urban growth

Urban Growth and Megacities

• Every second, the urban population grows by __ people.• In Africa and Asia, the urban population is expected to _____ between

2000 and 2030.• The poor pay more. A slum dweller in Nairobi –Kenya- pays __ to 7

times more for a litre of water than an average North American citizen.• 828 million people live in slum conditions, lacking basic services such as

drinking water and sanitation. This number is increasing by __ million each year to hit a total of 889 million by 2020.

• 62 % of the sub-Saharan Africa urban population and __ % of the urban population of south-central Asia lives in slums.

• One of ____ urban dwellers does not have access to improved sanitation facilities.

• ___% of the urban dwellers in the developing world does not have access to piped water at home.

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MegacitiesKinshasaLagosLahoreLimaLondonLos AngelesManilaMexicoMoscowMumbaiNew YorkOsakaParisRhine-Ruhr North

Rio de JaneiroSantiago de ChileSao PauloSeoulShanghaiTehranTianjinTokyoWuhan

BangaloreBangkokBeijing BogotaBuenos AiresCairoCalculltaChennaiChicagoDelhiDhakaHong KongHyderabadIstanbulJakartaKarachi

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Two areas of focus:

Urban Trends• Global urbanisation• Wealth of cities• Slum dwellers

Urban Divide• Economic Divide• Spatial Divide• Opportunity Divide• Social Divide

Convergent Urban Growth Patterns

• Much of worlds demographic growth over the next 30 years will be concentrated in urban areas.

• Urban population expected to grow at an annual average rate of 1.5 between 2025-2030.

• By 2050 urban dwellers likely to account for 86% of population in developed countries, 67% in developing countries.

Nairobi, Kenya Sao Paulo, Brazil

Chongqing, China

City-regions and urban corridors

Hong Kong-Shenzen-Guangzhou mega-region

Hong Kong-Shenzen-Guangzhou mega-region

Urban corridors: Delhi to Mumbai

Klang Valley conurbation

Beijing to Tokyo via Pyongyang and Seoul

City regions: São Paulo

Suburbanization

• Triggers for suburbanisation:– Regulation crisis, poor

planning control, improved commuting technologies, traffic congestion, lack of public amenities.

• Urban Sprawl– Horizontal spreading– Dispersed urbanization

Los Angeles

Urban Sprawl• Four dimensions:

– Population widely scattered in low-density developments

– Residential and commercial areas that are spatially separate

– Network of reads characterized by overstretched blocks and poor access

– Thriving activity hubs

• Implications: – Increased cost of public infrastructure– Inefficiency of transportation– High energy consumption– Loss of farmlands– Degradation of environmental resources.

San José – Costa Rica

Wealth of Cities• The transition from low-income to

middle-income country status is almost always accompanied by a transition from a rural to an urban economy.

• In some countries, such as Korea, Hungary and Belgium, it takes only a single city to contribute the more substantial share of national wealth

• Cities have become major hubs of economic activity, both within individual countries and as contributors to the global economy.

Land, Population and GDP of Selected Cities as a Share of the Country Total

Cities and Global GDP

Urbanization and Poverty

Poverty Ratio relative to National Poverty line by degree of urbanization1998-2007

Slum Dwellers• Growth in urban populations in

developing countries is often, strongly associated with urban poverty, many assume that urban growth in the poorest countries would be synonymous with slum growth.

• A number of countries have, to a significant extent, managed to curb the further expansion of slums and to improve the living conditions prevailing there.

Urban Population Living in Slums 1990-2010

Change in Slum proportions in Africa 1990-2000

Change in slum proportions 2005-2010

Change in slum proportions 1990-2000

Change in slum proportions 2005-2010

Slum proportions 1990

Slum proportions 2010

Cities with slums or ‘Slum cities’

• No universal prescription for slum improvement..

• Rapid urban growth without a proportional increase in basic urban infrastructure can only widen the urban divide, as it leads to further slum expansion.

Kibera, Kenya

Korail slum in the Dhaka, Bangladesh

‘Reclassified villages’ • The prevalence of slum households

varies dramatically across the cities of the developing world.

• Slums in the cities of man sub-Saharan Africa have become notorious for the extent and intensity of their deprivations

• macro-level programmes must be associated with micro-level schemes, including micro-credit, self help, education and employment. Housing services may be available, but families will use them only if they are affordable.

