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GEOGRAPHY IGCSE REVISION GUIDE
2020
What do you need to know?
You should use this CASE STUDY guide to learn all your case studies AND the IGCSE Cambridge
revision guide for theories and key terms
This is mainly for your 7 mark case study questions and there are exam questions included for you to
practise.
LEARN THEM!
Theme 1. Population and Settlement
1.1 Population dynamics
1.2 Settlement
Theme 2. The natural environment
2.1 Plate tectonics
2.2.1 Weathering
2.2.2 River processes
2.2.3 Marine processes
2.3.1 Weather/ 2.3.2 Climate/Ecosystems
2.3.3 Natural hazards
2.3.4 Human impacts: National Parks
Theme 3. Economic development and the use of resources
3.1 Agricultural systems
3.2 Industrial systems
3.3 Leisure activities and tourism
3.4 Energy and water resources
3.5 Environmental risks and benefits: resource conservation and management
Case studies by unit
Unit: Topic and case study:
1.1
Population
Rapid population growth: Case Study Niger
Overpopulation/anti natalist policy: Case Study: China
Under population: Pro natalist policy: Case Study Singapore / Italy
Population density and distribution: Case study: Botswana
International Migration: Mexico to USA
Rural to urban migration (internal migration) Case study: Brazil
HIV/AIDS: Case study: Botswana
1.2
Settlement
Case study: Rural settlements and Ethiopia and France
Case study: The reasons for the growth of an urban settlement: Seville
Case study: Urban model Seville
Case study: The effects of urbanisation / urban sprawl LEDC Case study: Rio de Janiero
Case study: The effects of urbanisation / urban sprawl MEDC Case study: Atlanta
Case study: Urban problems: Cairo, Egypt LEDC
2.1 Case study: Volcanic eruption MEDC Mount St Helens
Case study: Volcanic eruption LEDC: Mt. Pinatubo volcano in the Philippines 1991
Case study: Earthquake LEDC Haiti
Case study: Earth quake MEDC Kobe, Japan earthquake 1995
2.2.2 Case study: formation of a waterfall Niagara Falls
Case study: Living by Deltas Ganges, LEDC, Bangladesh
Case study: Flooding of the Brahmaputra and Ganges Rivers, Bangladesh (LEDC)
Case study: Flooding MEDC Boscastle UK
Case study: River management in MEDC: Mississippi River, USA
2.2.3 Case Study: Coastal erosion, transportation & deposition: The Hel Spit Poland
Case study: Coastal Landforms: The twelve apostles
Case study Coral Reefs: The Great Barrier Reef
2.3.1/2 Case study: Tropical Rainforest climate: Madagascar
Case study: Tropical Desert Climate: Sahel, Africa
2.3.3 Case study: Drought: Australia MEDC
Case Study: Drought Ethiopia LEDC
Case study: MEDC Tropical Storm: Hurricane Floyd, USA 1999 (MEDC)
Case study: LEDC Tropical Storm: Cyclone Myanmar
2.3.4 Case study: Deforestation of Tropical Rainforest: Amazon Rainforest
Case study: Sustainable Rainforest Scheme: Costa Rica
Unit 1.1 Population Dynamics
Population growth
The world’s population is increasing rapidly
Natural population change (NPC) is worker out by:
BIRTH RATE (BR) – DEATH RATE (DR) = NPC
If the answer is positive the growth rate is getting bigger and if the number is negative the growth
rate is getting smaller.
The unit is usually per 1000 people and to make it a percentage you must divide by 10.
Demographic transition model
The model shows that as a country develops the BR and DR change.
It is based on what happened in Europe and America in the past and is now used to predict the
population changes that will occur to developing nations (LEDCs)
Rapid population growth: Case Study Niger
Where is Niger?
West Africa, next to Algeria, Libya, Chad and Nigeria.
Information on Niger:
One of the poorest countries in the world
Mostly nomadic farming
Fertility rate of 7.1 babies born per woman
½ population is under 15 years old
It has a youthful population
Why are the birth rates so high?
Children needed to support farming
No sex education in countryside
Children wanted to look after parents when they are old
No social security
5% of people have access to contraception
Problems with population growth:
Limited access to clean water and resources
Population is rising as death rates fall and birth rates stay
the same or increase.
Why are death rates falling?
Vaccinations for children against diseases
Better supplies of water
Better diet
Better health care
Women becoming educated
No enough schools or jobs
Solutions:
Increase family planning clinics and education
Educate women
Higher age of marriage set to 18
Over or under population
Over or under population
Overpopulation: The number of people living in a place is more than the amount of resources
available – not enough resources to go around
Under population: The number of people living in a place is less than the number of resources
available – an excess of resources and a loss of money for the country, limited workforce
Overpopulation/anti natalist policy: Case Study: China
Where? Asia
What?People encouraged to have lots of children in the
1950s/60s to ensure Chinese victory in event of a war.
Problem: No enough food, jobs, healthcare, housing or
services for all the people and population was still rising
in 1970. The crime rate was rising and the country, air
and water were becoming polluted. A very low quality of
life.
Solution: One Child policy: Couples in cities only allowed
to have one child and must apply for permission from the
government. Free contraceptives and education on
family planning for all and an excessive propaganda
campaign. Couples in rural areas may have two children
if the first is girl or first child disabled or died.
Consequences:
Good:
China’s population of about 1.3 billion is said to be 300
million (.3 billion) smaller than it would likely have been
without the enactment of this policy.
The fertility rate has fallen to 1.7 births per woman.
Such a reduction in fertility reduced the severity of
problems that come with overpopulation, like epidemics,
slums, overwhelmed social services (health, education, law
enforcement, and more), and strain on the land from
farming and waste
Bad:
Uneven proportion of boys to girls as many girls are
aborted, heavy fines put on couples who wish to have a
second child so richer people can afford it while the poor
cannot. Spoiled children.
Some babies killed or sold if they are girls. Some women
forced to have abortions or be sterilised.
BUT: Population growth has been stabilised, policy has
been relaxed since 2003.
Under population: Pro natalist policy: Case Study Singapore / Italy
Where? Asia
What? Independent from the British since 1965, from
1950s tried to limit population by encouraging smaller
families but now has a declining population and a limited
Pro natalist 1980s: increased immigration, female
university graduates having children were given the best
school places, grants given to new parents, tax rebates
for third child, day care for children subsidised, 4 years
workforce
Anti natalist 1970s: Abortion and sterilisation made
legal, ‘stop at two’ campaign, extra tax on third child,
best schools’ places given to those with fewer children.
maternity leave for civil servants.
Outcomes: Not much change in the BR but immigration
has continued to help the economy
Where? Europe
Low fertility rates of 1.23 children per family
Ageing population
Some women feel that they cannot work and cope with
raising a family too
Some men not doing sufficient household chores
Poor service provision for childcare in preschool years
Childless no longer bears a stigma
Social pressure to marry and have childrenis less
Even though head of the catholic church is in Italy –
contraception use is high
Yuppiedom – preference for luxury goods delays
marriage and babies
Less than 1/3 mothers have children before 28 years
Young people live at home with parents longer to save
rent etc. which delays relationships and births
Solutions
10,000 euro bonus for births in a village in Mezzogiornio as
mayor concerned that young people will not enter village
otherwise
Population density and distribution:
Why are some places densely populated?
Employment, flat land, good communications, fertile soil, reliable water supply and natural
resources.
Why are some places sparsely populated?
Steep relief, infertile soil, cold climate, arid climate and marshy land.
Population density is the average number of people living in a given area (measured in people per
km2)
Total number of landtotal population = number of people per km2
But: Only if people are evenly spread out, which they are not!
Case study:Botswana, Kalahari desertPopulation density and distribution
Physical factors:
Kalahari area is semi desert with annual rainfall of less
than 400 mm
Soil is sandy and not fertile and other areas are protected
as national parks
Human factors:
Many people are nomadic farmers and have no fixed
settlements.
Other areas:
Deltas are wet and swampy
Economic factors:
Farming is very difficult in the Kalahari desert
Land cannot support animals or crops
Few roads and transport links
Chobe district has many dangerous wild animals
There are large areas of salt plains with no drinking water
Migration and its effects on population
Types of migrants:
Asylum seeker: person who has left due to fear of persecution
Refugee: person has left due to fear for their life from war, famine etc. FORCED MIGRATION
International migrant: person who moves to another country (if for work: an economic migrant)
National migrant: person who moves to lives somewhere else in their own/the same country
VOLUTARY MIGRATION
Illegal migrant: person who enters the country without permission
International Migration: Mexico to USA
What is the situation?
Mexicans make up 29.5 % of all foreigners in the USA.
Mexican immigrants account for about 20% of the legal
immigrants living in the USA.
Brain drain is occurring out of Mexico.
e.g. An estimated 14,000 of the 19,000 Mexicans with
doctorates live in the USA (International Organization for
Migration)
PUSH factors:
Push factors from Mexico (Santa Ines) (2010)
Poor medical facilities – 1800 per doctor
Low paid jobs – GDP per capita $14,406
Adult literacy rates 55% - poor education prospects
Life expectancy 72 yrs.
40% Unemployed
Unhappy life – poor standard of living
Shortage of food
Poor farming conditions
National average poverty level of 37 percent
PULL factors:
Excellent medical facilities – 400 per doctor
Well paid jobs – GDP per capita $46,860
Adult literacy rates 99% - good education prospects
Life expectancy 76 yrs.
Many jobs available for low paid workers such as
Mexicans
Better housing
Effects on USA
Illegal migration costs the USA millions of dollars for border
patrols and prisons
Mexicans are seen as a drain on the USA economy
Migrant workers keep wages low which affects Americans
They cause problems in cities due cultural and racial issues
Mexican migrants benefit the US economy by working for
low wages
Mexican culture has enriched the US border states with
food, language and music
The incidents of TB has been increasing greatly due to the
increased migration
Effects on Mexico (Santa Ines)
The Mexican countryside has a shortage of economically
active people
Many men emigrate leaving a majority of women
Women may have trouble finding marriage partners
Young people tend to migrate leaving the old and the very
young
Legal and illegal immigrants together send some $6 billion
a year back to Mexico
Certain villages such as Santa Ines have lost 2/3 of its
inhabitants
Family links
Bright lights
Rural to urban migration (internal migration) / Urbanisation Case study: Brazil, Sao Paulo
What and where: South America
Population urbanising in Brazil
Moving from north east rural areas e.g.
Pernambuco village
Moving to Sao Paulo
SP – On the south east coast of Brazil, West of
Rio de Janeiro
SP – Has expensive apartments and houses –
large gardens, swimming pools, maids, children
well educated, security guards etc.
BUT also favelas!
Push factors:
 Mechanisation of farms (bringing in
machinery to replace workers) results in high
rural unemployment
 Large landowners take back the land of
their tenant farmers to grow cash crops (crops
for money!) for export
 High infant mortality due to lack of clean
water, electricity, sewerage and medical care
 Housing in rural areas is even worse than
in the city
 Droughts and desertification (like the
Sahel!) in NE Brazil
 Lack of services e.g. schools, shops, etc.
NE Push Factors – milking by hand, drought +
desertification and Pernambuco village
Pull factors:
 Advertising campaigns were run in rural
areas in the 1950s and 1960s to attract workers
to the city
 More schools, doctors and other services
in the city
 Successful migrants encourage people to
join them
Café, better SOL / IT class better education /
Skyline “Bright Lights”
Problems: effects on rural areas
o Mainly young men who migrate
o Brian Drain – intelligent tend to move,
less intelligent stay
o Women, children and elderly left behind
o 27% of poor rural households headed by
women
o Lowers birth-rates as lack of men
o Elderly struggle to support themselves
o Lack of workforce for farming – child
labour is common
o Migrants send money back home to
families – called remittances (a positive!)
Problems: effects on Sao Paulo
• 2,000 migrants arrive per week!
• Do not have money for apartment – end
up in illegal favelas
• Favelas on outskirts of SP, on disused
land e.g. opposite factories or on steep hillsides
prone to landslides
• Made from wood, corrugated iron,
cardboard etc.
• Most have no clean running water
(cholera), toilets, safe electricity, rubbish
collection
• Overcrowded, disease spreads
• High birth-rate, 6 kids per shack!
Management of problem – Self-Help Scheme
 Run by local government and NGOs
(Non-government organizations)
 Local gov provides – breeze blocks,
roofing tiles, electricity, clean water, tarred
roads, community centre
 Self-help so favela dwellers – dig ditches
for pipes + build houses
 Gives sense of pride + community spirit
 Saves money so cheap houses
HIV/AIDS: Case study: Botswana
HIV: initial virus caught by the exchanging of bodily fluids, breast milk or blood – can be treated but
not cured.
AIDS: later stages of HIV virus which attacks the immune system and allows other infections into the
body.
Where: Africa (see above)
Problem:
In 2005 an estimated 270,000 people living with HIV (total
population below two million)
24.1% of people have HIV/Aids
Life expectancy less than 40 years in 2000-2005, a figure
about 28 years lower than it would have been without
AIDS.
An estimated 120,000 children have lost at least one
parent to the epidemic.
First case 1985
Many people have more than one sexual partner
Ignorance about AIDS and how it is spread
Sick people cannot contribute to the economy or to their
families
Large number of orphans with not enough government
money to help them - no education or possibilities for the
future
Solutions:
(1987-89) the screening of blood to eliminate the risk of
HIV transmission through blood transfusion.
(1989-97) information, education and communication
programmes– Botswana National Policy on AIDS.
(1997 onwards) education, prevention and comprehensive
care including the provision of antiretroviral treatment for
19,000 people.
HIV prevention programme:
Public education & awareness –
1. “ABC” of AIDS: Abstain, Be faithful and, if
you have sex, Condomize.
2. Safe-sex billboards and posters
everywhere.
3. Radio drama dealing with culturally specific
HIV/AIDS-related issues and encouraging
changes in sexual behaviour.
4. Workplace peer counselling.
Unit 1.2 Settlements
Rural Settlements:
Settlement: A place where people choose to live
MEDC: More economically developed country (richer countries like USA and European countries)
LEDC: Less economically developed country (poorer countries like Botswana, African countries)
Nomads: People who move from place to place and have no fixed settlement where they live
Urban settlements: Towns and cities (85% of people from MEDCs live in urban settlements)
Rural settlements: the countryside (75% of people in LEDCs live in rural settlements)
Site: The places people choose to build their settlements
Situation: The location of settlement
Shape: The shape the settlement has (nuclear, dispersed, linear)
Function: The main activities of the settlement
Nucleated settlement:buildings all clustered together around a central point
Dispersed settlement: buildings spread out in no particular pattern like farms or isolated dwellings
Where do/did people choose to site their settlements?
In places which have: water supply, gentle slopes, low altitude, good drainage, no flood risk,
resources (such as forests for building)
Case study: Rural settlements and Ethiopia and France
Ethiopia LEDC
Function: Farming maize
Advantages: water from 2 rivers, flat fertile soil, forests.
Services built like schools, mosques, a grain mill.
Disadvantages: lack of rain, drought, hunger, starvation,
heavy rain comes and then washes away dry soil, no market
or shops
Deforestation: due to the forest being cut down the soil is
more easily eroded
Solutions: irrigation system and diesel pumps sponsored by
American NGO
France MEDC – changes in rural settlement
Function: farming and tourism
Changes: larger fields, different crops, caravan parks,
increased tourism, land sold, young moving to the cities,
aging population, decline in services, more English owned
businesses.
Urban settlements:
Settlement hierarchy: settlements put in order of size and services they provide
Sphere of influence: The areas which a settlement serves (how far people are willing to travel to use
the services in that settlement)
Low order services: mostly in rural settlements, used frequently and selling basic and cheap
products; e.g. bread and milk – need low threshold population
High order services: mostly in or near to urban settlements, used less frequently with products that
are not needed on a day to day basis; e.g. televisions – need high threshold population
Threshold populations: The number of customers needed for a business to survive.
Functions of urban settlements
Market town: where farmers buy and sell goods
Port: where goods are loaded and unloaded by ship
Industrial town: where factories are located close to resources or transport on rivers
Resort: where tourists come to enjoy themselves
Case study: The reasons for the growth of an urban settlement: Seville
Where: Spain
Function of settlement: tourism, industry, market town
Original site features: flat fertile land to grow oranges
and food, water supply, Mediterranean climate.
Reasons for growth: close to sea, port leading to gold
coming from South America, factories grew along the river,
culture and history brought tourism, famous for oranges
Urban land use
Models: Burgess and Hoyt created models to show how land is usually used in an MEDC based on
the value of land. Burgess’ model comes from when cities and towns began to industrialise along
rivers for transport and therefore poorer people were forced to live nearer the factories in the
centre of the city. Hoyt then modernised the model as factories declined or moved further outside
the city as transport improved.
CBD: The central business district. You would expect to see: expensive land, high density of
buildings, crowded, high order shops, industry (in MEDCs), offices, and flats.
Case study: Urban model Seville
CBD
High order shops e.g. El Corte Ingles, pedestriansed,
transport links, metro, underground rail service, offices,
small medieval streets
Inner city
Residential areas with flats, rejuvenation of old factory
buildings, high density of living spaces, no gardens,
transport links and services, offices
Outer city
Larger houses with gardens, transport links developed, low
and high order services, shopping malls as land is cheaper.
E.g. Ikea, Aire Sur
Urbanisation
The movement from the countryside to the city
MEDCs: Took place mainly before the 1950s during the industrial era
LEDCs:Is now beginning to happen in LEDCs because of a) lack of resources in countryside PUSH b)
standard of living in urban areas are better PULL
Rural to urban migration
Push: poverty, not enough land, failed crops, high infant mortality, no prospects, loss of farm work,
lack of food, drought.
Pull: education, medical care, housing, jobs, shops, money
Problems: noise, dirt, pollution, over crowded, expensive land, low paid jobs
Urban sprawl: Urban settlements extending into the rural urban fringe. Planned in MEDCs, not
planned in LEDCs
Case study: Urbanisation in LEDC
USE CASE STUDY FOR RURAL URBAN MIGRATION BRAZIL, SAO PAULO FROM UNIT 1.1
OR:
Case study: The effects of urbanisation / urban sprawl LEDC Case study: Rio de Janiero
Where and what is it?
Rio was formerly the capital of Brazil until the government
decided to locate the capital inland in Brasilia.
Approximately 10 million people live in and around Rio.
It is a city of contrasts with rich people living in luxury
around Copacabana beach and the vast majority living in
poor conditions around the edge of the city.
Problems in the city include housing, crime, traffic and
pollution.
HOUSING
An estimated 0.5 million are homeless.
Approximately 1 million live in favelas (informal shanty
settlements). Two examples are Morro de Alemao and
Rocinha. (YOU MUST KNOW THESE NAMES!!)
Another million live in poor quality government housing on
the outskirts.
The favela housing lacks basic services like running water,
sewerage or electricity.
The houses are constructed from wood, corrugated iron,
broken bricks and tiles or other materials found lying
around.
Favelas are often found on land that is steep, by the side of
roads, railways etc. and flash floods can destroy such
houses and take people’s lives.
At first the government tried to bulldoze such
communities but now they remain because of the
community spirit, samba music and football etc.
CRIME
Favelas are thought to be associated with drugs, violence
etc. Tourists to Rio are warned not to enter favela areas or
take valuables to beaches etc.
Some wealthy are moving to new towns to avoid crime.
TRAFFIC AND POLLUTION
Mountains around the city keep the fumes in the city and
make the vehicles use a limited number of routes. This
results in congestion and noise
A vast amount of rubbish is produced and in favelas this is
not collected. Along with open sewerage drains it results
SOLUTIONS TO THESE PROBLEMS
SELF HELP HOUSING ROCINHA
Most of old temporary wooden houses replaced by brick and
tile and extended to use every square centimeter of land.
Many residents have set up their own shops and small
industries in the informal sector.
Government has added electricity, paving, lighting, water
pipes but the steep hills still restrict.
2. FAVELA BAIRRO PROJECT
1990S government chose 16 favelas to improve using 250
million euros.
Replaced wood buildings with brick and gave each house a
yard.
Widened the streets so that the emergency services and
waste collectors could get access.
Improved sanitation, health facilities and sports facilities.
Used residents for labour to develop their skills and in return
residents paid taxes.
3. NEW TOWN BARRA DA TIJUCA
Land outside to South of Rio was uninhabited until
motorway was built in 1970s
Rich moved out of Rio to avoid problems of city
It has 5km of shops, schools, hospitals, offices, places of
entertainment etc.
Spacious and luxury accommodation in 10-30 floor high rise
apartment blocks with security and facilities or detached
houses.
Both adults in each family chose to work in high paid jobs to
pay for expensive life.
Families with own cars but also well connected with public
transport.
BUT: These areas have own favelas as house keepers,
gardeners etc. cannot afford accommodation
in the spread of diseases.
Case study: The effects of urbanisation / urban sprawl and solutions MEDC Case study: Atlanta
Where:
Capital of Georgia, USA
What:
Between 2000 and 2006 there are1 million more people
moved there because of increased birth rate and
migration.
Problems:
urban sprawl, traffic congestion, polluted drinking water
from overflowing used septic tanks (where your poo
goes), farm land bought up, loss of green space and
ecosystems, flooding, loss of cultural sites, social divides
between poorer inner city and richer outer city,
temperatures rising due to removal of trees.
Solutions:
New public transport system for the inner city, investment
into ‘green buildings’ in the centre and on old factory sites;
e.g. 5000 flats being built on old steel mill site. Planting more
trees around Atlanta and persuading people to move back
into the centre with sustainable new buildings.
Urban problems and solution
Problems:
Cities cannot cope with the growing numbers
Limited housing, services, transport and jobs
Stressful living conditions and protests from residents
Urban decay: parts of city become run down and slum housing appears (think Tres Mil Viviendas),
