Contemporary Urban Environments Flashcards
Consequences of urbanisation - Urban Sprawl (HICs)
Less economically efficient to build roads/pipes over lower-density areas. Building on greenfield sites. Decentralisation of businesses from CBD
Urbanisation
The growth in the proportion of a country’s population that live in an urban environment compared to rural.
Majority of urbanisation occurs in Africa and Asia
Urban population expected to rise from 54% to 66% between 2014-2050
Consequences of urbanisation - Shortage of Housing (LICs)
large areas of informal or inadequate housing. 1 billion living in slums
Consequences of urbanisation - shortage of affordable housing
UK- rising demand for housing has led to increased housing costs
Consequences of urbanisation - lack of urban waste disposal
Financial restraints in LICs can lead to lack of basic services - council only able to deal with 66% in Addis Ababa
Consequences of urbanisation - Unemployment
Large amount of people moving to cities mean considerable pressure to create enough jobs - many people work in informal sector
Consequences of urbanisation - transport issues
Increased traffic which has created congestion and pollution
Suburbanisation
Outward growth of urban areas that has resulted in suburban and rural areas being engulfed. Facilitated by the growth of public transport systems.
In UK growth takes place along main roads, known as ribbon development. People move to the suburbs due to their desire for quieter, less congested and less polluted environment.
Negative impacts of suburbanisation
Environmental concerns - building on greenfield land
Can lead to social segregation as wealthier people are more likely to move to the suburbs → diversion of funding away from inner city
Counter urbanisation
Migration of people from major urban areas to smaller urban settlements and rural areas. This causes differences between urban and rural areas to be reduced.
People want to escape from the pollution and crime of the environment, car ownership and public transport allow people to commute from such areas.
Counter urbanisation impacts - migration
Out-migration of young adults from rural areas seeking education and employment opportunities elsewhere.
Decline of elderly, village-born population
In-migration of young families
In-migration of affluent people, resulting in increased house prices
Urban resurgence
Economic and structural regeneration of an urban area after a period of decline
Prevalent in previously industrial UK cities - Manchester, Leeds, Birmingham have transformed into cities of culture and commerce. They have developed strong financial, business and consumer service industries and have also attracted young university students, migrant workers and young professionals
They still display the marks of industrial architecture
Urban resurgence causes
Redevelopment by government and private companies has led to transformation of some UK cities and encourages further investment
City living has become more attractive due to a range of leisure and entertainment facilities and proximity to employment
Globalisation and technological improvements have led to an influx of people e.g. parts of East London due to its reputation for digital start-ups
Major sporting events can act as a catalyst for resurgence
Deindustrialisation - urban change
The fall in percentage of secondary industry to an economy in terms of value of input to GDP and importance of an employment sector
Causes of deindustrialisation
Mechanisation - machines do jobs better than people
Competition from abroad - less regulations for businesses e.g. minimum wage
Reduced demand for traditional products - new materials and technologies have been developed
Impacts of deindustrialisation
People lack the qualifications to work in service sector jobs
Urban change - decentralisation
Process currently taking place in urban areas, where functions once centred within the central location or local authority are dispersed. In terms of power and decision-making or in physical shops or offices
Decentralisation of retail
Decentralisation of food superstores - UK 1970s to 1994
Development of retail parks like B+Q or Ikea
Development of regional shopping centres like clothing outlets and leisure opportunities
Positives of decentralisation
Increased employment for locals
More room for expansion
Designed to be consumer friendly - proximity to businesses
Improve status of a town
Provide a stimulus for CBD retailing to improve
Cheaper land prices
Negatives of decentralisation
Disadvantages less mobile people
Potentially building on greenfield sites
Lack character and architecture of traditional city centre
Decentralised town centres can lead to decline
Restricted shopping choice
Increased reliance on cars → increased pollution
UK Urban Policy and regeneration
Urban policy relates to the strategies chosen by local or central governments to manage the development of urban areas. Early strategies in the UK focussed on ‘top down’ economic regeneration, subsequent policies have recognised the need to adopt a more holistic approach, tackling problems from the ‘bottom up’
Urban development corporations
Set up to regenerate inner city areas. Board made up of locals and were encouraged to spend money on buying land, building infrastructure and marketing to attract private investment . Funding came from central government
City challenge - 1990s
City challenge was a scheme were cities had to compete with each other for government regeneration grants. Led by local authorities
