SEBA CLASS 10 GEOGRAPHY SOLUTION CHAPTER-2 : ENVIRONMENT AND ENVIRONMENTAL PROBLEMS

 

SEBA CLASS 10 GEOGRAPHY SOLUTION

CHAPTER-2 : ENVIRONMENT AND ENVIRONMENTAL PROBLEMS

 

SUMMARY OF CLASS 10 GEOGRAPHY CHAPTER 2

1. Environment: The environment is the surrounding condition which is rich in organic and inorganic elements necessary for the survival of human, animals and other creatures. Geographically, the composition of the lithosphere (the earth's surface), hydrosphere (water), atmosphere, and biosphere is called the environment.

2. The four main zones/spheres of the environment:

a) Lithosphere or Landmass: A total of 29 percent of the earth is composed of soil, sand, rocks, etc., which is surrounded by mountains, rivers, valleys, plains, plateaus, deserts, etc.

b) Hydrosphere or Water mass: 71 per cent of the world is covered by canals, rivers, estuaries, seas and oceans which is covered by water.

c) Atmosphere: This atmosphere is a mixture of nitrogen, oxygen, carbon dioxide, hydrogen, argon etc. gases, fumes and dust extending up to an altitude of about 480 km from the surface.

d) Biosphere: The surface areas of the earth inhabited by about 1.75 million plants and animals.

3. The eminent geographer Peter Haggett defined the result of the interrelationship and interaction between water, land, air and living things as environment.

4. Environment is dynamic:

 The environment changes and varies from place to place and from time to time.

a) A region depends on where it is located on the surface of the earth. Due to this geographical location, in the river valley environment we are unable to find a desert.

b) The environment varies depending on how far north and south a region is from the equator.

c) The environment of 100 years ago is transformed into a new environment today due to the flow of time.

d) The environment has changed drastically through population growth, industrialization, urbanization, development of transportation, development of technology, etc.

e) People have made huge changes in the environment to meet the needs and aspirations of daily life.

f) As a result of various interactions in a natural way, the environment also changes through external and internal factors of the earth.

g) The environment of a small part of a region within a large environment may be different and may affect one another. Such as a village located adjoining the city.

5. Environmental problems:

If there is no balance between natural and man-made elements in the lithosphere, hydrosphere, atmosphere and biosphere, various environmental problems will arise such as floods, pollution, desertification, global warming, etc. In addition to natural problems such as earthquakes, volcanic eruptions, storms, etc., man is creating one of the most mountainous environmental problems by knowingly and unknowingly destroying his precious environment. The recent increase in the use of fossil fuels in industries, vehicles, etc., has led to an increase in the amount of carbon dioxide gas in the atmosphere, which is a major factor in increasing global warming. Problems such as deforestation, land degradation, desertification, landslide, artificial flooding, rising river-sea level etc. have been created.

6. Types of environmental problems:

a) Local problems: - Problems limited to a small area such as landslides, water and land pollution by factories, etc.

b) Regional Problems': - Problems arising across a geographical area such as floods in Brahmaputra and Barak, erosion problems in river basins etc.

c) Spherical Problems: - Those problems have no geographical boundaries related to the globe related to the whole world such as- increase in spherical heat or global warming, shrinkage of ice region, depletion of ozone layer etc.

7. The main problems of the environment are: -

a) Pollution         b) Desertification         c) Landslides       d) Land erosion   e) Increased spherical heat or global warming  f) Artificial flooding      g) Rise of river-sea level etc.

8. Pollution: - The process when harmful substances destroy the environment is called pollution.

9. Pollutants: - Man-made products or materials that can harm organisms and the world if added to the environment are called pollutants, for example dust, smoke, ash, odors, lead, sulfur dioxide, carbon monoxide, polythene, plastics Content etc.