vandalism, derelict housing.
Solutions:
Urban regeneration: rebuilding, renovating old factory sites or derelict houses, knocking down old
factory buildings and creating flats, medical centres and offices.
Introducing news transport systems such as elevated railways, undergrounds, metros
Pedestrianised areas for shoppers and workers in the CBD
Urban problems and solutions LEDC: Case study Cairo, Egypt
Where: Egypt, North Africa
Problems:
Rise of population from 2 million to 8 million
Increased demand for piped water, sewers, schools,
paved roads, electricity.
Traffic congestion brings noise, air and water pollution.
Lack of housing and lack of jobs
Solutions:
Satellite towns built outside the city with transport links
Homes and public services upgraded
Metro system built
Greater Cairo Water project to repair sewage system
Ring road built around the city
Exam style questions
Unit 1.1 and 1.2 IGCSE exam5 mark describing/explaining and 7mark case study questions:
e.g Population
Explain the advantages of educating girls and women in LEDCs. (5)
Describe the likely problems for an MEDC, such as New Zealand, of having so many old dependents.
(5)
For a named country which you have studied, describe the problems caused by overpopulation. (7)
Name an example of a country which has attracted large numbers of international migrants. Explain
the pull factors which have attracted people to your chosen country. (7)
Choose any example of international migration which you have studied and name the countries
between which people moved. Explain why many people made the decision to migrate. You should
refer both to pull and to push factors. (7)
1.2 Settlement
Describe the typical land uses and characteristics of the CBD of a city. (5)
Suggest how urban growth may have created problems for people in Maseru, the capital city of
Lesotho. (LEDC) (4)
Describe the effects of rapid urban growth on the natural environment. (5)
Describe the problems for people using the CBD of a large urban area. (5)
Name a city in an LEDC and describe what has been done to improve the quality of life of the people
who live there. (7)
Choose one problem of living in urban areas. For a named urban area, describe the attempts which
have been made to solve the problem you have chosen. (7)
Many settlements have grown over the years into large urban areas. For a named example of a large
settlement, explain the reasons for its growth. (7)
Unit 2.1 Plate tectonics
The world’s surface if made up of tectonic plates
These plates move around due to convection currents in the magma and when they do they causes
earthquakes and volcanic eruptions depending on the type of plate boundary the movement occurs
on.
Oceanic plate:tectonic plate under the ocean (denser)
Continental plate: tectonic plate under land (less dense)
Converging boundary: (destructive)
Oceanic plate sub ducts under a continental plate = earthquakes, fold mountains and volcanic
eruption
OR 2 oceanic plates or 2 continental plates collide = earthquakes and fold mountains
Diverging boundary: (constructive)
Plate move apart from each other = magma escapes gently from the earth forming shield volcanoes
Fold Mountains: e.g. mount Everest
Folding sedimentary rocks left beneath the seas or lakes
Sea or lake beds are squeezed together and pushed upwards over millions of years
Everest is still rising!
Structure and types of volcanoes
Case study: Volcanic eruption LEDC:Mt. Pinatubo volcano in the Philippines 1991 – This was your
own choice but if yours is not very good use this one.
Where? South East Asia to the East of China
What?
600 years dormant
Island arc of Luzon in Philippines
Philippines oceanic crust subducting under continental
Eurasian plate – i.e. destructive plate margin
Erupted June 1991
Effects: Short term
847 dead
300 killed by collapsing roofs
100 killed by lahars
Aetas tribe refused to leave or died in evacuation centres
from disease
1.2 million lost homes
Long term:
Measles, respiratory and gastric diseases
Responses:
2 April steam explosions – vegetation killed and dust on
villages
PHIVOLCS set up to monitor eruption– 5000 pop evacuated
in 10km zone
23 April continuing earthquakes- US Geological Survey set 7
seismographs at Clark Air Base
NW slope villages evacuated
9 June 8 hr eruption with pyroclastic flows – Alert 5 -
evacuated to 20km
10 June Clark Air Base evacuated
12 June Mushroom cloud 20km high – evacuated 30km –
58,000 people
15 June – eruption 40km high ash and 80km/hr pyroclastic
flows – summit collapses. Heavy rain causes mudflows.
Affects houses, bridges and river. Manila airport closed.
500,000 migrated to Manila
650,000 lost jobs
80,000 ha of cropland destroyed
1 million farm animals died
Case study: Volcanic eruption MEDC Mount St Helens
Where:
Mt St Helens is located on a destructive plate boundary
where a continental plate (North American) meets an
oceanic plate (Juan de Fuca).
What:
18th
May 1980 at 8.32am (5.1 on Richter Scale)
Effects:
All living things wiped out 27km north of the crater, up
rooted trees, 57 people dead.
Responses:
Immediate Responses – Mobilising helicopters, rescuing
survivors, emergency treatment and clearing ash to allow
the flow of traffic
Long Term Responses – Buildings and bridges rebuilding,
drainage had to be improved, replanting the forest and
rebuilding roads. $1.4 million was spent to transform the
area.
Case study: Earthquake LEDC Haiti
Where: Caribbean near Cuba.
Never major earthquakes before, buildings not built for
earthquakes. Capital, Port-au-Prince is overcrowded and
poor with people living in crowded conditions.
What:
21st
January 2010
Earthquake of 7.0 magnitude
Movement along destructive plate boundary between
Caribbean and North Atlantic plates
Effects:
20,000 killed
300,000 injured
Buildings, including house, hospitals, and government
Responses:
Aid supplies from other countries slow to arrive due to bad
transport links and airports
USA engineers cleared the roads
USA sent 10,000 soldiers
Temporary tents for housing and 20,000 relocated
Bottled water
Field hospitals
Relies completely on aid and recovery is slow – 1 year later
people still living in tents.
buildings destroyed and 1.3 million homeless
People went looting (stealing)
2 million with no water or food or electricity
Outbreak of Cholera from dirty drinking water
Case study: Earth quake MEDC Kobe, Japan earthquake 1995
Where?
South East Asia
What?
7.2 Richter on 17 January 1995
5.46am
Epicentre 20km south of Kobe in Osaka bay
14km depth so much ground shaking and soil
liquefaction
Effects
Short term:
Collapse of elevated roads and bridges e.g. 630m stretch
of Hanshin expressway collapsed
103,500 buildings collapsed
Only 20% buildings in CBD usable after earthquake – 62
high rise destroyed and only 19 rebuilt
Port facilities (30% Japans commercial shipping)
destroyed by soil liquefaction
Ruptured pipes and poles stopped city’s gas and
electricity
6300 deaths – 2900 more from suicides or neglect
35000 injuries
Area of Nagata badly affected – timber framed buildings
owned by poor were death traps
60% deaths were over 60 year old people
300 fires in city after gas pipes ruptured
300,000 immediately homeless – 20% of Kobe-
Long term:
95,000 in temporary accommodation 1 year later
$99.3 billion damage and $120 billion needed for
reconstruction – only 7% had insurance
20,000 lost jobs
Businesses moved away – Kawasaki shipping and
Sumitomo rubber
Responses:
State’s crisis management very poor
Inadequate communication between government and
administrators
People running through street hit by falling debris ignoring
fires
5 hr delay calling Self Defence Force / Army – only 200
troops
Only 21 Jan 30,000 troops
Took several days to designate disaster zone
3 days no electricity
Delays in accepting international help – US military based
in Japan, foreign medical teams and sniffer dogs
Kobe’s resident’s believed that not at risk
Improvements since then- recovered quickly
Solutions/management:
All school children now have earthquake and drills 4X per
year
Earthquake kits can be bought in department stores –
bucket, bottle water, food, radio, torch, first aid kit and
protective head gear
Earthquake Disaster Prevention Day 1 Sept every year for
offices etc.
Why live in a danger zone?
Fertile soil, limited transport to move away, family livesthere; feel they are not in danger, tourism.
Unit 2.2 Weathering
Weathering is the break-up and decomposition of rocks in-situ (in their place of origin). Weathering
does not involve the movement of material and this makes it different to erosion.
Erosion is the carrying away of material by a natural force e.g. water, wind, glaciers
Mechanical weathering: (physical) breaking down of rocks due to temperature changeor plants
(biological weathering)
Chemical weathering: decomposition of rocks by changing chemical composition such as rain
Biological weathering: Plants’ roots growing or animals burrowing into joints or cracks and force
apart or loosen the rock.
Unit 2.3 Rivers
The Water cycle:
The amount of water of earth never changes. It is only moved and stored in different ways.
- Evaporation: when the temperature of water or air changes water is turned to gas and
rises into the atmosphere
- Evapotranspiration: Plant suck up the water in the earth and then water can be
evaporated from their leaves called transpiration.
- Condensation: water vapour blown towards mountains is forced to rise and then cools
into droplets of water which form clouds and fall as rain or snow. (precipitation)
- Interception: some rainfall is intercepted (caught and absorbed) by plants or soil and
some flows on the surface of the earth. The water that is absorbed can saturate the land
and the water that run on top forms streams and rivers.
- Overland flow: streams flow on top of the ground and join to form rivers which feed
into lakes and streams.
Load: The material carried by the river
Types of erosion: Types of river transport:
Hydraulic action: the impact of the moving river
Corrasion: (abrasion) the wearing away of the bed and
river bank by the load being covered
Attrition: the wearing away of the load as particles bump
together while being carried by the river
Solution: (corrosion) the dissolving of material by the river
water
Solution: materials dissolved in the river water
Suspension: very light materials carried near the
surface of the river
Saltation: large particles bounced along the river
bed
Traction: heavy rocks and boulders rolled along the
river bed
River land forms:
Erosional land forms: shapes in the landscape formed by erosion
The river’s long profile:
Upper course:
Starts at the source
Valley sides are steep
Lots of vertical erosion
Heavy loads of boulders and large rocks
Water falls
Potholes
Interlocking spurs
Middle course:
Valley widens, slopes are not as
steep sand the gradient of the
river is less.
More lateral erosion (side to
side)
Meanders
Levees
Lower course:
River comes to an end and slows down
as it meets the sea or lake – mouth of
the river
Lots of deposition
Deltas
Flood plains
V shaped valleys Flood plains
Oxbow lakes
Waterfalls
Falling water and rock particles wear
away soft rock
- The hard rock is undercut as
- erosion continues
- Hard rock collapses and if moved
by the flow. The waterfall moves backwards
- Erosion continues and the waterfall
continues to move upstream
leaving a gorge of recession
Interlocking spurs
In the upper course the river does not have a huge amount of energy to erode as it does not have a
high discharge and it has to transport large pieces of sediment.
When the river meets areas of harder rock that are difficult to erode it winds around them. A series
of hills form on either side of the river called spurs. As the river flows around these hills they become
interlocked. So, a series of interlocking spurs are often found in the upper course of a river valley.
V-shaped valleys
Potholes
Rapids–places where the water is shallow and river bed is rocky and uneven. The water is rough and
the gradient is varied causing water to run faster. These can be used by white water rafters.
Meanders
Formed by large stones getting trapped in the river bed causing
corrosion which drills holes into rock bed which will eventually grow and
join together.
Formed by vertical erosion when
potholes grow and join together
eroding the rock beneath the river.
Rivers with big sweeping bends with
water flowing in corkscrew motions
and causing lateral erosion on the
outsides of bends and deposition on
the insides.
Depositional land forms: shapes in the landscape formed by deposition
Floodplains
Land next to the river which is liable to flood. Often very marshy and poorly drained. River deposits
silt, gravel as it floods.
Meanders (inside of bends) – as above
Deltas
Area of flat low lying, marshy land where a river
meets the sea or lake. They can form their own lakes
or lagoons. The loss of speed means the river
deposits its load which is usually mud or silt. As this
deposition takes places parts of the river are cut off
leaving small lakes or lagoons. The river breaks up
into distributaries.
Oxbow lakes
Levee
Naturally formed when rivers flood. When the river floods it loses energy and deposits its
load. This makes the banks of the river higher than the river or the flood plain. Sometimes
the natural levees occur and other times they are built to prevent against river flooding.
Continued erosion on the outside of
meanders or in the neck of the river,
may cause two parts of the river to
create a shorter path for the water.
The deposition on the inside of the
bend may cause the old path of the
river to become cut off and a lake is
formed. An oxbow lake.
Creating meanders and oxbow lakes
In this picture, soil and mud is being eroded from various points on the
bank. It’s being transported in the direction of the white arrows and
deposited downstream (the sandy patches). This is changing the course
of the river
This picture shows the same river many years later, the erosion and
deposition have created such a deep meander that it has nearly formed a
circle
Eventually, the river erodes so much that it cuts off part of the meander
and creates an oxbow lake
Case study: formation of a waterfall Niagara Falls
Where?
Two waterfalls in the Niagara River between New York
State and Ontario, Canada
What?
Spectacular waterfall carrying 90% of the world’s water
12,000,000 visit every year
Producer of hydroelectric power
Benefits:
Money from tourism, hydroelectric power, fame, water
supply
How was it formed?
1. Glaciers melted 12,000 years ago
2. Melted water poured down into the great lakes
3. As the lake overflowed it caused the Niagara River
to flow downhill and fell down the escarpment
(cliff)
4. The rocks at the falls are made of different layers of
soft and hard rock
5. The soft rock (shale) was eroded from underneath
the hard rock (sandstone)
6. The water could now fall freely
7. The force of the water eventually eroded away so
much rock that the top rock was undermined and
fell
8. This process happened over and again and is still
happening!
9. This means that the waterfall is retreating every
year.
10. The force of the water falling creates a plunge pool
at the bottom of the falls.
Case study: Living by Deltas Ganges, LEDC, Bangladesh
Deltas: Where the river slows as it reached the sea a large amount of deposition takes place as the
load can no longer be carried by the force of the water. The load deposited causes the river to split
up into smaller distributaries which flow to the sea. The sediment dropped by the river is often very
fertile and therefore much vegetation grows there.
Where: Bangladesh, bordered with India
Delta is at the end of the Ganges river which
flows from the Himalayas
Advantages: flooding and irrigation all crops to
be grown all year round such as rice and
vegetables. Preferable to city slums. Jute (used
Formed: Deposition of load at the end of the
Ganges river as it arrives at the coast and slows
down.
How? A) River carries a large amount of silt
which builds up to form islands
B) As more silt builds up flooding occurs and
creates small distributaries (small little streams
winding to the sea)
C) Between these distributaries land is rich and
fertile
for making burlap sacks) is grown and there are
many fish to catch.
Disadvantages: monsoons (heavy rain fall),
cyclones (strong winds and rain), floods
Case study: Flooding of the Brahmaputra and Ganges Rivers, Bangladesh (LEDC)
Causes of 1998 flooding:
Monsoon season- 80% of rain falls June to September
Deforestation in the Himalayas increases runoff below
Urbanization – building on floodplains
1998 both rivers peaked at the same time
Silt had been deposited near the mouth blocking the
main channel
Global warming melting Himalayas
Poorly maintained embankments
Flat low lying land over 80% of Bangladesh
Effects in 1998:
70% of land in Bangladesh affected
2/3rds of people affected
Dhaka 2ms deep in water
Electricity supply cut off for several weeks
Wells contaminated and not safe for drinking
7 million homes destroyed
25 million homeless people
1300 approximate death toll
2 million tonnes of rice destroyed
Roads, bridges, airports and a third of the railway
destroyed
$1.5 billion damages
Management: (how to prevent it)
Since 1989 Bangladesh has been trying to:
Build 5000 flood shelters with stilts to save lives
Improve forecasting with satellite technology
Early warning system with megaphones
Build dams
Control water with sluice gates and water pumps
Heighten embankments on side of river to 7m- more than
7500km already in place
Case study: Flooding MEDC Boscastle UK
Where: Cornwall UK
When: 2004
What: settlement was left in ruins by floods
Short term Causes:intense rainfall caused local rivers to
burst their banks, heaviest rains in living memory, 185
mm fell in just five hours, three million tonnes of water
was added to a tiny drainage basin
Long term causes:
The soils were already saturated from previous rainfall
earlier in the week, encouraging overland flow to begin
Effects: motor vehicle damage, shops were carrying
greater levels of stock due to tourist season and were
lost.
No one died but property damage was high. At least
thirty cars were washed straight into the harbour and
many more were left upturned and badly damaged.
A three-metre high wave of water was reported to have
crashed through one street at 80 kilometres per hour.
Fridge-freezers were picked up and swept out of kitchens
as water entered properties. Six properties collapsed
even sooner.
The three river valleys are very steep and narrow. A
broader floodplain would have helped to soak up water
and river energy more effectively.
The steep valley sides mean that soils are thin, with
limited water storage capacity when heavy rain comes.
Surrounding vegetation includes agricultural land with
limited interception storage, although there is some
forestry along the riverbanks.
The rain coincided with high tide in the bay. This
restricted the rate of exit of floodwater into the harbour.
entirely.
Infrastructure disruption – Both bridges in the village
were destroyed and sections of road were swept away.
Telephone, water, electricity and gas supplies were all
interrupted.
Irreplaceable loss of historical artefacts – The ‘Witch
Museum’ – which is fifty years old and receives 50,000
visitors a year – had some of its unique contents
damaged.
Physical injury No-one died, but at least one resident
suffered a heart attack.
Mental injury Many residents suffered stress and anxiety
in the year that followed. It was six months before many
properties were sufficiently repaired for homeowners to
permanently return home.
Case study: Flood management: Responses to Boscastle floods
Case study: River management in MEDC: Mississippi River, USA
Where/what is it?
Mississippi is 3800km long
Flows through ten states
Has over 100 tributaries
Has a drainage basin covering 1/3 of the USA
Causes of 1993 flooding:
Heavy rain in April 1993 saturated the upper Mississippi
basin
Thunderstorms in June caused flashfloods
Mid July 180mm of rain in one day
Levees in nearby towns collapsed
Management:
6 huge dams and 105 reservoirs
Afforestation to delay runoff
Strengthening the levees with concrete mattresses
25mx8m
Making the course shorter and straighter - from 530km to
300km by cutting through the neck of meanders to get the
water passed towns more quickly to the sea
Diversionary spillways – overflow channels 9km long
Less construction on the floodplain e.g. St Louis.
Little task for you ….
Unit 2.2.3 Marine Processes
Coast: Where land meets the sea
Fetch: the distance the wind has travelled over the sea – the longer the fetch the bigger the waves
Constructive waves: swash is stronger than backwash causing deposition
Destructive waves:backwash is stronger than swash causing erosion
Marine transport:
Suspension Solution Traction Saltation
Fine sediment carried
in the water
Dissolved material
carried in the water
Large pebbles and
stones rolling along sea
bed
Small pebbles hitting
one another and
bouncing along the sea
bed
Marine erosion:
Long shore drift: The movement of sediment along the beach
Groynes: beach protection against longshore drift
Hydraulic action Air forced between
cracks on rocks
Corrosion Sea water dissolving
parts of rocks
Attrition Large rocks and
sediment in water
collide and wear each
other down
Corrosion Large rocks and
sediment thrown
against the cliffs
Headlands and bays: Formed where there hard and soft rock. The soft rock is eroded away and the
hard rock is not.
Formation of caves, arches and stacks.
A line of weakness called a fault
appears in the rock
This fault increases in size until it
becomes a cave
The waves erode the cave until the
water breaks through the other side
creating an arch
The roof of the arch falls into the sea
creating a stack
The stack is eroded away to form a
stump
Case study: Coastal erosion: The twelve apostles Victoria, Australia
Coastal deposition:
Beach Spit Bar Salt marsh
Large particles at the
top of the beach and
smaller particles like
sand lower down the
beach
Created when
deposition occurs
when the swash is
greater than the
backwash
Caused by longshore
drift
Deposition of sediment
where coast changes
shape or at the mouth
of a river, the beach
continues where the
land stops forming a
sand island going out
to sea. When one end
is attached to land it is
called a spit.
If a spit connects two
pieces of land
(eventually) it becomes
a bar and the water
enclosed between the
bar and the land is
called a lagoon.
If this lagoon fills up
with sediment it
becomes a marsh. An
area of soft soggy land.
The water has very
little energy and so
deposits more and
more sediment behind
a bar. Many plants can
grow here and help to
cause more deposition
or sediment and salt
from the sea becoming
a salt marsh.
Case study: Coastal deposition: Hel Spit, Poland
Where:
Port Campbell National Park, Victoria, Australia
Limestone cliffs formed in layers from the
sediment on the sea floor forming sedimentary
rock.
9 remaining stacks of rocks off the Victoria coast
Formed:
Headlands formed where the rock was harder
Hydraulic action, corrosion and corrosion eroded
along the fault lines
Cliff base eroded away to form WAVE CUT
PLATFORMS, notches, arches, caves and stacks
When the arches collapsed stacks were formed
Where: Baltic sea, northern Poland
Formed:
Result of longshore drift from west to east
NW wind and sea carries sediment and deposits
it along the east end of the beach
Protection:
Sea walls
Groynes
Beach replenishment –replacing the sand from the east of
the beach back to where it came from
Sand dunes:
Ridges of sand which form behind beaches.
An obstacle is formed by a plant or sand hill and this slows down the wind coming from the sea. Any
and or dust that the wind is carrying is deposited around the obstacle and it grows; like a sand dune.
Plants begin to grown there and their roots stabilise the dune so it become stronger.
Over time the dune become grey as plants die and they decay leaving behind humus.
Eventually the plant life grows and the sand is able to hold more water and trees can now grow
here, transforming it into part of the earth.
Coral Reefs:
What is coral?
The solid skeleton of limestone
It grows in warm water 23-25°
Grows in clear shallow salt water
Needs plenty of sunlight
How are they formed?
Large amount of coral build up over a long period of time and get higher and higher.
They begin building from a rock base in the ocean
There are THREE different ways this can happen and therefore THREE different types of coral reef.
Biodiversity: Coral reefs contain a very large amount of different species of plants and animals.
Many of these are now becoming endangered species due to human impact
Threats: earthquakes, cyanide bombs used for fishing, humans standing on the coral
