RBSE Class 11 Geography Important Questions Chapter 12 World Climate and Climate Change

Rajasthan Board RBSE Class 11 Geography Important Questions Chapter 12 World Climate and Climate Change Important Questions and Answers. 

RBSE Class 11 Geography Important Questions Chapter 12 World Climate and Climate Change

Multiple Choice Questions

1. Which type of climate is found in Zaire?
(A) Amazon 
(B) Savana
(C) Desert 
(D) Mediterranean.
Answer:
(A) Amazon 

 

2. Which type of forests are found in Taiga region?
(A) Monsoon 
(B) Deciduous
(C) Coniferrous 
(D) Dry.
Answer:
(C) Coniferrous 

3. ‘E’ word represents the climate
(A) Hot 
(B) Cold
(C) Dry 
(D) Cool.
Answer:
(B) Cold

4. How many years ago, Rajasthan had a humid climate?
(A) 6000 years 
(B) 7000 years
(C) 8000 years 
(D) 9000 years.
Answer:
(C) 8000 years 

5. Which is a greenhouse gas?
(A) Oxygen 
(B) Nitrogen
(C) Methan 
(D) Ozone.
Answer:
(C) Methan 

6. In which latitudes are deserts located?
(A) 0-10° 
(B) 10°-15°
(C) 15°-20° 
(D) 20°-30°.
Answer:
(D) 20°-30°.

7. Which of the following is not an element of weather and climate?
(A) Temperature 
(B) Humidity
(C) Visibility 
(D) Rain.
Answer:
(C) Visibility 

8. Which climate has the highest annual temperature?
(A) Savannah Climate.
(B) Warm Desert Climate
(C) Steppe Climate
(D) High Mountain Climate.
Answer:
(B) Warm Desert Climate

Short Answer Type Questions

Question 1. 
What climatic data are used in Koeppen’s classification of climate?
Answer: 
(i) Temperature 
(ii)Rainfall
(iii) Evaporation (A)Evapo-transpiration
(vi) Water balance.

Question 2. 
Which are the two well-known classi¬fications?
Answer:
Many different classifications of climates have been devised. Of these, two classifications are well-known.

1. The German meteorologist Wladimir Koeppen devised a system based on temperature and rainfall.
2. The American climatologist C. Warren Thornthwaite drew up a classification based on precipitation efficiency.

Question 3. 
Divide the world into temperature zones.
Answer: 
Various attempts have been made by different climatologists to divide earth into different temperature zones. The early Greek philosophers distinguished three temperature zones :
(i) Torrid zone (Hot zone) Between 0°-30° N and S latitudes with a mean annual temperature of more than 20° C.

(ii) Temperate zone.
(a) Warm temperate (10° to 20°C temperature) 30° to 45°N and S.
(b) Cool temperate (0°C to 10°C temperature) 45° to 60°N and S.

(iii) Frigid zone (Cold zone) 60° to 90°N and South latitudes. (Less than 0°C Temp.).

Question 4. 
Which type of climate is known for the minimum range of annual temperature?
Answer: 
In Equatorial type of climate the annual range of temperature is the minimum (Below 5°C).

Question 5. 
Why is the amount of precipitation that! / defines the humid dry boundary variable? !
Answer: 
The seasonal distribution of precipitation is observed to define the humid dry boundary of climates. The temperature and potential evaporation also affect it. According to the effect of all these factors, the amount of precipitation varies.

Question 6. 
What is the significance of 10°C summer isotherm?
Answer: 
10°C isotherm in summer marks the limit of tree growth. Trees do not grow in Tundra because the temperature is below 1.0°C in Summer.

Question 7. 
What are characteristics of Savanna Climate?
Answer: 
The annual average temperature is 23°C. The range of temperature is 5°C. The annual rainfall is 160 cm. mostly in summer.

Question 8. 
Why the marine West European climate is formed only in a narrow belt along the coast in North and South America?
Answer: 
The presence of mountain barriers of the Rockies and Andes limit the West European climate to a narrow belt in Chile and Canada.

