NCERT Class 11 Geography Chapter 12 World Climate and Climate Change

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NCERT Class 11 Geography Chapter 12 World Climate and Climate Change

Also, you can read the NCERT book online in these sections Solutions by Expert Teachers as per Central Board of Secondary Education (CBSE) Book guidelines. CBSE Class 11 Geography Solutions are part of All Subject Solutions. Here we have given NCERT Class 11 Geography Part I: Fundamentals of Physical Geography, Part II: Indian: Physical Environment, Part III: Practical Work in Geography. NCERT Class 11 Geography Chapter 12 World Climate and Climate Change Notes, NCERT Class 11 Geography Textbook Solutions for All Chapters, You can practice these here.

World Climate and Climate Change

Chapter: 12

GEOGRAPY [ PART – I ]

SHORT ANSWER TYPE QUESTIONS

Q.1. What is a climatic region?

Ans. A climatic region is defined as an area on the earth’s surface where an approximately homogenous set of climate condition is produced by combined effect of climatic controls.

Q.2. Into how many regions was the earth divided by the ancient Greeks?

Ans. The ancient Greeks divided the earth into three regions:

(i) Winterless tropical regions.

(ii) The summerless polar regions.

(iii) Intermediate regions having both winter and summer.

Q.3. What criteria was followed by Koeppen to classify climates?

Ans. Koeppen’s classification is strictly empirical as it is neither based on weather process nor does it emphasise causes of formation of climatic types. The classification is based upon annual and monthly means of temperature and precipitation.

Q.4. What is Kyoto Protocol?

Ans. International efforts have been initiated for reducing the emission of GHGs into the atmosphere. Kyoto Protocol is the most important and was proclaimed in 1997. This protocol went into effect in 2005 ratified by 141 nations. Kyoto protocol bounds the 35 industrialised countries to reduce their emissions by the year 2012 to 5 percent less than the levels prevalent in the year 1990.

Q.5. Name the important elements of climate.

Ans. (i) Temperature. and

(ii) Precipitation.

Q.6. Which type of climate is known for the minimum range of annual temperature?

Ans. Equatorial climate.

Q.7. By whom was the first attempt to classify the climate begin?

Ans. By the ancient Greeks.

Q.8. Give the classification of climate according to ancient Greeks.

Ans. They divided earth into.

(i) Torrid zone.

(ii) Temperate zone.

(iii) Frigid zone.

Q.9. What climatic data are used in Koeppen’s scheme of classifying climates?

Ans. The Koeppen’s classification is based upon the following climatic data:

(i) Temperature.

(i) Precipitation. and

(iii) Their seasonal characteristics.

Q.10. What are the characteristics of steppe type of climate?

Ans. This climate region is found in North America and Eurasia. It is characterized by meagre rainfall, low temperature, located in the interiors and is affected by the mountain barriers.

SHORT ANSWER TYPE QUESTIONS

Q.1. What is ice coring programme? How do they help us know about the climate of earth in the past?

Ans. With a view to get a dependable picture of climatic changes in the past, ice coring programmes have been undertaken in several countries particularly in Antarctica and Greenland ice caps to analyse the tapped gases during the last 1,00,000 years. Ice core suggests that cooling trend in the Northern Hemisphere started from 1725 to 1920. It inferred from the study of oxygen isotopes record in Greenland.

Q.2. Explain about tropical wet and dry climate (AW).

Ans. Tropical wet and dry climate occurs north and south of Af type climate regions. It borders with dry climate on the western part of the continent and Cf or Cw on the eastern part. Extensive Aw climate is found to the north and south of the Amazon forest in Brazil and adjoining parts.

Q.3. Which two climatic variables were used by Koeppen for classification of the climate?

Ans. Temperature and Precipitation.

Q.4. How is the “genetic” system of classification different from the “empirical one”?

Ans. The genetic classification attempts to organise climates according to their causes while empirical classification is based on the observed data, particularly of temperature and precipitation.

Q.5. Which types of climates have very low range of temperature?

Ans. Tropical humid climates.

Q. 6. What type of climatic conditions would prevail if the sun spots increase?

Ans. If the sun spots increase, the weather will become more cooler and wetter and greater storminess will occur.

Q.7. Explain about humid and sub. tropical climate (Cfu).

Ans. Humid tropical climate lies on the eastern parts of the continent in sub-tropical latitudes. In this region the air masses are generally unstable and cause rainfall throughout the year. They occur in eastern United States of America, Southern and Eastern China Southern Japan, North-Eastern Argentina coastal South Africa and Eastern coast of Australia.

Features:

(i) The annual average of precipitation vary from 75-150 cm.

(ii) Thunder storms in summer and frontal precipitation in winter are common.

(iii) Mean monthly to temperature in summer is around 27°C and in winter it varies from 5°C-12°C.

