1. Chapter 2: Variable Weather and
Changing Climate

2. How do human activities contribute to
enhanced greenhouse effect?
1. Burning fossil fuels
• The major fossil fuels are oil, coal and natural gas.
• Energy produced from burning fossil fuels is used for
industries, transportation, domestic and commercial
activities.
• Fossil fuels produce more than 80percent of global energy.
• Fossil fuels contribute to the increase in greenhouse gases.
• The usage of fossil fuels has increased over the years.

3. Fossil Fuels Consumption

4. 2. Deforestation
• Loss of forests due to the removal or clearance of trees in forested
areas.
• Forests absorb millions of tonnes of carbon dioxide every year via
photosynthesis, thus taking in a significant amount of global
greenhouse gas emissions.
• With deforestation, there are fewer trees and other plants to absorb
carbon dioxide.
• Soil is one of the largest sources of carbon in the world.
• Deforestation exposes soil to sunlight.

5. 2. Deforestation
• This increases soil temperature and the rate of carbon oxidation in
the soil.
• Carbon oxidation is a process by which carbon in the soil reacts with
oxygen in the atmosphere to produce carbon dioxide.

6. •
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The greatest loss of forests
occur in South America.
Southeast Asia experiences
the second highest rate of
deforestation.
Great losses in forests also
occur in Australia and
Africa.
The need for development
is the cause for forest
clearance.
To reduce the problem of
deforestation, many
countries have planted
new trees or have imposed
laws restricting the trees
that have been felled.

7. 3. Changing Land Use
• (a) Agriculture
• Is the practice of cultivating land, producing crops and raising
livestock.
• Third highest contributor of greenhouse gases.

8. Tractors run
on fossil fuels
which release
carbon
dioxide.
The use of
inorganic fertilisers
increases the
amount of nitrous
oxide in the soil.
Nitrous oxide is
released when soil
is ploughed or when
rain flows through
the soil.
Organic matter
such as dead
leaves and
manure
releases
methane
during
decomposition
Decomposition
is very rapid in
rice fields due
to a high level
of moisture in
the soil.

9. 3. Changing Land Use
• (a) Agriculture
• Cattle farming
contributes to
greenhouse gas
emissions because cattle
release methane as a
waste gas. Millions of
tonnes of methane are
released each year from
cattle farming.

10. 3. Changing Land Use
• (b) Industries
• Refers to the production of goods and services within a country.
• Secondary industries which are industrial economic activities such
as manufacturing, involve the burning of fossil fuels that result in
greenhouse gas emissions.
• Greenhouse gases are also released as by-products when goods are
produced.
• Some processes or products result in greater emissions than
others.

11. http://www.theguardian.com/news/datablog/interactive/2
012/mar/29/carbon-map-infographicworld?guni=Article:in%20body%20link
http://www.rtcc.org/files/2012/11/carbon-map-forweb.jpg

12. 3. Changing Land Use
• (c) Urbanisation
• Is the process by which an increasing
number of people live in urban areas
such as cities or towns.
• Large amounts of fossil fuels are
burnt to provide energy for household
activities in urban areas.
• High concentration of cars, buses and
other forms of transportation in
urban areas also contribute to the
amount of greenhouse gases emitted
in these areas.

13. How does climate change affect people?

14. How does climate change affect people?
Causes
Sea level rise
• Sea level rise is the
• 600 million people
increase in the mean
height of the sea’s
surface between high
tide and low tide
relative to land.
woldwide live in areas
less than 10 metres
above sea level.
• Rising sea levels
threaten low-lying
areas and islands.
• High temperatures
cause the melting of
glaciers that cause a
rise in sea level.
• 2/3 of the world’s
• Higher temperatures in
the atmosphere cause
water in oceans and
seas to expand. This
increases the sea level.
Consequences
http://ensnewswire.com/2013/09/03/10coastal-cities-at-greatest-floodrisk-as-sea-levels-rise/
largest cities in
coastal areas are also
at risk due to rising
sea levels.