Essay Type Questions

Question 1. 
Describe the scheme of classification of climates according to Trewartha. 
Answer: 
Trewartha modified Koeppen’s classification of climates and gave some new suggestions. He included empirical as well as genetic both types of classifications. The main aim of Trewartha was to give a simple scheme of climates so that main types of climate can be identified. So he tried to keep the number of climates as minimum. Koeppen’s classification was difficult to remember. Trewartha divided the earth into five major climatic groups.

1. A type of Climate-Tropical Humid Climate These include low latitude areas which have high temperature and high rainfall throughout the year. There is no winter season. It is sub-divided into three sub-types.
Af = High rainfall throughout the year.
Aw = Low rainfall in winter.
Am = Monsoon type.

2. B Type of Climate (Dry Climate)
This climate is found in tropical Humid and mid-latitudes climates. Its sub-types are:

1. BWh - Tropical dry climate.
2. BSh - Sub-tropical steppe climate.
3. BWk -Mid-latitude dry climate.
4. BSk - Mid-latitude steppe climate.

The demarcation of tropical dry and steppe dry climate is by 32°F isotherm in coldest month.

3. C Type of Climate - Mid-latitude Humid climate
This type of climate has short winter season. It has three sub-types.

1. Cs-Sub-tropical semi-humid climate.
2. Ca - Sub-tropical humid climate.
3. Cb- Mid-latitude marine climate.

Cs climate is affected by anticyclones in Summer and Westerlies in winter. Ca climate gets Westerlies in winter Cb gets Westerlies throughout the year.

4. D Type of Climate
This climate is found in high mid-latitudes, where polar winds predominate in winter. It has sub-types :

1. Da- Humid Continental climate (20°C temp, in hottest month).
2. Dh - Humid Continental climate (22°C temp, in hottest month).
3. Dc - Sub-polar climate with short summer.
4. Dd - With coldest month a temp, of - 38°C.

5. E. Type of Climate (Polar climate) There is no summer season. Polar winds blow throughout the year. It has two sub-types :
(ET) - Tundra (ii) EF (ice caps), where temp, is below 0°C.

Question 2. 
Describe the broad climatic groups framed by Koeppen.
Answer: 
Koeppen’s Classification. The aims and objectives of Koeppen climatic classification were very clear. He opined that, people such as geographers, biologists, or agriculturists, who need to understand and use the climatic environment for their own purposes, should have the facts of climate presented realistically. At the same time he also recognised the merits of the genetic type of climatic classification. Koeppen classified world climates in six great climatic groups, out of which, five (A, C, D, E, F) are based on temperature criteria, and the sixth (B) is the dry group based on precipitation.

Simplified Version of Koeppen’s Climatic Classification System

(Symbol	Climatic Groups	Climatic Types
A	Tropical humid climate	Tropical wet (Ar)
C	Sub-tropical	Tropical wet and dry/Savana (Aw)
D	Temperate	Sub-tropical humid (Cfw) Sub-tropical dry summer (Cs)
E	Boreal	Temperate marine (Do) Temperate continental (Dc) Tundra (Ft)
F	Polar	Ice cap (Fi)
B	Dry	Arid / Desert type (BW) Semi-arid / steppe (BS)

Climatic Groups Based on Temperature Criteria
(1) Tropical Humid (A) Climate. 
The tropical humid (A) climate stretches along the equator, in the irregular belt of 20° to 40° latitude in both the hemispheres. The temperature and rainfall are high throughout the year. In the coastal region the average temperature of the coldest month is above 18° C. 

(i) Tropical Wet Climate (Ar). 
The core of the 'A' climatic region is constituted by wet sub-type, the tropical wet climate (Ar). This climate extends approximately 5° to 10° on either side of the equator. Along eastern margins of continents, this type of climate is under the influence of inter-tropical convergence zone and the sub-tropical jet-stream. It is also known as tropical rain forest. Closer inspection of tropical wet climate reveals that it widely extends (15° to 20°N and S) on the eastern margins of continents because trade winds blow on shore from northeast and southeast.

(ii) Tropical Wet and Dry Climate (Aw). The tropical wet and dry climate (Aw) exhibit winter dry season. It is dominated by dry trade winds. In this region average precipitation is less than the one in tropical wet climate. This type of climate is called savanna climate because tall grasses that grow between trees and thorny bushes, dominate the vegetation cover.