10. Types of pollution:

a) Soil pollution: Soil pollution is the loss of normal quality and fertility of the soil by mixing any chemical, toxic metals, industrial wastes, radioactive substances, acids etc. with the soil. It is noteworthy that soil pollution is mainly responsible for agriculture, expansion of factories and increasing deforestation.

b) Air Pollution: - A certain component of the atmosphere maintains the balance of the atmosphere. If the substances added to the atmosphere due to natural and man-made causes do great harm to living and inanimate things, then that air is called polluted air. Large-scale organized fires also pollute the air by emitting smoke, ash, and gas emitted during volcanic eruptions. Man-made factors include air pollution due to the expansion of factories, increased use of vehicles, excessive use of fossil fuels, nuclear explosions, etc.

c) Water pollution: Water pollution is the change in the natural quality of water by mixing chemicals, microorganisms and different types of dirt. When wastewater and wastewater from homes, cities and towns, factories, agriculture, etc. are mixed with the pure water of rivers, lakes, seas and oceans, all the water becomes unusable.

d) Desertification: - Desertification is a process which means turning the productive lands of the earth into deserts i.e. expanding the deserts to the surrounding areas of the deserts.

Desertification was defined at a United Nations conference in Nairobi, 1977, Africa, in this way: "Desertification is a process that destroys the biological potential of a land and eventually creates a desert-like condition." Drought, global warming, etc. cause desertification for natural factors. Notable among the man-made factors are deforestation, expansion of habitat and agriculture, overgrazing. Today the desert rates on the continents are in order - North America = 27%, South America = 22%, Asia = 20%, Africa = 18% and Australia = 8%

e) Increased global heat or global warming: The earth's surface and atmosphere balance the heat extracted from the sun. But some of the greenhouse gases available in the atmosphere, such as carbon dioxide, methane, nitrous oxide, water vapor, etc., vary in temperature. This is because these gases have the ability to absorb heat. But every day when these gases emitted from mills, industries, vehicles, etc. are mixed in the atmosphere, its range increases and the heat also increases. This increase in surface and atmospheric heat is called global warming.

11. Consequences of air pollution:

Increasing use of fossil fuels has resulted in increased levels of carbon monoxide, nitrogen dioxide, sulfur dioxide, hydrocarbons, and other toxic gases in the atmosphere, resulting in acid rain in Western Europe, the United States, and Canada. This rain destroys forests and also pollutes the water of canals, beels and rivers, endangering the lives of human beings.

12. Acid precipitation or Acid Rain:

When excessive amounts of sulfur dioxide and nitrogen dioxide are stored in the atmosphere, acid rain can occur and extinction of aquatic plants and animals can be seen.

13. Types of deserts: There are two types of deserts

a) Tropical Desert: A tropical, arid and rainless desert located in the tropics, such as the Thor Desert of India.

b) Cold Desert: Cold desert with icy, high water vapor located in the polar region.

14. Consequences of desertification: Today, about 35% of the land area is deserted. About 100 countries of the world are affected by drought due to lack of rainfall. Desertification can disrupt the way of life.

15. Absorption of heat in the atmosphere:

Out of the total heat of solar energy-

a) Reflected back to Floating clouds and surface = 30%

b) Absorption by Atmosphere = 19% and

c) Evaporation released by earth to atmosphere as latent heat = 51%

In this way it maintains the balance of atmosphere and surface heat.

16. Greenhouse Gas:

Carbon dioxide, methane, nitrous oxide, water vapor, etc. help in controlling the heat of the atmosphere by absorbing the solar energy reflected from the earth. That is why these gases are called greenhouse gases. The amount of greenhouse gases in the atmosphere is only 0.1%. As these gases increase, so does the heat. In the last 150 years alone the amount of carbon-di-oxide has increased by 30%, with the temperature rising by 0.76 degrees Celsius.

17. Result of global warming:

Global warming is due to an increase in the amount of greenhouse gases. Problems caused by global warming include melting of polar ice caps, rising sea levels, declining plant-crop production, desertification, changes in the natural environment, and degradation. If the temperature of the atmosphere increases by 2-3 degrees Celsius, the ice of the South Pole will melt and the sea surface will rise above one meter. In such a situation about 5 million square kilometers of coast will be submerged, many islands, delta islands, coral islands will be submerged under water.

