Causes And Effects Of Ozone Layer Depletion In Points Pdf
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Ozone depletion consists of two related events observed since the late s: a steady lowering of about four percent in the total amount of ozone in Earth's atmosphere the ozone layer , and a much larger springtime decrease in stratospheric ozone around Earth's polar regions. There are also springtime polar tropospheric ozone depletion events in addition to these stratospheric events.
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Ozone is a molecule composed of three oxygen atoms and it is present in a gaseous form in the atmosphere, specifically located in and extended throughout the stratosphere. Its molecules act as a shield protecting us from solar radiation. When the radiation reaches the ozone layer, it passes through the ozone molecules and these are responsible for returning part of radiation back to space, in this way the radiation that reaches us is minimized. It is a hole that allows the entry of large amounts of ultraviolent light and it is located at the poles, on the Antarctic continent and the Arctic Ocean, being especially large during the spring of both hemispheres and resulting in longer summer seasons. Although this hole is due to the natural fluctuations of ozone in the atmosphere, it also caused by human activities which emit gases that end up in the stratosphere and degrade the ozone molecules, increasing the size and effect of this hole in the ozone layer.
Ozone depletion is primarily caused by human activities. 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. These chemicals are found in cleaning agents, aerosols, insulating foam, and refrigerants. CFCs and halons break down into chlorine and bromine which in turn destroy the ozone layer.
She had just been looking at the record of average surface temperatures of the Earth. The year was the warmest since reliable temperature records have been kept, and the twentieth year in a row in which the average global surface temperature was higher than the year average. The next year, , was the fifth warmest on record; the six warmest years on record have occurred in the last decade. If the global warming trend continues, the results could be depressing indeed: melting polar ice along with thermal expansion of the oceans could raise the sea level, flooding coastal cities, and many agricultural landscapes could dry out, becoming deserts. And yet, as the class studied the issue further, we learned that the news is not all bad.
The thinning is most pronounced in the polar regions, especially over Antarctica. The Montreal Protocol , ratified in , was the first of several comprehensive international agreements enacted to halt the production and use of ozone-depleting chemicals. As a result of continued international cooperation on this issue, the ozone layer is expected to recover over time. In Dutch chemist Paul Crutzen published a paper that described the major nitrogen oxide catalytic cycle affecting ozone levels. Crutzen demonstrated that nitrogen oxides can react with free oxygen atoms , thus slowing the creation of ozone O 3 , and can also decompose ozone into nitrogen dioxide NO 2 and oxygen gas O 2. They feared that the potential emission of nitrogen oxides and water vapour from these aircraft would damage the ozone layer.
PDF | There are many situations where human activities have significant effects on the environment. the origin, causes, mechanisms and bio effects of ozone layer Department also point out that for the period to
What are the causes and effects of ozone depletion?
To understand the ozone layer , it would be helpful to know the different layers of the atmosphere. A lot of human activities such as gas balloons, mountain climbing, and small aircraft flights take place within this region. The stratosphere is the next layer above the troposphere stretching approximately 15 to 60 kilometers.
Jump to navigation. Ozone Layer Protection and You. Since about , scientists have detected a severe drop in ozone concentration in the layer over the Antarctica each spring. The situation then reached an alarming scale in when an international expedition found that half of the Antarctica's ozone have disappeared over a region twice the size of the United States, creating an enormous "hole" in the ozone layer.
Emissions were increasing rapidly until the s. Since then the world has achieved rapid progress: the near-elimination of ozone-depleting substances and the trend towards recovery of the ozone layer are arguably among the most successful international environmental collaborations to date. In this entry we present the data on ozone layer depletion, signs of recovery, emissions of ozone-depleting substances, international agreement and collaboration, and the consequences of ozone layer depletion. It is formed of three oxygen atoms giving it the chemical formula, O 3. This reactivity is significant in its interactions described in the entry below : the ozone layer can be depleted and broken down through its interaction with man-made compounds in the upper atmosphere.
Автобус тронулся, а Беккер бежал за ним в черном облаке окиси углерода. - Espera! - крикнул он ему вдогонку. Его туфли кордовской кожи стучали по асфальту, но его обычная реакция теннисиста ему изменила: он чувствовал, что теряет равновесие. Мозг как бы не поспевал за ногами. Беккер в очередной раз послал бармену проклятие за коктейль, выбивший его из колеи.
А что, подумала Сьюзан, если броситься мимо него и побежать к двери. Но осуществить это намерение ей не пришлось. Внезапно кто-то начал колотить кулаком по стеклянной стене. Оба они - Хейл и Сьюзан - даже подпрыгнули от неожиданности.
Он страстно желал разделить эту мечту со Сьюзан, осуществить ее с ней вместе, но знал, что это невозможно.