New deal for communities - 2000s
NDC partnerships were established to carry out plans to transform deprived neighbourhoods. Focus was that communities were at the heart of the regeneration
Megacities + timeline
Metropolitan area with a total population in excess of 10 million people. Usually has population density of >2000 people/km^2
Often have regional or national influence
In 1950, there were 2 megacities, NY and Tokyo, 30 in 2016, predicted to be 41 by 2030
Why are megacities on the rise
Globalisation and economic competition between countries and cities has led to the rise of megacities. More rural-urban migration and natural increase has fuelled their growth. Government policies such as enterprise zones in China encourage greater financial investment
Benefits of megacities
Average of 2.3% more GDP than other cities
Large population density means expanding services is economically efficient
Less environmentally damaging to provide transport, housing, electricity to densely populated areas
People have access to larger and diverse employment markets
Better levels of education and healthcare
Centres of innovation
World cities
Have large populations but are functionally different to mega cities. The reach of world cities are global. The top three ranking world cities are NY, London, and Tokyo. They are global service centres, specialising in advanced producer services such as finance, banking, accounting.
Magnets for highly educated, skilled workers, and home to world class universities.
They are hugely influential on a world scale in terms of economic, cultural and political factors e.g. the New York stock exchange
Slums
Informal settlements within cities that have inadequate housing and squalid, miserable living conditions.
They lack basic municipal services such as water, sanitation, waste collection and street lighting
Urban form
Relates to the physical characteristics that make up an urban area - shape, size, density of population
Urban model
A simplified view of a city
Urban zone
Part of a city with similar land use and buildings
Urban function
What happens in this zone (commercial/residential)
Urban landuse
What the land is used for
Urban morphology
Physical structure and layout of an urban area
Bid rent theory
The relationship between distance from the city centre and house prices. Rents are bid upwards close to the city centre as households attempt to minimise transportation costs
New urban landscapes - town centre mixed development
Many cities are encouraging the development of functions other than retailing to increase the attractions of the city centre. Including wide range of leisure facilities increased cinemas, theatres, cafes. e.g. Covent Garden
New urban landscapes - cultural and heritage quarters
Cultural quarter is where the is the presence of cultural activity, ideally both production and consumption of it. Could be developed in partnership or separately from heritage quarters, which focus on the historical uniqueness of areas based on small-scale industries.
Ouseburn Valley - National museum for children’s literature, art galleries such as the Biscuit factory, local breweries and pubs.
New urban landscapes - gentrification and reasons
The buying and renovating of properties often in more rundown areas by wealthier individuals. This can happen for a multitude of reasons; the rent gap (difference between between current rent price and potential rent of well developed land), community costs, ‘pioneer image’ - creative individuals moving into more ‘edgy’ neighbourhoods. e.g. Chapel Allerton, Leeds
New urban landscapes - fortress developments
Landscapes developed around security, protection, surveillance and exclusion. e.g. greater use of CCTV, railings and fencing, mosquito alarms, gated communities. e.g. Wythenshawe, Manchester
New urban landscapes - edge cities
When there is a concentration of firms, and entertainment and shopping centres in a previously known rural or residential area. Leads to a decline in CBD importance. e.g. Atlanta, Georgia
New urban landscapes - post modern western city
Introduced as a critique of modernist architecture in 1970s, buildings abandoned sharp edges. Often high-level/quaternary services. Fortress and edge cities viewed as features of post modern cities. e.g. London
Multicultural
Inequality
Differences in the levels of wealth, social opportunity or environmental quality
Social segregation
When populations are not equal throughout a defined space
Cultural diversity
The quality of different cultures and the extent to which they respect each others’ differences
Deprivation
A standard of living below that of the majority in a particular society that involves hardships and lack of access to resources
Index of Multiple Deprivation
UK government qualitative study of deprived areas in English local councils
Socio-economic segregation as a result of changing industries
As industry changes, people access or fail to access work. These people then live in different parts of the city
Over time low and high income zones emerge. Ethnic groups link to this pattern too as immigrants tend to cluster together in cheaper areas
Reasons for socioeconomic segregation - housing
Developers, builders and planners build housing with a certain market in mind. The requirement to include a proportion of ‘affordable housing’ may affect house value in some areas, but wealthier groups can choose where they live, paying premium prices for houses well away from poor areas.
