Urbanisation Flashcards
how many people live in urban areas now
50%
how many people lived in urban areas in 1950
30%
in developing countries where do most people live
in rural areas
4 processes that involve the movement of people into and out of urban areas
urbanisation, suburbanisation, counter-urbanisation, urban resurgance
whats urbanisation
growth in the proportion of people living in urban areas and occurs because of rural-urban migration and natural increase . many migrants are young adults looking for jobs,schools, healthcare
in developing countries what can urbanisation result in
results in shanty towns- unplanned and often illegal settlements made out of any material available
whats suburbanisation
this is the migration of people from city centres to the outskirts of cities . as urbanisation increases city centres become overcrowded and improvements in transport links means richer people move to the suburbs , this can lead to ethnic and economic segregation
whats counter-urbanisation
movement of people out of the city into surrounding villages and rural areas . people leave the cities because of high property prices or just preference . this can lead to housing estates being built and house prices may increase meaing locals may not be able to afford prices . can change the age structure of the area
urban resurgence
movement of people back to the city centre. this may be because of lack of jobs in rural areas, new shops and services may open in the citys as people move back creating jobs and boosting economy
whats a megacity and an example
a city with a population of over 10 mill eg instabull, tokyo
how many megacities were there in 1950
2, tokyo and new york
how many megacities in 1950
2 tokyo and new york
how many megacities in 2014
28
whats a world city
a city that has political and financial influence over the whole world eg london
why does it rain more often in urban areas
- the UHI effect means more warm air rises and warm air can hold more water . and so as this warm air cools it condenses into vapour and rains this is convectional rainfall
- urban areas produce dust and pollution , these act as condensation nuclei this encourages cloud formation
sources of particulates
vehicle exhausts
burning
construction, mining, quarrying
plants and moulds
whats photochemical smog
when pollutants such as NO, SO4, hydrocarbons come into contact with sunlight the UV light causes them to breakdown into harmful chemicals
what is photochemical smog linked to
health problems, breathing difficulties , respiratory disorders and headaches
how does congestion charges reduce air pollution
people are charged if they use their vehicles in certain places at certain times . this reduces pollution by reducing road traffic , in central london emissions reduced by 15% in the first year , however some people travel around the edge of the zones to avoid charges
how does pedestrianisation reduce air pollution
vehicles are restricted from entering certain places at certain times. reducing road traffic. can lead to shops receiving fewer customers because people can only get to them on foot
how does public transport improvements reduce air pollution
bus serves can be made cheaper faster and more efficient
park and ride schemes to make it easier to access public transport
trams and light railways services which run on lines so they dont get caught in road congestion
how do other schemes for reducing traffic help reduce air pollution
in mexico city drivers are banned from using their car one weekday per week based on the last digit of the number plate however rich people just buy 2 cars.
birmingham bristol and london have council run car sharing schemes to encourage people to share cars however this can be incovenient and some worry about sharing with strangers
how does legislation reduce air pollution (uk air acts)
uk clean air acts of 1956 and 1968 introduced smoke control areas where only smokeless fuels could be burned and reduced industrial pollution by introducing tall chimneys
road vehicle regulations means cars have to pass emmisions test in their MOT
how do alternate fuel sources reduce air pollution
petrol and diesel are replaced with cleaner fuels that pollute less like
- biofuels from plants , can replace petrol and deisel but can reduce biodiversity
- liquefied petroleum gas, produced from fossil fuels has lower emmisions but service stations and cars would have to be adapted for use
-electric vehicles - run off batteries , need recharging points and producing and disposing of batteries can cause environmental issues
why is photochemical smog pollution more common in hot climate
theres more sunlight so more UV to break down pollutants into harmfull chemicals
why is infiltration low in urban areas
as urban areas are covered in impermeable surfaces
whats catchment management
a way of managing rivers and improving drainage systems by looking at the whole river catchment and the interactions between water and land. aims to minimise issues such as flooding, draught, water pollution and erosion and to improve river ecosystems
hard engineering and managing river catchments
involves man made structures like dams, floodwalls and reservoirs which prevent against flooding and ensure a constant water supply.
however this can be very expensive and disrupt natural systems
soft engineering and managing river catchments
process that try to work with nature involving land use management eg planting trees and preventing building on flood plains. also involves river restoration .