South Africa

The Urban Divide• Cities are divided by invisible

borders. • Fragmentation of society.• In diverse urban landscapes, sharp

contrasts abound across neighbouring streets, buildings, public spaces, gardens, markets or offices.

• In places, these urban components merge and blend into one another; in others, they are separated by walls, doors, symbolic features or geographic factors such as topography, rivers or lakes.

Mumbai: A city divided

Slum targets• Over the past 10 years, the

proportion of the urban population living in slums in the developing world has declined from 39 per cent in the year 2000 to an estimated 32 per cent in 2010

• UN- HABITAT estimates that in developing countries, 22 million people have been lifted out of slum conditions every year over that decade, through slum upgrading or prevention.

Social and cultural divides

• A divided city is also one that fails to accommodate poorer residents, regardless of the cultural richness they might lend to the city as a whole.– Hip-hop groups in Africa

and Americas – Samba schools in Sao

Paulo – Tribus urbanus in Quito

Rio de Janeiro

Mexico City

The Spatial Divide• Socio-economic clustering.• The poor, unable to afford land or

shelter in the limited areas of the city that are fully serviced, have access only to the least desirable and most densely developed spaces

• When slum areas are physically isolated and disconnected from the main urban fabric, residents become cut off from the city.

Employment Restrictions• Mexico, 20% of workers spend

more than three hours commuting to and from work every day.

• Rio de Janeiro, some workers sleep on beaches during the week, saving commuting time as well as transportation costs that consume at least 20 per cent of their wages.

• Dhaka and Mumbai, slum-dwelling workers are often found sleeping on the pavement, travelling home only for weekends and holidays.

Social Exclusion and marginalization

• Mumbai: 50 per cent of slums have no access to primary schools, a percentage that is even higher in the informal areas on the outskirts of the city.

• Chittagong, the number of primary schools for wealthy households is on the increase, while many children in distant slums have almost no access to education.

Crime• Long distance commuting

in dark, underserved areas increases the risk of crime.

• São Paulo, for instance, the number of homicides in some isolated neighbourhoods has been reported to be more than five times as high as in the safest districts.

Social Divide• Hunger and malnutrition

caused by inequitable distribution of largely available food resources.

• Disease adds to economic pressures on the poor, and so do the costs of children’s schooling – although education is known for improving general health and reducing poverty.

Poverty and hunger: The nutritional divide

• Many country reports and publications from international agencies indeed show higher rates of malnutrition in rural than in urban areas.

• Hunger can be found in urban areas, too.

• In urban areas, the higher purchasing power of the rich contributes to inflation of food and health care costs, making these unaffordable for the poor. oo.

Environmental Diseases• Poor sanitation, combined

with unsafe water supply and lack of hygiene, claims the lives of many slum dwellers every year.

• Sanitation is the primary factor that protects water, air, soil and food from contamination, and thereby reduces the risk of disease.

Overcrowding

Nairobi, Kenya

• High-density accommodation in slums and squatter settlements, or poor-quality housing in general, intensifies the risk of disease transmission.

• In an overcrowded slum area, pit latrines expose more children to diarrhoeal diseases compared with a non-overcrowded rural area.

Waste Management

• Properly managed solid waste can clog storm drains, cause flooding, result in garbage heaps and provide breeding and feeding grounds for mosquitoes, flies and rodents.

• The combination of environmental hazards surrounding solid waste can lead to injuries and easy transmission of bacterial diseases and parasitic infections.

Indoor Air Pollution• It is estimated that indoor air

pollution is responsible for some three million deaths every year.

• Women who cook in enclosed quarters using biomass fuels and coal are at risk of chronic bronchitis and acute respiratory infections, as are their children, who are often exposed to significant indoor air pollution alongside their mothers on a daily basis.

• Indoor air pollution is a “quiet” and overlooked killer.

Modern environment of disease• Modern environmental health

hazards have become major contributors to the environmental diseases affecting the African continent.

• The major such hazards include water pollution from environmental degradation and industrial operations, urban air pollution from motor vehicles, radiation hazards, climate change, and emerging or re-emerging infectious diseases.

• How is urban growth changing? • What are the characteristics of modern

day cities? • What are the human side effects of urban

growth? • What are the environmental impacts of

urban growth?

Things to consider: