3.2.3.1 CUE>> Global patterns, significance and growth of urban areas Flashcards
(18 cards)
Urbanisation
Urbanisation - increase in the proportion of people living in urban areas
Causes of urbanisation:
- Rural to urban migration - happens due to push and pull factors
- Pull factors - lack of services, lack of job opportunities
- Push factors - better services, better job opportunities
- Natural increase (birth rate higher than death rate) - contributes to roughly 60% of urban growth
Urbanisation patterns:
- The number of people living in urban areas has increased dramatically since 1945. In 1950, 30% of people lived in urban areas. In 2014, just over 50% lived in towns or cities
Developed:
- Population has only increased slightly since 1945 - urbanisation began much earlier in the developed world. e.g. during the industrial revolution
Developing:
- Urbanisation is happening at a quicker rate. For example, in Beijing, China, the urban population increased by around 15 million in the past 45 years
Consequences of urbanisation:
- Urban sprawl - spread of an urban area into the surrounding countryside - loss of green space
Shortage of housing in LICs:
- Leads to informal settlements - these settlements have limited access to basic necessities and services - more likely to be ill - can’t go to work - have to continue living in these settlements
- Dharavi slum - people will build houses for themselves - slum conditions are poor - 1000 people sharing a toilet and approximately 14 people living in one room
Shortage of housing in HICs:
- Urban planners have built sky scrapers - small flats come with social problems - many people in tokyo face issues with social interaction and spend vast quantities of time by themselves - birth rate has decreased rapidly to 7.8 births per 1000 population —> - an ageing population which creates issues - less people working so less taxes - less government spending on healthcare which the ageing population need
Lack of urban services:
- When more people move to cities, the demand for services increases - lack of urban services due to high demand
Unemployment:
- High proportion of people who move to cities are young - lots of pressure on jobs - some people unable to find one due to high proportion of people wanting a job
Deindustrialisation and decentralisation
Deindustrialisation:
- Deindustrialisation - decrease in the amount of manufacturing taking place
Causes of deindustrialisation in the UK:
- Cheaper labour and manufacturing costs in countries such as China
- Technological advancements - automation reduces the need for manual labour
Example:
- Steel industry in sheffield collapsed - caused mass unemployment with 3 million being out of work
Negatives of deindustrialisation:
- Deindustrialisation —> people unemployed —> less money to spend —> local shops and services get less income —> schools and shops etc start to close
- Deindustrialisation —> people unemployed —> less money to spend —> increase in burglary —> people move out of the area —> services and shops start to close
- Deindustrialisation —> industrial buildings become derelict —> increase in graffiti etc —> people move out of the area —> services and shops start to close
Rise of the service economy:
- Deindustrialisation has led to a rise in the service economy
- In 2015, the service sector accounted for 77% of the UKs economy
Decentralisation:
- Decentralisation - as land prices in city centres increase, businesses may relocate to the suburbs e.g. meadowhall in sheffield
- This has caused shops in the city centre to close - urban decline
Regeneration policies
City challenge:
- City challenge - local authorities competed against each other for government funding to regenerate deprived urban areas
- The Manchester authority won the challenge with their proposal to regenerate Hulme
Issues in Hulme:
- Of the 5,500 dwellings in the Hulme area of Manchester, 98% were council owned
- There was a high number of single parents, and other people with social difficulties. There was some evidence that the local authority had used the area to dump some of its more unfortunate residents
- Perception of Hulme was bad so no one wanted to live there - area went into decline
Redevelopment:
- 3,000 new homes were built (social - area more attractive)
- The Moss Side Sports Centre was updated (social - area more attractive)
- The main shopping area was totally refurbished, including the addition of an ASDA supermarket (economic - jobs created) (social - area more attractive)
Successes:
- Hulme’s population has grown by 3.3%
- Of the original goals of regeneration of Hulme, it is estimated that 80% of them have been achieved
- It was found that crime levels had gone down, with the police reporting a 40% reduction in crimes
Failings:
- Unemployment rates in 2003 remained 6x higher than the national average
- Remain top 10 worst wards in Manchester
- The bid was awarded based on the most attractive ideas rather than based on need (negative of city challenge)
- A lot of deprived areas didn’t receive any funding (negative of city challenge)
New deal for communities:
- New deal for communities - 10 year strategies that were established to help the 39 most deprived regions of the country
Case study:
- Aston, inner city Birmingham - identified as one of the 39 most deprived regions in the country
Issues in Aston:
- Poor health (poor diet inherited from the cultural background)
- High levels of unemployment - in 2002, 40% of the working age population was unemployed - predominantly muslim population - lifestyle requirements such as friday afternoon prayers and english may not be their first language - not easily employable - if unemployed then no money - area goes into decline
Positives:
- £4 million was spent on healthcare - life expectancy is improving in Aston
- Health centre has introduced cooking clubs - gives advice to people about healthier meals
- They managed to help around 1000 people through work experience programmes
Issues:
- The increased development in cities resulted in town centres being rundown - more time and money centred on cities instead of towns - moves the problem to another area
- Even with help from work experience programmes, there still weren’t enough jobs in the area - many remained unemployed
UDCs:
- UDCs - the government set up the UDCs to try and reverse inner city decline - they set up the LDDC
- In the 19th century, Londons port was one of the busiest in the world but by the end of the 1950s, it was in significant decline
- Containerisation - few dockers were needed to lift containers from ships - reduced demand for workforce - had to find other work - transport services to the rest of london were poor - fewer people working - less income - less spent on goods and services - shops started to close - area went into decline
Positives of LDDC:
Environmental:
- Planting of 200,000 trees
Economic:
- Unemployment had fallen from 14% to around 7%
- Transport improved - docklands light railway carried 35,000 passengers a week
- Focused on attracting private investment and encouraging the growth of finance sectors e.g. opening of major banks such as HSBC, JPM
Social:
- 22,000 new homes built
- £100 million spent on health, education and job training
Issues of LDDC:
- Despite increased accessibility to jobs as well as increased private investment, dockers did not have the skills required - increased economic inequality and segregation
- However, housing developments were mainly aimed at wealthier residents
Enterprise zones:
- Enterprise zones - were established in areas with high unemployment - they offered lower taxes to businesses - aim was to attract start up businesses and create jobs
Positives:
- By 1990, the enterprise zones housed over 5000 companies, employing more than 125 000 people
Issues:
- Tax reductions encouraged many existing companies to move their premises and staff to the enterprise zones which limited the number of new jobs created
Example
- The Metro Centre Gateshead (Newcastle) was established as an enterprise zone on an old industrial site (a power station) in which the land was bought for just £100,000 - there were high levels of unemployment in Newcastle due to deindustrialisation
Megacity and world cities
Megacity:
- Megacity - A city with over 10 million people
- In 1950, there were 2 megacities - tokyo and new york
- By 2014, there were 28 megacities
- Rural-urban migration and natural increase
- Companies choose to build their headquarters in megacities - high number of skilled workers and good transport links - on average megacities produce 2-3 times more GDP than other cities - creates multiplier effect as growth encourages investment, leading to further growth
- Cultural diversity - increased tolerance
- Young people are drawn to live in megacities - natural increase
World city:
- World city - a city that has political and financial influence over the whole world e.g. London
- Most are in the developed world but some are in emerging economies e.g. Dubai
- The number of world cities is increasing - In 1950, the only world cities were London, Paris, Tokyo and New York
- More recently, economic growth in oil-rich countries such as Nigeria has allowed cities such as Lagos to become contenders for world city status
- World cities usually dominate international trade e.g. Tokyo plays a big role in trade between East Asian countries - These cities have strong transport links, making it easier for them to trade globally
- Since 1945, world cities such as London and New York have emerged as the leaders of banking and finance. Many banking companies, such as HSBC and Lloyds have headquarters in these cities
- World cities are generally home to prestigious universities
- Culturally diverse
Processes associated with urbanisation
Cities develop in lots of different ways as they urbanise:
Economic:
- Cities attract people from rural areas because they offer more job opportunities - economic growth - inward investment - further growth
Social:
- Higher living standards than rural areas, e.g. better access to healthcare and education
- Greater diversity - increased tolerance
Demographic:
- Greater diversity
- Many young people are attracted by jobs and entertainment. Older people tend to move away from cities into the suburbs in search of a better quality of life
Political:
- Urban growth may lead to increased inequalities between rich and poor people. A new ‘working class’ emerges, often made up of people who work in manufacturing industries
- New political movements emerge to represent the ‘working class’ population e.g. voice concerns on quality of housing and working conditions in factories
Technological:
- With the emergence of factories in cities, urban areas become hotspots for technological advancement - e.g. manchester was known as ‘cottonopolis’
- More recently, areas with a large number of high tech industries have emerged e.g. silicon valley - attracts people due to highly paid jobs
Urban form
- Urban form - the characteristics that make up a city including it’s size and shape, population density and how the city is arranged
- Cities were initially established in areas with good water supplies, fertile soil for growing good, natural resources (e.g. wood for fires) and good defensive positions (e.g. on top of a hill)
Human factors influencing urban form:
- Planning - urban expansion can be planned or unplanned e.g. a lot of urban growth in developing countries is caused by the unplanned expansion of slums
- Infrastructure - new developments are often built along transport links (e.g. motorways), leading to linear growth
- Land value - the highest value land is often found in the city centre, so profitable businesses (e.g. chain stores) normally locate there, while less profitable businesses (e.g. independent shops) may be found further from the centre
Physical factors influencing urban form:
- Topography - physical features often influence the growth of cities e.g. steep slopes are harder to build on and less accessible, so poorer housing (e.g. slums) may be built on them// large flat areas encourage low density developments because there’s lots of space to build
