Untitled

Page 1

HUMANITIES REVISION – Chapter 6

6.1 How do urban environments develop?

Glossary words:

· Conurbation: An urban area formed when two or more towns

or cities spread into ad merge with each other.

· Developing nation: A country whose economy is not well

developed, although it may be showing growth in key areas such as agriculture,

industries, tourism or telecommunications.

· Human-environment systems thinking: Using

thinking skills such as analysis and evaluation to understand the interaction

of the human and biophysical or natural parts of the Earth’s environment.

· Industrial Revolution: The period from the late 1700s

into the 1800s that saw the widespread into of mechanical processes in

industry.

· Infrastructure: The structural framework, systems of the

urban environment that provide services to a country, city or area.

· Urban environment: The human-made or built structures and

spaces in which people live, work and recreate on a day-to-day basis.

· Megacities: Commonly refers to urban settlements of

10 million inhabitants or more. Currently, about 280 million people live in at

least 25 megacities across the world. This population figure is expected to

rise to 3 billion by 2025.

Impacts of the growth of urban environments:

·

Rapid growth in city

populations has led to problems such as urban sprawl, traffic congestion and

air and water pollution, with significant impacts on the natural environment.

·

Social problems such as

unemployment, inadequate housing, infrastructure,

water, sewerage and electricity supplies; pollution; and the spread of slums

and crime are further problems.

·

In addition, with prospects of climate change through global warming, many of the world’s

coastal cities are under threat of rising sea levels. The application of human–environment systems thinking will be the key to

evaluating and solving these economic and social issues.

Development

of cities:

· The earliest cities emerged five to

six thousand years ago in Iraq, Egypt,

India and China. These cities became centres for merchants, craftspeople, traders and government officials and were

dependent on agriculture and domesticated animals from surrounding rural areas.

· With the Industrial

Revolution, people started moving from rural areas to cities or

migrated to other countries to take advantage of jobs in factories and to

improve their standard of living.

6.2 How do cities change the environment?

Glossary words:

· Biophysical environment: All elements or features of the natural or physical and the human or

urban environment including the interaction of these elements.

·

Water rights: Refer to the right through ownership to use

water from a water source such as a river, stream, or pond.

All forms of urban environments are

interconnected with the biophysical environment.

· The ‘bio’ elements are all forms of

plant and animal life including people and all their activity and industry.

· The ‘physical’ elements are the

atmosphere, hydrosphere and lithosphere or Earth’s surface.

What

are the limits and changes?

The biophysical elements impose limits on the development and

sustainability of all forms of urban

environment. On the other hand, the urban environment imposes significant

human-induced change on the biophysical world. The understanding of this

interconnection is particularly important in a world of increasing human

numbers and pressure for resources on the biophysical environment.

How

does the urban environment affect the atmosphere?

Where sources of potentially

dangerous gaseous emissions are high, such as from buildings, transport systems and industry, atmospheric pollution

can be a problem em. Examples such as hazy conditions, photochemical smogs, light and

noise pollution, and acid rain are significant problems that need to be

addressed. Hence, the development of clean air policies controlling emissions

of gases into the atmosphere is important. Some

examples are the introduction of lead-free petrol, banning the burning of

household waste and emission control systems on factory furnaces.

Cities and industries have huge

demands for energy, and the by-product of this is heat. What is known as the ‘heat island effect’, whereby urban

environment structures such as buildings and roads absorb heat from the sun,

raises the temperature of the city environment compared to rural surrounds.

The production of

greenhouse gases such as carbon dioxide and methane by urban environments is

recognised as probably the greatest contemporary climate issue. Global warming

leading to climate change is the result of emissions of these gases into the

atmosphere, particularly in large urban centres.

How

does the urban environment affect the hydrosphere?

Water

pollution caused by urban environments is also important as polluted waters are

a risk to all life forms in any environment. Considerations for biomes and

ecosystems of rivers, wetlands and swamps in terms of protecting habitats and

maintaining biodiversity is also a major management aim.

How

does the urban environment affect the lithosphere?

· These urban structures can cover areas of up to 100 square kilometres,

and this can lead to problems of urban sprawl, such as extended commuting times, congestion, air pollution and slums.

Other problems include the disposal of the enormous amount of garbage and waste

that cities produce, and the general impacts on agriculture, plants and animal

life in adjacent habitats and ecosystems.

· Urban

environment surfaces such as

car parks generate two to six times more run-off than a natural surface. Rain

that falls on car parks can be contaminated with petroleum residues,

fertilisers, pesticides and other pollutants.

6.4 What are the

challenges for fast-growing cities?

Glossary words:

· Alpha world city: A city generally considered to be an

important node in the global economic system.

· GDP: (gross domestic product) market value of all

goods and services produced within a country in a given period.

