Contemporary urban environments Flashcards
Urbanisation
Urbanisation is the increase in the proportion of people who live in urban
environments
Suburbanisation
The increased movement of people, services and infrastructure from the inner pats of a city outwards to the outer edge
How has suburbanisation been facilitated over the years
- Growth of public transport
- The increased use of the private car
- Railway lines and arterial roads
Suburbanisation- 1930s
Few planning controls and so urban growth took place along main roads known as ribbon development
Suburbanisation- 1940s
Continued growth between ribbons became a cause for concern and so it led to the creation of green belts
What are green belts?
Areas of open space and low density land use around towns where any further development are strictly controlled
Suburbanisation- 1950s
Increasing suburban expansion better planned. Large scale construction took place of council housing in the only land available (suburban fringe).
Surbanisation- 1970s
A move towards house ownership that led to private housing estates being built, also on the urban fringe, allowing for more land for gardens and public open space.
As car ownership grew in the edge of town there was more land available for car parking and so it became the favoured location for new offices, outlets and factories ignoring the ‘strict control’ of green belts
Suburbanisation in recent years
- New, well established housing
- Quieter
- Less congested
- Less polluted environments
- Relatively cime free environments
- Golf courses and playing fields
- Woodlands and parks
Negatives of suburbanisation
Increased social segregation within city as the wealthy move out to suburbs (inner London to Richmond) with poor remaining in the inner city
Diversion of funding away from inner city areas to the suburbs to pay for new infrastructure and services
Increased traffic congestion
Conversion of green spaces to artifical surfaces
Surburban expansion
Growth of the suburbs
Survey from Uni of Leicester about green spaces
A satellite survey by a research team at the University of Leicester (UofL) found that between 2006 and 2012, 22,000 hectares of green space was converted to “artificial surfaces” – mostly housing. More than 7,000 hectares of forest was felled, 14,000 hectares of farmland concreted and 1,000 hectares of precious wetland was drained to make way for urban sprawl. -The Guardian 2015
Counter- urbanisation
The migration of people from major urban areas to smaller urban settlements and rural areas reducing difference between rural and urban areas
Factors of counter- urbanisation
- Escape of air pollution, dirt and crime
- Cheaper land and house prices
- Aspiration to be the ‘rural idyll’
- Car ownership and greater affluence allows for commuting to work
- Rising demand for second homes and earlier retirement
- Farmers selling land for money
- Technology developments
Evidence for counter- urbanisation
- Increase in use of a commuter railway station in the area
- Increased value of houses
- Construction of more executive housing in area following demolition of old property
- Conversion of former farm buildings to exclusive residences
Negatives of counter- urbanisation
Tension between newcomers and locals
- local services closing down ( Bus services, schools, post offices, churches and parishes) as newcomers have wealth and mobility to continue use of urban services
Demographic change in rural settlement
- Out migration of young village born population for education and employment opportunities
- Decline of elderly village born population by death
- In migration of young to middle aged couples/ families with children
- In migration of younger, affluent people increasing house prices
Positives of counter urbanisation
-Some shops see an increase in business – newer residents/retired people have
more disposable income.
-Older housing and building are restored by housing developers.
-Farmers are able to make money by selling land.
-As newer residents (with families) move into smaller towns and villages the
local services, such as schools are able to stay open,they may have had to
close due to a lack of students previously
Negatives of counter- urbanisation
-The newer developments might affect the local character of the area.
-Due to more residents having the ability to travel to cities and shop online the local shops and services may close.
-Rural roads and infrastructure will struggle to cope with traffic. This causes congestion and air pollution.
-Schools may have to close if all the new residents are older people with no children.
-House prices are going to increase, this might mean only older people can afford the housing, and it may push the local people out of the area.
Management of housing in counter- urbanised rural settlements
-Sometimes the developments are only allowed to be built if they fit in with the rest of the area. e.g. Houses need to be built in the traditional style.
-Some companies will offer mobile services.e.g. NatWest has mobile banking vans which visit rural areas in Cornwall and Devon.
-Local occupancy clause – People need to have lived in the area for at least 3 years.
Example of counter-urbanisation
- St Ives
St Ives, Cambridgeshire
- In 1961 the population was just 3800, however in 2010 the population has reached 16,400 with a quarter commuting to London each day.
Impacts in St Ives
Along the A14 traffic congestion is causing a big problem during rush hour.
The average house price in St. Ives rose from £130,000 to £291,000 between 2000 and 2010. Commuters can afford these high
prices, whilst locals cannot.
To cope with the demand of housing, new developments are being built on the floodplain. This floodplain is on the South of the
River Great Ouse.
The population structure of the area has changed, the population was ageing, however now there are younger people and families putting a strain on schools.