- Water - the presence of lakes and seas limits urban growth in those areas
- Natural resources - rich resources (e.g. coal, metal) encourage growth in size and population of cities
- Land type - some ground surfaces are more difficult or expensive to build on than others e.g. swamps and wetlands can limit urban growth
Land use patterns in developed and developing countries:
Developed:
- Cities in developed countries tend to have a CBD
- The CBD is surrounded by housing. Although land value tends to be highest in the city centre, houses generally increase in value with distance away from the centre
- Inner city areas have high land value, so housing is typically high density e.g. terraced housing. Wages are often low, and many residents live in relative poverty. The proportion of people from ethnic minorities tends to be high
- Land value is lower in rural and semi-rural areas, so residential areas are less dense and have more open space
- Houses are usually larger and newer than those in inner city areas. Residents are generally quite wealthy and earn relatively high wages. The proportion of people from ethnic minorities tends to be low
Developing:
- Cities in the developing world also have CBDs
- The CBD is surrounded by housing, which decreases in value with distance away from the centre
- Land value is highest around the city centre, so high-cost housing (e.g. luxury apartments) is built there. Wages are generally high, and residents are wealthy
- Surrounding the high-cost housing there is often a zone of medium-cost housing. It may have started as an informal settlement, but gradually the housing has been improved and some services have been provided
- Land value is very low on the outskirts of cities, so low-cost and informal housing is built there, often with limited access to services such as clean water and electricity. Most residents have poorly paid jobs and poverty levels are high
New urban landscapes:
Town centre mixed developments:
- Areas where land use is mixed
- Luxury flats, offices, shops and entertainment facilities can all be found in one place. This promotes sustainable living by reducing the need for extensive commuting e.g. covent garden, london
- Creates a diverse and inclusive living environment —> people of all ages and backgrounds etc —> greater social integration —> increased tolerance —> reduces social segregation
Cultural and heritage quarters:
- These areas focus on the history or character of a city e.g. the cultural quarter in Southampton includes the SeaCity Museum, which tells us about the city’s maritime history
- These areas are often home to theatres, art galleries and historical buildings
- They are often developed by local councils to regenerate former industrial areas. They attract visitors, creating jobs
Fortress developments:
- Developments with lots of security such as CCTV, guards and high walls
- Fortress landscapes have reduced crime levels e.g. in Hulme, homes and offices were built with large windows facing fields. This leads to fewer crime levels and attracts businesses/homeowners into the area. As a result, property prices increase. Only affluent people can afford to live here so rich people concentrated in one area. This widens inequalities
Gentrified areas:
- Gentrified areas are places where wealthier residents move into poorer, rundown areas and improve the housing e.g. Chapel Allerton, Leeds
- Pushes original residents out as cost of living increases. This leads to social segregation between rich and poor. The poor are concentrated in one area. Schools are likely to be below average in poorer areas. This leads to worse exam performance and widens inequalities
Edge cities:
- Urban areas that develop on the outskirts of cities
- This is because land is cheaper on the outskirts of cities
- For example, Las Colinas
Post modern western cities:
- Multiple centres with different purposes e.g. technology, retail, heritage rather than a single centre for everything
- A focus on tertiary and quaternary sector
- Less uniform architecture - buildings have a wide range of styles e.g. in London, buildings such as the Gherkin and Cheesegrater are examples of post-modern architecture
- High levels of diversity
- Higher social and economic inequality
- Planning prioritises the aesthetics of the city (how it looks) over practical use
Urban issues - economic inequality, cultural diversity, social segregation
- Economic inequality - the unequal distribution of money amongst a population
- Economic inequalities are higher in the developing world than in developed countries. This is because many developing countries lack the resources to support their poorest citizens, whereas most developed nations have welfare states which provide basic services and income for people who are struggling financially
Issues caused by economic inequality:
- Political and social unrest e.g. rioting
- A rise in crime, drug use and violence
- Health problems e.g. cities with higher levels of income inequality have more malnourished children
- Social segregation
Cultural diversity:
- Cities tend to be culturally diverse - they have a wide mix of people from different ethnic and cultural backgrounds
Benefits:
- Ethnic diversity can enrich a city’s character
- Increased tolerance
- Cultural events and ethnic quarters within a city can attract tourists, boosting the city’s economy
Issues:
- Tensions between different groups, sometimes leading to violence
- Increased pressure on services e.g. schools may need extra staff for pupils who can’t speak the native language
- Minority communities can feel isolated and under-represented politically
- Social segregation - this is when different groups are separated from each other e.g. poorer people or people from a particular ethnic background are concentrated in a specific area of a city
Social segregation:
- This can be voluntary e.g. followers of a particular religion may choose to settle close to their place of worship