Case study: Coral Reef: Great Barrier reef, Australia
Where: Great Barrier reef Marine Park, Australia
National park since 1981
Only 100 meters deep and in some places less really
close to the Australian coast.
Economic importance:
6% of Australian workforce work here
12% of country’s exports come from here
Threats:
Human:
Agriculture: Pollutants from agriculture
Industry: metal pollutants, phosphates and nitrates from
sewage and 34industry
Fishing: Over fishing and cyanide bombs used to stun fish
kill marine life
Dredging: Sand and gravel taken from the sea for
building muddy the waters and reduce the amount of
sunlight needed for the reef to survive
Tourism: Ships, yachts and boats bring tourists who tread
on and kill the reef
Natural threats:
Starfish: warmer seas has seen the starfish move to new
areas, eating more algae and coral and leaving white coral
skeletons
Solutions:
World heritage site – now managed under particular laws
to protect from pollution, fishing and tourist damage
Zoning – only particular activities allowed in each zone
Advice – tourist advised on how to preserve the reef
e.g. no standing on the reef, no feeding the fish, no
smoking
Coastline development: Housing on the coast line brings
greater demand for building materials taken from the sea
Unit: 2.3.1/2 Weather and Climate/ ecosystems
When we wake up in the morning one of the first things we are interested in is the weather.
Weather is the condition of the lower atmosphere* at any particular time. If there were no
atmosphere there would be no weather. The moon has no atmosphere and no weather.
* The atmosphere is the layer of gases, called air, which surrounds the planet earth.
* The air in the atmosphere is a mixture of gases. These are mainly nitrogen (about 4/5) and oxygen
(about 1/5). There are also amounts of water vapour, carbon dioxide and some rare gases. The
amount of water vapour is very important as this gives us our cloud and rain.
The components of the weather
To describe the weather we must describe the state of the air. We can do this under 6 main
headings. These are called the elements of the weather:
1. air temperature - How hot or cold is it?
2. precipitation (rain, snow, hail, sleet, frost, fog, dew) - Is it wet or dry?
3. cloud cover and sunshine - Is it sunny or cloudy?
4. wind speed and direction -The movement of the air.
5. air pressure
6. Humidity – how much moisture there is in the air
The climate of a place is its average weather. To calculate this we must know what types of weather
occur there at different times of the year.
Air Temperature
We measure the temperature of the air in degrees Celsius (ºC) using a thermometer.
EQUIPMENT NAME PHOTO DESCRIPTION (WHAT DOES IT MEASURE)
Stevenson Screen A Stevenson screen is basically a white louvered wooden
box. The box is designed to contain some weather equipment
like thermometers and barometers. The Stevenson screen is
white to reflect sunlight and has slats to allow air to circulate
easily. The Stevenson should be placed above the ground
and away from the buildings. The idea is for the weather
instruments to take accurate readings of the air, rather than
direct sunlight or heat from the ground or from buildings. For
more detailed information about the siting of a Stevenson
Screen, read the attached document.
Barometer Barometers are used to measure air pressure. Air pressure is
normally measured in millibars. Barometers are normally kept
inside Stevenson screens to keep them safe. A barometer
has a movable needle (pointer). The pointer can be moved to
the current reading so that you can then make a comparison
with the reading from the following day.
Max./Min. Thermometer
(sometimes called a Six's
thermometer after its inventor)
A maximum and minimum thermometer records the maximum
temperature of the day and the minimum temperature of the
day (diurnal range). A maximum/minimum thermometer
contains a mixture of mercury and alcohol. The mercury sits in
the u-bend of the thermometer. The bulb at the top of the tube
reading the minimum temperature contains alcohol and the
bulb at the top of the tube reading the maximum temperature
contains a vacuum. On the minimum side the expansion of
the mercury is restricted by the contracting alcohol, on the
maximum side the expanding mercury can expand more
freely into the vacuum. At any given time both thermometers
should record the same temperature. However, during the day
they would have recorded the maximum and minimum
temperature - a steel marker should indicate these
temperatures.
Wet/Dry Bulb Thermometer
(hygrometer)
A hygrometer measures the humidity of the air. Humidity is
the amount of moisture (water vapour) in the air. A
hygrometer has two thermometers, a dry one and a wet.
Humidity is measured by using a table that looks at the
difference between the wet bulb and the dry bulb. A
hygrometer can also be used to find dew point. There is a
difference between the dry and wet bulb thermometers
because of latent heat created during the process of
evaporation.
Rain gauge Rain gauges are used to measure rainfall. Rainfall is normally
measured in millimetres. Rain gauges should be placed on
grass, because if they are placed on concrete, extra water
can splash into them. Rain gauges should also be checked
regularly to avoid evaporation.
Wind Vane Wind vanes are used to check the direction of the wind.
Compass points are used to give wind direction. Wind is
measured in the direction that the wind is coming from. Wind
vanes are often placed on top of buildings so that they are
fully exposed to the wind. When using a wind vane you need
to use a compass to make sure that it is properly aligned.
Anemometer Anemometers measure wind speed. Wind speed is normally
measured in mph or kph, but can also be measured in m/s
(metres a second). Digital anemometers are very accurate,
but the more basic plastic ones that many schools have aren't
very good or accurate at recording light winds. Anemometers
are normally placed on top of buildings so that they are not
protected from the wind and so they don't experience
channeling of wind e.g. if an anemometer was placed in a
corridor where wind was forced through the readings would
be higher than normal.
Cloud Cover It is also possible to count day light hours, sunshine hours or
cloud cover. To Calculate day light hours you need to record
the time between sun rise and sun set. To Calculate sun
shine hours is a lot harder, because you have to time every
time the sun comes out (stopwatch). To calculate cloud cover
a mirror is often used. You divide the mirror into squares and
then place the mirror on the ground. The mirror will reflect the
clouds and you can count the number of squares covered or
On a weather map we join places of equal pressure with lines called isobars e.g.
A High Pressure Area a Low Pressure Area
The weather we get from high air pressure is very different from that we get with low air pressure
Cloud types and extent of cloud cover
Clouds
Clouds are a collection of water droplets or ice crystals. The warmer the air temperature, the more
water vapour (gas) that the air can hold. However, when the air starts to cool, water vapour starts to
condense as long as it has condensation nuclei to condense around.
Cirrus
Found high in the atmosphere – usually over 5,500 metres
Common throughout the world
Thin and wispy in appearance
Move fairly quickly
Stratus
partially covered by cloud. You can do this as a percentage or
convert to oktas which is the normal measurement of cloud
cover. You have to take several readings to avoid anomalous
results.
Low level – below 2000m and sometimes reaching ground.
Usually grey and colour and move fast.
Can produce light rain and snow.
Cumulonimbus
Large clouds up to 10km high and across.
They resemble giant cauliflower.
Produce rain, thunder and lightening
Usually found in spring and summer
Cumulus
Fairly low clouds with bottom between 600m and 1200m
Look like lumps of cotton wool
Can produce light rain
Individual clouds have a short life cycle
Climate zones and graphs
Climate zones around the world depend on a variety of factors but more or less we can se they are
dependent on the lines of latitude around the earth as the further away or closer we are to the
equator will affect the temperature we experience.
See blow for the climate zones and the factors which can affect the climate within one country.
Factors affecting climate:
0
5
10
15
20
25
30
35
0
100
200
300
400
500
600
700
800
J F M A M J J A S O N D
Temp(oC)
Rainfall(mm)
Month
Climate Mumbai
Climate graphs show us the climate
over a year of different areas in the
world.
They concentrate on rainfall and
temperatures and you must be careful
to be sure you can use the following
terms to use terms to explain climate.
- Range of temperatures
- Maximum and minimum
temperatures
- Annual precipitation
- Minimum and maximum
precipitation
You must also be able to name the type
of climate from climate graph.
e.g. tropical, arid, Mediterranean
Eco systems
Ecosystems: A biological environment consisting of all the living organisms within a particular area
and the non-living that interact with the organisms e.g. weather, soil, air and water.
Tropical rainforest climates: Features of a rain forest environment:
- mostly found along the equator
- hot temperatures all year round
- Plenty of rain, over 1500 mm in some areas
- 10% of worlds rainfall depends on evaporation and transpiration from these rain forests
- Ever green forests with broad leaved trees
- Lots of flora and fauna (can be 40-100 tree species per hectare)
- Large amounts of shade at low levels
- Most plants grow up high where they can get to the light
- Plants that reach the sky are called emergent and they can create their own islands in
the canopy of the forest called the ‘lungs of the Earth’ as they produce oxygen.
- Low pressure weather allowing clouds to form and rain occurs all year but in varying
amounts.
Location of Rainforests
 The Congo Basin in central and west Africa
 The Amazon in Brazil, Peru, Bolivia and Ecuador
 SE Asia (Malaysia, Thailand, Vietnam, Indonesia and the Philippines)
 Madagascar
 North east Australia
 Southern India and Sri Lanka
 Central America
Tropical Rainforest Animals
Tropical rainforests have a huge amount of biodiversity within them - some estimates suggest that
up to 50% of the earth's biodiversity live there (flora and fauna). The are many big famous mammals
like tigers in SE Asia, jaguars in Central and South America and leopards in Africa. However, there are
also much smaller mammals like sloths and primates like lemurs that live in rainforests. All mammals
and primates have adapted in different ways to survive in the rainforest e.g. camouflage. As well as
mammals and primates there are many other animals like birds, amphibians, reptiles and insects.
Many rainforest animals are under threats. Threats include:
 Habitat loss (deforestation)
 Climate change (reduction in rainfall or increases in temperature)
 Pollution (especially reptiles and amphibians)
 Hunting (food food, skins and parts for Chinese medicine)
 Cross breeding with domestic animals
 Diseases (bird flu)
Case study: Human impact on tropical Rainforest climate: Madagascar
Where and what:
LEDC
9th
poorest in the world
4th
largest island in the world
Unique eco system and food chain
Nearly all the land was once forest
Gradually more and more land used for farming
leading to deforestation
The rainforest is disappearing.
Problem:
Cash crops being planted like rice and coffee
These make lots more money for the country
But the forest is being removed to plant more and more
The eco systems within the forest are dying and cannot be
replaced
Removing trees is done by burning them
The ash (which contains the trees nutrients) can be washed
away into rivers
Crops cannot grow in infertile soil
Animals lose habitats and humans must move their crops to
anew area when the soil become infertile.
Dispute!
People claim they need to earn a living
The need to hunt the animals there for food and clothing
They want their economy to develop
Deserts
Antarctica is sometimes classified as a desert because it actually has very low levels of precipitation.
However, when we talk about deserts in this section of the desert we mean sandy deserts.
Distribution of Deserts
Deserts are located near the tropics (Tropic of Cancer and the Tropic of Capricorn). Some of the
world's most famous deserts include:
 Sahara in Northern Africa
 Kalahari in Southern Africa
 Atacama in South America
 Gobi in Central Asia
 Arabian in the Middle East
 Great Victoria and Great Sandy in Australia
 Mojave and Chihuahuan of North America
Desert Climates
 Deserts are extremely dry (arid) places. True deserts normally have less than 250mm a year
although some deserts like the Atacama to the right can go years without any water.
 Deserts are very dry because the air that descends over them is very dry. The air is dry
because most of the moisture has fallen as precipitation over the Equator (tropical rainforests)
before being pushed out and falling near the tropics.
 The air is also very dry because the air travelling from the equator to the tropics travels over
land and not the sea. This means that no additional moisture is picked up.
 Because there is no moisture in the air, there are very few clouds in deserts which means
desert areas are exposed to high levels of incoming radiation from the sun. This means that
daytime temperatures in the desert are very high.
 However, the lack of cloud cover also means that a lot of outgoing radiation is able to escape,
making desert temperatures very cold at night. So even though the annual temperature range
in deserts is very low, the daily temperature range is very high.
 The daily temperature range is known as the diurnal temperature range.
Desert Fauna and Flora
Because of the very arid conditions found in deserts, both plants and animals have had to adapt to
survive. Adaptations include:
Succulents e.g. cacti:Succulents tend to be fairly fat fleshy plants that are able to store water in their
leaves, trunks and roots.
Ephemeral: These are plants with very short life cycles - typically 6-8 weeks. This means that they
can take advantage of very short wet seasons in order to pollinate.
Long and wide roots:Plants in deserts have very long roots so that they are able to absorb the
maximum amount of rainfall during periods of rainfall. It also makes them more stable in very lose soil.
Spiky and waxy surface:Many plants like cacti protect themselves with spikes and wax so that they
are not eaten or damaged by animals.
Deserts don't have the same variety of animals as tropical rainforests, but many insects, reptiles and
mammals have adapted to survive.
Nocturnal: Many animals will hide in burrows or behind rocks and vegetation during the hot daylight
hours and only emerge at night.
Camels: Camels store fatty tissue in their humps which when metabolised actually releases water as
well fat enabling them to survive in deserts.
Human Causes of Desertification Physical Causes of Desertification
 Overgrazing: Allowing too much livestock to graze on a piece of land
which means all the vegetation is eaten making the ground susceptible to
wind and water erosion.
 Overcultivation: If you farm land to intensively and don't have fallow
 Rising Temperatures: As global temperatures
increase it is becoming increasingly hard for
vegetation to grow thus reducing vegetation
cover and increasing the risk of wind and water
periods then all the nutrients in the soil get used.
 Deforestation: Cutting down trees which not only means the land will be
receiving less nutrients, but it also means it is more vulnerable to erosion
because there is no interception and less stability because the root
systems have been removed.
 Overpopulation: As the world population continues to grow (now about
7 billion) the demand for agricultural products (crops and meat) is
increasing, causing more land to be deforested, overcultivated and
overgrazed.
 Fertiliser and Pesticide Use: By using fertilisers and pesticides you can
artificially increase yields of crops. However, the process is unnatural and
prolonged periods of use can all naturally produced nutrients to be used
and local water sources to become polluted reducing the ability of land to
cultivate crops and therefore making it vulnerable to chemical
degradation as well as wind and water erosion.
 HYV and GM Crops: Like with fertilisers and pesticides, it is argued that
HYV and GM crops have encouraged overcultivation, diminishing natural
nutrients in the soil.
 Unsustainable Water Use (aquifer depletion, unsustainable
irrigation): If aquifers or rivers are used unsustainably then areas can
become increasingly arid as water resources are used up. A classic
example of unsustainable irrigation happened in the Aral Sea.
 Toyotarisation: This is basically the increased use of 4x4s to travel
across grasslands, deserts, etc. damaging topsoil and increasing wind
and water erosion.
erosion.
 Falling Rainfall: As the amount of rainfall
reduces in some areas like the Sahel, then it is
increasingly hard for vegetation to grow again
making the ground more vulnerable to wind and
water erosion.
 Flash floods: Intense periods of rainfall can
also cause erosion of topsoil which leads to
land degradation.
 Wind: If a region is particularly windy then the
amount of wind erosion is likely to increase.
Case study: Tropical Desert Climate / desertification: The Sahara and the Sahel, Africa
Where and what:
 The Sahel is a narrow belt of semi-arid land
South of the Sahara in Africa
 Rainfall is only in 1 or 2 months of the year
 Rainfall is irregular with no rain in some years
 Droughts in Ethiopia (1983), Sudan (1984-91) and
Somalia (1990s)
Causes of desertification:
 Climate change and global warming allow less
rain per year
 Water holes dry up
 Increased population growth – 3 or 4%increase
each year
 Overgrazing of cattle, camels, goats etc.
increased 40% since 1980s
 Animals taken to wells which decreases height of
water table
 Non drought resistant grasses die
Effects of desertification:
Desertification has caused many problems in the Sahel
including:
Famine
Dust storms
Conflict over diminishing resources
Solutions:
A number of solutions have been suggested to solve the
problem of soil degradation and desertification including:
A giant shelter break (the Green Wall) - see article to the
right
Population control
Finding alternatives to firewood e.g. solar cookers
Improved farming techniques e.g. reduced grazing
numbers
 Farming on marginal land
 Farming the same crop each year
 Lack of fallow land
 Taking local trees for firewood
All these increase the size of the desert, increase soil
erosion and cause famines for people
Unit 2.3.3 Natural Hazards
Case study: Drought: Australia MEDC – Murray Darling Basin
Where and what:
MEDC in southern hemisphere
Driest continent in the world
Since 2002 worse drought in 200 years
Murray-Darling river runs from the snowy mountains to
Adelaide in South Australia
River water is used for irrigation of farm land
Not enough rainfall to keep the reservoirs full
Not enough water for urban populations
Desert and semi-arid climate
Effects:
Fall in population in Bourke in New South Wales because
of drought
Towns are facing economic and social ruin as crops fail
and there is not enough water to supply the towns
Options are to move of to try and make a living from
tourists who go there to see the ‘outback’
Bush fires and homes destroyed due to lack of water
Responses:
Water restrictions put on citizens
Fines or imprisonments for using too much water
Case Study: Drought Ethiopia LEDC
Where and what:
Ethiopia is one of the poorest countries in the world
1983-84 saw the worst drought ever
Cause:
Rainfall level was considerably lower than average
Famine caused as civil war and poor roads made it
difficult to transport food
Effects:
Farmland dried out
Animals died and crops failed causing widespread
starvation and illness
500,000 people died
Millions of people needed food from MEDC charities like
Oxfam and Band-Aid
People migrated to other areas or refugee camps
People malnourished
People living in poverty
Tropical Storms
Tropical storms take different names in different parts of the world. In The Caribbean, US and Central
America they are known as hurricanes, in the Indian Ocean they are known as cyclones and in the
Pacific around the Philippines and Indonesia they are known as Typhoons. Tropical storms are
normally found between the tropics near the Equator. The formation of tropical storms is not fully
known, but scientists do know that they draw their energy from warm seas. Therefore tropical storms
tends to happen in late summer when temperatures are warmest (over 27 degrees Celsius). Because
tropical storms get their energy from the sea, when they do hit land they lose their energy quickly.
Most tropical storms last between one and two weeks. The main hazards caused by tropical storms
are:
 Winds: Very strong winds up to 250km/hr accompany tropical storms. Strong winds can damage
buildings, knock over trees and disrupt transport and communications
 Flooding: Heavy rainfall is associated with tropical storms. Heavy rainfall actually causes much more
damage and deaths than high winds.
 Storms urges: Tropical storms moving in land can create storm surges and big waves. If tropical
storms coincide with spring tides the impacts can be severe.
 Landslides: Landslides are a secondary hazard. Landslides can be triggered when large amounts of
rainfall saturate the ground increasing the stress on the slope.
Tropical storms are measured on the Saffir-Simpson Scale. The Saffir-Simpson currently has five
categories, although some meteorologists believe a sixth category should be introduced to describe
super hurricanes. Storms below 74mph (119kph) are described as only tropical storms. Anything
above this speed is officially a hurricane/cyclone/typhoon.
Case study: MEDC Tropical Storm: Hurricane Floyd, USA 1999 (MEDC)
What and where:
 Formed in Atlantic Ocean off coast of Africa
 Began 2 September 1999
 Cat 4 hurricane (211-240 kph) in Bahamas by 13
and 14 September
 Weakened by time reached USA near Cape Fear, N
Carolina
 Tropical storm by time reached New England
Effects:
 14 states (Florida to Maine) hit – N Carolina worse
hit
 79 deaths
 47 people died from storm of 500mm rain and
floods in N Carolina
 4 million evacuated in N Carolina, Georgia and
Florida
 1 million had no electricity or water
 4,000 Pennsylvanians homeless
 25000 claimed insurance - $460 million
 42973 homes damaged – 11779 destroyed
 144854 asked for assistance
 10x increase in Alabama benefits applications
 105580 people went to shelters
 $1 billion agricultural losses -10% N Carolina
tobacco lost
 N Carolina 500 roads impassable
 Storm surge in Nassau sunk boats
 Beaches in Bahamas destroyed – Wrightsville beach
20m sand on roads
Prediction
 National hurricane Centre in Florida government run
 Use geostationary satellites
 Allowed 2.5 mil to be evacuated
 N Carolina 800,000 evacuated – caused traffic on
Interstate 26
 150km journey took 10 hrs
Preparedness/Buildings/Land use planning
 Federal Emergency Management Agency (FEMA) gave
advice for family disaster plan and disaster supply kit
 Building codes to construct earthquake proof
buildings – not always applied though
 High risk coastal locations identified based on past
hurricanes and surges
 Building limited here
Case study: Effects of LEDC Tropical Storm: Cyclone Myanmar
Where and what:
Asia
LEDC
May 2008
Winds up to 300 km/hr
Heavy rain causes flooding and mudslides
Short term Effects:
Blew roofs of houses, schools and hospitals
Cut electricity to whole cities
In Bogdale, 3000 reported dead or missing
Blocked roads
Broken telephone wires
Casualties unknown but estimated at 140,000 killed or
missing
Residents and Buddhist monks cleared the roads by hand
People had to wash in lakes and queue to buy candles
and water to drink.
Long term effects:
75% of homes on the Irrawaddy Delta were made
homeless and is an area that is very important for
exporting fish and rice and feeding the country.
The country could not export any goods
Petrol was scarce so bus fares went up and people could
not afford to get to work
Sanitation plants were flooded and therefore disease
spread more quickly
Response:
It was not reported in the news and they claimed they
could recover without help from MEDCs
Unit 2.2.4 Human impacts / national parks
Importance of Tropical
Rainforests
Reasons for Deforestation Problems Caused by Deforestation
 Biodiversity: Although
rainforests cover only about
5/6% of the world's land mass, it
is estimated that they could
contain up to 50% of the world's
biodiversity. This is potentially up
to 15 million species.