Reasons for socioeconomic segregation - changing environments
Housing neighbourhoods change over time. Houses that were built for large families in Georgian and Victorian times are now too big for the average UK family. Many have been converted. On the other hand, former poor areas are being gentrified. The ‘right to buy’ legislation of the 1980s transformed many council estates. Right to buy legislation - allows tenants to buy their council home at a discounted place.
Reasons for socioeconomic segregation - the ethnic dimension
When migrants first arrive they may suffer discrimination in the job market and may be either unemployed or employed in low-paid jobs. This means they can afford to buy cheap housing or rent privately.
Newly arriving migrants often concentrate in poor areas in the city, often cluster into multicultural areas.
Urban social exclusion
Refers to the problems faced by residents in areas of multiple deprivation. People are excluded from full participation in society by their social and physical circumstances. In a city, inequality can cause lack of social cohesion and in extreme cases lead to civil unrest. Inner city areas have traditionally been the most deprived but today, there is no clear geographical pattern to urban poverty.
Tackling poverty and inequality in cities
Greater provision of public transport and ensuring it is affordable → access to other parts of the city e.g. Rio Cable Car
Encouraging decentralisation so not all economic growth is centred in the CBD
Providing schools and quality education
Youth clubs - keeps young people away from crime
Increase access to affordable housing
Support lower-skilled workers
Enforcing the living wage/provide urban subsidy
Enforce environmental standards. Poor health is strongly linked to poor conditions
Urban decline
The deterioration of the inner city often caused by lack of investment and maintenance. It is often but not exclusively accompanied by a decline in populations, decreasing economic performance and unemployment
The primary driver for urban inequality, social segregation and cultural diversity is economic change.
This can lead to deprivation in some areas which is where there are social, economic and environmental problems in an area e.g. poor housing, lack of services etc.
Diaspora
A group of people with similar heritage or homeland who have settled somewhere else in the world
Why do immigrants often settle in cities
Urban populations tend to be more tolerant
Job opportunities
Cities are already more diverse
Social opportunities
First point of entry for many immigrants
Tend to house immigrant groups with the same ethnicity
Benefits of immigrants in cities
Exposure to different foods, music, language, religion
Opportunities for people to experience different things
Improves understanding of different POVs leading to greater tolerance
Negatives of immigrants in cities
Extra pressure on stretched urban services e.g. language barrier
Hospitals may need to cater for different illnesses
School holiday patterns + timetables having to cater for different cultures
Can enable social segregation
Interculturalism
Emphasises interaction and the exchange of ideas between different cultural groups
Areas of mutual interest are found and community engagement is conducted in ‘intercultural spaces’
Anti-racial legislation
In the UK, there is anti-racism legislation as well as employment rights
Encouraging greater political involvement of different cultural groups can also encourage greater integration
Urban Heat Island Effect
A city that is significantly warmer than its surrounding rural areas due to human activities
The annual mean air temperature of a city with 1 million or more people can be 1-3 Degrees Celsius warmer than its surroundings
Microclimate
Small scale variations in temperature, precipitation, humidity, wind speed and evaporation that occur in an environment
UHI effect causes
Building materials - such as concrete, bricks and tarmac absorb large quantities of heat during the day. They have a higher thermal capacity than natural surfaces. Multi-storey buildings tend to concentrate the UHI in the surrounding streets by reflecting energy downwards.