- It can also be forced e.g. many Roma people in Italy can’t access social housing, so they end up in camps on city outskirts
Issues with social segregation:
- Lack of integration between different groups can cause prejudice and discrimination
- People in some areas may have less access to education and jobs, widening inequalities
- Segregation can lead to anxiety and have negative impacts on health and life expectancy
- In developing countries, poorer areas may lack access to facilities e.g. electricity, clean water, public transport
Strategies to manage urban issues:
Reduce economic inequalities:
- Improving transport systems can make it easier for the urban poor to access jobs
- Subsidising the construction of affordable housing can help less wealthy people to buy property
- Introducing minimum wages can help to stabilise wage inequalities between the poor and rich
- Governments can offer subsidies for new companies, increasing local employment opportunities
- In developing countries, many cities have introduced upgrading programmes for slum settlements e.g. Favela Bairro Project
Encourage integration:
- Governments can encourage political participation of minority groups e.g. by sending postcards and text messages encouraging them to vote. This ensures minority groups have opportunities to influence decision-making
- Governments can pass laws e.g. to prevent companies discriminating against employees on the basis of race
- New developments can include luxury homes and lower-cost housing, reducing divisions between rich and poor
London case study:
- London has issues associated with economic inequality, cultural diversity and social segregation
- London is home to some of the richest and poorest people in the UK — this gap has widened since the 1980s
- The average annual income in Kensington and Chelsea is more than £130,000, but in Newham it’s less than £35,000. Low wages and few job opportunities in some areas mean that more than 25% of people in London live in poverty
- Many inner city areas e.g. Notting Hill, have been gentrified — this has forced poorer residents out of the area
- London is culturally diverse - more than 50% of the population is not white British. Proportions of ethnic minorities differ widely between boroughs - e.g. in Brent over 60% of people are not white British, whereas in Havering the proportion is only around 16%, suggesting that ethnic segregation is an issue
- Hate crime based on race and religion is a problem in London e.g. in the twelve months before July 2015, there were over 800 anti-Muslim incidents in the city
- Social segregation based on age and class is also an issue - London residents have less interaction with people of different age groups and classes than people elsewhere in the UK. This could lead some residents to feel isolated
Strategies to tackle these issues:
1. The London Living Wage is £13.85. This should increase income and social mobility in deprived areas
2. London mayor, Sadiq Khan, plans to build more affordable homes in London - this could allow less affluent people to remain in more expensive areas, reducing social segregation
3. The police are working to tackle hate crime e.g. by encouraging people to report it and offering support to victims
4. Some charities are calling for better access to English language classes for immigrants, and mentoring schemes to help recent immigrants adjust to life in the UK, with the aim of increasing integration between groups
UHI
Urban heat island effect - urban areas being warmer than surrounding rural areas
Temperature peak - the highest temperatures are found in industrial areas and in densely built up areas e.g. the CBD
Temperature sink - pockets of cool air are found above parks and bodies of water (e.g. rivers or ponds)
Temperature plateaus - areas within the city with the same land use generally have the same temperature
Temperature cliffs - temperature can change rapidly when land use changes e.g. from inner city housing to CBD high rise buildings
4 main causes of UHI effect?
Absorption of heat by urban surfaces:
- Surfaces in urban areas have low albedo and tend to be much less reflective so they absorb a lot of heat —> concrete, brick and tarmac surfaces absorb and store heat from the sun during the day. This heat is slowly released as long wave radiation at night
- Rural areas tend to have more grass —> greater albedo —> temperatures lower
Air pollution:
- Air pollution from cars and factories increases cloud cover and creates a ‘pollution dome’ (layer of pollution over the city) —> both of these trap outgoing heat radiation and reflect it back to the surface
Heat from human activity:
- Cars, factories, offices, central heating, air conditioning units and people themselves all release heat
- People release heat so cities with large populations will be warmer —> positive feedback loop —> people will turn air conditioning on —> releases hot air into atmosphere —> temperatures rise
Less evapotranspiration:
- When it rains, water is quickly removed by drainage systems —> less evapotranspiration —> less cooling effect from water —> higher temperatures
UHI day and night:
- The UHI effect is stronger at night
- Urban daytime temperatures are on average 0.6 °C warmer than surrounding rural areas but at night time, temperatures in urban areas can be 3-4 °C warmer than rural areas —> rural areas cool down at night, but urban areas don’t cool as much because urban surfaces continue to release heat that they’ve absorbed during the day
UHI seasonally:
- UHIE is stronger in summer
- Average winter temperatures can be 2°C warmer, but average summer temperatures can be up to 5°C warmer in urban areas —> there’s more solar radiation in summer so urban areas absorb more heat
- UHIE is stronger when there’s an anticyclone —> anticyclones cause clear skies and low winds —> if there are no clouds, more solar radiation reaches and hits the ground —> low winds mean warm air isn’t blown away
How can the UHI effect be managed?