generally cheaper and can improve local environment however planning restrictions can limit construction and land use management is hard in places already urbanised
how many people were forced to move for the construction of the 3 gorges dam in China
1.2 million forced to move
13 cities and 140 towns flooded
what does SUDS stand for
sustainable urban drainage systems
whats a swale
vegetated trenches increase interception of rainfall and retention basins store water. they help to increase infiltration and water storage this decreases runoff and channel flow which lowers flood risks
how do vegetated roofs reduce floods
they intercept rainfall and increase evapotranspiration which reduces flood risks
how do containers reduce floods
containers on roofs of buildings catch and store rainwater for reuse this helps to reduce drought risk
the 3 primary sources of waste in urban areas
industrial waste- stuff from manufacturing process and industrial activity can be toxic
commercial waste- stuff thats produced by businesses eg shops and restaurants
personal waste - any waste produced by private homes eg plastic bottles, food packaging, newspapers
Social and economic issues associated with urbanisation
Economic inequality
Social segregation
Ethnic segregation
Cultural diversity ( puts pressures on services )
Ways of tackling poverty and inequality
Interculturalism
Enforcing living wage
Affordable housing
Public transport made affordable
Legislation on anti-racism, employment rights, prejudice
Social segregation because of housing
Developers and planners tend to build housing on land with a particular market in mind
In some areas where affordable housing is a requirement in new developments
Poorer groups have less choice
Social segregation due to changing environments
Housing neighbourhoods change overtime, housing built for large Victorian families are now too big for now family’s
Former poor areas are being gentrified
Right to buy legislation 1980s
Right to buy legislation 1980s
Allows council tenants to buy their council home at a discount. And they have the right to them sell it later at full price
Social segregation due to ethnic dimension
When migrants first arrive they may suffer to find high paying work
So they can only afford cheap housing
So newest arriving migrants after concentrate in poor areas
Multiple deprivation index
Qualitative studg measuring deprivation
Based on 7 factors which are combined
Good as it takes in so many factors like:
Income,employment, health,education, crimes,living environment, access to housing
Urban social exclusion
Term refers to problems faced by residents in areas of MD
People excluded from full participation in society by their social/physical circumstances
Leads to lack of social cohesion and in extreme cases civil unrest
What areas of a city are most deprived
Inner city’s
Cycle of poverty
Inequality tend to exist in terms of access to job opportunities, education, housing.
The knock on affects is poorer health, high unemployment and lack of social mobility
Hard to escape cycle of poverty
Diaspora
The term used to describe a large group of people with similar heritage or homeland who have settled elsewhere in the world. Eg the UAE state of Dubai where the majority of the city is made up of migrants. 2/3rd is Asian decent
Why is there greater cultural diversity in cities
Immigrants more likely to live in city as:
-More employment opportunities
-first point of entry in a city
-house earlier immigration groups of same ethnicity
-established cultural diversity
- urban populations more tolerant of 8mmigrants
Advantages of cultural diversity
Different and new foods, music, language and religion
Issues with cultural diversity
Language differences will require local authority’s to provide English lessons
Hospitals may need to cater for specific illnesses
Schools may need to alter curriculum and holiday to cater for different ethnic groups
Reasons for UHI
Building materials such as concrete and bitchamin are non reflective and absorb heat
Heat is absorbed during day and released at night
Air pollution from industries and vehicles increase cloud cover- reflecting radiation back to reface
Heat from buildings , vehicles and people
Relative humid
The ration of the amount of water in the air at a given temperature to the maximum amount it could hold at that temperature expressed as a percentage
Way is rainfall higher in urban areas
Higher temps encourages lower pressure.
Warmer air can hold more moisture and relative humidity levels are 6% lower
Urban areas have more frequent and thicker cloud cover than rural areas due to convection currents
Convection rainfall tends to be heavier and more frequent
Aims for suds
-Store runoff and release it slowly
-harvest and use the rain close to where it falls
-allows water to soak into ground
-slowly transport water
- filter out pollutants
-build up ecosystems and wildlife
Aesthetic
Wetlands
-Provide both storm water attenuation and treatment
-shallow ponds and marshy areas covered in aquatic vegetation
-provide ecological benefits
- slow flows for extended period to allow sediments to settle and to remove contaminates
What are the 3 Rs
Reduce
Re-use
Recycle
Reduce
-Best approach to prevent waste, businesses are encouraged to reduce the amount of packaging used
- consumers can help by refusing plastic bags
- charges for plastic bags
Re-use ( waste management)
Attempts to reuse jam jars, milk containers, soft drinks/ water bottles
Example, bag for life
Recycle ( waste management )
Paper, glass, metal cans, plastic and clothes can all be recycled
Problems- start up costs are high, households are often unwilling to sort recyclables
Benefits of landfills
Convenient and cheap
Gas produced can be collected to produce electricity
Problems of landfill
Threat to groundwater supplies and river quality ( contamination of water)
Methane
Nappies take 500 years to break down
Running out of space
Energy recovery (incineration)
Waste material converted into energy
Modern incinerators generate electricity or power neighbourhoods
7 licences municipal incinerators in uk
Advantages= can reduce vol of waste by up to 90%, can produce energy as output
Disadvantage= severe air pollution, quite expensive
Energy from east (efw) Leeds
306 000 tonnes of waste from homes in Leeds each year.
This incinerator currently recycle around 40% of this waste
Waste used to heat 20 000 homes
Saves the council 7mill each year compared with landfill
How much heating energy does Sweden gain from combusting waste
8% of total heating energy
Why is incineration preferred
Energy
Efficiency
Space
Landfill
Affordable
Convenient
However emissions are released
Public health threat from emissions
Why do urban areas have more fog
-Wind speeds lower so fogs not as easily dispersed
-Pressure of pollution provides hygroscopic
Nuclei for water droplets to form
Presence of pollution prevents suns rays penetrating to the ground and warming up the fog, so fog not dispersed
Why is air quality poorer in urban areas
Particulate pollution
Temperature inversions where cool sinking air can become trapped below a layer of warm air
Photochemical smog, which is low level o-zone pollution associated with cars and pollution
Strategies to minimise pollution and the UHI effect
Clean air acts
Green roofs
Urban greening
Zoning of industry’s
Lighter coloured buildings
Vehicle control and public transport
Open up spaces