Management in St Ives
-Future developments are going to be controlled so that they fit into the area.
-There are plans to expand primary schools which can give 240 more places
-Along the river they are building flood protection works that cost £8.8 million. This included new embankments and flood walls.
-A £116 million busway has been built that links St. Ives to Huntingdon and Cambridge. This will hopefully reduce congestion as they will not need to travel on the A14.
-In 2010 plans were approved to build 200 new homes. 75 of those houses are going to be affordable housing. The houses are going to be:
Social rent – Houses which are rented out by the council at low rates.
Low cost ownership – either buying a house at a discount, or buying a share of the house and rent the rest.
Urban resurgence
The resurgence, economically and structually, of an urban area which has suffered a period of decline
Resurgence of central Birmingham
The Jewellery Quarter
- Foreign competition, reduced demand and bombing of the area (the Blitz) caused sharp decline in the area’s fortune
- Early 2000’s lead to large scale impovements
Gas Street Basin canal area
- cleaned up canals and create attractive area
Importance of urban resurgence in the UK
Former industrial cities suffered from manufacturing decline in 1970s+80s but reinvented themselves as cities of culture and commerce
-London, Birmingham, Manchester and Leeds suffered from de-industrialisation
Sporting events amplifying urban resurgence
London Olympics 2012
Glasgow Commonweath Games 2014
‘Dead heart syndrome’ present in American cities
Where an urban area experiences population decline because of suburbanisation and loss of manufacturing and retail.
New York, Boston, Los Angeles
Resurgence in New York City
Successful redevelopment of High Line in NYC in 2000’s abandoned in 1980’s due to manufacturing decline.
- 5 million annual visitors
De- industrialisation
The loss of jobs in the manufacturing sector
- occurred in the UK in the second half of the twentieth century
Factors attributed to decline of manufacturing
Mechanisation (producing goods using machines rather than people for cheaper)
Foreign competition (rapidly industrialising countries like India, China, Taiwan)
Reduced demand for traditional products (new materials and technologies developed)
Decentralisation
The movement of population and businesses away from the established city center towards the urban fringe, leading to a dispersion of urban population or employment over a larger area.
Rise of service economy in urban areas
Tertiary structure- financial services, transport, education and health
Quarternary structure- knowledge or ideas are the main output, such as advertising, computer programming and software design
Service sector growth causes
- Financial services needed to suppot manufactuing industries
- Larger range of specialised services for more technologically sophisticated socities needed to keep them running
- Wealthier societies demand more leisure and retail services
Problems of de- inustialisation
- Many people still suffer from long tem unemployment
- Many services jobs created are part time or temporay
- Number of services jobs created not always met jobs lost by manufacturing decline
- Many inner city locations avoided by both service and manufacturing jobs leading to continuous decline
What is gentrification?
The buying and renovating of properties, typically in more run down areas, by wealthier individuals
Urban growth
The spreading of urban developments on undeveloped land near less densely populated city
Importance of urban areas
Hold much of a countries national economic activity, government institutions and transport links.
Cities also have higher levels of education, healthcare and social services- greater participation in cultural and political opportunities.
Nairobi, Kenya GDP
Nairobi contains 8.4% of the country’s population yet accounts 20% of country’s GDP
Causes of urban growth
-Natural population growth
-Rural to urban migration
-Industrialisation
Consequences of urban growth
-Urban sprawl
-Shortage of housing in lower income countries
-Shortage of affordable housing higher income cities
-Lack of urban services and waste disposal
-Unemployment/under employment
-Transport issues
Natural population growth
- Young adults migrating to urban areas for higher paid jobs, better education opportunities and more social/cultural diversity
- Between 2001 to 2011 the number of residents aged 22-29 nearly tripled in large city centres of England and Wales
- In London, ‘nappy valley’ claimed due to high number of young families
Rural to urban migration
- Movement of people from rural areas to urban areas
Pull factors- employment, better social provisions, good quality of life
Push factors- poverty, disease, war, natural disasters, agricultural problems
Industrialisation
People enticed to urban areas for the prospect of a service of industry job (factory) bringing better pay, working conditions and good social environments
- Not always good quality, dormitories in China to maximise working hours
How many people are expected to live in urban areas by 2030?
66%
What percentage of high skilled jobs are located in UK cities?
72%
What percentage of the UK’s population live in cities?
54%
Advantages of megacities
- Offer opportunites to expand education and healthcare services for large numbers of people
- Less environmentally damaging to provide to a dense popoulation
- Urban dwellers have access to larger employment markets
- Improvement of women’s lives
- Political pressure for change
What is a fortress landscape?
Landscapes designed around security, protection, surveillance and exlusion
What is a world city?
Cities with great influence on a global scale due to their financial and commercial status. They exert a dominant influence over continental and global economies and processes
Characteristics of a world city?