(2) Sub-Tropical (C) Climates. Sub tropical climates are found between tropical and temperate climatic zones. In this type of climate, the temperatures are 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. On the basis of seasonal distribution of precipitation, sub¬tropical climates have two sub-types: sub-tropical humid (Cfw) and sub-tropical dry summer (Cs).

(i) Sub-tropical humid climate (Cw). 
The sub-tropical humid climate is found on the eastern sides of continents. In this type, the rainfall is throughout the year. During summer, it is under the influence of sub¬tropical anticyclone and in winter under temperate cyclones. The summer months receive more rainfall than winter.

(ii) Sub-tropical dry climate (Cs). 
Sub tropical dry summer climate is characterised by moderate to scanty rainfall. Rainfall occurs in winter while summers are dry. This type of climate is found in the interior of 'C' climate region along the tropical margin of mid latitudes.

(3) Temperate (D) Climates. 
The micro thermal (D) climates receive relatively small amount of heat. It is found in the vast landmasses of middle latitudes (40° and 65°). This climatic band of severe winters is found between sub-tropical and boreal types of climate. The two sub-types of temperate climates are temperate marine (Do) and temperate continental (Dc). They are primarily demarcated on the basis of summer temperatures.

(i) Temperate Marine Climate (Do). 
Temperate marine climate has mild winters and fairly warm summers. Throughout the year, average temperature is above 0°C. The rainfall is experienced throughout the year. This type of climate is found on the western sides of continents in temperate zone.

(ii) Temperate Continental Climate (Dc). 
Temperate continental climate is found in the interiors of the continents in middle latitudes. The impact of land is visible as it is characterised by harsh winters and cool summers. The extreme cooling of the ground is associated with anticyclone. Annual precipitation is low, though it takes place throughout the year. This type of climate is found in north-eastern Asia, eastern Canada and Eurasia.

(4) Boreal (E) Climates. 
Boreal climate is found in the higher middle latitudes. In this climate, summers are short and cool, winters are long and cold with a very short frost-free season. Annual temperature ranges between 0° and 10° C. Annual precipitation is meager and most of it occurs during summers. This type of climate is noticed in the coniferous forest of the world.

(5) Polar (F) Climates. 
Polar climates are found in the high latitudes and higher reaches of the Himalayas and the Alps. These climates are confined to the northern hemisphere only. The average temperature does not exceed 10°C in any month. There is no summer season. On the basis of temperature the polar climates are classified into two types: (i) tundra (Ft); and (ii) ice cap (Fi).

(i) Tundra Climates (Ft). 
The Tundra climate on land is found only in the northern hemisphere where it occupies the coastal fringes of the Arctic Ocean, the ice-free shores of the northern Iceland, southern Greenland and higher reaches of the Himalayas and the Alps. This climate is characterised by extreme cold in which the average temperature of the warmest month does not normally rise above 0°C, but never above 10°C. It is associated with permanent frost formation leading to frozen sub-soil. During the summer, precipitation occurs in the form of snow and rain.

(ii) Ice cap (i). Ice cap climate has average temperature below freezing point. It is associated with the phenomena of permanent ice and snow. The winter and summer are windy and chilly and precipitation is very meagre. This type of climate is confined to ice caps of Greenland and Antarctica.

(6) Climatic Group Based on Precipitation Criteria Dry (B) Climates The dry climates are found on the poleward margins of 'A' group climates on the western sides of the continents. The most important feature of a dry climate is the higher rate of moisture-loss through evaporation and evapo-transpiration in relation to the annual receipt of water gain from precipitation. This climate is characterised by dry weather with a high range of temperature - 25° to 30° C. Dry B1 climates are associated with subsiding air of sub-tropical high pressure zone which, results in intrusion of arid climate into continents of both north and south hemispheres. 

The extreme seasonal temperatures cause large annual range of temperature. The average annual precipitation is meagre (nearly 0 to 50 cm) and is highly variable. On the basis of annual average range of precipitation, dry climates are sub-divided into desert (BW) and semi- arid (BS) type of climate. The capital letters ’S’ and 'W' indicate the degree of aridity in dry (B) climates, with 'S' and 'W designating semi arid and fully arid conditions respectively. The boundaries of these two sub-climates are set at one half of the annual rainfall separating dry (arid) from the semi-arid type.