· Slum: Rundown area of a city with substandard

housing.

Mumbai

is the most populous city in India, and the fourth most populous city in the

world, with a total metropolitan area population of approximately 20.5 million.

In 2009, Mumbai was named an alpha world city.

Although the richest city in India, with the highest GDP of any city in south, west or central

Asia, it also has much substandard housing and many people living in squalor.

The

growth of Mumbai:

· The large numbers of people and

rapid population growth have contributed to serious social, economic and environmental

problems for Mumbai. Mumbai’s business opportunities, as well as its potential

to offer a higher standard of living, attracted migrants from all over India

seeking employment and a better way of life. In turn, this made the city a

melting pot of many communities and cultures.

· Despite government

attempts to discourage the influx of people, the city’s population grew at an

annual rate of more than 4 per cent per year.

· Many newcomers end

up in abject poverty, often living in slums or sleeping in the streets. An

estimated 42 per cent of the city’s inhabitants live in slum conditions. Some

areas of Mumbai city have population densities of around 46 000 per square

kilometre — among the highest in the world.

Challenges:

·

Mumbai suffers from the same major urbanisation problems seen

in many fast-growing cities in developing countries: widespread poverty and

unemployment, urban sprawl, traffic congestion, inadequate sanitation, poor

public health, poor civic and educational standards, and pollution.

· Automobile

exhausts and industrial emissions, for example, contribute to serious air

pollution, which is reflected in a high incidence of chronic respiratory

problems.

Dharavi’s recycling entrepreneurs:

· Dharavi sprawls over 222 hectares

of land in the centre of Mumbai. Hidden amid the labyrinth of ramshackle huts

and squalid open sewers are an estimated 15

000 single-room factories, employing around a quarter of a million people and

turning over a staggering US$1 billion each year through recycling. Jewellery

and pottery are also predominant trades.

· In developed countries, communities

recycle because there is the understanding that it contributes to sustaining

the planet’s resources. However, for some of the poorest people in the

developing world, recycling often isn’t a choice, but a necessity of life.

· In India, almost 300 000 people

make their living by recycling waste. These people are known as ‘rag pickers’ and are made up of India’s

poorest and most marginalised groups. The rag

pickers wade through piles of unwanted goods to salvage easily recyclable

materials such as glass, metal and plastic, which are then sold to scrap

dealers who process the waste and sell it on either to be recycled or to be

used directly by the industry.

· Due to the lack of formal systems

of waste collection, it falls to Mumbai’s rag

pickers to provide this basic service for fellow citizens. Without them,

solid waste and domestic garbage would not be collected or recycled, let alone

sorted.

· Recycling is still very much the

focus of many developing countries, who continuously strive to improve their

recycling endeavours. Despite many of the social and ethical controversies

surrounding the recycling industry in India, Dharavi is seen as the ‘ecological

heart of Mumbai’, recycling up to 85 per cent of all waste material produced by

the city, an excellent example of human–environment systems thinking in action.

· In Dharavi, there

is only one toilet for every 1440 people. This results in floods of human

excrement during the monsoon season. Much of the water becomes contaminated

because of this, and death rates tend to be 50 per cent higher in Mumbai’s

slums than in upper- and middle-class areas.

· There are currently plans to

demolish and redevelop Dharavi, a project that not all residents of the slum

are in support of, as Mumbai is working on a facelift in order to become a

world city. This redevelopment would transform the slum into a series of

high-rise housing facilities, and each of Dharavi’s 57 000 registered families

would get 21 square metres of living space apiece.

· However, many Dharavi residents are

unhappy about this plan, as they are content with their current lifestyle. Most

residents of the slum do not mind squatting near Mahim Creek, and prefer not to

have their own flush toilets. Most are working and making a living, and many

have lived their entire lives in Dharavi and do not want to trade their culture

for the redeveloped life.

6.5 Has Melbourne sprawled

too far?

Glossary words:

· Urban Infilling: The divisions of larger house sites into

multiple sites for new homes.

· Urban Renewal: Redevelopment of old urban areas including

the modernisation of household interiors.

· Urban Sprawl: The spreading of urban developments (as

houses and shopping centres) into areas on the city boundary.

Across the

world cities are expanding at a rapid rate, bringing unprecedented change to

the built and natural environments. To accommodate growing populations there is

a need for more housing and the infrastructure to support so many people.

Where do you put all the people?

To house this number, urban

planners have basically two choices.

1. They can either infill (urban infilling), or ‘create’ land in the inner

and middle suburbs. This can be done by dividing older larger blocks into

smaller new blocks, urban renewal of old industrial sites, or building up and increasing

population density with high-rise apartments.

2. The second option is to expand

space by extending the city outwards into a zone known as the rural–urban

fringe.