- Considerable global decision making power
- Existence of financial headquarters
- Centres of new ideas and innovation
- High quality educational institutions
- Major manufacturing centres
- Good transport networks
- Domination of trade and economy
Urban morphology
The spatial structure and organisation of an urban area
Town centre mixed development
Methods set by cities to develop other functions of a city centre than retailing to increase attractions. Prevent the loss of economy to CBD
- Wider range of leisure facilities such as cinemas and restaurants
- availability of space like plazas and squares
- street entertainment and nightlife
- flagship attractions
Exeter’s mixed use city centre development
In 2007, Princesshay opened a new redevelopment replacing unattractive post war facilities into retail units, restaurants, flats and cafes, attracting tourists through events and festivals.
In 2019, a new plan called CityPoint was unveiled turning old bus stations into hotels, bars, office spaces and civic centres
Cultural or heritage quarters
Deliberate model for urban regeneration of declining inner urban areas to increase tourism and attraction
- Birmingham Jewellery Quarter
- Krakow Jewish Quarter
Gentrification
The buying and renovating of properties often in more run-down areas by wealthier individuals. It is an important process of housing improvement supported by groups
such as estate agents and local authorities and it has helped to regenerate large parts of British inner cities in the last few decades
Causes for gentrification
The Rent Gap- the price of property has fallen below its real value, due to lack of maintenance or investment, and there is a ‘gap’ between actual and potential
price. Such properties are attractive to builders, property developers or individuals who can afford to renovate the properties and then sell them on to make a profit.
Commuting costs- Commuting can be timeconsuming, expensive and stressful. Moving closer to the city centre can eliminate the need to commute.
The ‘pioneer’ image- This refers to the trend of creative individuals such as artists and designers moving into more ‘edgy’ neighbourhoods not interested in the conformity of suburban living but are drawn to the diverse cultural opportunities of the urban centre. The gentrication of areas such as Hoxton and Shoreditch in London has been linked to their reputation as the location of vibrant arts scenes.
Support of government and local decision
makers- keen to improve the economy and environment of inner city areas
Changing composition of households- Many cities have seen the growth of single or two-person households without children more likely to see the benefts of inner-city living.
Costs of gentfrication
- People on low incomes cannot afford higher property prices or rents
- Higher car ownership may increase congestion
- Potential loss of business for traditional local low order shops
- ‘Gentrifiers’ may be seen as a threat to the traditional community and friction may occur between ‘newcomers’ and original residents
Benefits of gentrification
- Rise in general level of prosperity and increasing number and range of services
and businesses - Increased local tax income for the local authority
- Physical environment of the area improved
- Greater employment opportunities created in areas such as design, building and refurbishment
Liverpool gentfrification
In 2013, Liverpool City Council sold
20 derelict homes in Kensington, Granby and Picton for £1 each with basic rules to improve and develop the house.
- The scheme has now been extended to other houses and shops in the area with the overall aim to improve the built environment and make it a thriving community again.
Properties of fortress landscapes
- greater use of closed-circuit television
- railings and fencing around private spaces
- ‘mosquito’ alarms, which emit a high pitched sound heard only by young people, to discourage loitering around certain buildings
- effective use of street lighting
- speed bumps to prevent joyriding
- anti homeless structures
Los Angeles fortress landscape
Los Angeles has developed a reputation as a city built on fear. Mike Davis has detailed how paranoia and fear of gangs, minorities and the homeless have led to a refashioning of the urban landscape which includes:
● gated communities
● armed-response security units in residential areas
● shopping malls surrounded by staked metal fencing and an LAPD surveillance tower.
What are edge cities?
Self-contained settlements which
have emerged beyond the original city boundary and developed as cities in their own right caused due to urban sprawl
- develop close to major roads and airports
- no clear structure but contain amenities like schools, malls, entertainment
- linked to extreme social segregation of the wealthy
Los Angeles edge city
In 2015, the core city of Los Angeles
which is about 30 kilometres wide, had a population of just under 4 million. However, this is surrounded by a metropolitan area of nearly 18 million people which is more than 100 kilometres at its widest point. Within this area there are more than 20 edge cities (for example, Pasadena and Century City).
Post modern western city characteristics
- fragmented urban form comprising
independent settlements (such as edge cities), economies, societies and cultures - greater emphasis on producer services and knowledge-based industries rather than industrial mass production
- eclectic and varied architecture as seen in the London cityscape
- spectacular flagship developments such as the Guggenheim museum in Bilbao, Spain
- greater ethnic diversity but heightened economic, social and cultural inequalities and polarisation.
Post modern western city
The changes that took place in Western society and culture in the late twentieth century. It mainly concerned art and architecture and marked a departure from
the conformity, uniformity and brutalist nature of modernism. Postmodernism is characterised by the mixing of different artistic styles and architecture.
Cultural diversity
The existence of a variety of cultural or ethnic groups within a society.
Economic inequality
The difference between levels of
living standards, income etc across the whole economic distribution.
Social segregation
When groups of people live apart
from the larger population due to factors such as wealth, ethnicity, religion or age.
Mumbai’s economic inequality
Antilia is the 27-storey home of Mukesh Ambani, chairman of a global energy conglomerate and estimated to be worth
over $35 billion. Within a short distance of the house is Byculla, an area inhabited by some of Mumbai’s nine million slum dwellers. Most people here survive
on less than $2 a day.
Reasons for social segregation
- Housing
- Changing environments
- Ethnic dimensions
Reasons for social segregation
- housing
Developers, builders and planners tend
to build housing on blocks of land with a particular market in mind. The requirement to include a proportion of ‘affordable housing’ may affect housing value in some areas but wealthier groups can choose
where they live, paying premium prices for houses well away from poor areas, with pleasing environments and services such as quality schools and parks. Poorer groups typically have less choice.
Reasons for social segregation
- changing environments
In the UK, houses that were built for large families in Georgian and Victorian times are now too big for the average family. Many have been converted into houses of multiple occupation (HMOs), often occupied by those on low incomes or students. Conversely, former poor areas
are being gentrified. The ‘right to buy’ legislation of the 1980s transformed many council estates, as houses were bought by their occupants and improved.
Reasons for social segregation
- ethnic dimension
Ethnic groups originally come to the country as new immigrants. When they first arrive they may suffer discrimination in the job market and may be either unemployed
or employed in low-paid jobs. They are only able to afford to buy cheap housing or they have to rent privately (for example, Moss Side in Manchester). Therefore, newly arrived migrants concentrate in poor areas in the city, often clustered into multicultural areas. Such ethnic groupings tend to persist into later generations.
How to measure poverty and inequality?
The Index of Multiple Deprivation (IoD) is a UK government qualitative study measuring overall deprivation for every neighbourhood in England. It is based on 37
separate indicators, organised across seven distinct domains of deprivation.
IoD2019 large concentrations of deprivation
- large urban conurbations
- areas that historically have had large, heavy manufacturing industry or mining sectors (such as Birmingham and Nottingham)
- coastal towns (such as Blackpool or Hastings)
- parts of east London.
Urban social exlusion
The problems faced by residents in areas of multiple deprivation. These people are
excluded from full participation in society by their social and physical circumstances. They cannot access a decent job because of poor education or obtain decent housing
because of poverty. They often suffer from poor health and from high levels of crime in an unattractive physical environment. In a city, inequality can cause lack of social cohesion and in extreme cases lead to civil unrest.
Tackling poverty and inequality in cities
Provision of schools
Supporting low-skilled workers who want to develop their abilities
Access to affordable housing
Greater provision of public transport
Enforcing a living wage
Minimum environmental standards
Why is there greater cultural diversity in cities?
- cities tend to offer a greater range of employment opportunities
- cities are the first point of entry into the country for many immigrants
- cities tend to house earlier immigrant groups with the same ethnicity
- established cultural diversity in cities means there are specialist shops and religious centres located there
- urban populations tend to be more tolerant of immigrants.
Albedo
The reflectivity of a surface. It is the ratio
between the amount of incoming insolation and the amount of energy reflected back into the atmosphere. Light surfaces reflect more than dark surfaces and so have a greater albedo.
Particulate air pollution
A form of air pollution caused by the release of particles and noxious gases into the atmosphere. Emissions of particles can occur naturally but they are largely caused by the combustion of fossil fuels.
Photochemical pollution
A form of air pollution that occurs mainly in cities and can be dangerous to health. Exhaust fumes become trapped by temperature inversions and, in the presence of sunlight, low-level ozone and other noxious gases form. It is associated with high-pressure weather systems.
Temperature inversion
An atmospheric condition in which temperature, unusually, increases with height. As temperature inversions do not allow convection, they trap pollution in the lower layer of the atmosphere.
What is an Urban heat island?
The zone around and above an
urban area, which has higher temperatures than the surrounding rural areas.
Urban microclimates
The small-scale variations in temperature, precipitation, humidity, wind speed and evaporation that occur in a particular environment such as an urban area.
Reasons why urban areas are warmer than rural areas
- less reflective surfaces and so less albedo absorbing large quantities of heat
- air pollution from industries and vehicles increases cloud cover and creates a ‘pollution dome’
- disposal of surface water quickly. This reduces the potential for cooling by evaporation. Reduced vegetation means less evapotranspiration.
