NCERT Solutions for Class 11 Geography Fundamentals of Physical Geography Chapter 11: World Climate and Climate Change

Chapter at a glance

Exercise Questions

Question 1 (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 (c) Mean monthly temperature of all the months more than 18°C (d) Average temperature for all the months below 10°C

Answer

3. Mean monthly temperature of all the months more than 18°C

Question 1 (ii)

Koeppen’s system of classification of climates can be termed as:
(a) Applied (b) Systematic (c) Genetic (d) Empirical

Answer

It is based on observed temperature and precipitation data.

4. Empirical

Question 1 (iii)

Most of the Indian Peninsula will be grouped according to Koeppen’s system under:
(a) “Af” (b) “BSh” (c) “Cfb” (d) “Am”

Answer

Of the options given, the large semi-arid interior of the Deccan, in the rain shadow of the Western Ghats, falls under BSh (hot steppe). Most of the rest of the peninsula is Aw (tropical wet and dry), which is not among the options.

2. “BSh”

Question 1 (iv)

Which one of the following years is supposed to have recorded the warmest temperature the world over?
(a) 1990 (b) 1998 (c) 1885 (d) 1950

Answer

2. 1998

Question 1 (v)

Which one of the following groups of four climates represents humid conditions?
(a) A—B—C—E (b) A—C—D—E (c) B—C—D—E (d) A—C—D—F

Answer

In Koeppen’s scheme A, C, D and E are humid climates; B is dry.

2. A—C—D—E

Question 2 (i)

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

Answer

Mean annual and mean monthly temperature and precipitation data, related to the distribution of vegetation.

Temperature and precipitation.

Question 2 (ii)

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

Answer

• The empirical classification is based on observed data — mainly temperature and precipitation — and describes climate as it is (e.g. Koeppen).
• The genetic classification groups climates according to their causes, such as air masses, pressure belts and winds.

Empirical classification is based on observed temperature and rainfall; genetic classification is based on causes such as air masses and circulation.

Question 2 (iii)

Which types of climates have very low range of temperature?

Answer

Tropical humid climates (A) — especially the tropical wet (Af) climate near the equator — have a very low annual range of temperature, since the sun is overhead throughout the year. Marine west coast climates (Cfb) also have low ranges.

Tropical humid (A) climates, especially equatorial Af; also marine west coast (Cfb).

Question 2 (iv)

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

Answer

According to some meteorologists, when sunspots increase, cooler and wetter weather and greater storminess occur. (A decrease is associated with warm and drier conditions, though the findings are not statistically significant.)

Cooler, wetter weather with more storms.

Question 3 (i)

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

Answer

A climates are hot and humid all year with heavy rain and low temperature range (Af, Am, Aw); B climates are dry, where evaporation exceeds precipitation, with high diurnal ranges (deserts and steppes).

Question 3 (ii)

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

Answer

A type (tropical humid)

• Af (tropical wet): dense tropical evergreen rainforests with many species, tall broad-leaved trees (mahogany, ebony, rosewood).
• Am (monsoon): tropical monsoon/deciduous forests (teak, sal) that shed leaves in the dry season.
• Aw (tropical wet and dry): savanna grasslands with scattered trees; deciduous forests.

C type (warm temperate/mid-latitude)

• Cfa (humid subtropical): mixed forests, broad-leaved evergreen and deciduous trees.
• Cs (Mediterranean): evergreen woody shrubs and trees with thick bark and waxy leaves (olive, cork oak, citrus).
• Cfb (marine west coast): deciduous broad-leaved forests (oak, beech, maple) and some conifers.
• Cwa/Cwb: mixed forests and grasslands.

A: tropical evergreen rainforests (Af), monsoon deciduous forests (Am) and savanna (Aw). C: mixed and broad-leaved forests (Cfa), Mediterranean evergreen shrubs (Cs), deciduous broad-leaved forests (Cfb).

Question 3 (iii)

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

Answer

Greenhouse gases are gases in the atmosphere that are transparent to incoming short-wave solar radiation but absorb the long-wave radiation emitted by the earth’s surface and re-radiate part of it back. Like the glass of a greenhouse, they trap heat and warm the earth (the greenhouse effect). Their increasing concentration due to human activities is causing global warming.

List of greenhouse gases

1. Carbon dioxide (CO₂)
2. Chlorofluorocarbons (CFCs)
3. Methane (CH₄)
4. Nitrous oxide (N₂O)
5. Ozone (O₃)
6. (Also water vapour, nitric oxide and carbon monoxide, which can affect them.)

Effect: the efficiency of a gas depends on its concentration, how long it stays in the atmosphere, and the wavelengths it absorbs. CFCs are highly effective; CO₂ is the most important in quantity. The Kyoto Protocol (1997) aimed to reduce emissions.

Gases that let in solar radiation but absorb outgoing long-wave radiation, warming the earth: carbon dioxide, CFCs, methane, nitrous oxide and ozone (and water vapour).

Topic checklist

• Approaches to climate classification
• Koeppen’s scheme: groups and types
• Climate change in the past and recent past
• Causes of climate change
• Greenhouse gases and global warming

Total questions answered: 12 of 12