Changing urban systems

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Variation in Pattern and global growth rate of urbanization

Only about 30% of the world’s population lived in urban areas in 1950
Today, 54 per cent of the world’s population lives in urban areas, a proportion that is expected to increase to 66 per cent by 2050.
refer: http://www.un.org/en/development/desa/news/population/world-urbanization-prospects-2014.html

Urban population grows as a result of

• Natural increase
• Net Migration: Internal rural-to-urban migration, International migration

Natural increase is the main cause of urban growth in LEDCs

About 60% of the urban population growth in developing countries is due to natural increase The remaining 40% is attributable to net rural-urban migration and reclassification of rural areas into urban sites. As fertility levels decline and economic development increases, migration assumes a greater role in determining the pace of urban growth.

In Africa, for example, natural increase accounts for 75% of urban growth, compared to 51% in Asia. In China, which has experienced rapid economic growth, only 28% of the urban growth results from natural increase (UN data).

According to UN report, between 2007 and 2030, the world’s population is expected to increase by 1.8 billion. Almost all population growth during this period will be in urban areas. The rural population will actually decrease by about 20 million.
Process will advance in developed nations, where 76% lived in urban areas in 2000, and will increase to 83% by 2030.Although the number of large cities is increasing, much of the urban population still lives in small cities
Urbanization trend in developing countries. Although developing countries are less urbanized, the rate of urbanization is much higher. The number of people added each year continues to rise because the rates are applied to an ever increasing population base. Despite their high levels of urbanization, the combined numbers of urban population in Europe, Latin America, Caribbean, North America (1.2 billion) is smaller than the number in Asia alone (1.4 billion). By 2030, Asia alone will account for 54% of the urban population of the world.
Throughout Southeast Asia and Sub-Saharan Africa, millions of people move back and forth between urban and rural areas to take advantage of income-earning opportunities—a phenomenon known as circular migration. Temporary migrants can cause large swings in population size. In some cities of China, for instance, temporary migrants are estimated to account for one-fifth to one-third of the total urban population

Centripetal and centrifugal movements within a city: Forces of urbanization

Cities are the products of many forces. They are engines of economic development, centers of cultural innovation, social transformation and political change. Cities vary in employment opportunities to pattern of land use and functions, ethnic composition and socio-cultural setup.

Urban Pull-Push Factor

Sub-urbanization vs Counter urbanization

The outward expansion of towns and cities largely due to the improvements in transport system and out of the city expansion of affordable housing is called suburbanization. 

The first UK Census, taken in 1801, recorded London’s population at just over 1 million people. The capital grew at a rate of around 20 per cent per decade reaching 6.5 million in 1901. The size of London’s population afterwards recorded a period of decline, initially resulting from the impact of the Second World War. By 1988 the population of London was 6.7 million, a decrease of around 22 per cent since 1939. Population in London again began to rise from the 1991 and in 2015; it reached 8.6million, the highest since its 1939 peak. According to the city authority, the boroughs with the largest percentage increase in numbers between 1939 and 2015 were all located in outer London, unsurprising given that overall the population of outer London increased by 24 per cent over this time.

Peripheral- suburban location could be a better choice for the following urban land-uses: Large assembling plants-car production, Floriculture, Industrial park, Out-of the town shopping malls like Blue water in Kent near London, airports, new modern and affordable residential uses.

Counter urbanization: This process involves movement of people away from the larger cities to smaller town and villages due to high land prices, congestion, pollution, high crime rates, lack of community and declining services in the urban areas.

Brownfield site

Abandoned, derelict, unused sites or contaminated industrial buildings and industrial waste disposal sites that have potential for redevelopment are considered as brownfield sites.

Example of re-deveopment of Brownfield site
Massachusetts City of New Bedford (2014)- Brownfield Solar project
Vast abandoned plot of land that harbored hazardous waste affecting the environment and population in New Bedford, an economically depressed coastal city in southeastern Massachusetts is now a shining example of how renewable energy can transform the environment and local economies.

Gentrification

Involves reinvestment of capital (money) in inner city areas marked by renovation and refurbishment old residential areas that lead to commercial redevelopment and residential rehabilitation of the old rundown areas. The term “gentrification” is attributed to the sociologist Ruth Glass who used it to describe the transformation that took place in London in the early 1960’s (refer). Gentrification has both pro and cons. Gentrification can be viewed both as a process of renewal or revitalization as it may attract capital investment as well as a process of displacement of the lower income group who used to be the residents of the area. This is known as urban filtering.

Examples

• New York- Greenwich village, Manhattan
• London- Fulham, Dockland

Major Problem of gentrification
Urban Filtering– may lead to displacement of poor people as the land value rises and young upwardly mobile people take their place.

Urban Sprawl

Unban sprawl denotes the physical expansion of city area outside the planned built up area as a consequence of unplanned urban growth.

• Pollution is a major cost of urban sprawl. Most sprawling towns are built for cars and force people to drive more frequently and for longer periods of time. Increased use of cars leads to more air and noise pollution as well traffic congestion. Sprawl can damage natural ecosystem through destruction of natural habitats and wetland. Loss of farmland and fringe forest increase the risk of flood. Cities are bound to grow, but they need planning to cope up with the problem of urban sprawl.

