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GEOGRAPHY- CLASS-11: FUNDAMENTALS OF PHYSICAL GEOGRAPHY

CHAPTER-11
World Climate and Climate Change

NCERTChapter-11 Solution

1. Multiple Choice Questions


(i) Which one of the following is suitable for Koeppen's "A" type of climate?

Answer: (c) Mean monthly temperature of all the months more than 18°C

Explanation:

Koeppen's "A" climate represents Tropical Humid Climate. In this type of climate, the average temperature of every month remains above 18°C. These regions are located near the Equator and receive abundant solar energy throughout the year.


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

Answer: (d) Empirical

Explanation:

Koeppen's classification is called an empirical classification because it is based on observed climatic data such as temperature, rainfall and natural vegetation rather than on the causes of climate.


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

Answer: (d) "Am"

Explanation:

Most parts of Peninsular India experience a Tropical Monsoon Climate (Am), characterized by high temperatures throughout the year and seasonal rainfall brought by the southwest monsoon.


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

Answer: (b) 1998

Explanation:

According to the NCERT textbook, 1998 was considered one of the warmest years globally due to the combined effects of global warming and a strong El Niño event.


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

Answer: (a) A—B—C—E

Correct Answer: (b) A—C—D—E

Explanation:

Humid climates in Koeppen's classification include:

  • A – Tropical Humid Climate
  • C – Warm Temperate Climate
  • D – Snow or Cold Continental Climate
  • E – Polar Climate

B Climate represents dry climates and is therefore excluded.


2. Answer the following questions in about 30 words.


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

Answer:

Koeppen used two main climatic variables:

  • Temperature
  • Precipitation (Rainfall)

He also considered the natural vegetation associated with different climatic regions.


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

Answer:

The genetic classification explains the causes and origin of climate, such as air masses, pressure belts and atmospheric circulation. The empirical classification is based on observed climatic elements like temperature, rainfall and vegetation without explaining their causes.


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

Answer:

Tropical Humid (A) climates, especially equatorial regions, have a very low annual range of temperature because they receive nearly equal solar radiation throughout the year.


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

Answer:

An increase in sunspots increases the amount of solar radiation reaching the Earth. As a result, temperatures may rise slightly, leading to relatively warmer climatic conditions.


3. Answer the following questions in about 150 words.


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

Answer:

According to Koeppen's classification, "A" represents Tropical Humid Climate, while "B" represents Dry Climate. In the "A" climate, the average monthly temperature remains above 18°C throughout the year. Rainfall is abundant and humidity is high. Dense forests such as tropical rainforests and monsoon forests are common in these regions. Examples include the Amazon Basin, Congo Basin and parts of India. In contrast, the "B" climate receives very little rainfall because evaporation exceeds precipitation. These regions experience dry conditions and sparse vegetation such as grasses, shrubs and thorny bushes. Deserts and steppes are included in this climate type. Temperature variations are generally higher, especially in deserts. Thus, while "A" climates are hot and humid with abundant rainfall, "B" climates are dry with limited rainfall and sparse vegetation.


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

Answer:

The "A" climate supports dense tropical vegetation because of high temperatures and abundant rainfall throughout the year. Natural vegetation includes tropical evergreen forests, tropical monsoon forests and tropical deciduous forests. These forests contain tall trees, rich biodiversity and thick undergrowth. In contrast, the "C" climate supports temperate vegetation. Depending on rainfall and seasonal conditions, natural vegetation includes temperate deciduous forests, mixed forests, evergreen broadleaf forests and grasslands. Trees such as oak, maple, beech and chestnut are commonly found. Mediterranean regions under the "C" climate support hard-leaved evergreen shrubs and small trees. Therefore, the vegetation in "A" climates is dense and luxuriant, whereas "C" climates have temperate forests adapted to seasonal changes.


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

Answer:

Greenhouse gases are gases present in the Earth's atmosphere that allow incoming solar radiation to pass through but absorb and trap the outgoing terrestrial (infrared) radiation. This process is known as the greenhouse effect, which keeps the Earth warm enough to support life. However, an excessive increase in greenhouse gases leads to global warming and climate change.

Major greenhouse gases are:

  • Carbon dioxide (CO2)
  • Water vapour (H2O)
  • Methane (CH4)
  • Nitrous oxide (N2O)
  • Ozone (O3)
  • Chlorofluorocarbons (CFCs)
  • Hydrofluorocarbons (HFCs)
  • Perfluorocarbons (PFCs)
  • Sulphur hexafluoride (SF6)

These gases play an important role in maintaining the Earth's temperature, but their excessive concentration is harmful to the environment.