(iv) The daily range of temperature is small.

Q.8. Explain about Tundra Climate.

Ans. The Tundra Climate (ET) is so called after the types of vegitation, like low growing mosses linches and flowering plants. This is the region of permafrost where the sub soil is permanently frozen. The short growing season and water logging support only low growing plants. During summer the Tundra regions have very long duration of day light.

LONG ANSWER TYPE QUESTIONS

Q.1. Describe the advantages of Trewartha’s climatic classification over Koeppen’s classification.

Ans. Koeppen’s classification is strictly empirical as it is neither based on weather processes (wind, air masses, fronts and storms) nor does it emphasise causes of climatic types. The climatic classification system devised by Trewartha represents a compromise between purely empirical and genetic methods. Besides being simple and explanatory it combines the fundamentals of the empirical as well as genetic classification schemes. Trewartha, while proposing his climatic classification was conscious of the fact that the classification system of Koeppen and Thornthwaite, being based on certain statistical parameters of a few weather elements were combersome and complex. Trewartha recognised only a limited number of climatic types.

Q.2. In which area do we find Marine West coast climate? Explain about the features of this climate.

Ans. Marine west coast climate (Cfb) is located poliward from the Mediterranian climate on the west coast of the continents. The main areas are North-Western Europe, West Coast of North America, North of California, Southern China, South-Eastern Australia and New Zealand.

Features:

(i) Due to marine influence the temperature is moderate and in winter it is warmer than for its latitude.

(ii) The main temperature in summer month ranges from 15°-20°C and in winter 4°-10°C.

(iii) The annual and daily ranges of temperature are small. 

(iv) Precipitation occurs throughout the year. Precipitation varies greatly from 50-250 cm.

Q.3. Describe the atmospheric distribution of carbon and the relationship between the carbon cycle and the greenhouse effect.

Ans. Three of the principal greenhouse gases-carbon, methane and the chlorofloro-carbon contain carbon, one of the most common elements in the environment and they which play a major roles in the greenhouse effect. Carbon is present in all organic substances and is a constituent of a great variety of compounds ranging from relatively simple gases to very complex derivative of petroleum hydrocarbons.

Q. 4. What is global warming? Discuss its causes.

Ans. The atoms and molecules of atmospheric gases cause absorption and back radiation of sunlight by the greenhouse gases, water, carbon dioxide and methane resulting in increased temperatures which called global warming.

Causes: Human activities add methane and carbon dioxide to the atmosphere by burning fossil fuels and by various agricultural activities.

Rapid industrialisation and technological changes; revolution in agriculture and transport system have resulted in large supplies of carbon dioxide, methane and CFCs to the atmosphere.

Q.5. Distinguish between:

(i) Genetic and empirical classification of climate.

Ans. There are different schemes of classifying climates of the world. On the basis of grouping, climate types are: Genetic and Empirical.

Genetic classification: It emphasises causes or origin or their formation based on weather processes.

Empirical classification: It is based on observation related factors for climatic differentiation.

(ii) ‘Ar’ and ‘Aw’ climates.

Ans. ‘Ar’ climates belongs the climate groups of tropical humid climate and the climatic type of tropical wet (Ar). The symbol of this type of group is ‘A’. The tropical wet (Ar) extends approximately 5° to 10° latitude on either side of the equator. Along eastern margins of continents, this type of climate is under the influence of I.T.C.Z. and the subtropical jet-streams. It is also known as tropical rainforest.

‘Aw’: ‘Aw’ belongs to the tropical wet and dry climate. It is dominated by dry trade winds. In this region average precipitation is less than the one in tropical wet climate. The winters are dry seasons. This type of climate is called Savanna climate because of the tall grasses that grow between trees and thorny bushes.

(iii) Boreal and Polar Climates.

Ans. Boreal: It belongs to E Type. The boreal climate is found in higher mid-latitudes. In this climate summers are short and cool, winters are long and cold with a very short frost- free season. Annual range of temperature is between 0° to 10°C and rainfall is meagre and most of it occurs during summers. It is found in coniferous forests of the world.

Polar climates: Polar climates are found in high latitudes and at higher reaches of the Himalayas and Alps. These climates are confined to the Northern Hemisphere only. The average temperature of the warmest month does not exceed 10°C. There is no summer season. The polar climates include Tundra and Ice cap.

(iv) Arid or semi-arid climates.

Ans. Arid climates: Arid or desert type of climate has driest climate variety in sub-tropical belt between 20° and 30° north and south latitudes. This type of climate is found in Peru and Chile in South America, Kalahari desert in Africa, Australia desert, Sahara and Arabian and Thar desert of India-and Pakistan and deserts of North Mexico. Annual rainfall is lowest.