Burning of fuel - from industries, buildings, and vehicles. People release heat.
Urban pollution dome - air pollution increases cloud cover and creates a dome. Mini greenhouse effect.
Water management - in urban areas, water falling on the surface is removed quickly. This changes the urban moisture and heat budget - there will be less evaporation so more energy is available to heat the atmosphere
Urban pollution dome
Occurs in cities with an inversion layer, and increased pollution in the city is trapped under the ‘lid’
Mini greenhouse effect
Albedo
The reflectivity of a surface. The ratio between the amount of incoming solar radiation and the amount of energy reflected back into the atmosphere by surfaces or the atmosphere. Lighter surfaces have a greater albedo.
Precipitation in urban areas
Precipitation is on average 10% greater in large urban areas than towns.
UHI generates convection
High rise buildings and a mixture of building heights, induces air turbulence and encourages vertical motion of air.
Cities produce large amounts of water vapour from industrial sources, various pollutants act as hydroscopic nuclei and assist in the formation of raindrops.
Snow is less common in cities and melts faster 25% greater chance of thunderstorms greater incidence of hailstorms.
Fog
A cloud that touches the ground
The occurrence of fog has increased with industrialisation
Urban areas have more fog than rural areas - wind speeds are higher, due to high-rise buildings, so fog is less easily dispersed
Presence of pollution provides condensation nuclei
Presence of pollution prevents suns rays from penetrating to the ground and warming up the fog
Smog
Increased amount of dust and smoke particles cause ‘smog’
Lower air quality in urban areas than surrounding countryside - 7 times more dust particles in their local atmosphere than rural.
Photochemical smog
Smog that is created by sunlight and dust/smoke to produce low-level ozone which is dangerous to health - volatile organic compounds react with sunlight.
Smog in Los Angeles
LA has a temperature inversion where air in the atmosphere is warmer than below. This means that all the pollution is trapped. The prevailing wind blows in the air of the Cold Pacific Ocean.
The air is trapped by the mountains which reach 10,000ft in elevation and, combined with the inversion layer, the smog that gets created in LA gets bottled.
London smog - 1952
Caused by burning of coal, forming sulphur dioxide
4300 Londoners still die each year from air pollution, air quality improved but since but still health dangers
1952 - ‘pea-souper’
People couldn’t see their feet
3500-4000
Pollution reduction policies - legislation
e.g. Clean Air Act
A way of improving the air quality
London Smog - 1952, British government decided legislation was needed to prevent so much smoke entering the atmosphere. This improved the air quality in London but, in 2015, Nitric Oxide levels were higher than UK and EU laws recommended
Pollution reduction policies - zoning of industry
Industry has been located downwind in cities and planning legislation has forced companies to build higher factory chimneys to emit pollutants above the inversion layer.
It can significantly impact local development by attracting business + jobs to an area whilst protecting existing neighbourhoods from harmful industrial activities
Pollution reduction policies - vehicle control and public transport
Greater provision of public transport and general restrictions on polluting vehicles - cars with high emissions have to pay a daily non-compliance charge in ULEZ. London ULEZ in 2020 very effective. Paired with congestion charge in 2003 and London bus fleet upgraded with hybrid engines and zero emission single-decker buses. Very effective at reducing CO2 and e.g. incentivising cycling. However, lots of people find it more convenient to drive a car.
Urban climate - wind - channelling and venturi effect
Channelling - wind redirected down long, straight canyon-like streets where there is less friction.
Venturi effect - the squeezing of the wind into an increasingly narrow gap resulting in a pressure decrease and velocity increase.