- heat comes from industries, buildings and vehicles, which all burn fuel
Concerns of urban heat island
- conditions can become uncomfortable in buildings and on city transport systems
- cases of heat stroke, asthma, organ damage and even death increase. In the heatwave of 2019, Paris recorded a high of 42.6°C. Most of the 1435 heat related deaths in France that year occurred in Paris.
- chemical reactions that produce ozone and smog are accelerated by high temperatures, while the lower wind speeds keep the heat and pollution trapped in the city.
- increased strain on the supply of energy for cooling and air conditioning.
- strain on the water supply infrastructure and can lead to water-use restrictions
- increase climate change
- risk of monuments detoritating
Strategies managing urban heat island
Cool surfaces- roofs built from materials with high albedo absorb and store less solar energy during the day and thus are not major emitters of heat into the urban atmosphere at night.
Green roads- roads with a more porous surface that allows water to seep in and grass to grow through reducing the amount of heat absorbed by the road surface.
Green roofs- these consist of a growing medium planted over a waterproof membrane and can
reduce rooftop temperatures by 20–40°C on a sunny day. They also green roofs reduce rainwater run-off, act as insulators and increase urban biodiversity by providing habitat space for birds and small animals.
Urban greening- planting trees and vegetation provides shade and can have a natural cooling effect. Urban trees also
act as carbon stores, can reduce urban flooding
Cool cars- Due to its higher reactivity, the interior of a light coloured car does not heat up as much as a darker one. This reduces the need for airconditioning and reduces the amount of heat that is emitted into the surrounding air.
Urban heat island
- precipitation
Rainfall can be higher over urban areas than rural areas. This is partly because higher urban temperatures encourage the development of lower pressure over cities in relation to the surrounding area. Convection rainfall tends to be heavier and more frequent, as does the incidence of thunder and lightning
Precipitation causes
- convection heats ground surfaces, rapid evapotranspiration takes place and can result in cumulus clouds and convectional weather patterns.
- presence of high-rise buildings and a mixture of building heights induces air turbulence and promotes increased vertical motion.
- city pollution can increase cloud formation and rainfall
- large amounts of water vapour
from industrial sources and power stations.
Urban heat island
- fog
It was discovered in the 1950s that the average number of particles in city air
in the more developed world was much greater than in rural areas. The particles acted as condensation nuclei and encouraged fog formation at night, usually under high-pressure weather conditions.
Cities such as New Delhi suffer regular winter fogs and the term ‘airpocalypse’
has been used to describe the high death toll which occurs when they trap pollutants to create a toxic smog.
Urban heat island
- thunderstorms
Thunderstorms develop in hot humid air and are characterised by violent and heavy precipitation associated with thunder and lightning. In urban areas the chance of thunderstorms is increased, particularly
during the late afternoon and early evening in the summer months.
Urban heat island
- wind
Buildings artificially increase the
friction on urban winds and reduce wind speed. Urban designers and architects strive to reduce the negative impacts of
effects of wind.
Wind effects
- On calm and clear nights, when the urban heat island effect is at its greatest, convectional processes can draw in strong localised winds from cooler surrounding areas.
- In many cities, the domination of high-rise buildings has caused an increase in the channelling effect where wind may be artificially increased or reduced based on the orientation of the surrounding street. The venturi effect then intensifies this speed
- Spacing of buildings as widely spaced cause each building to act as an isolated block. In the case of closely spaced buildings, the wake of one building interferes with the airflow around the next. The closer they are together, the greater the skimming effect, leaving ‘dead-air’ zones between them where pollution and litter can build up
Types of urban air pollutants
Carbon monoxide
Nitrogen oxide
Particular matter
Sulphur dioxide
Urban air pollutants
- carbon monoxide
A colourless, tasteless, odourless and poisonous gas produced by incomplete combustion of fuel.
It is estimated that road transport is
responsible for almost 90 per cent of all
carbon monoxide emissions in the UK.
Carbon monoxide affects the transport
of oxygen around the body by the blood.
Breathing in low levels can result in
headaches, nausea and fatigue
Urban air pollutants
- nitrogen oxide
When exposed to sunlight, react with hydrocarbons to produce the components of petrochemical smog.
Road transport is estimated to be
responsible for about 50 per cent of total
emissions of nitrogen oxides
Nitrogen oxides can inflame the lining of
the lung and impacts are more pronounced
in people with asthma. They can also cause
accelerated weathering of buildings and acid rain.
Urban air pollutants
- particulate matter
Tiny bits of solids or liquids suspended in the air
Particles originate mainly from power
stations and vehicle exhausts. Other
particulate matter includes small bits of
metal and rubber from engine wear, dust,
ash, sea salt, pollens and soil particles.