 Photosynthesis: Tropical
rainforests are often referred to
as the 'lungs of the earth' and
convert large amounts of the
greenhouse gas carbon dioxide
back into oxygen. It is estimated
that the Amazon rainforest alone
produces about 20% of the
earth's oxygen.

 Flood control (interception,
transpiration): Rainforests are
 Cattle Ranching: As the world's
population gets bigger and richer, the
demand for meat is increasing. To rear
the cattle increasing tracts of the
rainforest are being cleared to make
pastures for grazing.

 Subsistence Farming: Because of the
large amounts of poor people that still
live in tropical areas, subsistence farming
is still widespread. Because rainforest
soil loses its fertility quickly after
deforestation, the most common form of
subsistence farming is slash and burn.
With growing populations this method of
farming can cause widespread
deforestation.

 HEP: Many of the world's great rivers
flow through rainforests e.g. the Amazon.
 Flooding: Flash floods become more
common after deforestation because there
is less interception and less root uptake and
transpiration. As such rainwater reaches the
ground quick, saturating it and causing
surface run-off and potential flooding.

 Landslides: By removing trees and
vegetation, you are making the soil less
stable. Combine this with saturated ground
and the likelihood of floods increases.

 Biodiversity loss: Because all the species
that live in the rainforest are not known it is
hard to calculate species loss. However,
scientists believe that 1 mammal or bird
extinction can be extrapolated to
approximately 23,000 extinctions.

 Reduced photosynthesis: As more and
an excellent natural measure to
reducing flooding. There is leaf
cover in rainforests all year so
interception continually happens,
extending rivers lag time. All
vegetation uptakes water and
transpires it.

 Control of soil erosion: The
root systems of trees and shrubs
hold the very thin soil of
rainforest in place. If trees are
removed then both erosion of
topsoil and landslides are more
likely

 Source of nutrients to humus
layer in soil: The topsoil in
rainforests is very thin and relies
on the nutrients provided by
rotting plants and animals.
Because of the rainforests
climate, there is a constant
supply of leaf litter.

 Medical remedies: Rainforests
have been the source of many of
today's drugs, including the basic
ingredients for the hormone
contraceptive pill, quinine (a anti-
malaria drug) and curare (a
paralysing drug).

 Cash crops and agricultural
products: Yam, coffee, rubber,
mango, banana, sugarcane,
cocoa and avocado were all first
discovered in rainforests.

 Ecotourism: With people
becoming ever more
environmentally conscious and
looking for increasing
adventures, ecotourism to
rainforests is increasing. This not
only helps protect rainforests, but
creates income for locals.
These great rivers often have the most
HEP potential. Unfortunately when a dam
and reservoir are built it causes damage
during construction, but also floods large
areas.

 Mining: With an ever increasing demand
for the world's natural resources,
countries and companies are looking at
increasingly isolated locations, places
like rainforests and Antarctica. The
rainforests are believed to have many
resources including metals and fossil
fuels beneath their soils. Gold mining can
be particular damaging as mercury is
used in its extraction and often runs off
into rivers.

 Road building: Building new roads like
Trans Amazon highway from Brazil to
Bolivia not only causes deforestation
itself, but its also opens up new areas to
urbanisation, mining and farming causing
further deforestation.

 Urban growth: With the world population
increasing as well as rates of
urbanisation increasing many cities like
Manaus in Brazil are growing rapidly
causing deforestation.

 Population growth: As populations
grow, particularly in countries like Brazil,
Peru, India and Vietnam that contain
rainforests the demand for land
increases, both to grow food and to live).

 Plantations: Primary products are often
seen as an income source for LEDCs,
many of who have large areas of
rainforest. At the same time with fossil
fuels running out, alternative fuels
sources are been searched for including
biofuels e.g. Palm oil. This has lead to
widespread deforestation in countries like
Malaysia and Indonesia to plant cops like
palm oil.
more trees are removed the rate of
photosynthesis reduces, releasing more
carbon dioxide into the atmosphere and
contributing to the greenhouse effect.

 Silting of rivers: With increased flooding
and surface run-off moil soils and silt is
washed into rivers, this can not only change
local ecosystems (water temperature and
clarity) but can also reduce the depth of
rivers making navigation harder.
 Silting of seas and oceans: With the
increased frequency of flooding and
landslides more silt gets washed into the
oceans. The increased amount of silts
reduces the transparency of the sea
reducing the light reefs receive and the
temperature of the water. Increased silt can
also block important shipping lanes.

 Breaking of nutrient cycle: The top soil of
rainforests is very thin an receives the
majority of its nutrients from rotting flora and
fauna. Be removing trees you also remove
animals and therefore the source of the soils
nutrients. With increased erosion the top soil
(humus) layer is quickly washed away.

 Sandification/desertification: Because
rainforest soil loses its fertility very quickly
after deforestation it quickly becomes hard
to grow any vegetation on it, leading to
sandification and possibly desertification.

 Loss of indigenous homes: By clearing
rainforests you are obviously destroying the
homes of indigenous groups. But also
moving close to indigenous groups can
spread disease and alter local culture and
traditions.

 Reduced rainfall: Deforestation can lead to
reduction in local rainfall because less water
is intercepted and transpired from
vegetation into the atmosphere reducing the
formation of clouds and rainfall.
Ecotourism is an important
income to countries like Costa
Rica and Belize.

 Home to indigenous
groups: Although the number of
indigenous groups and people
have declined rapidly since
colonisation in South America, it
is estimated that there are still
over 200,000 people that
consider the Amazon their home.

 Timber (hardwoods): Hardwoods like
mahogany and teak that take hundreds
of years to grow are still in high demand
to make things like furniture. The
extraction of these trees can kills trees
around them. Also many countries like
China are also demanding large amounts
of normal timber that are not always
taken from sustainable sources.