(i) Desert type (Bw).
Desert or arid type of climate has driest climatic variety in sub-tropical belt between 20° to 30° north and south latitudes. This type of climate is found in coastal deserts of Peru and Chile in South America, Kalahari deserts of coastal Angola, south-west Africa, Great Australian desert, Sahara and Arabian deserts. Thar desert of Pakistan and India and deserts of northern Mexico. In these regions stability of air mass leads to extreme dryness with no rainy days. The influence of cold ocean currents is also there. These areas receive lowest annual rainfall in the world despite their location adjacent to the one answer: This type of climate is associated with xerophytic (thorny/spiny) type of vegetation.

(ii) Semi-desert (Bs).
The semi arid or steppe type of climate borders 'A' and 'C' type of climate and has an annual rainfall range of 30 to 60 cm. These areas lie in the heart of the grasslands of western North America and Eurasia. That is why they are called steppe type of climate. The lands of this climatic type are away from the oceanic influence. It is found in both north and south tropical deserts from Morocco to Tunisia and from Dakar in Senegal to Ethopia deserts of Afghanistan, large strip of land adjoining Thar Desert and rain shadow area of peninsular India.

Question 3. 
Describe the Global Warming in details.
Answer: 
Global Warming. Global warming means the increase in the average temperature of the earth.
Processes of Heating the Earth:
The atoms and molecules of atmospheric gases cause absorption and back radiation of sun light, by the green house gases (discussed in later part of this chapter) especially water, carbon dioxide, and methane. The concentration of water in the atmosphere is controlled by evaporation from one answer: Carbon dioxide is introduced in the atmosphere by volcanism. Equivalent amount of carbon dioxide is removed by precipitation as calcium carbonate in one answer: Methane, which is twenty times more effective than carbon dioxide, is produced by metabolization of bacteria in wood / grass-eating animals. The methane rapidly gets oxidised into carbon dioxide. 

Effects of Human activities:
Human activities add methane and carbon dioxide to the atmosphere by burning fossil fuels and by various agricultural activities. The carbon dioxide contents of atmosphere play a dominant role in causing worldwide climatic change. The gas is transparent to incoming solar radiation, but absorbs outgoing long-wave terrestrial radiation. The absorbed terrestrial radiation is radiated back to the earth's surface. 

Thus, it is clear that any appreciable change in carbon dioxide content would bring about changes in the temperature in lower layers of the atmosphere. Rapid industrialisation and technological changes, revolution in agriculture and transport sectors has resulted in large supplies of carbon dioxide gas, methane and chlorofluorocarbon gases to the atmosphere. Some of these gases are consumed by vegetation and part of it is dissolved in ocean. However, about 50 per cent is left over in the atmosphere.

Examples : 
(i) During past 100 years the concentration of methane has more than doubled (from 7.0 x 10-7 to 15.5 x 10-7).

(ii) Carbon dioxide has increased by 20 per cent (from 2.90 xHT4 to 3.49 xHT4).

(iii) In 1880-1890 the carbon dioxide content was about 290 parts per million (ppm). It rose to about 315 ppm in 1980, 340 ppm in 1990 and 400 ppm in 2000.

(iv) This means that proportion of carbon dioxide had increased to 9 per cent by 1950 and nearly 17 per cent by 1990. The rate of increase has become still greater during last one decade. Effects of industrialisation Of the many climatic parameters, temperature is the most affected one due to urbanisation and industrialisation. The thermal characteristics of urban areas are in marked contrast to those of surrounding countryside. The analysis of temperature data for last fifty years reveals that there is an increase of 0.7°C in winter and 1.4°C in summer in India. 

Effects of Agriculture Man is considered an engine of climatic change. In support of this, rice farmers, coal miners, dairy farmers and shifting agriculturists contribute their mite in global warming. According to some estimates, rice cultivation in the world is responsible for 20 per cent methane being added to atmosphere, and the coal mining accounts for 6 per cent of methane. The deforestation is responsible for 20 per cent of the carbon dioxide gas being added to the atmosphere. Similarly, industrialisation is adding 25 per cent of chlorofluorocarbon to the aerosol of the atmosphere. Consequently, global temperature increase is by about 1.5°C. 