Particles smaller than about 10 micrometers are referred to as PM10 and can settle in the airway and deep in the lungs, causing health problems
Urban air pollutants
- sulphur dioxide
A colourless gas with a sharp odour. It reacts easily with other substances to form harmful compounds, such as sulphuric acid, sulphurous acid and sulphate particles.
In the UK the major contributors are coal
and oil burning by industry, such as power
stations and refineries
Short-term exposure may cause coughing,
tightening of the chest and narrowing of the
airways. Sulphur dioxide can also produce
haze, acid rain, damage to lichens and plants and corrosion of buildings
Urban heat island
- air quality
Air quality is typically worse in urban areas than rural. Emissions of particles can occur naturally but they are largely caused by the combustion of fossil fuels. A combination of dust, soot and gases are produced from vehicles and industrial processes and this has had a negative impact on human health in many cities around the world.
Coping with the wind
- the Burj Khalifa, Dubai
At over 828 m high, the Burj Khalifa is the tallest building in the world. At such heights, a major concern for any structure is wind stress and, in particular, wind vortexes
pulling the building from side to side. The Burj Khalifa has to withstand gusts of over 240 kilometres per hour and a series of aerodynamics improvements had to be made to ensure the building could withstand these.
- softened edges of the building deflect the wind around the structure and prevent it from forming whirlpools or vortices,
- the entire tower was orientated relative to the prevailing wind direction
Los Angeles River channel management
A fail-safe design as devastating flash flooding of the LA River led the city authorities in the 1930s to convert it from natural and meandering to cement and controlled.
- it helped control flooding
- it has removed the
ecosystem services that a river typically provides.
- the entire system could be paralysed if one part of the structure sustains significant damage, such as from an earthquake.
Sustainable urban drainage systems (SUDS)
SUDS is a relatively new approach to managing rainfall
by using natural processes in the landscape to reduce and control flooding and provide amenity for the community
- Roofwater is collected in water butts for use in gardens swales. It then travels on to grass basins where it is stored before being
released into local ditches.
What are swales?
shallow, broad and vegetated grass channels designed to store and/or convey runoff and remove pollutants
Impacts of increasing waste generation
- The costs of collecting and treating waste are high.
- Environmentally, waste is a large source of methane, a powerful greenhouse gas. Waste also contributes to water, ground and air pollution.
- Untreated or uncollected waste can lead to health problems such as respiratory ailments, diarrhoea, cholera and dengue fever.
- Many city authorities are struggling to collect increasing quantities of urban waste. The 2012 World Bank report on waste found that 30–60 per cent of urban solid waste in lower-income countries is
uncollected. - Cities are running out of landfill space. The Borj Hammoud landfill site in Beirut, Lebanon, was planned to be shut down by 2019. This has been delayed because of a nearly 30 per cent reduction in daily waste production following mass protests and the COVID-19 lockdown
Methods of waste management and disposal
- landfilling
- thermal treatment (incineration)
- recycling
- trade
Methods of waste management and disposal
- landfilling
Burial is the placement of waste in man-made or natural excavations, such as pits or landfills. Landfill sites are a common final disposal site for waste from urban areas. In lower-income countries there may
simply be a hole in the ground where open dumping occurs.
In higher-income countries, there are much stricter regulations and the types of material that can be sent to landfill are often defined by law. In the UK, most landfill sites now control and collect the gas that is released by the decomposing waste, often using it to generate electricity through turbines.
The environmental problems caused by landfills can be numerous. The greenhouse gas methane is produced by rotting organic matter and other chemicals like bleach
and ammonia can produce toxic gases that negatively impact the quality of air in the vicinity. Dust and other forms of non-chemical contaminants can also make
their way into the atmosphere. Landfills can also affect groundwater and river quality because toxic chemicals can leach out and contaminate the water.
Methods of waste management and disposal
- incineration
Incineration of waste (with energy recovery) can reduce the volume of disposed waste by up to 90 per cent. General waste can be safely burned at high temperatures and under carefully controlled conditions
to produce electricity and heat.
An increasing number of cities are processing their waste in this way. Incineration without energy recovery is still common but it is not a preferred option due to costs and pollution.
The open-burning of waste, which is common in poorer countries, is particularly discouraged due to severe air pollution associated with low temperature combustion.
Methods of waste management and disposal
- trade
Waste may be moved between and within countries. The global waste trade is the international trade of waste between countries for further treatment,
disposal, or recycling. Toxic or hazardous wastes are often exported from high to low-income countries. However, these LICs often do not have safe recycling processes or facilities and hazardous wastes are not properly disposed of or treated, leading to
contamination of the surrounding
environment.
International laws such as the Basel Convention have been introduced to prevent transboundary movement of hazardous waste but evidence suggests it still happens.