 Hunting: Hunting takes two forms, one
form is for bushmeat to feed families and
enough the sale of animals either alive
e.g. parrots or dead for their skins e.g
jaguars.
Case study: Deforestation of Tropical Rainforest: Amazon Rainforest, Brazil
Where and what:
Brazil, Peru, Bolivia – South America
1/3 of the world’s trees in Amazon
Estimates that 15-40% has been cleared
Effects:
 30000 known species could be threatened
 May lose species that are as yet undiscovered
 Could lose the cure for diseases like Aids and
15 football pitches per minute cleared for:
 Slash and burn farming by Amerindian tribes like
the Yanomami
 Subsistence farming by 25 million landless
peasants
 Commercial cattle ranching for fast food chains
 5300km Amazonian highway
 900km railway line from Carajas to the coast
 Timber/ logging companies
 Mineral mining e.g. diamonds, gold
 HEP
 Settlements e.g.Carajas
cancer e.g. periwinkle found to cure Leukemia
 Loss of Amerindians due to European diseases
 Loss of Amerindian traditions
 Soil erosion as lack of interception as canopy
removed
 Loss of nutrients in soil
 Climate change and global warming
 Global balance of carbon and oxygen affected
Ways to protect Amazonia:
 Zones for different activities
 Loggers use selective logging practices
 Laws
 Limit licenses to be given out
 Restricting use of heavy destructive machinery
 Encourage logging-uses helicopter
 Community forestry development scheme to
educate local people
 Avoid construction where local tribes exist
 Fines and prosecution for law-breaking
 Increased patrols
Case study: Sustainable Rainforest Scheme: Costa Rica
Where and what:
Central America
29 National Parks covering 12% of landscape
Protect 208 species of mammals and 850 species of
birds
9000 different plant types
Park contains volcanoes, caves and tropical forests and
beaches
Benefits:
Brings many tourists, scientists and nature lovers which
boosts the local economy
Parks are managed so the environment is not damaged
and is SUSTAINABLE
Problems:
As it is very famous many people come to visit and this may
need to be controlled in the future to limit excessive
tourism
BUT if you limit the numbers then less money will be made
and nature will become exclusive
Need to educate people so as not to affect the park’s eco
system
Facilities are needed to cater for the tourists such as toilets
and campsites
Exam Style questions
Unit 2.1 to 2.6 IGCSE exam 5 marks describing/explaining and 7mark case study questions:
Unit 2.1 Plate Tectonics
Describe what can be done to protect people from volcanic eruptions. (4)
Suggest how volcanoes are likely to benefit the people who live in countries such as Iceland.(5)
Explain why people live in areas where there are active volcanoes. (5)
Why do many people live in areas which are at risk from earthquakes? (5)
Name an area which you have studied where there has been an earthquake. Describe the impacts of
this earthquake. (7)
Unit 2.2.2 Rivers
Describe the advantages and difficulties for people of living close to a river (5)
Describe and explain how an oxbow lake is formed. You should use label diagrams. (5)
Explain how and why a delta has formed in a named area which you have studied. You should use a
labelled diagram or diagrams in your answer. (7)
Explain the change in the shape and characteristics of a river as it travels from source to mouth (7)
Unit 2.2.3
Marine processes
Explain how headlands are formed along some coasts. (4)
Explain why coral reefs are only found in some sea areas. (5)
For a place you have studied, explain how humans have an impact on a coral reef. (7)
Unit 2.3.1 – 2.3.4
Weather and Climate/ Ecosystems / Natural hazards/ Human impact
The thermometers used at the meteorological station are kept in a Stevenson Screen. Explain how
this ensures that reliable readings are obtained. (4)
Give reasons for the climate of an area of tropical rainforest such as Kisangani. ? (5)
Explain how the natural vegetation of tropical desert areas can survive in the hot, dry climate. (5)
Another type of natural environment is tropical rain forest.
Describe the impact of human activity on a tropical rain forest ecosystem which you have studied.
(7)
Explain why the effects of tropical storms of the same strength are likely to be greater in an LEDC
than an MEDC. Refer to examples which you have studied. (7)
An earthquake is an example of a natural hazard. Choose an example of one of the following: a) a
tropical storm, b) a drought. For a named area, describe the causes and effects of your chosen
hazard. (7)
For a named area which you have studied, describe the impacts of a tropical storm. (7)
Name an area of tropical rainforest which you have studied and explain why deforestation is taking
place there. (7)

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Geography igcse revision guide 2020

