This document discusses weather, climate, and climate change. It begins by defining weather and climate, and describes the key elements of weather including temperature, relative humidity, clouds, rainfall, air pressure, and wind. It then explains the major climate types and their locations: equatorial, monsoon, and cool temperate marine west coast climates. The document goes on to discuss evidence that the global climate has changed in recent decades due to both natural and human factors like the greenhouse effect. It may lead to more extreme weather and affect people. Responses to address climate change are also mentioned.

1. VARIABLE WEATHER AND
CHANGING CLIMATE
A Continuing Challenge?
1

2. VARIABLE WEATHER AND CHANGING
CLIMATE
A Continuing Challenge?
In this Chapter you will explore three key
questions:
1.Why do different places experience different
weather and climate?
2.What is happening to the earth’s climate?
3.Is the weather becoming more extreme?
2

3. Gateway 1: Why do different places experience
different weather and climate?
a. What is the difference between weather and climate?
b. What are the elements of weather?
-Temperature, relative humidity, clouds, rainfall, air
pressure and wind.
c. What are the climatic types and where are they
experienced?
VARIABLE WEATHER AND CHANGING CLIMATE
3

4. a. What is the difference between
weather and climate?
Weather: Condition of atmosphere at a
particular place and specific time.
Climate: Average condition of the atmosphere of
a particular place over a long period of time,
usually 30 years.
4

5. b. What are the elements of weather?
Temperature
• Temperature: Degree of hotness or coldness of a
place.
5

6. b. What are the elements of weather?
Temperature
• Factors influencing temperatures at
different
locations.
- Latitude
- Altitude
- Distance from the sea
- Cloud cover
6

7. Factors influencing temperatures at different
locations (LATITUDE)
• Latitude: Distance of any point on the earth
measured north or south from the Equator.
– Imaginary horizontal lines east to west of Equator.
– Equator is at a latitude of 0°
North Pole is 90°N.
South Pole is 90°S.
Latitude is the most important factor affecting
temperature!
7

8. Factors influencing temperatures at
different locations (LATITUDE)
The nearer the
Equator, the
higher the
temperatures.
The further
from the
Equator, the
lower the
temperatures.

9. Factors influencing temperatures at
different locations (ALTITUDE)
• Altitude: Height of a place in relation to sea
level.
- General decrease of 6.5°C for every 1,000 m increase in
altitude.
9

10. Factors influencing temperatures at
different locations (ALTITUDE)
How does altitude affect temperature?
• Distance from surface of the earth
- Longwave radiation is heat emitted by the earth
after absorbing shortwave radiation
- Most heat absorbed by the earth at lower
altitudes -> little heat at high altitudes -> cooler
• Density of air
- Air is less dense at higher altitudes -> absorb less
long wave radiation -> lower temperatures
10

11. Factors influencing temperatures at
different locations (DISTANCE FROM SEA)
LOCATION LATITUDE DISTANCE
FROM SEA
TEMPERATURE
RANGE
ANCHORAGE 61.1919° N 1 KM 20°C
FAIRBANKS 64.8378° N 420KM 40°C
The sea heating and cooling more slowly
than land influences the temperatures of
inland and coastal areas.
11

12. Factors influencing temperatures at
different locations (DISTANCE FROM SEA)
Maritime Effect: Effect large ocean bodies have on
climate of coastal areas.
• Small temperature range
• Cool summers and warm winters
Continental Effect: Effect huge land surfaces have
on climate of inland areas.
• Large temperature range
• Hot summers and cold winters
12

13. Factors influencing temperatures at
different locations (CLOUD COVER)
• Cloud cover: Extent of sky covered by clouds
- Higher amount of cloud cover results in smaller daily
temperature range
Do you know?
The average daily temperature
range of the Sahara desert is
30°C? During very hot months,
the temperature can be as high
as 55°C in the day.
Temperatures may also fall to
below 0°C at night! 13

14. Factors influencing temperatures at
different locations (CLOUD COVER)
With cloud cover Without cloud cover
Day: Cooler
-> Clouds reflect sun’s energy back to
space.
Night: Warmer
-> Clouds prevent heat radiated from
ground from escaping.
Day: Warmer
-> Large amount of sun’s energy reaches
earth’s surface.
Night: Cooler
-> Allows more heat radiated from ground
to escape.
14