Methods of waste management and disposal
- recycling and recovery
Resource recovery is the selective extraction of disposed materials for a specific next use, such as recycling, composting or energy generation.
In recent years, the global market for recyclables has increased significantly. The world market for post-consumer scrap metal is estimated at 400 million tonnes annually and around 175 million tonnes annually for paper and cardboard (UN-Habitat 2009).
This represents a global value of at least $30 billion per year. Recycling, particularly in low- and middle-income countries,
occurs through an active, although usually informal, sector. Estimates suggest that about 1 per cent of the
urban population – at least 15 million people – survive by salvaging recyclables from waste.
However, there are some negative environmental issues. Notably, energy may be required for the operation of material recovery from waste and this leads to greenhouse gas emissions. Informal recycling by waste pickers will have little greenhouse gas emissions, except for
processing the materials for sale or reuse, which can be relatively high if improperly burned (for example, metal recovery from e-waste).
Advantages of landfilling
- Facilities are properly sited with necessary controls
- Different types of waste accepted and ordered
Disadvantages of landfilling
- Unsightly
- Often opposed by neighbouring residents
- Potential leaching of chemicals threatens groundwater supply
- Decaying matter produces methane, a strong greenhouse gas which is also explosive
- Landfill takes up a lot of space
- High transportation costs
Advantages of incineration
- Can reduce volume of waste needing disposal by 90 per cent
- Can inactivate disease agents
- Can reduce toxicity of waste
- Can be used to produce energy
- Incinerator bottom ash can be recycled as a secondary aggregate
Disadvantages of incineration
- Expensive
- Not all waste is combustible
- Poses challenges of air pollution and incinerator bottom ash disposal
- Capacity limitations
- Unpopular with local residents
Managing air pollution
Measures include:
- houses are energy efficient
- urban development is well served by public transport routes
- street design is appealing and safe for pedestrians and cyclists
- waste is well managed.
The environmental company AECOM has calculated that London’s 8.3 million trees provide £95 million worth of air filtration every year in terms of health costs avoided. Together, these strategies serve as a catalyst for local economic development and the promotion of healthy urban lifestyles.
Causes of water pollution in urban areas
- Surface run-off from streets carrying oil, heavy metals and other contaminants from motor vehicles.
- Industrial waste.
- Untreated or poorly treated sewage which is low in dissolved oxygen and high in pollutants such as nitrates, phosphorus and bacteria. Treated sewage can still be high in nitrates.
- Rubbish dumps, toxic waste, chemical and fuel storage, which can all leak pollutants.
- Intentional dumping of hazardous substances.
- Air pollution can lead to acid rain, nitrate deposition and ammonium deposition, which can alter the water chemistry of an area.
Water pollution
The contamination of water sources including rivers, lakes, oceans, aquifers and
groundwater. It occurs when pollutants are directly or indirectly discharged into water without adequate treatment to remove harmful compounds.
Consequences of water pollution
- Over 1.2 billion people lack access to clean water and waterborne infections account for 80 per cent of all infectious diseases
- Heavy metals from industrial processes can slow development, result in birth defects and may be carcinogenic.
- Industrial waste often contains toxic compounds that damage the health of aquatic animals and those who eat them. They can cause immune suppression, reproductive failure or poisoning.
- Microbial pollutants from sewage often result in infectious diseases that infect aquatic life and terrestrial life through drinking water like cholera and
typhoid fever, which are a major cause of infant mortality in low-income countries. - Organic matter and nutrients can cause an increase in aerobic algae and deplete oxygen from the water. This can lead to the suffocation of fish and other aquatic organisms.
- Suspended particles in freshwater reduce the quality of drinking water for humans and the aquatic environment for marine life. They can also reduce the amount of sunlight penetrating the water, disrupting the growth of photosynthetic plants and micro-organisms.
Water pollution strategies
- Low-impact development (LID) is a stormwater management approach that can help to reduce stormwater run-off. This is done primarily through the use of vegetation and permeable surfaces to allow
infiltration of water into the ground. Permeable streets and pavements, ‘green’ roofs, rain gardens and more urban parks allow water to infiltrate into soils rather
than flow directly into sewers. - Legislation, regulation and enforcement, anti-pollution laws and agreements in
operation worldwide. However, these laws need to be enforced. Some cities have adopted incentive-based approaches, charging polluters per unit. Charges start
low but are increased if pollution continues, creating an incentive to reduce discharges and purchase wastewater treatment technologies. - Education and awareness: The more people know about the causes and effects of pollution, the more likely they will be to avoid adding to the problem.
- Improvements in sewage and wastewater processing.
Appropriate technology
What is land remediation
The removal of pollution or
contaminants from the ground, which enables areas of derelict former industrial land to be brought back into commercial use.