Rise in Sea-level Today, there is much concern that continuing addition of carbon dioxide and methane gases to the atmosphere will increase atmospheric temperature to an extent that it will cause ice to melt in the Arctic Ocean and in Antarctica. As a result, sea level will rise causing drowning of coastal lowlands and islands, altering rainfall and evaporation patterns, creating new plant diseases and pest problems and enlarging the ozone hole. 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 trapped gases during the last 1,00,000 years.

The results have been fascinating and offer glimpses of the earth’s recent history going beyond the phenomena of global warming. During last 10,000 years of the earth’s history, climate regime has been exceptionally stable compared to earlier history. Study of oxygen isotope records in Greenland ice core suggests that cooling trend in the northern hemisphere started from 1725 to 1920.

These were associated with emissions of volcanic dust at a regular interval of two to three decades but after 1945 there has been increase in temperature globally leading to warming without any major volcanic eruption and increase in level of carbon dioxide concentration in the atmosphere. Future scientists predict that by 2020, temperature all over the world, would be higher than ever during the last 1,000 years. As such, it is evident that increasing carbon dioxide content would lead to rise in global temperature.

Source Based Questions

1. Read the following paragraph and answer the questions given below:
Empirical classification is based on observed data of temperature and precipitation. Genetic classification attempts to organise climates on the basis of their causes. A type of climate is tropical humid climate that exists between Tropic of Cancer and Tropic of Capricorn. There is low range of temperature. Temperature is uniformly high (above 30°C). B type of climate is dry with low rainfall. It is found in in 15°-60° latitudes. The rainfall is low in interiors of continents. It is semi-desert type. In C type of climate, temperate forests are found. Here, trees with long roots and thick leaves are found.

2. Read the following paragraph and answer the questions given below:
Human activities add methane and carbon dioxide to the atmosphere by burning fossil fuels and by various agricultural activities. The carbon dioxide contents of atmosphere play a dominant role in causing worldwide climatic change. The gas is transparent to incoming solar radiation, but absorbs outgoing long-wave terrestrial radiation. The absorbed terrestrial radiation is radiated back to the earth’s surface. 

Thus, it is clear that any appreciable change in carbon dioxide content would bring about changes in the temperature in lower layers of the atmosphere. constituent of a great variety of compounds, ranging from relatively simple gases to very complex derivatives of petroleum hydrocarbons. The carbon in the environment is mobile, readily changing its affiliation with other elements in response to biological, chemical and physical processes. This mobility is controlled through a natural bio-geochemical cycle, which works to maintain a balance between the release of carbon compounds from their source and their absorption in sinks. 

(i) Which of the following is a gas added by human activities to the atmosphere?
(a) Methane 
(b) Carbon dioxide
(c) Both (a) and 
(b) (d) None of these
Answer: 
(c) Both (a) and (b)

(ii) Which gas play a dominant role in climatic change?
(a) Methane 
(b) Carbon dioxide
(c) Carbon monoxide 
(d) Oxygen
Answer: 
(b) Carbon dioxide

(iii) Which gas is transparent to incoming solar radiation?
(a) Methane
(b) Carbon dioxide
(c) Nitrogen 
(d) Oxygen
Answer: 
(b) Carbon dioxide 

Question 1
Describe the atmospheric distribution of carbon and greenhouse effect. A
Answer: 
The Carbon Cycle and Greenhouse Effect:
Three of the principal greenhouse gases - carbon dioxide (C02), methane (CH4) and the chlorofluorocarbon (CFC) - contain carbon, one of the most common elements in the environment, and one which plays a major role in the greenhouse effect. It is present in all organic substances and is a  

SELF EVALUATION TEST 

1. What do you mean by ‘Am’ type of climate?
2. Which type of climate has low range of temperature? 
3. Which elements are considered as basis of climate classification? 
4. Name a greenhouse gas. 
5. Which are two well-known classifications? 
6. What is torrid zone? 
7. What is Savanna climate?
8. Describe ‘E’ type of climate. 
9. What is Tundra type of climate? 
10. Explain the effects of global warming.