- Increased vegetation —> plants absorb sunlight and reduce the amount of heat absorbed by buildings// trees also release moisture into the air through evapotranspiration —> cools the air down
- Urban design —> e.g. using lighter coloured materials for buildings and roads and creating more open spaces
Urban drainage
- Infiltration is low and surface run off is high in urban areas - this means that water enters rivers quickly - short lag time and high peak discharge
- Urban areas are covered in impermeable materials e.g. concrete and tarmac - low infiltration and high surface run off
- Urban areas are designed to remove water quickly e.g. cambered roads, sloping roofs - low infiltration and high surface run off
Catchment management in urban areas:
- Managing rivers by looking at the whole river catchment
- Aims to minimise issues such as flooding, drought and water pollution etc
- Hard engineering - man-made structures e.g. dams and reservoirs
- Dams - used to prevent flooding, reservoirs - ensure a constant water supply
- However, hard engineering schemes are often expensive// people may to displaced to make room for dams and reservoirs e.g. construction of the Three Gorges Dam in China flooded forced over 1.2 million people to move
- Soft engineering - uses knowledge of the river basin and its processes to try to work with nature
- It involves land use management e.g. planting trees to decrease flood risk and water pollution, and preventing building on the flood plain
- It is generally cheaper than hard engineering
- However, land use management is hard in areas that are already urbanised
SUDS:
- SUDS aim to imitate natural drainage systems, rather than channelling water through pipes and drains
Examples:
- Vegetated trenches (swales) - increased interception - reduced runoff - lower flood risk
- Vegetated roofs - increased interception - reduced runoff - lower flood risk
- Containers on the roofs of buildings catch and store rainwater for reuse
Urban drainage case study
- Cheong Gye Cheon is a natural river flowing west to east through the centre of Seoul
- In 2003, a $281 million scheme was launched to restore the river - highway concrete was dismantled to create a 5.8km green pedestrian corridor
- Prior to the project, the river had been covered by a highway, which contributed to significant environmental problems such as traffic congestion and air pollution
Successes:
Social:
- -10% in air pollution)
- Before the restoration, residents were more than twice as likely to suffer from respiratory disease than those in other parts of the city
Economic:
- Cheonggyecheon river has become a tourist attraction - 18.1 million visitors by 2008
- Increased the price of land by 30-50% for properties within 50m of the project
- Increased number of businesses in the area by 3.5%
Environmental:
- Removal of large numbers of cars and more pedestrianisation// increased vegetation —> -4.5% reduction in UHIE
- Seoul is vulnerable to monsoon rains, which can lead to flooding - restoring the river led to increased green spaces and less pavement, which allowed more water to infiltrate into the ground instead of running off the surface - reduced surface runoff - decreases flooding
Failures:
- Expensive - $281 million
- The scheme gentrified the area - icreased the price of land by 30-50% for properties within 50m of the restriction project - forced people to move away as they couldn’t afford increasing prices
- 80,000 tonnes of waste was generated from the project
Sustainable cities
Ecological footprint:
- An individual’s ecological footprint is the amount of land that is needed to produce everything they consume, and to absorb their waste
The ecological footprint of a city depends on:
- Wealth - e.g. consumption and waste production is higher in cities in richer countries
- Size of city - e.g. compact cities are easier to travel around on foot or by bike, so they produce less pollution
- Quality of public transport — efficient public transport systems decrease car use, and therefore reduce pollution
Dimensions to sustainability:
- To be sustainable, a city must meet the needs of people today without preventing future generations from meeting their needs
Natural:
- Natural sustainability is to do with the environment
- Rely on renewable energy sources
- Produce relatively little waste, and reuse or recycle the waste they produce
- Cities where people walk, cycle and use public transport a lot produce less pollution
Physical:
- Physical sustainability is about how well a city is able to support the people living there
- Enough jobs to support the population
- Plentiful high quality housing
- Safe water and energy for all residents
Social:
- Social sustainability is about how people live together, their quality of life, and the availability of basic services e.g. healthcare
- Hospitals and schools are within easy reach
- Peaceful and tolerant
Economic:
- Economic sustainability is about maintaining economic growth without causing long-term negative effects e.g. environmental damage, social inequality
- Wealthy, have low levels of inequality and little debt
- home to profitable, ethical businesses that offer plenty of well-paid jobs
Liveability:
- Sustainability can affect the liveability of a city - this is a measure of how good living conditions in an area are
- Liveability depends on many factors, including job opportunities, crime rates, open space and access to education