  • 1. GEOGRAPHY IGCSE REVISION GUIDE 2020 What do you need to know? You should use this CASE STUDY guide to learn all your case studies AND the IGCSE Cambridge revision guide for theories and key terms This is mainly for your 7 mark case study questions and there are exam questions included for you to practise. LEARN THEM! Theme 1. Population and Settlement 1.1 Population dynamics 1.2 Settlement Theme 2. The natural environment 2.1 Plate tectonics 2.2.1 Weathering 2.2.2 River processes 2.2.3 Marine processes 2.3.1 Weather/ 2.3.2 Climate/Ecosystems 2.3.3 Natural hazards 2.3.4 Human impacts: National Parks Theme 3. Economic development and the use of resources 3.1 Agricultural systems 3.2 Industrial systems 3.3 Leisure activities and tourism 3.4 Energy and water resources 3.5 Environmental risks and benefits: resource conservation and management
  • 2. Case studies by unit Unit: Topic and case study: 1.1 Population Rapid population growth: Case Study Niger Overpopulation/anti natalist policy: Case Study: China Under population: Pro natalist policy: Case Study Singapore / Italy Population density and distribution: Case study: Botswana International Migration: Mexico to USA Rural to urban migration (internal migration) Case study: Brazil HIV/AIDS: Case study: Botswana 1.2 Settlement Case study: Rural settlements and Ethiopia and France Case study: The reasons for the growth of an urban settlement: Seville Case study: Urban model Seville Case study: The effects of urbanisation / urban sprawl LEDC Case study: Rio de Janiero Case study: The effects of urbanisation / urban sprawl MEDC Case study: Atlanta Case study: Urban problems: Cairo, Egypt LEDC 2.1 Case study: Volcanic eruption MEDC Mount St Helens Case study: Volcanic eruption LEDC: Mt. Pinatubo volcano in the Philippines 1991 Case study: Earthquake LEDC Haiti Case study: Earth quake MEDC Kobe, Japan earthquake 1995 2.2.2 Case study: formation of a waterfall Niagara Falls Case study: Living by Deltas Ganges, LEDC, Bangladesh Case study: Flooding of the Brahmaputra and Ganges Rivers, Bangladesh (LEDC) Case study: Flooding MEDC Boscastle UK Case study: River management in MEDC: Mississippi River, USA 2.2.3 Case Study: Coastal erosion, transportation & deposition: The Hel Spit Poland Case study: Coastal Landforms: The twelve apostles Case study Coral Reefs: The Great Barrier Reef 2.3.1/2 Case study: Tropical Rainforest climate: Madagascar Case study: Tropical Desert Climate: Sahel, Africa 2.3.3 Case study: Drought: Australia MEDC Case Study: Drought Ethiopia LEDC Case study: MEDC Tropical Storm: Hurricane Floyd, USA 1999 (MEDC) Case study: LEDC Tropical Storm: Cyclone Myanmar 2.3.4 Case study: Deforestation of Tropical Rainforest: Amazon Rainforest Case study: Sustainable Rainforest Scheme: Costa Rica
  • 3. Unit 1.1 Population Dynamics Population growth The world’s population is increasing rapidly Natural population change (NPC) is worker out by: BIRTH RATE (BR) – DEATH RATE (DR) = NPC If the answer is positive the growth rate is getting bigger and if the number is negative the growth rate is getting smaller. The unit is usually per 1000 people and to make it a percentage you must divide by 10. Demographic transition model The model shows that as a country develops the BR and DR change. It is based on what happened in Europe and America in the past and is now used to predict the population changes that will occur to developing nations (LEDCs) Rapid population growth: Case Study Niger Where is Niger? West Africa, next to Algeria, Libya, Chad and Nigeria. Information on Niger: One of the poorest countries in the world Mostly nomadic farming Fertility rate of 7.1 babies born per woman ½ population is under 15 years old It has a youthful population Why are the birth rates so high? Children needed to support farming No sex education in countryside Children wanted to look after parents when they are old No social security 5% of people have access to contraception Problems with population growth: Limited access to clean water and resources
  • 4. Population is rising as death rates fall and birth rates stay the same or increase. Why are death rates falling? Vaccinations for children against diseases Better supplies of water Better diet Better health care Women becoming educated No enough schools or jobs Solutions: Increase family planning clinics and education Educate women Higher age of marriage set to 18 Over or under population Over or under population Overpopulation: The number of people living in a place is more than the amount of resources available – not enough resources to go around Under population: The number of people living in a place is less than the number of resources available – an excess of resources and a loss of money for the country, limited workforce Overpopulation/anti natalist policy: Case Study: China Where? Asia What?People encouraged to have lots of children in the 1950s/60s to ensure Chinese victory in event of a war. Problem: No enough food, jobs, healthcare, housing or services for all the people and population was still rising in 1970. The crime rate was rising and the country, air and water were becoming polluted. A very low quality of life. Solution: One Child policy: Couples in cities only allowed to have one child and must apply for permission from the government. Free contraceptives and education on family planning for all and an excessive propaganda campaign. Couples in rural areas may have two children if the first is girl or first child disabled or died. Consequences: Good: China’s population of about 1.3 billion is said to be 300 million (.3 billion) smaller than it would likely have been without the enactment of this policy. The fertility rate has fallen to 1.7 births per woman. Such a reduction in fertility reduced the severity of problems that come with overpopulation, like epidemics, slums, overwhelmed social services (health, education, law enforcement, and more), and strain on the land from farming and waste Bad: Uneven proportion of boys to girls as many girls are aborted, heavy fines put on couples who wish to have a second child so richer people can afford it while the poor cannot. Spoiled children. Some babies killed or sold if they are girls. Some women forced to have abortions or be sterilised. BUT: Population growth has been stabilised, policy has been relaxed since 2003. Under population: Pro natalist policy: Case Study Singapore / Italy Where? Asia What? Independent from the British since 1965, from 1950s tried to limit population by encouraging smaller families but now has a declining population and a limited Pro natalist 1980s: increased immigration, female university graduates having children were given the best school places, grants given to new parents, tax rebates for third child, day care for children subsidised, 4 years
  • 5. workforce Anti natalist 1970s: Abortion and sterilisation made legal, ‘stop at two’ campaign, extra tax on third child, best schools’ places given to those with fewer children. maternity leave for civil servants. Outcomes: Not much change in the BR but immigration has continued to help the economy Where? Europe Low fertility rates of 1.23 children per family Ageing population Some women feel that they cannot work and cope with raising a family too Some men not doing sufficient household chores Poor service provision for childcare in preschool years Childless no longer bears a stigma Social pressure to marry and have childrenis less Even though head of the catholic church is in Italy – contraception use is high Yuppiedom – preference for luxury goods delays marriage and babies Less than 1/3 mothers have children before 28 years Young people live at home with parents longer to save rent etc. which delays relationships and births Solutions 10,000 euro bonus for births in a village in Mezzogiornio as mayor concerned that young people will not enter village otherwise Population density and distribution: Why are some places densely populated? Employment, flat land, good communications, fertile soil, reliable water supply and natural resources. Why are some places sparsely populated? Steep relief, infertile soil, cold climate, arid climate and marshy land. Population density is the average number of people living in a given area (measured in people per km2) Total number of landtotal population = number of people per km2 But: Only if people are evenly spread out, which they are not!
  • 6. Case study:Botswana, Kalahari desertPopulation density and distribution Physical factors: Kalahari area is semi desert with annual rainfall of less than 400 mm Soil is sandy and not fertile and other areas are protected as national parks Human factors: Many people are nomadic farmers and have no fixed settlements. Other areas: Deltas are wet and swampy
  • 7. Economic factors: Farming is very difficult in the Kalahari desert Land cannot support animals or crops Few roads and transport links Chobe district has many dangerous wild animals There are large areas of salt plains with no drinking water Migration and its effects on population Types of migrants: Asylum seeker: person who has left due to fear of persecution Refugee: person has left due to fear for their life from war, famine etc. FORCED MIGRATION International migrant: person who moves to another country (if for work: an economic migrant) National migrant: person who moves to lives somewhere else in their own/the same country VOLUTARY MIGRATION Illegal migrant: person who enters the country without permission International Migration: Mexico to USA What is the situation? Mexicans make up 29.5 % of all foreigners in the USA. Mexican immigrants account for about 20% of the legal immigrants living in the USA. Brain drain is occurring out of Mexico. e.g. An estimated 14,000 of the 19,000 Mexicans with doctorates live in the USA (International Organization for Migration) PUSH factors: Push factors from Mexico (Santa Ines) (2010) Poor medical facilities – 1800 per doctor Low paid jobs – GDP per capita $14,406 Adult literacy rates 55% - poor education prospects Life expectancy 72 yrs. 40% Unemployed Unhappy life – poor standard of living Shortage of food Poor farming conditions National average poverty level of 37 percent PULL factors: Excellent medical facilities – 400 per doctor Well paid jobs – GDP per capita $46,860 Adult literacy rates 99% - good education prospects Life expectancy 76 yrs. Many jobs available for low paid workers such as Mexicans Better housing Effects on USA Illegal migration costs the USA millions of dollars for border patrols and prisons Mexicans are seen as a drain on the USA economy Migrant workers keep wages low which affects Americans They cause problems in cities due cultural and racial issues Mexican migrants benefit the US economy by working for low wages Mexican culture has enriched the US border states with food, language and music The incidents of TB has been increasing greatly due to the increased migration Effects on Mexico (Santa Ines) The Mexican countryside has a shortage of economically active people Many men emigrate leaving a majority of women Women may have trouble finding marriage partners Young people tend to migrate leaving the old and the very young Legal and illegal immigrants together send some $6 billion a year back to Mexico Certain villages such as Santa Ines have lost 2/3 of its inhabitants
  • 8. Family links Bright lights Rural to urban migration (internal migration) / Urbanisation Case study: Brazil, Sao Paulo What and where: South America Population urbanising in Brazil Moving from north east rural areas e.g. Pernambuco village Moving to Sao Paulo SP – On the south east coast of Brazil, West of Rio de Janeiro SP – Has expensive apartments and houses – large gardens, swimming pools, maids, children well educated, security guards etc. BUT also favelas! Push factors:  Mechanisation of farms (bringing in machinery to replace workers) results in high rural unemployment  Large landowners take back the land of their tenant farmers to grow cash crops (crops for money!) for export  High infant mortality due to lack of clean water, electricity, sewerage and medical care  Housing in rural areas is even worse than in the city  Droughts and desertification (like the Sahel!) in NE Brazil  Lack of services e.g. schools, shops, etc. NE Push Factors – milking by hand, drought + desertification and Pernambuco village Pull factors:  Advertising campaigns were run in rural areas in the 1950s and 1960s to attract workers to the city  More schools, doctors and other services in the city  Successful migrants encourage people to join them Café, better SOL / IT class better education / Skyline “Bright Lights” Problems: effects on rural areas o Mainly young men who migrate o Brian Drain – intelligent tend to move, less intelligent stay o Women, children and elderly left behind o 27% of poor rural households headed by women o Lowers birth-rates as lack of men o Elderly struggle to support themselves o Lack of workforce for farming – child labour is common o Migrants send money back home to families – called remittances (a positive!) Problems: effects on Sao Paulo • 2,000 migrants arrive per week! • Do not have money for apartment – end up in illegal favelas • Favelas on outskirts of SP, on disused land e.g. opposite factories or on steep hillsides prone to landslides • Made from wood, corrugated iron, cardboard etc. • Most have no clean running water (cholera), toilets, safe electricity, rubbish collection • Overcrowded, disease spreads • High birth-rate, 6 kids per shack! Management of problem – Self-Help Scheme  Run by local government and NGOs (Non-government organizations)  Local gov provides – breeze blocks, roofing tiles, electricity, clean water, tarred roads, community centre  Self-help so favela dwellers – dig ditches for pipes + build houses  Gives sense of pride + community spirit  Saves money so cheap houses HIV/AIDS: Case study: Botswana
  • 9. HIV: initial virus caught by the exchanging of bodily fluids, breast milk or blood – can be treated but not cured. AIDS: later stages of HIV virus which attacks the immune system and allows other infections into the body. Where: Africa (see above) Problem: In 2005 an estimated 270,000 people living with HIV (total population below two million) 24.1% of people have HIV/Aids Life expectancy less than 40 years in 2000-2005, a figure about 28 years lower than it would have been without AIDS. An estimated 120,000 children have lost at least one parent to the epidemic. First case 1985 Many people have more than one sexual partner Ignorance about AIDS and how it is spread Sick people cannot contribute to the economy or to their families Large number of orphans with not enough government money to help them - no education or possibilities for the future Solutions: (1987-89) the screening of blood to eliminate the risk of HIV transmission through blood transfusion. (1989-97) information, education and communication programmes– Botswana National Policy on AIDS. (1997 onwards) education, prevention and comprehensive care including the provision of antiretroviral treatment for 19,000 people. HIV prevention programme: Public education & awareness – 1. “ABC” of AIDS: Abstain, Be faithful and, if you have sex, Condomize. 2. Safe-sex billboards and posters everywhere. 3. Radio drama dealing with culturally specific HIV/AIDS-related issues and encouraging changes in sexual behaviour. 4. Workplace peer counselling. Unit 1.2 Settlements Rural Settlements: Settlement: A place where people choose to live MEDC: More economically developed country (richer countries like USA and European countries) LEDC: Less economically developed country (poorer countries like Botswana, African countries) Nomads: People who move from place to place and have no fixed settlement where they live Urban settlements: Towns and cities (85% of people from MEDCs live in urban settlements) Rural settlements: the countryside (75% of people in LEDCs live in rural settlements) Site: The places people choose to build their settlements Situation: The location of settlement Shape: The shape the settlement has (nuclear, dispersed, linear) Function: The main activities of the settlement Nucleated settlement:buildings all clustered together around a central point Dispersed settlement: buildings spread out in no particular pattern like farms or isolated dwellings Where do/did people choose to site their settlements? In places which have: water supply, gentle slopes, low altitude, good drainage, no flood risk, resources (such as forests for building)
  • 10. Case study: Rural settlements and Ethiopia and France Ethiopia LEDC Function: Farming maize Advantages: water from 2 rivers, flat fertile soil, forests. Services built like schools, mosques, a grain mill. Disadvantages: lack of rain, drought, hunger, starvation, heavy rain comes and then washes away dry soil, no market or shops Deforestation: due to the forest being cut down the soil is more easily eroded Solutions: irrigation system and diesel pumps sponsored by American NGO France MEDC – changes in rural settlement Function: farming and tourism Changes: larger fields, different crops, caravan parks, increased tourism, land sold, young moving to the cities, aging population, decline in services, more English owned businesses. Urban settlements: Settlement hierarchy: settlements put in order of size and services they provide Sphere of influence: The areas which a settlement serves (how far people are willing to travel to use the services in that settlement) Low order services: mostly in rural settlements, used frequently and selling basic and cheap products; e.g. bread and milk – need low threshold population High order services: mostly in or near to urban settlements, used less frequently with products that are not needed on a day to day basis; e.g. televisions – need high threshold population Threshold populations: The number of customers needed for a business to survive. Functions of urban settlements Market town: where farmers buy and sell goods Port: where goods are loaded and unloaded by ship Industrial town: where factories are located close to resources or transport on rivers Resort: where tourists come to enjoy themselves
  • 11. Case study: The reasons for the growth of an urban settlement: Seville Where: Spain Function of settlement: tourism, industry, market town Original site features: flat fertile land to grow oranges and food, water supply, Mediterranean climate. Reasons for growth: close to sea, port leading to gold coming from South America, factories grew along the river, culture and history brought tourism, famous for oranges Urban land use Models: Burgess and Hoyt created models to show how land is usually used in an MEDC based on the value of land. Burgess’ model comes from when cities and towns began to industrialise along rivers for transport and therefore poorer people were forced to live nearer the factories in the centre of the city. Hoyt then modernised the model as factories declined or moved further outside the city as transport improved. CBD: The central business district. You would expect to see: expensive land, high density of buildings, crowded, high order shops, industry (in MEDCs), offices, and flats. Case study: Urban model Seville CBD High order shops e.g. El Corte Ingles, pedestriansed, transport links, metro, underground rail service, offices, small medieval streets Inner city Residential areas with flats, rejuvenation of old factory buildings, high density of living spaces, no gardens, transport links and services, offices Outer city Larger houses with gardens, transport links developed, low and high order services, shopping malls as land is cheaper. E.g. Ikea, Aire Sur Urbanisation The movement from the countryside to the city MEDCs: Took place mainly before the 1950s during the industrial era LEDCs:Is now beginning to happen in LEDCs because of a) lack of resources in countryside PUSH b) standard of living in urban areas are better PULL Rural to urban migration Push: poverty, not enough land, failed crops, high infant mortality, no prospects, loss of farm work, lack of food, drought.
  • 12. Pull: education, medical care, housing, jobs, shops, money Problems: noise, dirt, pollution, over crowded, expensive land, low paid jobs Urban sprawl: Urban settlements extending into the rural urban fringe. Planned in MEDCs, not planned in LEDCs Case study: Urbanisation in LEDC USE CASE STUDY FOR RURAL URBAN MIGRATION BRAZIL, SAO PAULO FROM UNIT 1.1 OR: Case study: The effects of urbanisation / urban sprawl LEDC Case study: Rio de Janiero Where and what is it? Rio was formerly the capital of Brazil until the government decided to locate the capital inland in Brasilia. Approximately 10 million people live in and around Rio. It is a city of contrasts with rich people living in luxury around Copacabana beach and the vast majority living in poor conditions around the edge of the city. Problems in the city include housing, crime, traffic and pollution. HOUSING An estimated 0.5 million are homeless. Approximately 1 million live in favelas (informal shanty settlements). Two examples are Morro de Alemao and Rocinha. (YOU MUST KNOW THESE NAMES!!) Another million live in poor quality government housing on the outskirts. The favela housing lacks basic services like running water, sewerage or electricity. The houses are constructed from wood, corrugated iron, broken bricks and tiles or other materials found lying around. Favelas are often found on land that is steep, by the side of roads, railways etc. and flash floods can destroy such houses and take people’s lives. At first the government tried to bulldoze such communities but now they remain because of the community spirit, samba music and football etc. CRIME Favelas are thought to be associated with drugs, violence etc. Tourists to Rio are warned not to enter favela areas or take valuables to beaches etc. Some wealthy are moving to new towns to avoid crime. TRAFFIC AND POLLUTION Mountains around the city keep the fumes in the city and make the vehicles use a limited number of routes. This results in congestion and noise A vast amount of rubbish is produced and in favelas this is not collected. Along with open sewerage drains it results SOLUTIONS TO THESE PROBLEMS SELF HELP HOUSING ROCINHA Most of old temporary wooden houses replaced by brick and tile and extended to use every square centimeter of land. Many residents have set up their own shops and small industries in the informal sector. Government has added electricity, paving, lighting, water pipes but the steep hills still restrict. 2. FAVELA BAIRRO PROJECT 1990S government chose 16 favelas to improve using 250 million euros. Replaced wood buildings with brick and gave each house a yard. Widened the streets so that the emergency services and waste collectors could get access. Improved sanitation, health facilities and sports facilities. Used residents for labour to develop their skills and in return residents paid taxes. 3. NEW TOWN BARRA DA TIJUCA Land outside to South of Rio was uninhabited until motorway was built in 1970s Rich moved out of Rio to avoid problems of city It has 5km of shops, schools, hospitals, offices, places of entertainment etc. Spacious and luxury accommodation in 10-30 floor high rise apartment blocks with security and facilities or detached houses. Both adults in each family chose to work in high paid jobs to pay for expensive life. Families with own cars but also well connected with public transport. BUT: These areas have own favelas as house keepers, gardeners etc. cannot afford accommodation
  • 13. in the spread of diseases. Case study: The effects of urbanisation / urban sprawl and solutions MEDC Case study: Atlanta Where: Capital of Georgia, USA What: Between 2000 and 2006 there are1 million more people moved there because of increased birth rate and migration. Problems: urban sprawl, traffic congestion, polluted drinking water from overflowing used septic tanks (where your poo goes), farm land bought up, loss of green space and ecosystems, flooding, loss of cultural sites, social divides between poorer inner city and richer outer city, temperatures rising due to removal of trees. Solutions: New public transport system for the inner city, investment into ‘green buildings’ in the centre and on old factory sites; e.g. 5000 flats being built on old steel mill site. Planting more trees around Atlanta and persuading people to move back into the centre with sustainable new buildings. Urban problems and solution Problems: Cities cannot cope with the growing numbers Limited housing, services, transport and jobs Stressful living conditions and protests from residents Urban decay: parts of city become run down and slum housing appears (think Tres Mil Viviendas), vandalism, derelict housing. Solutions: Urban regeneration: rebuilding, renovating old factory sites or derelict houses, knocking down old factory buildings and creating flats, medical centres and offices. Introducing news transport systems such as elevated railways, undergrounds, metros Pedestrianised areas for shoppers and workers in the CBD Urban problems and solutions LEDC: Case study Cairo, Egypt Where: Egypt, North Africa Problems: Rise of population from 2 million to 8 million Increased demand for piped water, sewers, schools, paved roads, electricity. Traffic congestion brings noise, air and water pollution. Lack of housing and lack of jobs Solutions: Satellite towns built outside the city with transport links Homes and public services upgraded Metro system built Greater Cairo Water project to repair sewage system Ring road built around the city
  • 14. Exam style questions Unit 1.1 and 1.2 IGCSE exam5 mark describing/explaining and 7mark case study questions: e.g Population Explain the advantages of educating girls and women in LEDCs. (5) Describe the likely problems for an MEDC, such as New Zealand, of having so many old dependents. (5) For a named country which you have studied, describe the problems caused by overpopulation. (7) Name an example of a country which has attracted large numbers of international migrants. Explain the pull factors which have attracted people to your chosen country. (7) Choose any example of international migration which you have studied and name the countries between which people moved. Explain why many people made the decision to migrate. You should refer both to pull and to push factors. (7) 1.2 Settlement Describe the typical land uses and characteristics of the CBD of a city. (5) Suggest how urban growth may have created problems for people in Maseru, the capital city of Lesotho. (LEDC) (4) Describe the effects of rapid urban growth on the natural environment. (5) Describe the problems for people using the CBD of a large urban area. (5) Name a city in an LEDC and describe what has been done to improve the quality of life of the people who live there. (7) Choose one problem of living in urban areas. For a named urban area, describe the attempts which have been made to solve the problem you have chosen. (7) Many settlements have grown over the years into large urban areas. For a named example of a large settlement, explain the reasons for its growth. (7)
  • 15. Unit 2.1 Plate tectonics The world’s surface if made up of tectonic plates These plates move around due to convection currents in the magma and when they do they causes earthquakes and volcanic eruptions depending on the type of plate boundary the movement occurs on. Oceanic plate:tectonic plate under the ocean (denser) Continental plate: tectonic plate under land (less dense) Converging boundary: (destructive) Oceanic plate sub ducts under a continental plate = earthquakes, fold mountains and volcanic eruption OR 2 oceanic plates or 2 continental plates collide = earthquakes and fold mountains Diverging boundary: (constructive) Plate move apart from each other = magma escapes gently from the earth forming shield volcanoes Fold Mountains: e.g. mount Everest Folding sedimentary rocks left beneath the seas or lakes Sea or lake beds are squeezed together and pushed upwards over millions of years Everest is still rising!