15. b. What are the elements of weather?
Relative humidity
• Relative humidity: Ratio (usually expressed in
percentage) between the actual amount of
water vapour present in a mass of air and the
maximum amount of water vapour the air can
hold at a given temperature.
- Air at 15°C with 5 g/m3 of water vapour but can
contain max 10 g/m3 of water vapour -> R.H. 50%
- If actual amount of water vapour the air holds
increases to 6 g/m3, relative humidity will be 60
percent instead.
15

16. b. What are the elements of weather?
Relative humidity
• The effect of temperature on relative
humidity
- At higher temperatures, the air will be able
to hold more water vapour.
- As air molecules are more spread out,
more water vapour can fill the spaces.
- Therefore, assuming the actual water
vapour in air is constant, relative humidity is
lower at higher temperatures and higher at
lower temperatures. 16

17. b. What are the elements of weather?
Clouds
What will happen when relative humidity is at 100%
and more evaporation takes place after that?
Clouds will be formed when dew point
temperature is reached.
17

18. b. What are the elements of weather?
Rainfall
• Rainfall: Water that falls from the
atmosphere to the surface of the
earth.
• Two main kinds of rainfall we will
learn about:
- Convectional rainfall
- Relief rainfall
18

19. Convectional rain
19
Cumulonimbus clouds are usually
associated with convectional rain

20. Convectional rain
• Most common rainfall type in the tropics.
- Linked to lightning and thunder.
- Short but intense periods of rain.
• Formation
Sun’s rays heat up earth’s surface
Air expands and rises
Temperature drops at high altitudes and air cools to dew point
Condensation occurs and clouds are formed
Rain falls
20

21. Convectional rain
21

22. Relief rain (Orographic)
• Relief rain: Occurs when warm, moist air is forced to rise
over landforms such as a mountain range.
22

23. b. What are the elements of weather?
Air Pressure
• Air Pressure: Force exerted on a unit area
of the earth’s surface by the weight of a
column of air above it.
- Measured in millibars (mb) using a
barometer
- Air pressure decreases as altitude increases
Air is less dense hence the weight of the
column of air at higher altitudes is lower.
23

24. b. What are the elements of weather?
Wind
• Wind: Moving air created when neighbouring
locations have different air pressures.
- Air moves from high to low pressure.
- The larger the difference in pressure, the faster
the wind speed.
• Two kinds of wind systems we will learn
about:
- Land and sea breezes
- Monsoons 24

25. Land and sea breezes
• Local winds that occur in coastal areas
• Helps to regulate temperature, lowering the
diurnal range.
25

26. Sea breeze
• Sea breeze: Wind that blows from sea to land
26

27. Sea Breeze
• Sea breeze occurs during the day
Land absorbs heat faster than water
Higher temperatures over land than sea
Pressure is lower over land than sea
Wind blows from high pressure area over the sea to low pressure
area over the land
27

28. Land breeze
• Land breeze: Wind that blows from land to sea
28

29. Land Breeze
• Land breeze occurs during the night
Land loses heat faster than water
Higher temperatures over sea than land
Pressure is lower over sea than land
Wind blows from high pressure area over the land to low
pressure area over the sea
29

30. Monsoon winds
30
Why does Singapore
receive more rainfall
from November to
January than the rest
of the year?

31. Monsoon winds
• Regional wind pattern that reverses direction
seasonally. This will result in seasonal changes in
precipitation.
• Monsoon winds affected by the Coriolis effect.
- Coriolis effect is a force produced by the earth’s rotation
- Earth’s rotation will deflect the wind’s direction.
31

32. Monsoon wind — Coriolis Effect
32

33. What are the climatic types and where
are they experienced?
33

34. What are the climatic types and where
are they experienced?
We will learn about 3 key climate types:
1) Equatorial Climate
2) Monsoon Climate
3) Cool temperate (marine west coast)
34

35. Equatorial climate
35

36. Equatorial climate
36
• High temperatures, high rainfall, high
humidity all year round.
• Dominantly convectional rain with large
cloud
cover: small diurnal range
• Places are located between 10° north
and south of Equator.
- Examples: Singapore, Malaysia, Congo,
Brazil

37. Monsoon climate
37

38. Monsoon climate
• High temperatures, high rainfall, high
humidity all year round.
• Distinct wet and dry season
• Moderate temperature range (7.5° C)
• Located between 5° and 25° north and
south of Equator
- Examples: India, Sri Lanka, Vietnam
38

39. Cool temperate (marine west-coast)
climate
39

40. Cool temperate (marine west coast)
climate
• Mild winters and cool summers
• Rainfall evenly distributed but total
annual rainfall is lower than in places
with equatorial and monsoon climates.
• Large temperate range of 25°C
• Located between 45° and 60° north and
south of Equator.
- Examples: France and Canada
40

41. Gateway 2: What is happening to the Earth’s
climate?
a. How has global climate changed?
b. What are some natural causes of climate change?
c. What is the greenhouse effect?
d. How do human activities lead to enhanced greenhouse
effect?
e. How does climate change affect people?
f. What are the responses to climate change?
41
CHAPTER 2
VARIABLE WEATHER AND CHANGING CLIMATE

42. a. How has global climate changed?
• Global Climate Change: variation in the global
climate or climatic patterns in the long term.
How has
temperatures
changed from
1800 until 2000?
42

43. • Changes in global climate since 1881.
- Earth warmed up by 0.74° C in 100 years.
- Greatest increase after 1980s
- Some places recorded much higher temperature increases.
 Arctic, Asia and Africa (1.2° C to 1.4 ° C)
a. How has global climate changed?
43
• Variations in solar output
• Volcanic eruptions
b. What are some natural causes of
climate change?

44. Variations in solar output
• The magnetic activity of the
sun has a cycle that lasts
about 11 years.
• An increase in solar
radiation is due to an
increase in sun spots.
– Areas surrounding the
sunspots radiate more
energy to make up for the
cooler sunspot areas.
• With higher solar radiation,
earth’s temperatures will
increase. Sunspots represented by the dark spots
on surface of the sun.
44

45. Volcanic eruptions
• Global dimming: Gradual reduction in the amount of
sunlight reaching the earth’s surface. Temporarily
cools the earth for months or years.
– Dust particles from eruption form condensation nuclei,
creating more cloud cover.
– Dust and ash also reflect away incoming solar radiation.
• For example, Mount Pinatubo eruption lowered
temperatures by as much as 0.6°C for as long as two
years.
45

46. c. What is the greenhouse effect?
• Greenhouse effect: Natural process in which the
gases in the Earth’s atmosphere trap longwave
radiation emitted from the earth’s surface, warming
the atmosphere.
• Water vapour, carbon dioxide, methane, nitrous
oxide ozone and halocarbons such as
chlorofluorocarbons (CFCs) are good absorbers of
longwave radiation.
– They are known as greenhouse gases and are found in
the atmosphere.
46

47. 47

48. What is the enhanced greenhouse
effect?
• Enhanced greenhouse effect: Increase
in the concentration of greenhouse
gases in the atmosphere, leading to a
rise in global temperatures.
–Generally due to human activities that
release an increased amount of
greenhouse gases, most notably carbon
dioxide.
48

49. 49

50. d. How do human activities lead to
enhanced greenhouse effect?
• Burning fossil fuels
• Deforestation
• Changing land use
– Agriculture
– Industries
– Urbanisation
50
Proportion of greenhouse
gases in atmosphere
Carbon
Dioxide
(72%)
Methane
(10%)
Nitrous
Oxide (5%)
CFCs (13%)

51. Burning fossil fuels
• Fossil fuels: formed from decomposition
of dead organic matter over millions of
years
- For example, petroleum, coal and natural
gas.
- Powers 80% of the world’s energy
- Contains high carbon content, releases huge
amount of carbon dioxide when burnt
- Highest contributor of greenhouse gases.
51

52. Burning fossil fuels
52

53. Deforestation
• Deforestation: Loss of forests due to the
removal or clearance of trees in forested
areas.
• Causes increase in levels of carbon
dioxide in two ways:
–Fewer trees to absorb carbon dioxide
–Carbon oxidation: Carbon in soil reacts with
oxygen to produce carbon dioxide, aided by
higher temperatures when soil is exposed
to sunlight. 53

54. Changing land use
54
Agriculture Industries Urbanisation

55. Agriculture
Agriculture: Practice of cultivating land,
producing crops and raising livestock.
55

56. Agriculture
• Cattle farming releases millions of tonnes of
methane into the atmosphere annually, as gases are
released from the digestive systems of cattle.
56
Greenhouse gas emissions
from agriculture and land use

57. Industries
• Industries:
Production of goods
and services within a
country.
- Major contributor of
carbon dioxide
through the burning
of fossil fuels to
create energy
needed to run
factory processes. 57

58. Urbanisation
• Urbanisation: Process by which an increasing
number of people live in urban areas.
58
- Various human
activities are
concentrated or are
necessary in urban
places. All of them
contribute to the
amount of greenhouse
gases in the
atmosphere.

59. e. How does climate change affect people?
Four key impacts of climate change we will
learn about:
1) Sea level rise
2) Frequent extreme weather events
3) Spread of infectious insect-borne
diseases
4) Lengthening of growing season in
certain regions 59

60. Sea level rise
• Sea level rise: Increase in the mean
height of the sea’s surface between
high and low tide relative to land.
–Higher temperatures causes water to
expand
–Higher temperatures causes glaciers to
melt, adding meltwater to the sea 60

61. Frequent extreme weather events
• Extreme weather events: severe
and rare weather phenomenon
that results in significant
economic losses and the loss of
lives
- Eg. Heat waves, floods, droughts
and tropical cyclones
61

62. Spread of infectious insect-borne
diseases
• Link between insect-borne diseases
and climate change:
- Increased rainfall and temperatures is
favourable for mosquitoes to breed
(allows spread of malaria and dengue
fever)
- As temperate countries get warmer,
mosquitoes are able to breed further up
north of the Equator 62

63. 63

64. Lengthening of growing season in
certain regions
• Higher temperatures have lead to longer growing
seasons for some regions.
- Advantage (Cold regions are now warmer, more
conducive for crop growing)
• Increase in types of crops that can be grown in UK.
• Increase in fruit, soybeans, potatoes and wheat in
Canada.
- Disadvantage (Cool regions are now getting hotter,
less conducive for crop growing)
• Apples and cherries production in Yunnan is reduced as they
need cool conditions.
• Wheat yield has decreased in Canada.
64

65. f. What are the responses to climate
change?
• International Level
–Kyoto Protocol (1997)
–Copenhagen Conference (2009)
• National Level
–Singapore
–India 65

66. Kyoto Protocol
• Kyoto Protocol: An international agreement to
reduce greenhouse gases emission into the
atmosphere.
– Drawn up on 11/12/97, came into effect 16/02/05
– Different countries have different targets to hit
and progress of carbon emissions will be tracked
and reported for review.
66

67. Kyoto Protocol
Successes
• Many countries met or exceeded targets
set by Kyoto Protocol as there was
constant monitoring and reporting by
countries for self and peer assessment.
• Encouraged sustainable development.
- Developed countries are encouraged to
work with developing countries in carbon-
reducing projects (Clean Development
Mechanism — CDM) 67

68. Kyoto Protocol
Limitations
• Not all countries are able to meet their goals and not
all countries have the same emission targets.
- Denmark, Sweden and the United Kingdom did not achieve
their targets
• Many countries did not sign the Kyoto Protocol and
continue to contribute to global emissions.
- A large portion of the increase in global emissions came
from China, India and the United States of America
68

69. Copenhagen Conference
• Copenhagen Conference:
Held in Denmark, hosted
the United Nations Climate Change Conference to
build upon measures developed in previous
conferences for addressing climate change.
69