- Different factors matter more to different people, so everyone’s view of what makes a city liveable will be different
What makes sustainable development of urban areas easier than rural areas (opportunities to make cities more sustainable):
- People are more densely concentrated in cities than in rural areas, so the provision of services such as public transport is easier and cheaper
- Governments may invest more in urban sustainability than rural sustainability because it benefits more people
Challenges:
- LICs don’t have enough money to invest in expensive sustainable ways of living e.g. changing transport to be renewable etc
- Fast urbanisation rates makes it difficult to meet the needs of an ever-growing population
- Many people living in HICs aren’t willing to change their lifestyle habits e.g. using less water or driving less
- Some cities don’t have appropriate infrastructure e.g. roads may be too narrow to build cycle lanes
Strategies to develop sustainable cities:
- Reducing number of cars on roads - Constructing new cycle lanes, introducing park and ride schemes and improving public transport —> decreases CO2 emissions
- Green space - Green spaces e.g. parks can reduce pollution or flooding, as well as making the area more attractive and pleasant for its residents
- Reducing water use - authorities can insist that new buildings are fitted with water metres and water-efficient fittings to ensure that people use less water e.g. in Cape Town, South Africa, water pressure was reduced so that showers, hosepipes etc would use less water
- Making buildings energy efficient - Houses have to be built to be energy efficient e.g. installing solar panels and energy efficient lightbulbs
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Sustainable city case study
Curitiba case study- sustainable city
Curitiba location?
- South East of Brazil around 1000km from Rio de Janeiro
Issues with urban growth?
- Lots of cars on roads —> increases fossil fuel consumption —> increases pollution —> trigger different microclimate responses/impacts health
- Unemployment—> high proportion of people who move to cities are young —> lots of pressure on jobs —> some people unable to find one due to high proportion of people wanting a job
- Lack of urban services —> when more people move to cities, the demand for services increases —> lack of urban services due to high demand —> ill —> can’t go to work —> can’t pay tax
- Shortage of housing —> leads to informal settlements
What has been done to make the city sustainable?
Transport
- Central bus lane —> speeds up journey
- Bendy buses —> boosted number of passengers per bus to 4000 per day
- Bus doors are wider and open directly into the tube —> maximises use for all types of users// faster loading and unloading on bus —> cuts travel times —> more attractive option
(lots of cars on roads)
Parks and open space
- Curitiba has 4x the green space recommended —> trees take in CO2 —> better air quality
- Curitiba has 4x the green space recommended —> interception increases —> less flooding —> reduces damage to infrastructure —> helps save money and resources —> more sustainable
Housing and social projects
- Site and service schemes —> residents are trained to build the houses —> adequate conditions —> electricity, sewage and running water —> not ill so able to go to work (shortage of housing)
Waste
- Green exchange —> Curitiba reuses 2/3 of its waste —> people in slums collect rubbish + the council pay for the weight using fruit and veg —> council gains as people collect rubbish in narrower roads where the councils collection trucks can’t get to —> saves on expensive road widening// generates jobs and reduces landfill (unemployment)
urbanisation, suburbanisation, counter urbanisation, urban resurgence
4 processes that affect the population of cities:
- Urbanisation
- Suburbanisation - movement of people from inner city to the suburbs (outskirts of cities)
- Counter urbanisation - movement of people from urban areas to rural areas
- Urban resurgence - regeneration of an area after a period of decline (deindustrialisation) - movement of people back into the city
Causes of suburbanisation/counter-urbanisation:
- Push factors from urban areas: congestion, pollution
- Pull factors to suburbs/rural areas: more space, better quality of life, larger houses, green spaces, lower crime rates
What has allowed suburbanisation/counter urbanisation to take place:
- Improvements in transport links - people can commute to work
- Better communications - people can work from home
Impacts:
- More car dependant lifestyle increases pollution
- Segregation - wealthier middle-class people may move to the suburbs/rural areas and those that are left behind are poorer and may include foreign immigrants
- As more people move, house prices may increase - can displace local people
Urban resurgence:
How did they try regenerate areas after decline:
- Convert derelict buildings and industrial areas into houses
- Create new jobs
- Enhance the environment through the creation of open green spaces
Deindustrialisation and resurgence in Leeds:
- During the Industrial Revolution, Leeds developed into a major mill town - In 1950, 55% of the Leeds workforce was employed in manufacturing but by 1960 this had declined to 35% - jobs lost - less income - less money spent in goods/services so shops relocate - decline of area
- Leeds Trinity opened in 2013 and transformed the centre - attracted more people into Leeds
- Leeds arena opened - attracts people into the city
