World Climate and Climate Change

NCERT Solutions • Class 11 Geography • Chapter 11
1. Multiple Choice Questions
(i) Which one of the following is suitable for Koeppen’s “A” type of climate?
(c) Mean monthly temperature of all the months more than 18° C
Reason: Koeppen defined the Tropical Humid Climate (Group A) as a climate where the mean temperature of the coldest month is at least 18°C, meaning winter is absent.
(ii) Koeppen’s system of classification of climates can be termed as:
(d) Empirical
Reason: It is largely empirical because it is based on observed data of temperature and precipitation rather than the causes (genetic) of climate.
(iii) Most of the Indian Peninsula will be grouped according to Koeppen’s system under:
(d) “Am”
Reason: “Am” stands for Tropical Monsoon climate, which characterizes the majority of the Indian Peninsula (High rainfall with a short dry season).
(iv) Which one of the following years is supposed to have recorded the warmest temperature the world over?
(b) 1998
Note: According to the traditional text context, 1998 was a landmark warm year due to a strong El Niño. (Recent data shows newer records like 2016, 2023, and 2024, but 1998 is the expected answer based on the textbook edition).
(v) Which one of the following groups of four climates represents humid conditions?
(b) A—C—D—E
Reason: Group B is explicitly defined as “Dry Climates.” Therefore, the other major groups (A, C, D, E) are generally categorized as humid (or at least non-dry) climates.
2. Short Answer Questions
(i) Which two climatic variables are used by Koeppen for classification of the climate?
Koeppen used Mean Monthly Temperature and Mean Monthly Precipitation. He associated these values with the distribution of vegetation to classify climatic zones.
(ii) How is the “genetic” system of classification different from the “empirical one”?
  • Empirical Classification: Based on observed data (temperature/rainfall) (e.g., Koeppen). It focuses on “what” the climate is.
  • Genetic Classification: Based on the causes or origin of the climate (e.g., air masses, solar radiation). It focuses on “why” the climate exists.
(iii) Which types of climates have very low range of temperature?
Tropical Climates (Group A), specifically the Tropical Wet Climate (Af) found near the equator, have a very low daily and annual range of temperature because the sun is almost vertical year-round and humidity is high.
(iv) What type of climatic conditions would prevail if the sun spots increase?
An increase in sunspots is generally associated with an increase in solar irradiance. This usually leads to warmer climatic conditions and more active weather patterns on Earth due to higher energy input from the sun.
3. Long Answer Questions
(i) Make a comparison of the climatic conditions between the “A” and “B” types of climate.
Criteria Group A: Tropical Humid Climates Group B: Dry Climates
Location Between Tropic of Cancer and Tropic of Capricorn. Subtropical highs and middle latitudes.
Temperature Warm throughout the year. Coldest month mean temp $> 18^\circ C$. Variable. Can be hot (Subtropical) or cold (Mid-latitude), but defined by aridity, not just temperature.
Precipitation High rainfall (Precipitation $>$ Evaporation). Very low rainfall (Evaporation $>$ Precipitation).
Seasonality No winter season. Often have extreme seasonal variations (hot summers/cold winters in mid-latitudes).
(ii) What type of vegetation would you find in the “C” and “A” type(s) of climate?
Vegetation in Group A (Tropical Humid):
Due to high heat and moisture, this zone supports dense vegetation.
  • Af (Tropical Wet): Tropical Rainforests (Evergreen, dense canopy, high biodiversity).
  • Am/Aw (Monsoon/Savanna): Deciduous forests (shed leaves in dry season) and tropical grasslands (Savanna).

Vegetation in Group C (Warm Temperate):
Characterized by mild winters and distinct seasons.
  • Cs (Mediterranean): Hard-leafed evergreen trees (Olives, Oaks) adapted to dry summers.
  • Cf (Marine West Coast): Deciduous trees (Oak, Beech, Maple) and mixed forests.
  • Cw (China Type): Broadleaf evergreen forests and grasslands.
(iii) What do you understand by the term “Greenhouse Gases”? Make a list of greenhouse gases.
[Image of greenhouse effect diagram]
Definition: Greenhouse gases (GHGs) are gases in the atmosphere that absorb and emit radiant energy within the thermal infrared range. They are transparent to incoming short-wave solar radiation but opaque to outgoing long-wave terrestrial radiation. This traps heat near the earth’s surface, causing the Greenhouse Effect.

List of Greenhouse Gases:
  • Carbon Dioxide ($CO_2$): Major contributor from fossil fuels.
  • Methane ($CH_4$): From livestock, paddy fields, and wetlands.
  • Nitrous Oxide ($N_2O$): From fertilizers and industrial processes.
  • Chlorofluorocarbons (CFCs): Synthetic gases used in refrigeration (also damage ozone).
  • Water Vapour: The most abundant natural GHG.
  • Ozone ($O_3$): In the troposphere.
Project Work
Topic: Kyoto Declaration (Kyoto Protocol)
Information Summary:
  • What is it? An international treaty adopted in Kyoto, Japan, in 1997 (entered into force in 2005) under the UN Framework Convention on Climate Change (UNFCCC).
  • Goal: To reduce the emission of greenhouse gases ($CO_2$, $CH_4$, etc.) that contribute to global warming.
  • Key Features:
    • It placed heavier burdens on developed nations under the principle of “common but differentiated responsibilities.”
    • It introduced market-based mechanisms like Carbon Trading and the Clean Development Mechanism (CDM).
  • Status: It was the first major step in global climate action, though it has now been succeeded by the Paris Agreement (2015).
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