70. Copenhagen Conference
Successes
• Allow countries to discuss measures to deal with
climate change effectively, including improvements
to CDM.
• International agreement to keep increase in global
temperature to below 2°C.
• Pledges were made and developed countries pledged
to:
- Reduce greenhouse gas emissions by 2020.
- Provide US$30 billion for developing countries to fight
climate change.
70

71. Copenhagen Conference
71

72. Copenhagen Conference
Limitations
• Lack for concrete plans on how to reduce
greenhouse gases
• Copenhagen Accord (Agreement) was
not adopted by all countries.
- The Accord was a guideline and no countries
will
be binded/punished if they do not fulfill their
pledges. 72

73. National response: Singapore
1) Singapore Green Plan 2012
• Reduce energy consumption and greenhouse
emission from burning fossil fuels
2) Green Mark Scheme
• Constructing ‘green’ buildings
3) Plant-A-Tree programme
• Planting more trees and plants 73

74. Singapore Green Plan 2012
74

75. Singapore: Green Mark Scheme
75

76. Singapore: Plant-A-Tree programme
76

77. National response: India
1) National Urban Transport Policy (NUTP)
- Emphasising public transport
2) Energy Labelling Programme
- Reducing energy consumption and greenhouse
emissions from burning fuels
3) Indian Network of Climate Change
Assessment (INCCA)
- Promoting India-specific climate change research
77

78. National Urban Transport Policy
(NUTP)
Description of strategy
• Launched in 2006 by Ministry of Urban
Development
• Aim to reduce motor vehicles on road by:
- Developing public transport
- Encourage non-motorised transport
• Use of cleaner technologies 78

79. National Urban Transport Policy
(NUTP)
Successes
• Rail, cycle, bus and pedestrian infrastructure
improved tremendously with funding from
Jawaharlal Nehru National Urban Renewal
Mission (JNNURM).
- Pedestrian infrastructure improve in Hyderabad.
- Bus Rapid Transport System (BRTS) expanded from 20
in 2006 to 68 by 2010.
- Carbon credits given to Delhi’s metro rail, whose 186
km of rail kept 91,000 vehicles off road and reduced
6.3 million tonnes of greenhouse gas annually. 79

80. National Urban Transport Policy
(NUTP)
Limitations
• Huge capital costs (billions) and many
years needed to build competent
public transport systems a hindrance.
• Increasingly affluent citizens will prefer
private vehicles over public transport.
80

81. Energy Labelling Programme
Description of strategy
• Started by Bureau of Energy Efficiency in 2007.
• Programme informed consumers of energy
efficiency of products. (The more efficient, the
cheaper)
• The label is mandatory for frost-free
refrigerators, fluorescent lamps, air conditioners,
distribution transformers.
• Voluntary for other appliances such as ceiling
fans, television sets, washing machines and
computers. 81

82. Energy Labelling Programme
Successes
• Consumers will be encouraged to buy products that
conserve energy, reducing country’s greenhouse gas
output.
• Sales of energy efficient appliances have steadily
increased since 2007
• Two major laptop producers pledged to adopt
labelling in 2011 with other major manufacturers
expected to follow. 82

83. Energy Labelling Programme
Limitations
• Many appliances are still not on the program
and most of public are still not aware of how
the labelling works/ what it means.
• Country has urgent need to provide energy for
citizens and using coal-powered stations
negate the labelling efforts.
83

84. Indian Network of Climate Change
Assessment (INCCA)
Description of strategy
• 220 scientists from 120 research
institutions promote domestic research
on climate change.
• They provide Indian-based climate data
for better reference during policy
implementation.
84

85. Successes
• Released first assessment (on issues such as
sea level, agriculture, water supply, human
health) of climate change impacts in India for
the next 20 years.
• Recommend constant monitoring and
research of India’s physical and biological
system by specific regional committees,
developing concrete plans thereafter.
85
Indian Network of Climate Change
Assessment (INCCA)

86. Limitations
• India is a rapidly developing economy and can
only sustain its development through
industrialisation and urbanisation.
• Recommendations by INCCA might go
unheeded by the government should concrete
plans made by them interfere with India’s
development.
86
Indian Network of Climate Change
Assessment (INCCA)