Urban climate
Winds:
1. Average wind speed is usually lower in cities than in rural areas. This is because tall buildings create friction that slows down the moving air
2. You get turbulence around buildings. This happens when wind hits the face of a building — some of it’s deflected down, some around the sides and some over the top. When these winds hit other buildings or the ground they causes vortices (bodies of swirling air)
3. You get powerful gusts of wind when wind is channelled down streets this is known as the canyon effect
Rain:
1. It rains more often in urban areas than in the surrounding countryside (Precipitation is 5-15% greater in urban areas than in rural areas)
2. The rain is also more intense and there are more thunderstorms
There are two main reasons for these things:
- The UHI effect means the air in urban areas is warm, and warm air can hold more water. The warm, moist air rises. As it rises it cools, the water vapour condenses and it rains. This type of rain is called convectional rainfall
- Urban areas generate huge amounts of dust and pollution - act as condensation nuclei - encourages clouds to form and therefore leads to rainfall
Fog:
- The higher concentration of condensation nuclei in urban areas also increases the frequency of fog
- Wind speeds are lower in urban areas so fogs are not so easily dispersed
- Presence of pollution prevents sun’s rays penetrating to the ground. The suns rays warm up the fog instead - fog is not dispersed
Snow:
- It doesn’t snow as often in urban areas, and when it does, the snow melts faster. This is because it’s warmer due to the UHI effect
air quality
- Air quality is worse in urban areas due to human activities creating particulates that stay suspended in the air
- This can cause health problems e.g. asthma
Sources of particulates:
- Vehicle exhausts - about 80% of fine particulates in urban areas are from vehicle exhausts
- Construction work is more prevalent in cities - these activities produce coarse particulates e.g. bits of brick and cement
- Industrial activities e.g. coal burning factories
Photochemical smog:
- Created when sunlight and pollutants react to produce low level ozone which is very dangerous to health
- Photochemical smog is a problem in many cities e.g. Los Angeles (USA), Beijing (China)
- These locations often have a temperature inversion, which keeps the pollutants at ground level
- Photochemical smog is linked to health problems such as asthma
Ways to reduce pollution:
Congestion charging:
- In Central London congestion charging reduced traffic and emissions in the congestion zone by around 15% in its first year of operation ✅
- However, some people travel around the edge of zones to avoid being charged - traffic increases in these areas - so it just moves the problem to other areas ❌
Pedestrianisation:
- Vehicles are restricted from entering certain places. Many cities have pedestrianised zones e.g. London
Public transport improvements:
- Improved bus services - cheaper and faster e.g. many cities have introduced bus lanes so buses don’t get caught in traffic
- Trams and light railway services - don’t get caught in road congestion e.g. The Metrolink in Manchester - has taken around 2.6 million cars off the roads
- Public transport improvements are often expensive e.g. construction of the Metrolink cost over £1 billion ❌
Other schemes reducing traffic:
- In Mexico City drivers are banned from using their cars one weekday per week, based on the last digit of their number plate e.g. number plates ending in 5 or 6 can’t be used on Mondays ✅ However, some richer households get around the system by buying two cars ❌
- Car sharing schemes encourage people making the same journey to share a car ✅ However, some people find car sharing inconvenient, or worry about sharing a car with a stranger ❌
Larger scale ways to tackle pollution:
Legislation/laws:
- Introducing tall chimneys - pollutants are dispersed higher in the atmosphere so they’re less harmful to people in the city
- The Road Vehicles Regulations reduce exhaust emissions by ensuring cars pass an emissions test in their MOT
- Throughout the UK, local authorities can issue fines to people who leave their engines running unnecessarily
Alternative fuels:
- Petrol and diesel are replaced with cleaner fuels that pollute less e.g. biofuels are produced from plants ✅ However, increased deforestation to grow plants ❌
- Electric vehicles have lower emissions because they run off batteries, rather than conventional fuel ✅ Electric vehicles are more expensive ❌
Urban waste
Sources of waste:
- Personal waste - waste produced by private homes e.g. food waste, plastics, cardboard
- Industrial waste - waste generated by manufacturing or industrial processes e.g. chemicals
- Commercial waste - waste produced by businesses like restaurants or shops e.g. plastics, food
Ways to manage urban waste:
Unregulated:
- Waste is dumped in places that aren’t official disposal sites e.g. solid waste left on streets or untreated liquid waste entering water courses
- Can damage ecosystems e.g. animals can be harmed if they swallow or get tangled in plastic waste ❌
Recycling:
- Converting waste into new products
- Recycling reduces demand for raw materials - resource extraction decreases ✅
- Producing products from recycled products generally uses less energy than making them from scratch - less GHG emitted ✅
- Recycling requires waste to be separated and categorised - some people cannot be bothered ❌