  • 16. Structure and types of volcanoes Case study: Volcanic eruption LEDC:Mt. Pinatubo volcano in the Philippines 1991 – This was your own choice but if yours is not very good use this one. Where? South East Asia to the East of China What? 600 years dormant Island arc of Luzon in Philippines Philippines oceanic crust subducting under continental Eurasian plate – i.e. destructive plate margin Erupted June 1991 Effects: Short term 847 dead 300 killed by collapsing roofs 100 killed by lahars Aetas tribe refused to leave or died in evacuation centres from disease 1.2 million lost homes Long term: Measles, respiratory and gastric diseases Responses: 2 April steam explosions – vegetation killed and dust on villages PHIVOLCS set up to monitor eruption– 5000 pop evacuated in 10km zone 23 April continuing earthquakes- US Geological Survey set 7 seismographs at Clark Air Base NW slope villages evacuated 9 June 8 hr eruption with pyroclastic flows – Alert 5 - evacuated to 20km 10 June Clark Air Base evacuated 12 June Mushroom cloud 20km high – evacuated 30km – 58,000 people 15 June – eruption 40km high ash and 80km/hr pyroclastic flows – summit collapses. Heavy rain causes mudflows. Affects houses, bridges and river. Manila airport closed.
  • 17. 500,000 migrated to Manila 650,000 lost jobs 80,000 ha of cropland destroyed 1 million farm animals died Case study: Volcanic eruption MEDC Mount St Helens Where: Mt St Helens is located on a destructive plate boundary where a continental plate (North American) meets an oceanic plate (Juan de Fuca). What: 18th May 1980 at 8.32am (5.1 on Richter Scale) Effects: All living things wiped out 27km north of the crater, up rooted trees, 57 people dead. Responses: Immediate Responses – Mobilising helicopters, rescuing survivors, emergency treatment and clearing ash to allow the flow of traffic Long Term Responses – Buildings and bridges rebuilding, drainage had to be improved, replanting the forest and rebuilding roads. $1.4 million was spent to transform the area. Case study: Earthquake LEDC Haiti Where: Caribbean near Cuba. Never major earthquakes before, buildings not built for earthquakes. Capital, Port-au-Prince is overcrowded and poor with people living in crowded conditions. What: 21st January 2010 Earthquake of 7.0 magnitude Movement along destructive plate boundary between Caribbean and North Atlantic plates Effects: 20,000 killed 300,000 injured Buildings, including house, hospitals, and government Responses: Aid supplies from other countries slow to arrive due to bad transport links and airports USA engineers cleared the roads USA sent 10,000 soldiers Temporary tents for housing and 20,000 relocated Bottled water Field hospitals Relies completely on aid and recovery is slow – 1 year later people still living in tents.
  • 18. buildings destroyed and 1.3 million homeless People went looting (stealing) 2 million with no water or food or electricity Outbreak of Cholera from dirty drinking water Case study: Earth quake MEDC Kobe, Japan earthquake 1995 Where? South East Asia What? 7.2 Richter on 17 January 1995 5.46am Epicentre 20km south of Kobe in Osaka bay 14km depth so much ground shaking and soil liquefaction Effects Short term: Collapse of elevated roads and bridges e.g. 630m stretch of Hanshin expressway collapsed 103,500 buildings collapsed Only 20% buildings in CBD usable after earthquake – 62 high rise destroyed and only 19 rebuilt Port facilities (30% Japans commercial shipping) destroyed by soil liquefaction Ruptured pipes and poles stopped city’s gas and electricity 6300 deaths – 2900 more from suicides or neglect 35000 injuries Area of Nagata badly affected – timber framed buildings owned by poor were death traps 60% deaths were over 60 year old people 300 fires in city after gas pipes ruptured 300,000 immediately homeless – 20% of Kobe- Long term: 95,000 in temporary accommodation 1 year later $99.3 billion damage and $120 billion needed for reconstruction – only 7% had insurance 20,000 lost jobs Businesses moved away – Kawasaki shipping and Sumitomo rubber Responses: State’s crisis management very poor Inadequate communication between government and administrators People running through street hit by falling debris ignoring fires 5 hr delay calling Self Defence Force / Army – only 200 troops Only 21 Jan 30,000 troops Took several days to designate disaster zone 3 days no electricity Delays in accepting international help – US military based in Japan, foreign medical teams and sniffer dogs Kobe’s resident’s believed that not at risk Improvements since then- recovered quickly Solutions/management: All school children now have earthquake and drills 4X per year Earthquake kits can be bought in department stores – bucket, bottle water, food, radio, torch, first aid kit and protective head gear Earthquake Disaster Prevention Day 1 Sept every year for offices etc. Why live in a danger zone? Fertile soil, limited transport to move away, family livesthere; feel they are not in danger, tourism. Unit 2.2 Weathering
  • 19. Weathering is the break-up and decomposition of rocks in-situ (in their place of origin). Weathering does not involve the movement of material and this makes it different to erosion. Erosion is the carrying away of material by a natural force e.g. water, wind, glaciers Mechanical weathering: (physical) breaking down of rocks due to temperature changeor plants (biological weathering) Chemical weathering: decomposition of rocks by changing chemical composition such as rain Biological weathering: Plants’ roots growing or animals burrowing into joints or cracks and force apart or loosen the rock.
  • 20. Unit 2.3 Rivers The Water cycle: The amount of water of earth never changes. It is only moved and stored in different ways. - Evaporation: when the temperature of water or air changes water is turned to gas and rises into the atmosphere - Evapotranspiration: Plant suck up the water in the earth and then water can be evaporated from their leaves called transpiration. - Condensation: water vapour blown towards mountains is forced to rise and then cools into droplets of water which form clouds and fall as rain or snow. (precipitation) - Interception: some rainfall is intercepted (caught and absorbed) by plants or soil and some flows on the surface of the earth. The water that is absorbed can saturate the land and the water that run on top forms streams and rivers. - Overland flow: streams flow on top of the ground and join to form rivers which feed into lakes and streams.
  • 21. Load: The material carried by the river Types of erosion: Types of river transport: Hydraulic action: the impact of the moving river Corrasion: (abrasion) the wearing away of the bed and river bank by the load being covered Attrition: the wearing away of the load as particles bump together while being carried by the river Solution: (corrosion) the dissolving of material by the river water Solution: materials dissolved in the river water Suspension: very light materials carried near the surface of the river Saltation: large particles bounced along the river bed Traction: heavy rocks and boulders rolled along the river bed River land forms: Erosional land forms: shapes in the landscape formed by erosion The river’s long profile: Upper course: Starts at the source Valley sides are steep Lots of vertical erosion Heavy loads of boulders and large rocks Water falls Potholes Interlocking spurs Middle course: Valley widens, slopes are not as steep sand the gradient of the river is less. More lateral erosion (side to side) Meanders Levees Lower course: River comes to an end and slows down as it meets the sea or lake – mouth of the river Lots of deposition Deltas Flood plains
  • 22. V shaped valleys Flood plains Oxbow lakes Waterfalls Falling water and rock particles wear away soft rock - The hard rock is undercut as - erosion continues - Hard rock collapses and if moved by the flow. The waterfall moves backwards - Erosion continues and the waterfall continues to move upstream leaving a gorge of recession Interlocking spurs
  • 23. In the upper course the river does not have a huge amount of energy to erode as it does not have a high discharge and it has to transport large pieces of sediment. When the river meets areas of harder rock that are difficult to erode it winds around them. A series of hills form on either side of the river called spurs. As the river flows around these hills they become interlocked. So, a series of interlocking spurs are often found in the upper course of a river valley. V-shaped valleys Potholes Rapids–places where the water is shallow and river bed is rocky and uneven. The water is rough and the gradient is varied causing water to run faster. These can be used by white water rafters. Meanders Formed by large stones getting trapped in the river bed causing corrosion which drills holes into rock bed which will eventually grow and join together. Formed by vertical erosion when potholes grow and join together eroding the rock beneath the river. Rivers with big sweeping bends with water flowing in corkscrew motions and causing lateral erosion on the outsides of bends and deposition on the insides.
  • 24. Depositional land forms: shapes in the landscape formed by deposition Floodplains Land next to the river which is liable to flood. Often very marshy and poorly drained. River deposits silt, gravel as it floods. Meanders (inside of bends) – as above Deltas Area of flat low lying, marshy land where a river meets the sea or lake. They can form their own lakes or lagoons. The loss of speed means the river deposits its load which is usually mud or silt. As this deposition takes places parts of the river are cut off leaving small lakes or lagoons. The river breaks up into distributaries.
  • 25. Oxbow lakes Levee Naturally formed when rivers flood. When the river floods it loses energy and deposits its load. This makes the banks of the river higher than the river or the flood plain. Sometimes the natural levees occur and other times they are built to prevent against river flooding. Continued erosion on the outside of meanders or in the neck of the river, may cause two parts of the river to create a shorter path for the water. The deposition on the inside of the bend may cause the old path of the river to become cut off and a lake is formed. An oxbow lake.
  • 26. Creating meanders and oxbow lakes In this picture, soil and mud is being eroded from various points on the bank. It’s being transported in the direction of the white arrows and deposited downstream (the sandy patches). This is changing the course of the river This picture shows the same river many years later, the erosion and deposition have created such a deep meander that it has nearly formed a circle Eventually, the river erodes so much that it cuts off part of the meander and creates an oxbow lake Case study: formation of a waterfall Niagara Falls Where? Two waterfalls in the Niagara River between New York State and Ontario, Canada What? Spectacular waterfall carrying 90% of the world’s water 12,000,000 visit every year Producer of hydroelectric power Benefits: Money from tourism, hydroelectric power, fame, water supply How was it formed? 1. Glaciers melted 12,000 years ago 2. Melted water poured down into the great lakes 3. As the lake overflowed it caused the Niagara River to flow downhill and fell down the escarpment (cliff) 4. The rocks at the falls are made of different layers of soft and hard rock 5. The soft rock (shale) was eroded from underneath the hard rock (sandstone) 6. The water could now fall freely 7. The force of the water eventually eroded away so much rock that the top rock was undermined and fell 8. This process happened over and again and is still happening! 9. This means that the waterfall is retreating every year. 10. The force of the water falling creates a plunge pool at the bottom of the falls. Case study: Living by Deltas Ganges, LEDC, Bangladesh Deltas: Where the river slows as it reached the sea a large amount of deposition takes place as the load can no longer be carried by the force of the water. The load deposited causes the river to split up into smaller distributaries which flow to the sea. The sediment dropped by the river is often very fertile and therefore much vegetation grows there. Where: Bangladesh, bordered with India Delta is at the end of the Ganges river which flows from the Himalayas Advantages: flooding and irrigation all crops to be grown all year round such as rice and vegetables. Preferable to city slums. Jute (used
  • 27. Formed: Deposition of load at the end of the Ganges river as it arrives at the coast and slows down. How? A) River carries a large amount of silt which builds up to form islands B) As more silt builds up flooding occurs and creates small distributaries (small little streams winding to the sea) C) Between these distributaries land is rich and fertile for making burlap sacks) is grown and there are many fish to catch. Disadvantages: monsoons (heavy rain fall), cyclones (strong winds and rain), floods Case study: Flooding of the Brahmaputra and Ganges Rivers, Bangladesh (LEDC) Causes of 1998 flooding: Monsoon season- 80% of rain falls June to September Deforestation in the Himalayas increases runoff below Urbanization – building on floodplains 1998 both rivers peaked at the same time Silt had been deposited near the mouth blocking the main channel Global warming melting Himalayas Poorly maintained embankments Flat low lying land over 80% of Bangladesh Effects in 1998: 70% of land in Bangladesh affected 2/3rds of people affected Dhaka 2ms deep in water Electricity supply cut off for several weeks Wells contaminated and not safe for drinking 7 million homes destroyed 25 million homeless people 1300 approximate death toll 2 million tonnes of rice destroyed Roads, bridges, airports and a third of the railway destroyed $1.5 billion damages Management: (how to prevent it) Since 1989 Bangladesh has been trying to: Build 5000 flood shelters with stilts to save lives Improve forecasting with satellite technology Early warning system with megaphones Build dams Control water with sluice gates and water pumps Heighten embankments on side of river to 7m- more than 7500km already in place Case study: Flooding MEDC Boscastle UK Where: Cornwall UK When: 2004 What: settlement was left in ruins by floods Short term Causes:intense rainfall caused local rivers to burst their banks, heaviest rains in living memory, 185 mm fell in just five hours, three million tonnes of water was added to a tiny drainage basin Long term causes: The soils were already saturated from previous rainfall earlier in the week, encouraging overland flow to begin Effects: motor vehicle damage, shops were carrying greater levels of stock due to tourist season and were lost. No one died but property damage was high. At least thirty cars were washed straight into the harbour and many more were left upturned and badly damaged. A three-metre high wave of water was reported to have crashed through one street at 80 kilometres per hour. Fridge-freezers were picked up and swept out of kitchens as water entered properties. Six properties collapsed
  • 28. even sooner. The three river valleys are very steep and narrow. A broader floodplain would have helped to soak up water and river energy more effectively. The steep valley sides mean that soils are thin, with limited water storage capacity when heavy rain comes. Surrounding vegetation includes agricultural land with limited interception storage, although there is some forestry along the riverbanks. The rain coincided with high tide in the bay. This restricted the rate of exit of floodwater into the harbour. entirely. Infrastructure disruption – Both bridges in the village were destroyed and sections of road were swept away. Telephone, water, electricity and gas supplies were all interrupted. Irreplaceable loss of historical artefacts – The ‘Witch Museum’ – which is fifty years old and receives 50,000 visitors a year – had some of its unique contents damaged. Physical injury No-one died, but at least one resident suffered a heart attack. Mental injury Many residents suffered stress and anxiety in the year that followed. It was six months before many properties were sufficiently repaired for homeowners to permanently return home. Case study: Flood management: Responses to Boscastle floods Case study: River management in MEDC: Mississippi River, USA Where/what is it? Mississippi is 3800km long Flows through ten states Has over 100 tributaries Has a drainage basin covering 1/3 of the USA Causes of 1993 flooding: Heavy rain in April 1993 saturated the upper Mississippi basin Thunderstorms in June caused flashfloods Mid July 180mm of rain in one day Levees in nearby towns collapsed Management: 6 huge dams and 105 reservoirs Afforestation to delay runoff Strengthening the levees with concrete mattresses 25mx8m Making the course shorter and straighter - from 530km to 300km by cutting through the neck of meanders to get the water passed towns more quickly to the sea Diversionary spillways – overflow channels 9km long Less construction on the floodplain e.g. St Louis. Little task for you ….
  • 29. Unit 2.2.3 Marine Processes Coast: Where land meets the sea Fetch: the distance the wind has travelled over the sea – the longer the fetch the bigger the waves Constructive waves: swash is stronger than backwash causing deposition Destructive waves:backwash is stronger than swash causing erosion Marine transport: Suspension Solution Traction Saltation Fine sediment carried in the water Dissolved material carried in the water Large pebbles and stones rolling along sea bed Small pebbles hitting one another and bouncing along the sea bed
  • 30. Marine erosion: Long shore drift: The movement of sediment along the beach Groynes: beach protection against longshore drift Hydraulic action Air forced between cracks on rocks Corrosion Sea water dissolving parts of rocks Attrition Large rocks and sediment in water collide and wear each other down Corrosion Large rocks and sediment thrown against the cliffs
  • 31. Headlands and bays: Formed where there hard and soft rock. The soft rock is eroded away and the hard rock is not. Formation of caves, arches and stacks. A line of weakness called a fault appears in the rock This fault increases in size until it becomes a cave The waves erode the cave until the water breaks through the other side creating an arch The roof of the arch falls into the sea creating a stack
  • 32. The stack is eroded away to form a stump Case study: Coastal erosion: The twelve apostles Victoria, Australia Coastal deposition: Beach Spit Bar Salt marsh Large particles at the top of the beach and smaller particles like sand lower down the beach Created when deposition occurs when the swash is greater than the backwash Caused by longshore drift Deposition of sediment where coast changes shape or at the mouth of a river, the beach continues where the land stops forming a sand island going out to sea. When one end is attached to land it is called a spit. If a spit connects two pieces of land (eventually) it becomes a bar and the water enclosed between the bar and the land is called a lagoon. If this lagoon fills up with sediment it becomes a marsh. An area of soft soggy land. The water has very little energy and so deposits more and more sediment behind a bar. Many plants can grow here and help to cause more deposition or sediment and salt from the sea becoming a salt marsh. Case study: Coastal deposition: Hel Spit, Poland Where: Port Campbell National Park, Victoria, Australia Limestone cliffs formed in layers from the sediment on the sea floor forming sedimentary rock. 9 remaining stacks of rocks off the Victoria coast Formed: Headlands formed where the rock was harder Hydraulic action, corrosion and corrosion eroded along the fault lines Cliff base eroded away to form WAVE CUT PLATFORMS, notches, arches, caves and stacks When the arches collapsed stacks were formed
  • 33. Where: Baltic sea, northern Poland Formed: Result of longshore drift from west to east NW wind and sea carries sediment and deposits it along the east end of the beach Protection: Sea walls Groynes Beach replenishment –replacing the sand from the east of the beach back to where it came from Sand dunes: Ridges of sand which form behind beaches. An obstacle is formed by a plant or sand hill and this slows down the wind coming from the sea. Any and or dust that the wind is carrying is deposited around the obstacle and it grows; like a sand dune. Plants begin to grown there and their roots stabilise the dune so it become stronger. Over time the dune become grey as plants die and they decay leaving behind humus. Eventually the plant life grows and the sand is able to hold more water and trees can now grow here, transforming it into part of the earth. Coral Reefs: What is coral? The solid skeleton of limestone It grows in warm water 23-25° Grows in clear shallow salt water Needs plenty of sunlight How are they formed? Large amount of coral build up over a long period of time and get higher and higher. They begin building from a rock base in the ocean There are THREE different ways this can happen and therefore THREE different types of coral reef.
  • 34. Biodiversity: Coral reefs contain a very large amount of different species of plants and animals. Many of these are now becoming endangered species due to human impact Threats: earthquakes, cyanide bombs used for fishing, humans standing on the coral Case study: Coral Reef: Great Barrier reef, Australia Where: Great Barrier reef Marine Park, Australia National park since 1981 Only 100 meters deep and in some places less really close to the Australian coast. Economic importance: 6% of Australian workforce work here 12% of country’s exports come from here Threats: Human: Agriculture: Pollutants from agriculture Industry: metal pollutants, phosphates and nitrates from sewage and 34industry Fishing: Over fishing and cyanide bombs used to stun fish kill marine life Dredging: Sand and gravel taken from the sea for building muddy the waters and reduce the amount of sunlight needed for the reef to survive Tourism: Ships, yachts and boats bring tourists who tread on and kill the reef Natural threats: Starfish: warmer seas has seen the starfish move to new areas, eating more algae and coral and leaving white coral skeletons Solutions: World heritage site – now managed under particular laws to protect from pollution, fishing and tourist damage Zoning – only particular activities allowed in each zone Advice – tourist advised on how to preserve the reef e.g. no standing on the reef, no feeding the fish, no smoking
  • 35. Coastline development: Housing on the coast line brings greater demand for building materials taken from the sea
  • 36. Unit: 2.3.1/2 Weather and Climate/ ecosystems When we wake up in the morning one of the first things we are interested in is the weather. Weather is the condition of the lower atmosphere* at any particular time. If there were no atmosphere there would be no weather. The moon has no atmosphere and no weather. * The atmosphere is the layer of gases, called air, which surrounds the planet earth. * The air in the atmosphere is a mixture of gases. These are mainly nitrogen (about 4/5) and oxygen (about 1/5). There are also amounts of water vapour, carbon dioxide and some rare gases. The amount of water vapour is very important as this gives us our cloud and rain. The components of the weather To describe the weather we must describe the state of the air. We can do this under 6 main headings. These are called the elements of the weather: 1. air temperature - How hot or cold is it? 2. precipitation (rain, snow, hail, sleet, frost, fog, dew) - Is it wet or dry? 3. cloud cover and sunshine - Is it sunny or cloudy? 4. wind speed and direction -The movement of the air. 5. air pressure 6. Humidity – how much moisture there is in the air The climate of a place is its average weather. To calculate this we must know what types of weather occur there at different times of the year.
  • 37. Air Temperature We measure the temperature of the air in degrees Celsius (ºC) using a thermometer. EQUIPMENT NAME PHOTO DESCRIPTION (WHAT DOES IT MEASURE) Stevenson Screen A Stevenson screen is basically a white louvered wooden box. The box is designed to contain some weather equipment like thermometers and barometers. The Stevenson screen is white to reflect sunlight and has slats to allow air to circulate easily. The Stevenson should be placed above the ground and away from the buildings. The idea is for the weather instruments to take accurate readings of the air, rather than direct sunlight or heat from the ground or from buildings. For more detailed information about the siting of a Stevenson Screen, read the attached document. Barometer Barometers are used to measure air pressure. Air pressure is normally measured in millibars. Barometers are normally kept inside Stevenson screens to keep them safe. A barometer has a movable needle (pointer). The pointer can be moved to the current reading so that you can then make a comparison with the reading from the following day. Max./Min. Thermometer (sometimes called a Six's thermometer after its inventor) A maximum and minimum thermometer records the maximum temperature of the day and the minimum temperature of the day (diurnal range). A maximum/minimum thermometer contains a mixture of mercury and alcohol. The mercury sits in the u-bend of the thermometer. The bulb at the top of the tube reading the minimum temperature contains alcohol and the bulb at the top of the tube reading the maximum temperature contains a vacuum. On the minimum side the expansion of the mercury is restricted by the contracting alcohol, on the maximum side the expanding mercury can expand more freely into the vacuum. At any given time both thermometers should record the same temperature. However, during the day they would have recorded the maximum and minimum temperature - a steel marker should indicate these temperatures.
  • 38. Wet/Dry Bulb Thermometer (hygrometer) A hygrometer measures the humidity of the air. Humidity is the amount of moisture (water vapour) in the air. A hygrometer has two thermometers, a dry one and a wet. Humidity is measured by using a table that looks at the difference between the wet bulb and the dry bulb. A hygrometer can also be used to find dew point. There is a difference between the dry and wet bulb thermometers because of latent heat created during the process of evaporation. Rain gauge Rain gauges are used to measure rainfall. Rainfall is normally measured in millimetres. Rain gauges should be placed on grass, because if they are placed on concrete, extra water can splash into them. Rain gauges should also be checked regularly to avoid evaporation. Wind Vane Wind vanes are used to check the direction of the wind. Compass points are used to give wind direction. Wind is measured in the direction that the wind is coming from. Wind vanes are often placed on top of buildings so that they are fully exposed to the wind. When using a wind vane you need to use a compass to make sure that it is properly aligned. Anemometer Anemometers measure wind speed. Wind speed is normally measured in mph or kph, but can also be measured in m/s (metres a second). Digital anemometers are very accurate, but the more basic plastic ones that many schools have aren't very good or accurate at recording light winds. Anemometers are normally placed on top of buildings so that they are not protected from the wind and so they don't experience channeling of wind e.g. if an anemometer was placed in a corridor where wind was forced through the readings would be higher than normal. Cloud Cover It is also possible to count day light hours, sunshine hours or cloud cover. To Calculate day light hours you need to record the time between sun rise and sun set. To Calculate sun shine hours is a lot harder, because you have to time every time the sun comes out (stopwatch). To calculate cloud cover a mirror is often used. You divide the mirror into squares and then place the mirror on the ground. The mirror will reflect the clouds and you can count the number of squares covered or
  • 39. On a weather map we join places of equal pressure with lines called isobars e.g. A High Pressure Area a Low Pressure Area The weather we get from high air pressure is very different from that we get with low air pressure Cloud types and extent of cloud cover Clouds Clouds are a collection of water droplets or ice crystals. The warmer the air temperature, the more water vapour (gas) that the air can hold. However, when the air starts to cool, water vapour starts to condense as long as it has condensation nuclei to condense around. Cirrus Found high in the atmosphere – usually over 5,500 metres Common throughout the world Thin and wispy in appearance Move fairly quickly Stratus partially covered by cloud. You can do this as a percentage or convert to oktas which is the normal measurement of cloud cover. You have to take several readings to avoid anomalous results.
