NCERT Solutions for Class 11 Geography Chapter 11 - World Climate and Climate Change

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73. Multiple choice questions.

(i) Which one of the following is suitable for Koeppen’s “A” type of climate?

(a) High rainfall in all the months

(b) Mean monthly temperature of the coldest month more than freezing point

(d) Average temperature for all the months below 10°C

Ans. (a) High rainfall in all the month

(ii) Koeppen’s system of classification of climates can be termed as :

(a) Applied

(b) Systematic

(d) Empirical

Ans. (d) Empirical

(iii) Most of the Indian Peninsula will be grouped according to Koeppen’s system under:

(a) “Af”

(b) “BSh”

(d) “Am”

Ans. (d) “Am”

(iv) Which one of the following years is supposed to have recorded the warmest temperature the world over?

(a) 1990

(b) 1998

(d) 1950

Ans. (b) 1998

(v) Which one of the following groups of four climates represents humid conditions?

(a) A—B—C—E

(b) A—C—D—E

(d) A—C—D—F

Ans. (b) A—C—D—E

74. Answer the following questions in about 30 words.

(i) Which two climatic variables are used by Koeppen for classification of the climate?

Ans. It is an empirical classification based on the variables mean annual and mean monthly temperature and precipitation data. In order to define climatic groupings and kinds, he proposed the use of capital and small letters. Four of the primary climatic groupings that Koeppen identified are based on temperature, while one is based on precipitation.

(ii) How is the “genetic” system of classification different from the “empirical one”?

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

(iii) Which types of climates have very low range of temperature?

Ans. The temperature range in the humid tropical environment is relatively narrow. It’s located close to the equator. The main regions are the islands of the East Indies, western equatorial Africa, and the Amazon Basin in South America. Every month of the year has significant amounts of rainfall in the form of afternoon thundershowers. The yearly temperature range is negligible, and the temperature is consistently high. Every day, the minimum temperature is about 20°C, and the maximum temperature is about 30°C. This climate supports tropical evergreen forests with substantial biodiversity and a strong canopy cover.

(iv) What type of climatic conditions would prevail if the sun spots increase?

Ans. Sunspots are dark and cooler patches on the sun which increase and decrease in a cyclical manner. According to some meteorologists, cooler and wetter weather and greater storminess occur when the number of sunspots increase. A decrease in sunspot numbers is associated with warm and drier conditions.

75. Answer the following questions in about 150 words.

(i) Make a comparison of the climatic conditions between the “A” and “B” types of climate.

Ans.

“A” Type of Climate	“B” Type of Climate
It belongs to a tropical climate.	It belongs to the subtropical climate.
It exists between the Tropic of Cancer and the Tropic of Capricon.	These are found in low or midlatitudes in the area of subtropical high where subsidence and inversion of temperature do not produce rainfall.
The annual range of temperature is very low, and annual rainfall is high	Very low rainfall that is not adequate for the growth of plants.
The tropical group is divided into three types, namely (i) Af- Tropical wet climate; (ii) Am- Tropical monsoon climate; (iii) Aw- Tropical wet and dry climate.	Dry climates are divided into steppe or semi-arid climate (BS) and desert climate (BW).

(ii) What type of vegetation would you find in the “C” and “A” type(s) of climate?

Ans. Vegetation “A” type of climate: The sun being overhead throughout the year and high rainfall make the condition appropriate for the growth of plants. It supports rainforests. Tropical evergreen forests with dense canopy cover and large biodiversity are found in Tropical wet climates. Deciduous forests and tree-shredded grasslands occur in the Tropical wet and dry climate.

Vegetation in “C” type of climate: Warm temperature climates extend from 30-50 of latitude, mainly on the eastern and western margins of continents. These climates generally have warm summers with mild winters. It is the same as a tropical forest. The forests have trees, shrubs, and bushes. Broadleaf trees provide a continuous and dense canopy in summer and shed their leaves in winter. The shorter trees and shrubs of different heights and increase in summer and warm spring. Ferns, mosses and other plants grow quickly in spring but disappear in winter.

(iii) What do you understand by the term “Greenhouse Gases”? Make a list of greenhouse gases.

Ans. (a) The word “greenhouse” comes from a comparison to a greenhouse that is used in cold climates to retain heat. The glass makes up a greenhouse. Incoming short-wave solar radiation passes through the glass that is opaque to long-wave solar radiation. Therefore, the glass lets in more radiation and blocks long-wave radiation from leaving the glass house, making the interior of the structure warmer than the exterior.

(b) Greenhouse gases are those gases that increase atmospheric temperature and contribute to global warming. These gases absorb longwave radiation. The processes that warm the atmosphere are collectively called the greenhouse effect. Greenhouse Gases (GHGs):

The primary GHGs of concern today are carbon dioxide (CO₂), chlorofluorocarbons (CFCs), methane (CH₄), nitrous oxide (N₂O) and ozone (O₃). Some other gases, such as nitric oxide (NO) and carbon monoxide (CO) easily react with GHGs and affect their concentration in the atmosphere. The effectiveness of any given GHG molecule will depend on the magnitude of the increase in its concentration, its lifetime in the atmosphere and the wavelength of radiation that it absorbs.