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Climate Change and Atmosphere Science Notes Class 10

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by

Pooja Ghimire
in

Table of contents

  1. Introduction
  2. Efforts made for reducing climate change
  3. Layers of atmosphere
  4. Ozone layer and Chlorofluorocarbons
  5. Artificial greenhouse and its advantages
  6. Greenhouse effect
  7. Adverse effect of

Introduction

Atmosphere is the layers of gases that surround the earth. Earth’s atmosphere mainly consists of Nitrogen(78%), oxygen(21%), carbon dioxide(0.03%) and other gases.

Climate change is the change in average conditions such as temperature and humidity in a particular region over a long period of time.

Efforts made for reducing climate change

Efforts made in international level

  1. United States Convention About Climate Change
  2. Agenda 21
  3. Kyoto Protocol
  4. Conference of the Concerned and the Recognized Countries about Climate Change

Efforts made in national level

  1. National Communication Report
  2. Climate Change Policy, 2067 Bs
  3. National Climate Change Adjustment Programmes
  4. Local Level Adjustment Programmes against Climate Change

Layers of Atmospheres

  1. Troposphere
  2. Stratosphere
  3. Mesosphere
  4. Thermosphere
  5. Exosphere
Troposphere(0-16km)

It is the lowermost layer. The upper boundary of troposphere is called tropopause. The temperature gradually decreases with the increase in height. Different climatic activities like rainfall, cloud formation, fog, tornado, lightening, etc. occur in this layer.

Stratosphere(16-50km)

The temperature of this boundary increases with the increase in height. This layer contains ozone. Hence, it is also called ozonosphere. The upper boundary of this layer is called stratopause.

Mesosphere(50km-80km)

The temperature of this layer decreases with increase in altitude. This is the coldest layer of the atmosphere. Most of the meteors burn up in this layer.

Thermosphere(80-700km)

Temperature of this layer increases with the increase in height. Solar radiations affect this layer directly. The solar radiations ionize the molecules present in upper layer of this layer. Therefore, it is also called ionosphere. The International Space Station orbits in thermosphere.

Mesosphere(700-10,000km)

It is the topmost layer of earth’s atmosphere . In this layer, the earth’s gravity is weak. Therefore, only few atoms and molecules of gases are present.

Ozone layer and Chlorofluorocarbons

Ozone is a pale blue gas made up of three atoms of oxygen. The atmospheric oxygen dissociates into nascent oxygen when exposed to u-v rays. This nascent oxygen combines with other oxygen molecule to form ozone molecule.

Importance of ozone layer

The ozone layer absorbs about 99% of u-v rays and protects the terrestrial and aquatic ecosystems on the earth. It also helps to maintain temperature on the earth.

Ozone layer depletion

Ozone layer depletion is the thinning of ozone layer. The chlorine and bromine atoms destroy ozone molecules when they come in contact with ozone layer.

Chlorofluorocarbons(CFCs): CFCs are stable, non-poisonous, non-flammable cheap gas which contains atoms of hydrogen, carbon, chlorine and fluorine. They are used as, refrigerant cooling agent or solvent.

The major cause of ozone layer depletion is the release of CFCs in atmosphere. The chlorine molecules react with ozone molecules and convert them into oxygen.

Ozone Depletion by CFCs

$\text{CFCl}_3 \rightarrow \text{CFCl}_2 + \text{Cl}$

$\text{CFCl}_2 \displaylines{ _{\text{UV}} \\ \rightarrow} \text{CFCl} + \text{Cl}$

$\text{Cl} + \text{O}_3 \rightarrow \text{ClO} + \text{O}_2$

$\text{ClO} + \text{O}_3 \rightarrow \text{Cl} + 2\text{O}_2$

Effects of ozone layer depletion

  1. Can cause different diseases like eye cataract, loss of immunity, skin cancer, etc. in humans.
  2. Affects the DNA of human body.
  3. Reduces the rate of photosynthesis and crop production in plants.
  4. Hampers the development of aquatic and terrestrial organisms.
  5. Increases global warming

Greenhouse

Greenhouse is an artificial house which consists of plastics or glass roofs and walls.

When the short wave solar radiations enter a greenhouse and strike on the earth’s surface, they change into long wave radiations. The long wave radiations cannot escape through the walls and roofs of greenhouse. As a result, heat gets trapped and the temperature inside the greenhouse increases.

Advantages of Artificial Greenhouse

  1. Helps to grow summer plant in winter season.
  2. Desert plants can be grown in Himalayan region.
  3. Helps to grow exotic plants.

Greenhouse effect

Greenhouse effect is the increase in earth’s temperature due to the trapping of solar heat by the atmosphere. The gases like carbon dioxide, carbon monoxide, methane, water vapour, etc. cause the greenhouse effect. Therefore, such gases are called greenhouse gases.

Advantages of greenhouse effect

  1. Warm temperature is maintained on the earth’s surface due to the greenhouse effect which makes the life possible on the earth.
  2. Nights are not to cold due to greenhouse effect.
Disadvantages of greenhouse effect
  1. Causes global warming.
  2. Changes the pattern of rainfall and weather condition.
  3. Causes melting of ice of polar region which increases the sea level. The increased sea level causes the sinking of many islands.
  4. Affects water cycle, soil moisture, etc. As a result, there occurs change in cultivation and harvesting of crops.
Ways of controlling green house gases
  • Expand the use of renewable source of energy.
  • Reduce the use of fossil fuels.
  • Minimize tropical deforestation.
  • Decrease the use of appliances that cause the production of CFCs and oxides of nitrgen.
  • Build a clean energy economy by investing in efficient energy technologies and industries.

Industrial gases

The use of fuels in the industries results in the production of various gases like carbon dioxide(CO2), sulphur dioxide(SO2), Carbon Monoxide(CO). Such gases are industrial gases. As a result of such gases, air gets polluted. Polluted air affects human health. And also causes negative effects on animal and plant life.

Effects of industrial gases
  1. Acid rain occurs.
  2. Dust, smoke, lead, etc. affect the muscular functioning of human being. They cause blood deficiency and also affect mental functioning.
  3. May cause ozone layer depletion.
  4. Cause global warming.
Acid rain

Acid rain means the falling of acids along with rain during rainfall. When industrial gases like carbon dioxide, carbon monoxide, nitric oxide, etc. react with the water in the atmosphere, they form different acids. Such acids get mixed with the rain and fall in the form of rain.

Effects of acid rain
  • Corrodes historical monuments like statue, sclupture, etc.
  • Increases acidity of soil and affects the production of crops.