  • 40. Low level – below 2000m and sometimes reaching ground. Usually grey and colour and move fast. Can produce light rain and snow. Cumulonimbus Large clouds up to 10km high and across. They resemble giant cauliflower. Produce rain, thunder and lightening Usually found in spring and summer Cumulus Fairly low clouds with bottom between 600m and 1200m Look like lumps of cotton wool Can produce light rain Individual clouds have a short life cycle Climate zones and graphs Climate zones around the world depend on a variety of factors but more or less we can se they are dependent on the lines of latitude around the earth as the further away or closer we are to the equator will affect the temperature we experience. See blow for the climate zones and the factors which can affect the climate within one country.
  • 41. Factors affecting climate: 0 5 10 15 20 25 30 35 0 100 200 300 400 500 600 700 800 J F M A M J J A S O N D Temp(oC) Rainfall(mm) Month Climate Mumbai Climate graphs show us the climate over a year of different areas in the world. They concentrate on rainfall and temperatures and you must be careful to be sure you can use the following terms to use terms to explain climate. - Range of temperatures - Maximum and minimum temperatures - Annual precipitation - Minimum and maximum precipitation You must also be able to name the type of climate from climate graph. e.g. tropical, arid, Mediterranean
  • 42. Eco systems Ecosystems: A biological environment consisting of all the living organisms within a particular area and the non-living that interact with the organisms e.g. weather, soil, air and water. Tropical rainforest climates: Features of a rain forest environment: - mostly found along the equator - hot temperatures all year round - Plenty of rain, over 1500 mm in some areas - 10% of worlds rainfall depends on evaporation and transpiration from these rain forests - Ever green forests with broad leaved trees - Lots of flora and fauna (can be 40-100 tree species per hectare) - Large amounts of shade at low levels - Most plants grow up high where they can get to the light - Plants that reach the sky are called emergent and they can create their own islands in the canopy of the forest called the ‘lungs of the Earth’ as they produce oxygen. - Low pressure weather allowing clouds to form and rain occurs all year but in varying amounts. Location of Rainforests  The Congo Basin in central and west Africa  The Amazon in Brazil, Peru, Bolivia and Ecuador  SE Asia (Malaysia, Thailand, Vietnam, Indonesia and the Philippines)  Madagascar  North east Australia  Southern India and Sri Lanka  Central America Tropical Rainforest Animals Tropical rainforests have a huge amount of biodiversity within them - some estimates suggest that up to 50% of the earth's biodiversity live there (flora and fauna). The are many big famous mammals like tigers in SE Asia, jaguars in Central and South America and leopards in Africa. However, there are also much smaller mammals like sloths and primates like lemurs that live in rainforests. All mammals and primates have adapted in different ways to survive in the rainforest e.g. camouflage. As well as mammals and primates there are many other animals like birds, amphibians, reptiles and insects. Many rainforest animals are under threats. Threats include:  Habitat loss (deforestation)  Climate change (reduction in rainfall or increases in temperature)  Pollution (especially reptiles and amphibians)  Hunting (food food, skins and parts for Chinese medicine)  Cross breeding with domestic animals  Diseases (bird flu)
  • 43. Case study: Human impact on tropical Rainforest climate: Madagascar Where and what: LEDC 9th poorest in the world 4th largest island in the world Unique eco system and food chain Nearly all the land was once forest Gradually more and more land used for farming leading to deforestation The rainforest is disappearing. Problem: Cash crops being planted like rice and coffee These make lots more money for the country But the forest is being removed to plant more and more The eco systems within the forest are dying and cannot be replaced Removing trees is done by burning them The ash (which contains the trees nutrients) can be washed away into rivers Crops cannot grow in infertile soil Animals lose habitats and humans must move their crops to anew area when the soil become infertile. Dispute! People claim they need to earn a living The need to hunt the animals there for food and clothing They want their economy to develop Deserts Antarctica is sometimes classified as a desert because it actually has very low levels of precipitation. However, when we talk about deserts in this section of the desert we mean sandy deserts. Distribution of Deserts Deserts are located near the tropics (Tropic of Cancer and the Tropic of Capricorn). Some of the world's most famous deserts include:  Sahara in Northern Africa  Kalahari in Southern Africa  Atacama in South America  Gobi in Central Asia  Arabian in the Middle East  Great Victoria and Great Sandy in Australia  Mojave and Chihuahuan of North America Desert Climates  Deserts are extremely dry (arid) places. True deserts normally have less than 250mm a year although some deserts like the Atacama to the right can go years without any water.  Deserts are very dry because the air that descends over them is very dry. The air is dry because most of the moisture has fallen as precipitation over the Equator (tropical rainforests) before being pushed out and falling near the tropics.  The air is also very dry because the air travelling from the equator to the tropics travels over land and not the sea. This means that no additional moisture is picked up.
  • 44.  Because there is no moisture in the air, there are very few clouds in deserts which means desert areas are exposed to high levels of incoming radiation from the sun. This means that daytime temperatures in the desert are very high.  However, the lack of cloud cover also means that a lot of outgoing radiation is able to escape, making desert temperatures very cold at night. So even though the annual temperature range in deserts is very low, the daily temperature range is very high.  The daily temperature range is known as the diurnal temperature range. Desert Fauna and Flora Because of the very arid conditions found in deserts, both plants and animals have had to adapt to survive. Adaptations include: Succulents e.g. cacti:Succulents tend to be fairly fat fleshy plants that are able to store water in their leaves, trunks and roots. Ephemeral: These are plants with very short life cycles - typically 6-8 weeks. This means that they can take advantage of very short wet seasons in order to pollinate. Long and wide roots:Plants in deserts have very long roots so that they are able to absorb the maximum amount of rainfall during periods of rainfall. It also makes them more stable in very lose soil. Spiky and waxy surface:Many plants like cacti protect themselves with spikes and wax so that they are not eaten or damaged by animals. Deserts don't have the same variety of animals as tropical rainforests, but many insects, reptiles and mammals have adapted to survive. Nocturnal: Many animals will hide in burrows or behind rocks and vegetation during the hot daylight hours and only emerge at night. Camels: Camels store fatty tissue in their humps which when metabolised actually releases water as well fat enabling them to survive in deserts. Human Causes of Desertification Physical Causes of Desertification  Overgrazing: Allowing too much livestock to graze on a piece of land which means all the vegetation is eaten making the ground susceptible to wind and water erosion.  Overcultivation: If you farm land to intensively and don't have fallow  Rising Temperatures: As global temperatures increase it is becoming increasingly hard for vegetation to grow thus reducing vegetation cover and increasing the risk of wind and water
  • 45. periods then all the nutrients in the soil get used.  Deforestation: Cutting down trees which not only means the land will be receiving less nutrients, but it also means it is more vulnerable to erosion because there is no interception and less stability because the root systems have been removed.  Overpopulation: As the world population continues to grow (now about 7 billion) the demand for agricultural products (crops and meat) is increasing, causing more land to be deforested, overcultivated and overgrazed.  Fertiliser and Pesticide Use: By using fertilisers and pesticides you can artificially increase yields of crops. However, the process is unnatural and prolonged periods of use can all naturally produced nutrients to be used and local water sources to become polluted reducing the ability of land to cultivate crops and therefore making it vulnerable to chemical degradation as well as wind and water erosion.  HYV and GM Crops: Like with fertilisers and pesticides, it is argued that HYV and GM crops have encouraged overcultivation, diminishing natural nutrients in the soil.  Unsustainable Water Use (aquifer depletion, unsustainable irrigation): If aquifers or rivers are used unsustainably then areas can become increasingly arid as water resources are used up. A classic example of unsustainable irrigation happened in the Aral Sea.  Toyotarisation: This is basically the increased use of 4x4s to travel across grasslands, deserts, etc. damaging topsoil and increasing wind and water erosion. erosion.  Falling Rainfall: As the amount of rainfall reduces in some areas like the Sahel, then it is increasingly hard for vegetation to grow again making the ground more vulnerable to wind and water erosion.  Flash floods: Intense periods of rainfall can also cause erosion of topsoil which leads to land degradation.  Wind: If a region is particularly windy then the amount of wind erosion is likely to increase. Case study: Tropical Desert Climate / desertification: The Sahara and the Sahel, Africa Where and what:  The Sahel is a narrow belt of semi-arid land South of the Sahara in Africa  Rainfall is only in 1 or 2 months of the year  Rainfall is irregular with no rain in some years  Droughts in Ethiopia (1983), Sudan (1984-91) and Somalia (1990s) Causes of desertification:  Climate change and global warming allow less rain per year  Water holes dry up  Increased population growth – 3 or 4%increase each year  Overgrazing of cattle, camels, goats etc. increased 40% since 1980s  Animals taken to wells which decreases height of water table  Non drought resistant grasses die Effects of desertification: Desertification has caused many problems in the Sahel including: Famine Dust storms Conflict over diminishing resources Solutions: A number of solutions have been suggested to solve the problem of soil degradation and desertification including: A giant shelter break (the Green Wall) - see article to the right Population control Finding alternatives to firewood e.g. solar cookers Improved farming techniques e.g. reduced grazing numbers
  • 46.  Farming on marginal land  Farming the same crop each year  Lack of fallow land  Taking local trees for firewood All these increase the size of the desert, increase soil erosion and cause famines for people Unit 2.3.3 Natural Hazards Case study: Drought: Australia MEDC – Murray Darling Basin Where and what: MEDC in southern hemisphere Driest continent in the world Since 2002 worse drought in 200 years Murray-Darling river runs from the snowy mountains to Adelaide in South Australia River water is used for irrigation of farm land Not enough rainfall to keep the reservoirs full Not enough water for urban populations Desert and semi-arid climate Effects: Fall in population in Bourke in New South Wales because of drought Towns are facing economic and social ruin as crops fail and there is not enough water to supply the towns Options are to move of to try and make a living from tourists who go there to see the ‘outback’ Bush fires and homes destroyed due to lack of water Responses: Water restrictions put on citizens Fines or imprisonments for using too much water Case Study: Drought Ethiopia LEDC Where and what: Ethiopia is one of the poorest countries in the world 1983-84 saw the worst drought ever Cause: Rainfall level was considerably lower than average Famine caused as civil war and poor roads made it difficult to transport food Effects: Farmland dried out Animals died and crops failed causing widespread starvation and illness 500,000 people died Millions of people needed food from MEDC charities like Oxfam and Band-Aid People migrated to other areas or refugee camps People malnourished People living in poverty Tropical Storms Tropical storms take different names in different parts of the world. In The Caribbean, US and Central America they are known as hurricanes, in the Indian Ocean they are known as cyclones and in the Pacific around the Philippines and Indonesia they are known as Typhoons. Tropical storms are normally found between the tropics near the Equator. The formation of tropical storms is not fully known, but scientists do know that they draw their energy from warm seas. Therefore tropical storms tends to happen in late summer when temperatures are warmest (over 27 degrees Celsius). Because tropical storms get their energy from the sea, when they do hit land they lose their energy quickly.
  • 47. Most tropical storms last between one and two weeks. The main hazards caused by tropical storms are:  Winds: Very strong winds up to 250km/hr accompany tropical storms. Strong winds can damage buildings, knock over trees and disrupt transport and communications  Flooding: Heavy rainfall is associated with tropical storms. Heavy rainfall actually causes much more damage and deaths than high winds.  Storms urges: Tropical storms moving in land can create storm surges and big waves. If tropical storms coincide with spring tides the impacts can be severe.  Landslides: Landslides are a secondary hazard. Landslides can be triggered when large amounts of rainfall saturate the ground increasing the stress on the slope. Tropical storms are measured on the Saffir-Simpson Scale. The Saffir-Simpson currently has five categories, although some meteorologists believe a sixth category should be introduced to describe super hurricanes. Storms below 74mph (119kph) are described as only tropical storms. Anything above this speed is officially a hurricane/cyclone/typhoon. Case study: MEDC Tropical Storm: Hurricane Floyd, USA 1999 (MEDC) What and where:  Formed in Atlantic Ocean off coast of Africa  Began 2 September 1999  Cat 4 hurricane (211-240 kph) in Bahamas by 13 and 14 September  Weakened by time reached USA near Cape Fear, N Carolina  Tropical storm by time reached New England Effects:  14 states (Florida to Maine) hit – N Carolina worse hit  79 deaths  47 people died from storm of 500mm rain and floods in N Carolina  4 million evacuated in N Carolina, Georgia and Florida  1 million had no electricity or water  4,000 Pennsylvanians homeless  25000 claimed insurance - $460 million  42973 homes damaged – 11779 destroyed  144854 asked for assistance  10x increase in Alabama benefits applications  105580 people went to shelters  $1 billion agricultural losses -10% N Carolina tobacco lost  N Carolina 500 roads impassable  Storm surge in Nassau sunk boats  Beaches in Bahamas destroyed – Wrightsville beach 20m sand on roads Prediction  National hurricane Centre in Florida government run  Use geostationary satellites  Allowed 2.5 mil to be evacuated  N Carolina 800,000 evacuated – caused traffic on Interstate 26  150km journey took 10 hrs Preparedness/Buildings/Land use planning  Federal Emergency Management Agency (FEMA) gave advice for family disaster plan and disaster supply kit  Building codes to construct earthquake proof buildings – not always applied though  High risk coastal locations identified based on past hurricanes and surges  Building limited here
  • 48. Case study: Effects of LEDC Tropical Storm: Cyclone Myanmar Where and what: Asia LEDC May 2008 Winds up to 300 km/hr Heavy rain causes flooding and mudslides Short term Effects: Blew roofs of houses, schools and hospitals Cut electricity to whole cities In Bogdale, 3000 reported dead or missing Blocked roads Broken telephone wires Casualties unknown but estimated at 140,000 killed or missing Residents and Buddhist monks cleared the roads by hand People had to wash in lakes and queue to buy candles and water to drink. Long term effects: 75% of homes on the Irrawaddy Delta were made homeless and is an area that is very important for exporting fish and rice and feeding the country. The country could not export any goods Petrol was scarce so bus fares went up and people could not afford to get to work Sanitation plants were flooded and therefore disease spread more quickly Response: It was not reported in the news and they claimed they could recover without help from MEDCs Unit 2.2.4 Human impacts / national parks Importance of Tropical Rainforests Reasons for Deforestation Problems Caused by Deforestation  Biodiversity: Although rainforests cover only about 5/6% of the world's land mass, it is estimated that they could contain up to 50% of the world's biodiversity. This is potentially up to 15 million species.   Photosynthesis: Tropical rainforests are often referred to as the 'lungs of the earth' and convert large amounts of the greenhouse gas carbon dioxide back into oxygen. It is estimated that the Amazon rainforest alone produces about 20% of the earth's oxygen.   Flood control (interception, transpiration): Rainforests are  Cattle Ranching: As the world's population gets bigger and richer, the demand for meat is increasing. To rear the cattle increasing tracts of the rainforest are being cleared to make pastures for grazing.   Subsistence Farming: Because of the large amounts of poor people that still live in tropical areas, subsistence farming is still widespread. Because rainforest soil loses its fertility quickly after deforestation, the most common form of subsistence farming is slash and burn. With growing populations this method of farming can cause widespread deforestation.   HEP: Many of the world's great rivers flow through rainforests e.g. the Amazon.  Flooding: Flash floods become more common after deforestation because there is less interception and less root uptake and transpiration. As such rainwater reaches the ground quick, saturating it and causing surface run-off and potential flooding.   Landslides: By removing trees and vegetation, you are making the soil less stable. Combine this with saturated ground and the likelihood of floods increases.   Biodiversity loss: Because all the species that live in the rainforest are not known it is hard to calculate species loss. However, scientists believe that 1 mammal or bird extinction can be extrapolated to approximately 23,000 extinctions.   Reduced photosynthesis: As more and
  • 49. an excellent natural measure to reducing flooding. There is leaf cover in rainforests all year so interception continually happens, extending rivers lag time. All vegetation uptakes water and transpires it.   Control of soil erosion: The root systems of trees and shrubs hold the very thin soil of rainforest in place. If trees are removed then both erosion of topsoil and landslides are more likely   Source of nutrients to humus layer in soil: The topsoil in rainforests is very thin and relies on the nutrients provided by rotting plants and animals. Because of the rainforests climate, there is a constant supply of leaf litter.   Medical remedies: Rainforests have been the source of many of today's drugs, including the basic ingredients for the hormone contraceptive pill, quinine (a anti- malaria drug) and curare (a paralysing drug).   Cash crops and agricultural products: Yam, coffee, rubber, mango, banana, sugarcane, cocoa and avocado were all first discovered in rainforests.   Ecotourism: With people becoming ever more environmentally conscious and looking for increasing adventures, ecotourism to rainforests is increasing. This not only helps protect rainforests, but creates income for locals. These great rivers often have the most HEP potential. Unfortunately when a dam and reservoir are built it causes damage during construction, but also floods large areas.   Mining: With an ever increasing demand for the world's natural resources, countries and companies are looking at increasingly isolated locations, places like rainforests and Antarctica. The rainforests are believed to have many resources including metals and fossil fuels beneath their soils. Gold mining can be particular damaging as mercury is used in its extraction and often runs off into rivers.   Road building: Building new roads like Trans Amazon highway from Brazil to Bolivia not only causes deforestation itself, but its also opens up new areas to urbanisation, mining and farming causing further deforestation.   Urban growth: With the world population increasing as well as rates of urbanisation increasing many cities like Manaus in Brazil are growing rapidly causing deforestation.   Population growth: As populations grow, particularly in countries like Brazil, Peru, India and Vietnam that contain rainforests the demand for land increases, both to grow food and to live).   Plantations: Primary products are often seen as an income source for LEDCs, many of who have large areas of rainforest. At the same time with fossil fuels running out, alternative fuels sources are been searched for including biofuels e.g. Palm oil. This has lead to widespread deforestation in countries like Malaysia and Indonesia to plant cops like palm oil. more trees are removed the rate of photosynthesis reduces, releasing more carbon dioxide into the atmosphere and contributing to the greenhouse effect.   Silting of rivers: With increased flooding and surface run-off moil soils and silt is washed into rivers, this can not only change local ecosystems (water temperature and clarity) but can also reduce the depth of rivers making navigation harder.  Silting of seas and oceans: With the increased frequency of flooding and landslides more silt gets washed into the oceans. The increased amount of silts reduces the transparency of the sea reducing the light reefs receive and the temperature of the water. Increased silt can also block important shipping lanes.   Breaking of nutrient cycle: The top soil of rainforests is very thin an receives the majority of its nutrients from rotting flora and fauna. Be removing trees you also remove animals and therefore the source of the soils nutrients. With increased erosion the top soil (humus) layer is quickly washed away.   Sandification/desertification: Because rainforest soil loses its fertility very quickly after deforestation it quickly becomes hard to grow any vegetation on it, leading to sandification and possibly desertification.   Loss of indigenous homes: By clearing rainforests you are obviously destroying the homes of indigenous groups. But also moving close to indigenous groups can spread disease and alter local culture and traditions.   Reduced rainfall: Deforestation can lead to reduction in local rainfall because less water is intercepted and transpired from vegetation into the atmosphere reducing the formation of clouds and rainfall.
  • 50. Ecotourism is an important income to countries like Costa Rica and Belize.   Home to indigenous groups: Although the number of indigenous groups and people have declined rapidly since colonisation in South America, it is estimated that there are still over 200,000 people that consider the Amazon their home.   Timber (hardwoods): Hardwoods like mahogany and teak that take hundreds of years to grow are still in high demand to make things like furniture. The extraction of these trees can kills trees around them. Also many countries like China are also demanding large amounts of normal timber that are not always taken from sustainable sources.   Hunting: Hunting takes two forms, one form is for bushmeat to feed families and enough the sale of animals either alive e.g. parrots or dead for their skins e.g jaguars.
  • 51. Case study: Deforestation of Tropical Rainforest: Amazon Rainforest, Brazil Where and what: Brazil, Peru, Bolivia – South America 1/3 of the world’s trees in Amazon Estimates that 15-40% has been cleared Effects:  30000 known species could be threatened  May lose species that are as yet undiscovered  Could lose the cure for diseases like Aids and
  • 52. 15 football pitches per minute cleared for:  Slash and burn farming by Amerindian tribes like the Yanomami  Subsistence farming by 25 million landless peasants  Commercial cattle ranching for fast food chains  5300km Amazonian highway  900km railway line from Carajas to the coast  Timber/ logging companies  Mineral mining e.g. diamonds, gold  HEP  Settlements e.g.Carajas cancer e.g. periwinkle found to cure Leukemia  Loss of Amerindians due to European diseases  Loss of Amerindian traditions  Soil erosion as lack of interception as canopy removed  Loss of nutrients in soil  Climate change and global warming  Global balance of carbon and oxygen affected Ways to protect Amazonia:  Zones for different activities  Loggers use selective logging practices  Laws  Limit licenses to be given out  Restricting use of heavy destructive machinery  Encourage logging-uses helicopter  Community forestry development scheme to educate local people  Avoid construction where local tribes exist  Fines and prosecution for law-breaking  Increased patrols Case study: Sustainable Rainforest Scheme: Costa Rica Where and what: Central America 29 National Parks covering 12% of landscape Protect 208 species of mammals and 850 species of birds 9000 different plant types Park contains volcanoes, caves and tropical forests and beaches Benefits: Brings many tourists, scientists and nature lovers which boosts the local economy Parks are managed so the environment is not damaged and is SUSTAINABLE Problems: As it is very famous many people come to visit and this may need to be controlled in the future to limit excessive tourism BUT if you limit the numbers then less money will be made and nature will become exclusive Need to educate people so as not to affect the park’s eco system Facilities are needed to cater for the tourists such as toilets and campsites
  • 53. Exam Style questions Unit 2.1 to 2.6 IGCSE exam 5 marks describing/explaining and 7mark case study questions: Unit 2.1 Plate Tectonics Describe what can be done to protect people from volcanic eruptions. (4) Suggest how volcanoes are likely to benefit the people who live in countries such as Iceland.(5) Explain why people live in areas where there are active volcanoes. (5) Why do many people live in areas which are at risk from earthquakes? (5) Name an area which you have studied where there has been an earthquake. Describe the impacts of this earthquake. (7) Unit 2.2.2 Rivers Describe the advantages and difficulties for people of living close to a river (5) Describe and explain how an oxbow lake is formed. You should use label diagrams. (5) Explain how and why a delta has formed in a named area which you have studied. You should use a labelled diagram or diagrams in your answer. (7) Explain the change in the shape and characteristics of a river as it travels from source to mouth (7) Unit 2.2.3 Marine processes Explain how headlands are formed along some coasts. (4) Explain why coral reefs are only found in some sea areas. (5) For a place you have studied, explain how humans have an impact on a coral reef. (7) Unit 2.3.1 – 2.3.4 Weather and Climate/ Ecosystems / Natural hazards/ Human impact The thermometers used at the meteorological station are kept in a Stevenson Screen. Explain how this ensures that reliable readings are obtained. (4) Give reasons for the climate of an area of tropical rainforest such as Kisangani. ? (5) Explain how the natural vegetation of tropical desert areas can survive in the hot, dry climate. (5) Another type of natural environment is tropical rain forest.
  • 54. Describe the impact of human activity on a tropical rain forest ecosystem which you have studied. (7) Explain why the effects of tropical storms of the same strength are likely to be greater in an LEDC than an MEDC. Refer to examples which you have studied. (7) An earthquake is an example of a natural hazard. Choose an example of one of the following: a) a tropical storm, b) a drought. For a named area, describe the causes and effects of your chosen hazard. (7) For a named area which you have studied, describe the impacts of a tropical storm. (7) Name an area of tropical rainforest which you have studied and explain why deforestation is taking place there. (7)