Semi-arid or Steppe type of climate: has an annual rainfall range of 30 to 60 cm. These areas are in the heart of the grassland of western North America and Eurasia. That is why they are called steppe type of climate. It is found in tropical deserts from Morocco to Tunisia and from Dakkar in Senegal to Ethiopia and deserts of Afghanistan.

(v) Temperate marine climate and Temperate continental climate.

Ans. Temperate marine climate: It has mild winters and fairly warm summers throughout the year. The mean temperature in summer months ranges from 15°-20° and in winter 4°-10°C. The rainfall is experienced throughout the year. This type of climate is found on the western margins of continents of the temperate zone.

Temperate continental climate: It is found in the interiors of the continents in middle latitudes. There are harsh winters and cool summers. Annual precipitations is low. This type of climate is found in North-eastern Asia, Eastern Canada and Eurasia.

Q.6. Write short notes on:

(i) Koeppen’s classification of climate.

Ans. Koeppen’s Classification of Climate: Koeppen’s classification of climates is based on temperature, precipitation and their seasonal characteristics. He aimed at providing a quantitative scheme which would relate climate to vegetation in an objective manner. He recognised five principal groups of climates which are intended to correspond with five principal vegetation groups. Besides these five groups, the climates of highlands has been also included here. Each group has been designated by a capital letter.

(ii) Sub-Tropical Climate (C).

Ans. Sub-tropical climates are formed between tropical and temperate climatic zones. In this type of climate, the temperature is generally above 18°C for nearly 8 months. Winters are mild and short. The coastal areas have rainfall throughout the year while continental areas receive less rainfall. Tropical climate has two subtypes-subtropical humid and sub tropical dry. The subtropical humid climate is found on the eastern side of continents where rainfall occurs throughout the year. During summer it is under anticyclone and in winter under temperate cyclone. Subtropical dry summer climate has moderate to scanty rainfall. Rainfall occurs in winter while summers are dry.

(iii) Global climatic changes.

Ans. Atmosphere is well structured and fairly dynamic in nature. The dynamism is more complex near the earth’s surface where changes take place both spatially and temporarilly. These changes may be internally induced within the earth’s atmospheric system or externally induced by extra terrestrial factors. Some of the changes are the results of human efforts. The global warming is one of the changes caused by man.

Q.7. Make a comparison of the climatic conditions between the ”A” and “B” types of climates.

Ans.

‘A’ Type Climate	‘B’ Type Climate
1. A type belongs to tropical climates.	1. B type belongs to sub-tropical climate.
2. These are of three types- Tropical wet, Monsoon and tropical wet and dry.	2. These are found in low latitudes.
3. No dry season is there in tropical wet.	3. Mid-latitudes are semi-arid or dry.
4. Winters are dry season.	4. Mid-latitudes are arid or dry.

Q.8. What type of vegetation would you find in the ‘C’ and ‘A’ type(s) of climate?

Ans. Vegetation in ‘C’ type climate: The ‘C’ type climate belongs to warm temperate climates. It extends from 30° to 50° latitudes mainly on the eastern and western margins of the continents. Therefore, different types of vegetation is found in this region. It includes the vegetation of Mediterranean type, humid sub- tropical climate type vegetation and marine west coast type vegetation.

Vegetation in ‘A’ type climate: This type of climate belongs to tropical humid climates and monsoon climates. Vegetation is also found in this region belonging the tropical humid type of climate.

Q.9. What do you understand by the term ‘Greenhouse Gases’? Make a list of greenhouse gases.

Ans. The concept of heating the atmosphere indirectly from the earth surface is called Green house effect or commonly known as atmospheric effect. Obviously the effect of atmosphere is analogous to that of glass pane which its through most of incoming short wave solar energy but greatly retards the out going long wave earth radiation. Thus maintaining surface temperature considerable higher them they otherwise would be. 

Growing tomatoes in winter can be accomplished by capitalising on transparancy of glass roof in green house to short wave.

The greenhouse gases are:

1. Carbon dioxide.

2. Cholorofluro carbons (CFCs)

3. Methane (CH₄)

4. Nitrous Oxide (N₂O)

5. Ozone and some other gases such as nitric oxide and carbon monoxide.

Q.10. Describe the broad climate groups formed by Trewartha. What are the basis of this classification?

Ans. The basis of the Trewartha’s classification is temperature. 

The classification of climate by Trewartha is as under:

Symbol	Climate Group	Climatic Types
A	Tropical Humid climatic	Tropical (Ar) Tropical wet and dry/Savanna (AW)
C	Subtropical	Subtropical humid (EFW) Subtropical dry summers (CS)
D	Temperate	Temperate marine (DO) Temperate continental (DC)
E	Boreal
F	Polar	Tundra (FT) Ice cap (Fi) Arid/Desert type (BW)
B	Dry	Semi Arid/Steppe (BS)