Ozone layer depletion.
By~ Tishita Chauhan
We all know that our planet Earth revolves round the sun. Our planet is very close to the sun due to which there is lot of heat on Earth and this heat is increasing day by day.
It comes as no surprise to anyone sweated through it:2023 was the hottest year in the Human history. 
As we are seeing that this year 2024 will also be very hot and it may continue to increase. Global warming is also increasing due to heat on Earth. Large glaciers are melting and the water level is rising in the oceans.
Now let’s talk about the reason for all this.
let us first know about the Earth’s atmosphere~
The cover of air around us is known as atmosphere. Atmosphere covers the earth like a blanket. Our atmosphere consists of various layers or zones above the ground. The composition of air and gases is different in each layer or zone.
These are the four layers or zones of atmosphere. 
1. Troposphere [upto 8-16 km abovethe ground]
2. Stratosphere[upto 16-50 km above the ground]
3. Mesosphere[upto 50-100 km above the ground]
4. Thermometer[upto 100-500 km above theground]
Existence of life on this planet is only possible due to the presence of atmosphere. There are many important roles played by atmosphere on Earth but we’ll discuss about the role of atmosphere in climate control.
Climate is the long term pattern of weather in a particular area. This includes rainfall, temperature, snowfall or any other weather condition. We usually define a region’s climate over a period of 30 years.
Temperature is the major factor which controls the climate on Earth. Our atmosphere maintains a life supporting range of temperature. Because air is the bad conductor of heat, atmosphere maintains an average steady temperature on the earth.
Atmosphere forms a thick layer of gases over the Earth’s surface. Gases like Carbon dioxide allow heat of sunlight to enter the Earth’s atmosphere but do not allow their escape. This effect is known as Green house effect.
Excessive rise in temperature of earth during day time and sudden fall in temperature at night is controlled by atmosphere. During day time it absorbs the heat of sun and helps in reflection of excessive heat. As a result, the average temperature of earth remains satisfactory steady during the day and night during the year.
The biggest reason for increase in temperature, melting of large glaciers and increase in water level of oceans is the thinning of ozone layer.
The Ozone layer or Ozone shield is a region of Earth’s Stratosphere.
The air contains oxygen mainly as a diatonic molecule(O2). But upper layer of atmosphere contains oxygen in the form of of triatomic molecule (O3).
Ozone is formed when harmful ultraviolet rays splits O2 molecule into O. And this free oxygen atomic highly reactive and reacts with another O2 molecule and forms an Ozone (O3) molecule.
The Ozone forms a continuous layer in the upper atmosphere. This layer absorbs harmul ultraviolet rays of sunlight and prevent them reaching the Earth’s surface.
Due to increase in air pollution, many human activities and use of certain chemicals the Ozone layer is being depleting. The pollutants released in air are one of the cause of depletion of ozone layer. Another major cause of depletion of ozone layer is Chloro-Fluoro-Carbons[CFCs]. In some parts small holes have been noted in this layer
The hole formation in ozone layer can be very dangerous for us. The Ozone hole was first discovered on May 1985 over Antarctica.
In 2024, this hole still exists. The annual Antarctic Ozone Hole reached an area of 26 Million Square km in size, roughly three times the size of Brazil.
During the period 1956-1970 spring time ozone thickness above Antarctica varied from 280 to 325 Dobson unit[1DU=1 PART PER MILLION]. The thickness was then reduces to 225 DU in 1979 and to 136 DU in 1985 and 94 DU in 1994.
CFCs are the synthetic chemicals which are used as coolants in refrigerators and air conditioners. These are also used in aerosols, in fire extinguishers, scent spray and propellers etc. When CFCs are sprayed in air they produce active Chlorine and Fluorine radicals in the ultraviolet radiations.
Through further these reactions, this convert Ozone (O3) into Oxygen(O), thereby destroying Ozone . As a result, the layer of Ozone keeps becoming thinner.
Ozone depletion is also caused due to substances such as Nitrogen Oxides, Halogens, Carbon Tetrachloride, Methyl Bromide and many Hydrocarbons. Because of the Ozone layer hole more ultraviolet radiations are able to reach the earth. These radiations cause adverse effects on human beings, plants and animals.
Some such effects are~
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Skin cancer.
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Reduced plant yield due to death of seedlings.
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Damage to immune system.
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Increased occurrence of harmful diseases i.e Herpes.
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Increased embryonic mortality rate.
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Loss of sight in human beings and in animals.
By~Tishita Chauhan
Hope you liked and understand.
Excellent
Good work👏👍
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