Urban Land use

Location of Residential areas

Residential choices are determined mainly by

• The ability to pay for housing
• The age of the population and family circumstances, stages in family life cycle (wealth, age and family status)
• History (age, quality of buildings, modern energy efficient and cost saving building structures in the suburbs)
• Topographical characteristics (geology, drainage, and relief may mean that higher class buildings are built in less hazardous locations). For example the slums of Dharavi in Mumbai particularly become vulnerable to floods during the wet season as the Mithi river overflows in every rainy season.
• Religious and ethnic influences
• Government policy and redevelopment efforts eg. construction of the Tianjin eco-city in China.
• Proximity to services, such as schools, hospitals, shops, accessibility and transport links, job location.
• Proximity to congested roads; inner-city slums, derelict land, waste sites and sewages can have negative effect on house prices.
• Perception of better surroundings for example, leafy spacious suburbs.
• Urban processes like: Suburbanization, gentrification, sprawl, counter urbanization etc.

Residential segregation: is the physical separation of population on the basis of culture, ethnicity, income and other criteria. Common examples of residential segregation are the existence of ghettos and China town in certain specific parts of the large cities.

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Murdie’s composite ecological model of urban residential structure

To understand the aspects of cities residential structure Murdie (1969) identified two main dimensions of urban space.
1. Physical space -physical characteristics of land like presence or absence of river or coastlines, slope of the land, micro climate etc.
2. Social space– is differentiated into three aspects like economic status, cultural or ethnic status and family status.

• Social spaces have been superimposed on physical space to explain the distribution of urban residential structure.
• The model explains that cities are complex entities.
• People’s choice of home is usually constrained by their income. At each stage in family life-cycle, people have different housing needs.
• For example, a young person may seek a rented flat in the inner ring of the city while in the later stage of life the same person may relocate to a garden house in the suburbs.
• Thus different parts of the city may reflect different stage of family life cycle.
• On the other hand, specific ethnic minorities tend to cluster in specific parts of the city, creating a pattern which is neither sectoral nor concentric.

Growth of urban transport infrastructure over time

Managing traffic problems in cities

Activities

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Solid Waste Management in urban areas

Solid waste management deals with generation, prevention, characterization, monitoring, treatment, handling, reuse and residual disposition of solid wastes.
Solid waste management is a challenge for the city authorities particularly in the developing countries mainly due to the increasing generation of waste. This huge quantity of Solid wastes imposes stress on the municipal budget as a result of the high costs associated to its management. Increasing population levels, booming economy, rapid urbanization and the rise in community living standards have greatly accelerated the municipal solid waste generation rate in developing countries (Minghua et al., 2009). It has been reported that collection, transfer and transport practices are affected by improper bin collection systems, poor route planning, lack of information about collection schedule, insufficient infrastructure, poor roads and number of vehicles for waste collection and to the pricing for disposal.

Statistics:
According to the World Bank report, 2015 (What a waste: A global review of solid waste management) the amount of municipal solid waste (MSW), one of the most important by-products of an urban lifestyle, is growing even faster than the rate of urbanization. Ten years ago there were 2.9 billion urban residents who generated about 0.64 kg of MSW per person per day (0.68 billion tonnes per year). This report estimates that today these amounts have increased to about 3 billion residents generating 1.2 kg per person per day (1.3 billion tonnes per year). By 2025 this will likely increase to 4.3 billion urban residents generating about 1.42 kg/capita/day of municipal solid waste (2.2 billion tonnes per year).

What is meant by a Sustainable city?

Sustainable urban development aims to meet the needs of the present generation without compromising the needs of the future generations.

How to achieve sustainability?

• Ensure environmental quality- preservation of urban areas and green field- less pollution, more recycling (example of Hamburg)
• Greater access to employment and adequate livelihood
• Safe, secure and affordable housing
• Better provision of water, sanitation, better and efficient transport, healthcare, education (example of Curitiba)
• Use of renewable resources and systems like rain water harvesting, solar energy etc (example of Tianjin Eco city)
• Introduction of new sustainable concept such as urban agriculture (roof top farming in Hamburg and Singapore )
• Stress minimization and creation of urban community- the sense of belonging together and sharing the same resources (For example the city of Copenhagen -Denmark ranks at the top in the OECD better life index, 2015)
• Reduction of urban ecological footprint by following circular metabolism system to minimize new inputs and maximize recycling(refer Roger‘s model)

Ecological footprint is the theoretical measurement of the total area of ecologically productive land and water (cropland, pasture, forest, marsh, river, sea, etc.) that a population requires in order to produce the resources (the energy and materials consumed) it consumes and to absorb its wastes, under prevailing technology.

Read Article: why Curitiba in Brazil is a sustainable city

Case Study: Tianjin Eco-city, China

Tianjin Eco City is an ambitious joint project between the People’s Republic of China and the State of Singapore, located 150 kilometers south east of Beijing, within the coastal city of Tianjin. China’s rapid urbanization calls for low carbon footprint producing sustainable cities. Tianjin Eco city aims at being the world’s biggest sustainable city and is intended to showcase both countries’ state of art in terms of sustainable cities. It is designed to be practical, replicable and scalable.
This eco city will feature several innovations and sustainable attributes, starting from the land area in which it is being constructed: an old industrial waste site: this means that the city provides an example of brownfield site redevelopment.
Wet lands and the arable land nearby can be used to provide food, reducing food miles and carbon footprint.
The backbone of transportation within the city is the main line: a central axis, which connects all the districts and area with a light tramway. It also has dedicated bicycle lanes and walkways: this should reduce car usage within the city to less than 10%.
Other innovations include:

• Wetlands should help to attract birds and animals creating an unique urban eco-system.
• Wind turbines and solar panels already in place provide 20% of the energy used in the city
• Organic waste is used for power generation (bio gas).
• Desalinated water from the sea,
• Smart buildings have been built with automated blinds and efficient temperature control using solar and geo-thermal power. Power and water consumption is self sustained in many of the cases and is produced within the residential estates. Rainwater harvesting and gray water management are the essential components of the system.

Read Article: Sustainable urban living in Tianjin