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TEXTUAL QUESTIONS AND ANSWERS

EXERCISES FROM THE TEXTBOOK

1. Write in your own words the meaning of the environment. 

Ans. The term ‘environment’ means the conditions existing around an organism which include biotic elements such as microbes, plants, animals and large mammals, and abiotic elements such as land, water, air and all other lifeless elements which through their interaction create the necessary conditions for life. From a geographical point of view, the environment refers to the four spheres of the earth. i.e. lithosphere, hydrosphere, atmosphere and biosphere. The conditions created by the interaction of these four spheres is called an environment. According to the geographer Peter Haggett, “environment is the outcome of interaction among land, water, air and life”

OR

Ans: The condition created by the interaction among the four spheres, ie lithosphere, hydrosphere , atmosphere and biosphere may broadly be called environment. It denotes the condition around an organism or a community of organism and such a condition includes all the necessary elements for survival. These elements are both biotic and abiotic. These biotic and abiotic elements through their interaction create necessary condition or environment for life.

2. Mention some of the biotic and abiotic elements of the environment. 

Ans. The elements of environment are:

(i) Biotic elements: All plants and animals ranging from microbes to large mammals. 

(ii) Abiotic elements : Land, water, air and all lifeless elements.

3.Write the meaning of lithosphere. 

Ans. Lithosphere means the land surface of the earth which consists of rocks, soils, minerals, etc. It covers mountains, hills, plateaus, plains, valleys and coasts over the continents. Hydrosphere, atmosphere and biosphere individually and collectively determine the characteristics of the lithosphere and how it changes in the course of time.

OR

Ans: The Land component of the earth composed of rocks , soils, minerals etc forms the Lithosphere. The lithosphere covers all the contents where we find the mountains chills, plateaus, plains, valleys and coasts. The characteristics of the lithosphere and its change in courses of time depends on the other three components of the earth's environmental system, i.e hydrosphere, atmosphere and bio sphere. 

4. What are the features included in the hydrosphere?

Ans. Hydrosphere refers to the water bodies of the earth which include the following features: seas, oceans, rivers,  lakes, wells, etc.

OR

Ans: The features included in the hydrosphere are rivers, lakes and other water bodies distributed in the continents. The status and change in the hydrosphere depend on the states of the lithosphere, atmosphere and biosphere.

5. Write about the composition of the atmosphere. 

Ans. The gaseous layer which surrounds the earth up to a height of 480 is known as atmosphere. It mainly consists of 78.08% nitrogen, 20.94% oxygen, 0.035% carbon kms from the earth’s surface dioxide, 0.93% argon, and other gases like hydrogen etc. 

OR

Ans: The atmosphere is composed with two elements i.e permanent card temporary elements, Oxygen, Nitrogen , Hydrogen , Carbon- dioxide, Argon etc gases are permanent elements while water vapour smoke, dust particles are temporary elements. 

6. Give an outline of the extent of the biosphere.

Ans. Biosphere covers those parts of the earth’s environment where life forms exist, i.e. lithosphere, atmosphere and hydrosphere. This area includes the earth’s surface, down to a few meters from the earth’s surface, the lower stratum of the atmosphere and most parts of the seas and oceans.

OR

Ans:  The biosphere covers those parts of the earth's environment with life forms occur. These include the earth's surface, down to a few meters from the earth's surface, the seas and oceans and the lowest stratum of the atmosphere where birds and insects fly.

7. Discuss briefly the relation among the four major components of the environment. 

Ans. Environment consists of four components namely lithosphere, atmosphere, hydrosphere and biosphere. There is close interdependence and interaction among these four components of the environment. In fact, they are interdependent on each other for their nature and existence. Different cycles of nature such as hydrological cycle, carbon cycle, nitrogen cycle, energy cycle, etc. pass through all the four components. There is a close complex network of relationships among the various elements of these components.

Any change that occurs in any one of the major components affects the other three components of the environment. When the atmosphere is affected by over radiation from the sun, it in turn affects the hydrosphere, lithosphere and biosphere. It leads to the melting of snow which in turn causes a rise in the sea level bringing a lot of changes in the coastal regions of the earth’s surface. As a result, many regions of the lithosphere get submerged. Many of the microorganisms, flora and fauna that live on the lithosphere, hydrosphere and biosphere perish as a result of this overheating of the atmosphere. Cutting down of trees of the lithosphere leads to overabundance of greenhouse gases in the atmosphere leading to global warming which affects not only living organisms on the earth but also those of the oceans. Thus, it is evident that all the four components of the environment are closely connected and interdependent.