15. How does climate change affect people?
Causes
• These include
heatwaves, floods,
droughts and tropical
cyclones.
• Increasing due to
higher land and sea
surface
temperatures.
More frequent extreme
weather events.
Consequences
• An extreme weather
event is a severe and
rare weather
phenomenon that
results in significant
economic losses and
loss of lives.

16. More frequent extreme weather events.
• Case Study – UK
• Examples of extreme weather events in the UK:
• Drought - caused by a lack of rain.
• Flash floods - caused by too much rain in a short period of time.
• Strong winds and storms.
• An extreme cold spell.
• An extreme heat wave.
• All of these have happened in the UK between 2000 and 2010:
• A lack of rainfall leading to drought
• During 2004-06 the UK received below average rainfall. This meant that reservoirs
and groundwater supplies were not recharged with the water needed.

17. More frequent extreme weather events.
• An extreme cold spell
• In December 2010 much of the UK was under snow. Arctic air
caused the temperatures to drop significantly below the
average. At night temperatures of -10°C were not uncommon.
• An extreme heat wave
• In summer 2003 Europe suffered from an intense heat wave. In
the UK the temperature of 38.5°C was the highest ever to be
recorded.

18. • Case study: extreme weather in the UK
• During December 2010 winds from the north east brought cold arctic air and snow. Scotland
and North East England were significantly affected, with snow 50 cm deep in places.
Temperatures were mainly below 0°C, making it the coldest December in the last 100 years.
• The impacts were:
• Roads were closed. People were stranded in their cars overnight on the M8 and A9 in
Scotland.
• Airports closed, including Heathrow and Gatwick, disrupting travel plans over Christmas.
• Schools closed.
• On 20 December the AA reported its busiest-ever day because of car breakdowns.
• More people than usual were admitted into hospital because of accidents and falls.
• Emergency services and local authorities were all put under pressure.
• After areas thawed, there were problems with burst water pipes. In Northern Ireland 40,000
homes were without water.

19. Case Study – UK
• Flash flooding
• Emergency services on the scene of flooded village of
Boscastle
• Boscastle in Cornwall suffered a flash flood in August 2004.
Nearly three times the average rainfall for the whole of
August fell in just one day. The rain ran down the steep valley
sides causing flooding in the village. The floodwater picked
up cars and trees in its path.
• Strong winds and storms
• In January 2005 stormy weather brought havoc to roads in
the North of England as lorries overturned. Power was also
cut off in 80,000 homes. Winds of over 100 mph were
recorded.
Emergency services on the
scene of flooded village of
Boscastle.

20. How does climate change affect people?
Causes
• Climate change could
result in increased
temperatures and rainfall
in various parts of the
world.
• Insects thrive in these
favourable conditions.
• The distribution of the
occurrence of infectious
insect – borne diseases is
also changing. Regions
with moderate
temperatures such as
Europe and North
America are facing
diseases once confined to
the tropics
Spread of infectious
insect-borne diseases.
Consequences
• Heavy rainfall may
allow mosquitoes to
grow in numbers in
aquatic habitats
resulting in the
spread of malaria
and dengue fever.

21. How does climate change affect people?
Advantages
Disadvantages
• An increase in the
• In the Yunnan
types of crops that
can be grown in the
United Kingdom.
• New crops such as
blackberries and
maize can be
cultivated.
• The production of
fruit, soyabeans,
potatoes and wheat
is projected to
increase in Canada.
Lengthening the growing
season in certain regions.
• Higher temperatures may
result in growing season.
• The growing season refers
to the period during which
crops can be grown.
province, China, the
production of fruits
such as apples and
cherries and nuts
such as almonds
and walnuts is
reduced as these
fruits and nuts
require cool
weather conditions.

22. • http://environment.nationalgeographic.com/environment/global-
warming/gw-impacts-interactive/