for short, which were widely used in early refrigeration and cooling systems. Ozone hole pdf ozone hole pdf ozone hole pdf download. What is ozone depletion burning issues free pdf download. Designation of amount of such depletion as an ozone hole is made when the detected. 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.
Depletion of the ozone layer results in increased uv radiation reaching the earths surface, which in turn leads to a greater. Ozone layer is healing, could fully recover ary news. Ozone holes are first discovered in antarctica in 1970. The manner in which the arctic ozone layer evolves in the future will depend not only on the elimina. The ozone layer for key facts and information at a glance, please read our ozone layer factsheet. Ozone depletion consists of two related events observed since the late 1970s. 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. Largestever arctic ozone hole that developed this spring is. Cfcs, short for chlorofluorocarbons, are one of the most detrimental gases to the ozone layer. 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. May 25, 2020 to restore the ozone layer, in 1987, countries adopted the montreal protocol to stem the use of ozone depleting chemicals. In 2015, nerccommissioned analysis investigated the impact of ozone science read about these impacts in the downloads section. The montreal protocol has very rightly been termed the worlds most successful environmental convention. It is clear that under cloud free skies there is a strong correlation between ground level erythemal uv radiation and levels of atmospheric ozone 4.
Stratospheric ozone depletion, ultraviolet radiation and. The ozone hole initially appeared in the early 1980s and increased in size until the early 1990s. If each chlorine atom released from a cfc molecule destroyed only one ozone molecule, cfcs would pose very little threat to the ozone layer. Less dramatic, but still significant, depletion of ozone levels has been recorded around the globe. The average concentration of ozone in the atmosphere is 300 dobson units. The ozone layer sits between 9 and 22 miles above the earth. The antarctic hole now measures about 9 million square miles, nearly the.
Humangenerated cfcs were indeed destroying earths protective ozone layer. Scientists have discovered a hole in the ozone layer over the antarctic. The ozone hole is an annual thin spot that forms in the stratospheric ozone layer over antarctica in midseptember and october. Few years ago ozone holes are also discovered in arctic region. However, the stunning discovery of the antarctic ozone hole in 1985 proved the skeptics wrong. Click any map image to bring up a new page with a highresolution map. How severe is the depletion of the antarctic ozone layer.
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