OR

Ans:  The four major components are- Lithosphere, Hydrosphere,  Atmosphere and Biosphere.

          These four spheres are interconnected. The condition created by the interaction among the four sphere may be called the environment. The lithosphere comprises the elements of rocks, soils, minerals etc. While hydrosphere contains the whole water body of the world. The atmosphere composes of various important gases. All these elements of these three spheres make the characters of biosphere. That means the biosphere those parts of the earth's environment where life form occur.

          The  innumerable elements of four squares through a complicated network of relationships have determined the earth's present environment. The environment is changing both in terms of space and time. Each of the geographical regions of the world has its own characteristics, although they are interrelated. There are regional variations with respect to land, water, climate, natural vegetation and wildlife.

8. Mention the major causes of environmental change. 

Ans. Today the environment is changing both in terms of space and time. The major causes of environmental change are the various anti-nature human activities such as urbanisation, industrialisation, expansion of transport and communication, shrinking of forest cover and wetlands, etc. These activities have profoundly affected all the four spheres. The spread of population and human activities to the mountainous and desert areas are causing rapid environmental changes there. Thus, we can say that the primary cause for environmental change is human activities. Briefly, the major causes of environmental change are:

(i) Increase in population. 

(ii) Industrialisation and urbanisation.

(iii) Increase of carbon-dioxide in the atmosphere.

(iv) Deforestation and decrease in wetlands.

(v) Expansion of human activities in the mountainous and desert areas.

OR

Ans:  The major causes of the environmental change are overdoing human activities like human settlement, expansion of agricultural land, growth of industries and urban centres.

Expansion of transport and communication have together disturb the interrelationship among the environmental elements. This has created severe problems in the environmental system.

9. Explain the meaning of environmental problems. 

Ans. For a long time, there existed no environmental problems. This was because there existed a proper balance among the natural and man-made elements. But as a result of the rapid growth of human population, spread of urbanization, industrialization, deforestation, extensive use of fossil fuels, shrinking of wetlands, etc., ecological equilibrium that existed among the four spheres of the earth got disturbed. This caused the emergence of many problems such as pollution, desertification, global warming, melting of snow, rise of sea level, etc. Since all these problems are linked to the environment, they are called environmental problems.

OR

Ans:  The environment means the combination of four spheres like lithosphere, hydrosphere, atmosphere and biosphere. The elements of all these four spheres are the key factors of the constitution of environment. No environmental problem occurs if the quality of the environmental elements and the natural relationship among them remain normal. But at present environment faces various problems due to overgrowing human activities. Factors like spread of human settlement, expansion of agricultural land, growth of industries, expansion of transport and communication have together disturb the interrelationship among the environment elements. This has created the severe problem in the environmental system. The major environmental problems created by these activities are pollution, desertification, global warming etc.

10. Write geographical divisions of the environmental problems.

Ans. The geographical divisions of the environmental problems are:

(I) Local problem: An environmental problem which affects only a particular place or a. small area so far as their genesis and spread are concerned is called a local environmental

problem. e.g. land pollution created by a small-scale industry, water scarcity in winter due to swallowing of wetlands, bank erosion caused by a local river, etc. 

(ii)Regional problem: Regional problem exists in a large region or in one or more nations e.g. flood problem in the state of Assam as a result of the over flooding of the Brahmaputras or the Barak rivers, water pollution in a vast industrials, scarcity of underground water in a city, soil erosion in a river basin, etc.

(iii) Global problem: The environmental issues that affect the entire world are termed as global problems. These problems need international efforts for solution and management. eg. global warming which affects the atmosphere and thus has no geographical boundary.

OR

Ans:  Environmental problems can be geographically divided into three different areas - Local problems, Regional problems and Global problems.

The local problems may remain confined to small areas. The example of such problem may be the land pollution created by a small scale industry. There are some problems that may occur on a regional basis. The flood problems of the Brahmaputra river, water pollution in a vast industrial region, etc. So there are some another environmental problems that may cover the entire world. Such problems do not have any two graphical area, for example global warming.

11. What is a local environmental problem? Give examples. 

Ans. (I) Local problem: An environmental problem which affects only a particular place or a. small area so far as their genesis and spread are concerned is called a local environmental problem. e.g. land pollution created by a small-scale industry, water scarcity in winter due to swallowing of wetlands, bank erosion caused by a local river, etc. 

OR

Ans:  At the time passed, the environmental problems are spreading everywhere in the world. Now these problems can be divided into locally, regionally and globally. The local environmental problems may remain confined to a small area. So far as their genesis and spread are concerned, the instances of such problems may be the land pollution created by the small scale industry, water scarcity in winter due to swallowing of wetland, bank erosion problem created by a river, water pollution, land pollution created by a brick industry ,etc.

12. Give two examples of regional environmental problems.

Ans. (ii)Regional problem: Regional problem exists in a large region or in one or more nations e.g. flood problem in the state of Assam as a result of the over flooding of the Brahmaputras or the Barak rivers, water pollution in a vast industrials, scarcity of underground water in a city, soil erosion in a river basin, etc. 

OR

Ans:  The two examples of regional environmental problems are the flood problem of the river Brahmaputra valley and the water pollution in a vast industrial region.

13. Which problems are considered as global environmental problems?

Ans. (iii) Global problem: The environmental issues that affect the entire world are termed as global problems. These problems need international efforts for solution and management. eg. global warming which affects the atmosphere and thus has no geographical boundary

OR

Ans:  Global warming, desertification, rise of sea levels, etc. are considered as global environmental problems.

14. Mention the major environmental problems of the world. 

Ans. The major environmental problems of the world are: 

(i) Land, air, and water pollution

(ii)Desertification

(iii) Landslide and soil erosion

(iv) Global warming 

(v) Artificial floods

(vi) Increase in sea level, etc.

OR

Ans:  The major environmental problems of the world are pollution, desertification, landslide, soil erosion, artificial flood, rise of sea level and global warming. The impact of these problems felt in the lithosphere, hydrosphere, biosphere and atmosphere.

15. Give the meaning of the term pollution.

Ans. The process of contamination of the environment by harmful substances is called pollution. It is caused by adding or dumping of pollutants into the environment. Zinc, sulphur dioxide, carbon monoxide, etc. are some major pollutants of the environment and air and water pollution causes harm to human beings and all life forms.

OR

Ans:  The process of contamination of the environment by harmful substances is simply called pollution. Many of the man made substances, if added largely to the environment, it may harm to the biotic world. Such substances are generally called pollutants. The major elements of environment - land, water and air being polluted for various reasons may cause harm to human beings and other life forms.  

16. What is water pollution? How does it occur?

Ans. The process by which the natural state or quality of water gets changed on addition or passing through of harmful items such as chemical substances, particles, radiation, microbes, etc. is known as water pollution. It occurs when there are human settlements, industries, agricultural fields, etc, near the water sources, from where wastes get mixed with the water, making it polluted.

OR

Ans:  The normal state or quality of water gets changed when certain chemical substances, particles, microbes, radiation are added to or passed through it. The process of such change in water is called water pollution.

          Generally, the industrial and urban wastes pollute the water of the river flowing through or by the side of the town. The sulphur dioxide and nitrogen oxide present in the atmosphere may cause down in the form of acid rain and pollute the water bodies. The application of the chemical fertilizer, insecticides, pesticides, etc. in the agricultural field disrupts the normal condition of the water covered with that land and cause water pollution.

17. Write a short note on land pollution.

Ans. Today land pollution has reached an alarming rate in most countries of the world. Land is being polluted mainly due to human activities. Land loses its natural quality and fertility when it comes into contact with certain chemical substances, poisonous metals, industrial wastes, radioactive wastes, urban wastes, etc. Agricultural pesticides, land filling and increasing scale of deforestation, application of chemical fertilisers, irrigation, insecticides, etc. for higher agricultural production also pollute land. For all these reasons, land pollution in most countries has become a major problem today and a lot of measures are being undertaken to rectify the problems. Use of underground water in the fields degrades the natural soil quality. Application of insecticides and weedicides in the fields destroys useful life forms with the harmful ones and hence polluting the land by changing its natural properties. Industrialization and Industrial wastes mix with the soil to pollute it, and improper mining of coal and petroleum also pollutes the land.

OR

Ans:  The normal composition or quality of land gets disrupted due to mixing of some harmful, unnecessary substances and form a new process is called land pollution. It is occurred when it comes into contact with certain chemicals, poisonous metals, industrial wastes, radioactive substances, acid rain, chemical fertilizer, pesticides used in the agricultural land and so on. Due to land pollution, land looses its natural properties and fertility, this causes the decrease of crop productivity capacity.

18. Write how air is polluted.

Ans. Air pollution has become one of the serious environmental problems of today. Atmosphere mostly consists of gases such as nitrogen (78.08%), oxygen (20.94%), argon (0.93%) and carbon dioxide (0.035 %). By maintaining a definite proportion, these gases keep the atmospheric temperature in balance. When any of these gases increases substantially, or if other solid, liquid or gaseous substances are added to the atmosphere, it disturbs the atmospheric balance which results in air pollution. Such pollution cause harm to biotic and abiotic elements.

Air pollution is caused by:

(I) Natural factors:

(a) Volcanic eruption: Air is polluted by the smoke, ashes and gases that come out in a volcanic eruption. e.g. 15-20 million tones of sulphur dioxide (SO) was emitted in the eruption of Mount Pinatubo in the Philippines.

(b) Forest fire: In many parts of the earth, forest fires contribute largely to polluting the air.

(II)Human factors:

(a) Industrialization and urbanization.

(b) Increase in vehicular traffic and natural explosions.

(c) Increased use of fossil fuels.

All these human activities have led to the addition of harmful gases like carbon monoxide, nitrous oxide, hydrocarbons, sulphur dioxide, etc. to the air, leading to its pollution. 

OR

Ans:  The accurate proportion of Nitrogen, Oxygen, Carbon dioxide, Argon gases, etc. keep the atmosphere in a balance in somewhat disturbed, the normal state of the atmosphere may be changed, if certain solid, liquid or gaseous substances are added to the atmosphere by some natural or human processes. If such a change causes some harm to the biotic and abiotic elements, then the atmosphere is said to be polluted.

19. What is a desert? Give the definition of desertification. 

Ans. The parts of the earth where evaporation is high and rainfall is scarce, making it difficult for plants, animals and human beings to survive are known as deserts. They cover around 20% of the world’s land surface.

Desertification is defined as the process of the spread of desert conditions to the peripheral areas. Currently about 35% of the world’s land surface is affected by the process of desertification. According to a meeting held in Nairobi in 1977 by the United Nations, desertification is “the dimunition or destruction of the biological potential of the land leading ultimately to desert-like conditions. “

OR

Ans:  A vast landmass where rainfall is scarce but evaporation is more, the entire environment is dry, natural vegetation is also found scarce. Such type of characteristics occurring landmass is called desert.

Desertification is such a process which renders the productive areas of a tropical region a desert like situation. The term desertification however denotes the spread of the desert to this peripheral area.

20. Mention the causes of desertification.

Ans. The causes of desertification are:

(1) Natural factors:

(a) Drought: It affects productivity of land and growth of natural vegetation, 

(b) Global warming: Increase in temperature due to global warming makes the thereby leading to desertification. desert environment more dry, accelerating desertification. 

(ii) Human factors: 

(a) Human activities: It includes overgrazing, expansion of agriculture deforestation. and

(b) Population growth: Growth in population has increased pressure in the desert and semi-desert areas which creates expansion of deserts.

OR

Ans:  Desertification is caused due to a number of natural and human factors. Among the natural factors drought and global warming are found significant. Among the human factors overgrazing expansion of agriculture and deforestation are important.

21. Is it possible to control desertification?

Ans. Yes, though a challenging task, it is possible to control desertification through measures like deforestation, rainwater harvesting, prevention of soil erosion, construction of artificial irrigation systems, extension of canal systems into semi-arid regions, etc. Since it is not one nation’s problem, it must be tackled on a global basis. As desertification is associated with global warming. measures to reduce global warming will definitely lead to a decrease in the process of desertification.

OR

Ans:  As desertification is linked with the global warming and global warming linked with the air pollution. So the solution of the problems of desertification is now a challenging task for the people of the world. Without international cooperation it will not be possible to resolve this issue. The problem will be more intensive if human activities are directed against nature.

22. What is global warming? Mention its causes.

Ans. Global warming has become the most important environmental problem of our world today. The increase of temperature over the earth’s surface as a result of the emission of greenhouse gases into the atmosphere is known as global warming. The main cause of global warming is emission of greenhouse gases.

Gases that can trap the energy reflected back by the earth’s surface, viz. carbon dioxide (CO₂). methane (CH), nitrous oxide (NO), water vapour, etc. increase the atmospheric temperature.

These gases are called greenhouse gases and constitute about 0.1% of the total volume of atmospheric gases. Variation in composition of such gases has increased the atmosphere’s temperature leading to global warming

Among all the greenhouse gases, the role of carbon dioxide gas has been most significant, as it alone has increased by 30% in the atmosphere in the last 150 years. After the industrial revolution, use of fossil fuels and deforestation greatly increased. This has led to a rise in carbon dioxide gas in the atmosphere and hence a rise in the atmospheric temperature. Volcanic eruptions have increased the composition of greenhouse gases in the atmosphere, increase in the proportion of chlorofluorocarbons (CFC) has also increased in the atmosphere all contributing to global.

OR

Ans:  The gases like carbon dioxide, methane, nitrous oxide, water vapour help in increasing the temperature in the atmosphere. The gases normally help in maintaining a balance in the temperature on the earth surface and in the atmosphere. But somehow, the volume of these gases increased which causes the increase of temperature in the atmosphere. This is called global warming. The role of carbon dioxide among all greenhouse gases in global warming is the most significant. We all know that the use of fossil fuels started increasing gradually after the industrial revolution and just to meet the demands of certain industries cutting of trees also increased. As a result, the proportion of carbon dioxide gas in the atmosphere started rising. In addition to human activities, volcanic eruption also caused increase of greenhouse gases in the atmosphere. Moreover there has also been increase in the proportion of gases like methane, nitrous oxide, chlorofluorocarbons(CFCs), etc. All these gases have caused increase in the atmospheric and earth's surface temperature by trapping more and more solar energy.

23. What are the probable consequences of global warming?

Ans  The consequences of global warming are:

(i) Increase in a atmospheric temperature: From the pre-industrial revolution era, surface temperature has increased by 0.76°C and has been estimated to increase average by 5.8°C in the future. 

(ii) Melting of snow in the polar areas: Increase in temperature by 2-3°C will cause

melting of snow in the north and south polar areas. 

(iii) Rise of sea level: Melting of snowcaps will lead to rise in sea level. Rise in sea level by one meter will submerge 5 million sq. km. of coastal areas, many deltas and coral islands.

(iv)Change in growth and distribution of plants and animals.

(iv)Decrease in crop output.

(vi) Expansion of desertification.

OR

Ans:  The global warming is the most burning matter in relation to the environment. The probable consequences of global warming are- 

(a) Melting of glaciers that led to the rising of the level of sea water.

(b) Coastal areas will be submerged due to the rising of the water level from sea.

(c) Deforestation, desertification, etc are also another consequences of global warming.

24. Write how to control global warming.

Following measures should be taken to control global warming:

(i) Avoid cutting down trees unless urgently required.

(ii)Controlling the high population growth rate. 

(iii)Reducing the use of gadgets that release chlorofluorocarbons

(iv) Reducing the use of fossil fuels such as mineral oil, natural gas, etc.

(v)Increased use of non-conventional sources of energy such as solar, wind, biomass energy, etc. 

OR

Ans:  There are many ways to control global warming. Some of them are -

(a) Reduce, Reuse and Recycle:

We should reduce our need to buy new products or use less, resulting in a smaller amount of waste. Reusing bottles, plastic containers, etc are worth mention in this regard. Recycling things are also a method to reduce waste.

(b) Go solar:

Many people have got the energy efficient band wagon of solar energy. Having solar panels installed store a valuable amount of solar energy which we can use to lit bulbs etc.

