NCERT Solutions for Class 11 Geography Chapter 12 World Climate And Climate Change

Ans : (i) (a) High rainfall in all the months
(ii) (d) Empirical
(iii) (d) "Am"
(iv) (b) 1998
(v) (b) A-C-D-E 

Ans : (i) Temperature and precipitation are climatic variables are used by Koeppen for classification of the climate.


(ii) Empirical classification is based on observed data, particularly on temperature and precipitation. Genetic classification attempts to organise climates according to their causes.


(iii) Tropical Humid Climates have very low range of temperature. It exist beüeen Tropic of Cancer and Tropic of Capricorn.


(iv) When the number of sunspots increase, cooler and wetter weather and greater storminess occur. 

Ans : (i) 



(ii) Vegetation in "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 Climate. Deciduous forest and tree-shredded grasslands occur in Tropical Wet and Dry Climate. 
Vegetation in "C" type of climate: Warm temperate climates extend from 300 - 500 of latitude mainly on the eastern and western margins of continents. These climates generally have warm summers with mild winters. It is same as 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 grow rapidly in summer and warm spring. Ferns, mosses and other plants which grow quickly in spring but disappear in winter.


(iii) A greenhouse is made up of glass. The glass which is transparent to incoming shortwave solar radiation is opaque to outgoing longwave radiation. The glass, therefore, allows in more radiation and prevents the long wave radiation going outside the glass house, causing the temperature inside the glasshouse structure warmer than outside. Due to the presence of greenhouse gases, the atmosphere is behaving like a greenhouse. The atmosphere also transmits the incoming solar radiation but absorbs the vast majority of long wave radiation emitted upwards by the earth's surface.
The gases that absorb long wave radiation are called greenhouse gases. The processes that warm the atmosphere are often collectively referred to as the greenhouse effect.
The primary Greenhouse Gases are:
 Carbon dioxide (C02)
 Chlorofluorocarbons (CFCs)
 Methane (CH4)
 Nitrous oxide (N20)
 Ozone (03).
Some other gases such as nitric oxide (NO) and carbon monoxide (CO) easily react with GHGs and affect their concentration in the atmosphere.