Effects of urban structure on wind
Uneven surface area due to varying height of the buildings. Buildings exert a powerful frictional drag on air moving over and around them. This creates turbulence - abrupt changes in wind direction and speed
High-rise buildings may slow air movement but they also channel air into the canyons
UHI - on calm, clear nights, where UHI is at its highest, convectional processes can draw in strong localised winds from cooler surrounding areas.
Bridgewater Place, Leeds
Wind tunnel effect - very dangerous when there is strong winds.
Strong high winds are funnelled down and smooth building surfaces reduce friction meaning there are very strong winds on the ground.
In 2013 a woman was crushed by toppled lorry caused by the increased winds. Put in ‘baffle boards’ to block winds.
Burj Khalifa - mitigating effects of wind
Tallest building in the world - 828m. At this height, wind vortexes pulling the building from side to side are a concern - gusts of up to 240km/h
Softened edges deflect wind + prevent vortexes forming
Entire tower is oriented relative to prevailing wind
Will sway slowly by around 2 metres at the very top
Hydrograph in urban areas
Shorter basin lag time due to impermeable surfaces
Steeper rising limb - water management systems allow water to flow into the river quicker
Steeper falling limb - less underground storage of water so the vast majority of water will have entered the river quicker so the base level will return quicker.
Rural has opposite effects
Types of flood management in urban areas
Fail safe - reducing problems that have occurred in the past
Safe to fail - sustainable urban drainage systems and river restoration schemes
Los Angeles river restoration
1930s - made river into concrete channel, increasing capacity of the river, destroying most of the floodplain.
The restoration aims to restore 11 miles of the LA river. It has improved wildlife biodiversity and accommodates recreational and natural uses of the river while maintaining the city’s flood risk management levels
Water Pollution
The contamination of water sources including rivers, lakes, oceans, aquifers and groundwater
Causes of water pollution
Surface run-off from streets - contaminants from motor vehicles
Industrial waste
Untreated sewage
Rubbish dumps, toxic waste, chemical + fuel storage
Air pollution leading to acid rain which enters water systems
Water pollution management
In HICs, remediation focusses on construction of treatment facilities, regulations aimed at ‘point source’ pollutants such as factories which discharge chemicals into water systems
Non-point source pollution is more challenging to manage as it comes from run-off of a wide range of sources
In LICs, lack of money and inadequate technology has resulted in lower water quality standards.
Water pollution strategies
Low-impact development - to reduce stormwater run-off, done primarily through the use of vegetation and permeable surfaces
Legislation, regulation and enforcement
Education + awareness
Improvement in sewage and wastewater processing
Appropriate technology - Janicki omni-processor - small-scale innovation providing clean water in low-income countries
Waste
The average person in the UK produces 500kg of household waste each year - estimated to account for 5% of GHG emissions
Globally, waste increases by about 7% each year, increasing in amount, toxicity, duration of toxicity
Waste tends to be higher in HICs due to higher wealth and consumption. However, HICs are increasingly focussed on management
China has the fastest growth in urban waste
Negatives of increasing waste
Loss of recyclable resources
Loss of potential resources (energy from incineration)
Contamination of water and land
Air pollution - methane
Risk to human health - respiratory problems
Cost
Cities are running out of landfill space
Sources of urban waste
Domestic
Municipal
Commercial
Institutional
Construction and demolition
Industrial
Impacts of increasing waste generation
Cost of collecting and treating waste are high. In LICs, waste management is usually a city’s single largest budgetary item
Untreated or uncollected waste can lead to health problems
Many cities are struggling to collect increasing quantities of urban waste. In 2012, 30-60% of urban solid waste in LICs is uncollected
Waste is a large source of methane
Cities are running out of landfill space, leading to rubbish being left in public places
Energy recovery
Burning waste (incineration) to convert it to energy. Practical method of disposing of certain hazardous waste. Some modern incinerators generate electricity and power neighbourhoods. Harmful gases are emitted
Energy from waste - Leeds
Veolia hi-tech waste plant to treat waste and stop it going to landfill
Waste is burnt which can generate thermal energy used to heat local homes and offices - 13MW which is enough for 22,000 homes
Ash recycled to construction aggregate
Air pollution control
‘Green wall’ on side of plant helps biodiversity
Composting
Used for organic waste - from small-scale compost heaps to industrial scale. Recycled to use for agriculture or landscaping. Waste gases from the process (methane) can be captured and used to generate electricity
Landfill
UK produces about 280 mil tonnes of waste - 2014
1996- Landfill tax was introduced
2009 - 90% of the country’s waste was going to landfill, now only 10%
Unsightly
Decaying matter produces methane
Issues with windblown litter
Urban dereliction
Refers to the state of having been abandoned and become delapidated
Causes of urban dereliction
In urban areas derelict buildings are often associated with former industrial sites or run-down housing estates
In the UK, de-industrialisation led to many people leaving the inner city and industrial buildings being abandoned, this may lead to pubs and services such as pubs and shops will have become vacant as areas became subject to decline
Impacts of urban dereliction
Crime and vandalism rates tend to be higher
House prices decreasing
Outmigration of residents takes place
Land can pose a risk to human health
High cost of urban renewal often discourages authorities
Presence of listed buildings can increase the investment needed
Management of urban dereliction
Regeneration schemes - UDCs, City Challenge, New Deal for Communities
Focus on using Brownfield sites rather than Greenfield sites
1997-2009 - dwellings built on brownfield land increased from 56% to 80%
Advantages of building on brownfield sites
Not damaging ecosystems
Easier to get planning permission
Regenerate derelict area
Disadvantages of building on brownfield sites
Risk of pollutants
Limited space
Why is use of Brownfield sites falling?
Cost of infrastructure and decontamination combined with lengthy planning permission waits
Land remediation
The removal of pollution of contaminants from the ground, which allows large areas of derelict former industrial land to be brought back into commercial use
Ecological footprint
The total area of productive land required to produce the resources a population consumers and absorb the waste produced.
Can be modelled as an open system:
Inputs - food, water, building materials
Outputs - waste, emissions
Ecological output = inputs + outputs
Urban areas in HICs often have ecological footprint 10x higher than an urban area in an LIC
Why do HICs have higher ecological footprint than LICs
Increased education - more people travel abroad for business which increases use of transport
Increased access to healthcare - longer life expectancy - people work and commute for longer and travel in retirement
GDP - more disposable income
Natural sustainability
Considers how successfully the environment is managed
Physical sustainability
The ability of the city’s resources to support current and future generations - hosuing, transport, amenities
Social sustainability
Ensuring residents have of good QoL, being socially cohesive with access to leisure
Economic sustaimability
Ability for a city to grow economically continuously without any negative effects
2022 Sustainable Development Goals
Intensified focus on 1 billion slum dwellers - >50% of urban dwellers in sub-Saharan Africa live in informal settlements
Increased monitoring of air quality in cities - pollution resulted in 4.2 million deaths in 2019
Only half of urban dwellers have convenient access to public transportation
Problem of municipal solid waste continues to mount - only 82.4% of waste collected worldwide
Main challenge is money - basic infrastructure takes precedent over sustainable goals in rapidly growing NEEs/LICs
Strategies to develop sustainable cities
Reducing waste - unsustainable environmentally, physically, and economically. Waste can be reduced through recycling schemes, encouraging composting and farmers markets to reduce food packaging waste
Transport - large issues in urban areas with the number of vehicles. People need to travel for work, shopping, and leisure. e.g. Curitiba
Green space - can reduce the effects of pollution and flooding, and make an area more attractive for its residents, improving physical, natural and social sustainability
Efficiency of buildings - BEDZED
Historic and natural preservation - often done by keeping architecture but altering functions of buildings e.g. Liverpool Waterfront
Involving locals - if people feel involved they are more likely to respond positively and care about the the development
Urban liveability
Which cities provide the best or worst living conditions for their residents. Sustainable cities must be liveable in the present and future