- Requires construction of new facilities to process waste - can be expensive and contributes to GHG emissions ❌
Recovery:
- Using waste instead of new products e.g. waste concrete can be crushed and used as a base for new roads and buildings
- Reduces the amount of waste going to landfill ✅
- Recovery reduces demand for raw materials - resource extraction decreases ✅
Incineration:
- When waste is burnt - can be used to generate electricity - called energy recovery
- Reduces the amount of waste going to landfill ✅
- Reduces use of fossil fuels ✅
- Burning waste can release toxic chemicals into the air ❌
Burial:
- Waste goes to landfill
- Convenient and cheap ✅
- Contamination of water supplies - rainwater passes through waste and picks up harmful chemicals/pollutants ❌
- Methane is released - GHG ❌
Waste submergence:
- Dumping waste under water
- Submerged waste can damage ecosystems e.g. animals can be harmed if they swallow or get tangled in plastic waste ❌
Trade in waste:
- Waste can be bought and sold by countries e.g. developed countries may pay developing countries to take their hazardous waste
- Developing countries may not dispose of hazardous waste safely ❌
Types of waste and methods of disposal vary between countries:
- Waste stream - flow of waste from its origin through to its eventual disposal
- Developed countries (2kg per person per day) tend to produce more waste than developing countries (0.5kg per person per day) - they tend to consume more goods as they’re richer
- Many developed countries have a throw-away culture - results in high levels of waste
- The components of waste also vary depending on the development level of the country// in developed countries, the main components are paper (30%), organic material (28%) and plastic// in developing countries, the largest components are organic material (65%), plastic and paper (5%)
- Developed countries have better systems in place to collect waste - over 90% of waste is burnt or dumped in unregulated areas in developing countries
Singapore has moved from landfill to incineration:
- In the 1960s, most waste was sent to landfill sites around the city. However, in the late 1970s the government changed their main waste disposal method to incineration with energy recovery
- The first incineration plant was constructed in 1979. Today, there are four plants across the city, which provide about 3% of Singapore’s energy needs
- Singapore now has only one landfill site. It is lined with an impermeable membrane and a layer of clay to prevent leaching of chemicals
- In 2015, only 2% of waste was sent to landfill and 40% was incinerated
Environmental issues in urban areas
Environmental problems in urban areas
Atmospheric pollution:
1. Atmospheric pollution is often a problem in urban areas
2. In many developed countries, reliance on fossils fuels is decreasing, and use of less-polluting energy sources (e.g. natural gas) is increasing. As a result, air quality in many cities has improved since 1950. However, car ownership is increasing and congestion can cause significant atmospheric pollution
3. Many developing countries and emerging economies still rely heavily on fossil fuels. Increases in industrial activity and car ownership, combined with a lack of regulation of emissions, mean that atmospheric pollution is often severe. In many developed countries, there are strategies to limit air pollution, such as promoting green’ modes of transport e.g. cycling, and expanding green spaces
Water pollution:
- Cities have a high population density, so they produce a lot of waste. Waste can enter and pollute watercourses
- Many cities have a high concentration of factories. Industrial waste and pollute can enter watercourses
- Water pollution can cause damage to ecosystems, and contaminated drinking water can cause health problems e.g. cholera. Strategies such as catchment management and SUDS can also help
- In developed countries, there are strict regulations about untreated water, and water quality is monitored. However, litter dropped in or around water can still cause pollution
- In many developing countries and emerging economies, there are few regulations and inadequate provision of treatment facilities. This means that untreated industrial waste and sewage often enter watercourses and water pollution is common
Urban dereliction:
- Urban dereliction happens when economic activity in urban areas declines and buildings become run down
- The movement of manufacturing overseas and the decentralisation of industry leads to industrial decline.
Many unemployed people leave urban areas in search of work
- If lots of people leave the area, shops may be forced to close and services go into decline. As industry, people and services move out, they leave empty buildings
- Empty buildings and derelict areas often have problems with vandalism, graffiti and crime
- Strategies to manage urban dereliction include the redevelopment of former factories into commercial and residential properties, the construction of new housing in derelict areas and the creation of green spaces
Global scale:
- At a global scale, cities increase demand for resources such as food, water and energy. Cities are home to around half the world’s population, but account for about three-quarters of resource use. This is putting pressure on finite resources
- Cities are also responsible for about 60% of greenhouse gas emissions, which contribute to climate change