- In preparation for the 2012 London Olympic Games, a 350-hectare area of East London was ‘cleaned up’ and has now become the largest new urban park
in Europe, with 100 hectares of open land and 45 hectares of new habitat. A total of
235,000 m3 of contaminated groundwater was successfully treated.
Strategies to deal with derelict urban sites
Regeneration schemes.
UK government-led schemes such as Urban Development Corporations, City Challenge and City Deals
What is an ecological footprint?
A measure of the environmental
impact of communities or individuals.
A sustainable city
A city which provides employment, a
high standard of living, a clean, healthy environment and fair governance for all its residents.
Strategies for developing more sustainable cities
- Investment in infrastructure such as roads, water, sewers and electricity and services such as schools and healthcare
- Green investment in low-income countries can help poorer cities ‘leapfrog’ from high-carbon energy use to a zero-carbon development path. This could provide
employment for the ‘youth bulge’ within these cities. - Investment in the production and use of renewable energy sources, as well as the renovation of infrastructure, retrofitting of buildings and improved electricity and water efficiency
- Investment in the reduction of waste production and improvement of waste collection and recycling
- Provision of more ‘green’ areas
- Investment in more sustainable and affordable housing
- Adoption of a local currency
- Active participation of different city stakeholders including government, residents and local businesses in urban planning.
- Disaster risk reduction. Schemes such as tidal barrages and early warning systems can help mitigate the impacts of floods, storm surges and other hazards
Features of sustainable cities
- Resources and services in the city are accessible to all
- Public transport is seen as a viable alternative to cars
- Public transport is safe and reliable
- Walking and cycling are safe
- Areas of open space are safe, accessible and enjoyable
- Wherever possible, renewable
resources are used instead of non-renewable resources - Cultural and social amenities
are accessible to all - Waste is seen as a resource and
is recycled wherever possible - New homes are energy efficient
- Access to affordable housing
- Community links are strong and communities work together to deal with issues such as crime and security
Challenges to sustainable cities
- The main obstacle to cities becoming more sustainable tends to be financial. In the context of rapidly growing urban populations and limited budgets, city authorities often choose short-term ‘cheaper’ solutions over longterm planning. - Likewise, in cities where large numbers of
people still lack access to water and electricity, providing basic infrastructure tends to take priority over investment
in environmental projects and sustainable development. - Further challenges to developing sustainable cities include poor infrastructure, weak institutions and lack of
enforcement of planning regulations
Pillars of reaching urban sustainability
- Social development
- Economic development
- Environmental management
- Urban governance
Urban resilience
The capacity of individuals, communities, institutions, businesses and systems within
a city to survive, adapt and grow, no matter what kinds of chronic stresses and acute shocks they experience.
Why is dereliction a urban environment issue?
(brownfield sites)
- contaminated with previous industrial use posing a threat to human health and the environment
- no physical access necessary for residential development
- neighbouring land may still be used to industrial purposes making it unsuitable for homes
How is dereliction caused?
- inevitable ageing and decay of buildings due to increasing maintenance costs
- movement of urban activities to better and more profitable locations
- changes in urban economy brought about by deindustrialisation
How are brownfield sites a valuable urban resource?
- starts to address pressing need for more homes
- improves urban environment
- reduces urban sprawl protecting green belt
- reduces demand on car use
Brownfield regeneration of London Docklands necessity
Loss of the docks due to containerisation
During the 1950s and 60s poor tower blocks were built and are now commonly used as state housing with high levels of crime and deprivation
Boats became too large to fit and therefore couldn’t move down the Thames. As a result the docks moved down stream where the boats could access
Between 1970 and 1980 there was 30,000 jobs lost, with, in 1981 50% of the Docklands were derelict (1000 hectares)
Unemployment levels were at 21%, with males at 24%, twice the national average.
There were inadequate transport links by both road and rail meaning that people didn’t invest in the area as it couldn’t be accessed easily.
Advantages of London Docklands regeneration
The investment led to developments of very large scale and expensive developments such as Canary Wharf, the O2 arena
Improvements to the transport system like the eastward extension of the Jubilee line with 144 km of new and improved roads.
The land became available through the selling off of 431 hectares of land and reclaiming derelict land - 762 hectares of derelict land was reclaimed so improvement of building could be made
24,046 new homes built, an extra 2,700 businesses are now trading, 85,000 people are now working and services like education and health centres have all been improved
Disadvantages of London Docklands regeneration
Very expensive, £1.86 billion public money was spent along with £7.7 billion of private money.
Many locals were unable to afford the high costs of the new expensive houses / flats (still a lack of low-cost housing in the area
Despite an increase in jobs with new businesses coming in, most required skills that the old dockers did not have
Example of a sustainable city
Freiburg, Germany