(c) Planting:

Planting trees can help much in reducing global warming than any other method. Not only give oxygen but also take in carbon dioxide which is the main cause of global warming.

25. Is there any environmental problem in your own locality? If yes, then explain their causes and indicate some measures for their solution.

[Ans. Do yourself.]

MCQ ON ENVIRONMENT AND ENVIRONMENTAL PROBLEMS

1. The land component of the earth composed of rocks, soils, minerals etc. forms the –

(a) hydrosphere (b) atmosphere (c) biosphere (d) Lithosphere

Ans:- (d) Lithosphere

2. The hydrosphere covers about _____ of the earth’s surface.

(a) 61% (b) 71% (c) 81% (d) 87%

Ans:- (b) 71%

3. The gas which has made the highest contribution to Global Warming is ____

(a) Methane (b) Chlorofluorocarbon (c) Nitrous Oxide (d) Carbon Dioxide

Ans:- (d) Carbon Dioxide

4. The increase of global warming is a-

(a) Local problem (b) Regional problem (c) International problem (d) Personal problem.

Ans:-(c) International problem

5. At present around —– of the land surface is affected by desertification.

(a) 25% (b) 28% (c) 35% (d) 40 %

Ans:-(c) 35%

6. Acid rain is caused by —

(a) Carbon monoxide (Co) and Carbon dioxide (CO₂)

(b) Sulphur dioxide (SO₂) and Carbon dioxide (CO₂)

(c) Sulphur dioxide (SO₂) and Nitrogen dioxide (NO₂)

(d) Nitrogen dioxide (NO₂) only.

Ans:-(c) Sulphur dioxide (SO₂) and Nitrogen dioxide (NO₂)

EXTRA QUESTION & ANSWER

1. What are biotic elements?

Ans:-The biotic elements include all sorts of plants and animals ranging from microbes to large mammals.

2. What are abiotic elements?

Ans:-The abiotic elements are land, water, air, and all other lifeless elements.

3. Name the famous geographer who said, “the environment is the outcome of the interaction among land, water, air, and life.”

Ans:-Peter Haggett.

4. What has formed the earth’s hydrosphere?

Ans:-The seas and oceans have formed the earth’s hydrosphere.

5. How much area of the earth’s surface is covered by hydrosphere?

Ans:-The hydrosphere covers about 71% of the earth’s surface.

6. What is the height that the atmosphere extends from the surface of the earth?

Ans:-The atmosphere extends to a height of about 480 km from the surface of the earth.

7. What part of the earth’s environment does the biosphere cover?

Ans:-the biosphere covers those parts of the earth’s environments where life forms occur.

8. What is the Carbon-dioxide (CO₂) content in the atmosphere in normal condition?

Ans:-In normal condition the CO₂ content in the atmosphere is 0.035%.

9. Name some environmental pollutants.

Ans:-Zinc, sulphur dioxide, carbon monoxide etc. are some of the environmental pollutants.

10. What is the Nitrogen content in the atmosphere?

Ans:-78.08%

11. What is the Oxygen content in the atmosphere?

Ans:-20.94%

12. what is the Argon content in the atmosphere?

Ans:-0.93%

13. When was the atmosphere started getting polluted in Europe?

Ans:- The atmosphere started getting polluted after the beginning of the industrial revolution in Europe.

14. How much of the world’s land surface do deserts cover?

Ans:-20% of the world’s land surface are covered by deserts.

15. Where is the Sahara desert?

Ans:-The Sahara desert is on the continent of Africa.

16. What percent of the world’s land surface is affected by the process of desertification?

Ans:-35% of the world’s land surface is affected by the process of desertification.

17. Name the continent where the proportion of area severely affected by desertification is very high.

Ans:-The continent where the proportion of area severely affected by desertification is very high in North America.

18. How much solar energy does the atmosphere absorb?

Ans:-19%

19. What are CFCs?

Ans:-CFCs are the proportion of gases like Methane, Nitrous oxide, chlorofluorocarbons which have caused increase in the atmospheric and earth’s surface temperature by trapping more and more solar energy.

20. What is the environment?

Ans:-Environment is everything that is around us. It can be living or non-living things. It includes physical, chemical and other natural forces.

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