How

can we increase density in established suburbs?

To increase the density of housing

in older suburbs, one concept is to establish activity centres. These consist

of higher-density housing in specific locations, where people shop, work, meet,

relax and live in the local environment. These centres are focused on existing

infrastructure, transport networks, popular shopping centres, employment

opportunities and community facilities. New housing tends to be medium-rise

(three to five storeys) apartments built along main transport routes.

What

changes are taking place on the rural–urban fringe?

The rural–urban fringe is typically

the urban zone that is undergoing the most rapid change. Former farmland, often

market gardens and orchards, are sold off and new housing and industrial

estates are built. These are usually low-density, planned estates sometimes

built around a theme or geographical feature such as a built lake or wetland. Urban expansion into the rural–urban fringe brings

environmental, economic and social impacts.

What are the

effects of change on the rural–urban fringe?

Cost of

infrastructure:

A major

problem of urban sprawl is the cost to provide

infrastructure (for example, roads

and other transport systems and services such as water, gas and electricity) to

new areas on the rural–urban fringe. New suburbs such as Narre Warren, in the

City of Casey, are examples of planned developments designed to meet the needs

of the families who will live there. Being on the urban fringe, the blocks vary

in size, and are more affordable for first home buyers and young families.

These suburbs will develop activity centres that will include shopping

complexes, medical centres, open spaces, schools and recreational facilities

such as green zones, although there are often time delays in construction until

a population is established.

Loss of

fertile farm lands:

Possibly the

largest issue with urban sprawl is the loss of fertile farmlands. The Casey

Council, 48 kilometres south-east of Melbourne’s city centre, has resisted

moves for subdivision of farmlands at Clyde, arguing that the sandy loam soils

that produce most of Melbourne’s fruit and vegetables should be set aside for

growing food, not houses.

Some local farmers have different

viewpoints on this matter as re-zoning their properties into the urban boundary

immediately boosts the value of their land. These farmers prefer to relocate

further out and reap the financial gains from the sale of the land for housing.

Loss of green spaces:

The expansion of urban areas can significantly

alter the natural environment. Clearing of vegetation can reduce habitat and

biodiversity. Natural drainage and topography can be altered, with streams

redirected or even converted to pipes. Today there is a growing awareness of

the need to preserve environments for the important functions they provide for

wildlife and people. There is a trade-off, however, as the push for housing

into rural areas can increase bushfire risks. Planners these days try to

incorporate and retain as much of the natural environment as possible when

developing housing estates.

‘Green zones’ are open landscapes set aside to conserve and protect

significant natural features as well as resources such as farms, bushland and

parks. They ensure habitats for native flora and fauna are preserved.

The construction or expansion of

wetlands in the rural–urban fringe can have many benefits, including:

·

Acting

as flood retention basins and receiving and purifying stormwater run-off from

residential areas.

· Providing habitats which can

increase plant and animal biodiversity.

· Providing recreational

opportunities.

6.6

Can we stop Venice from sinking?

Glossary words:

· Historical Architecture: Urban

environment that has significant value due to its unique form and history of

development.

· Lagoon: A shallow body of water separated from the

sea by a sand barrier or coral reef.

· River Delta: A landform composed of deposited sediments

at the mouth of a river where it flows into the sea.

Urban centres that are built on low-lying

coastal plains, where features such as river deltas, wetlands,

lagoons, sand dunes, bars and barriers are found, are susceptible to the

environmental impacts of the sea.

Storms and high tides, when added together,

can lead to destructive surges causing erosion and damage to cities. The

prospect of rising sea levels as a result of the melting of ice caps due to

global warming will require specialised management techniques such as the

construction of coastal defence works to protect property and life.

Venice:

Venice, Italy, is a city built on mud islands

in a coastal lagoon at the head of the Adriatic Sea.

Although Venice has a population of only 60 000, its historical

architecture, life on the canals and cultural events such as

Carnivale attract over two million tourists per year. Not surprisingly, the

Venetians are keen to

protect their heritage and manage the impacts of erosion and rising sea levels

into the future.

Why

is Venice sinking?

When Venice was established almost

2000 years ago, the sea level was two metres lower than current levels and

buildings seemed secure from the impacts of the sea. Over time, the sea level

has risen, and in more recent times this rate of increase has accelerated due

to global warming. Also affecting the stability of buildings was the removal of

fresh water from artisan wells near Venice in the 1950s. This practice, which

fortunately has stopped, led to building subsidence. Another problem has been

the erosive force of waves generated by powerful motor boats splashing

corrosive sea salt onto the buildings.

Floods

or ‘aqua alta’:

Venetians refer to floods as ‘aqua

alta’ or high water. In December 2008, high sea waters with a depth of 1.56

metres above average sea levels caused the fourth highest flood level in Venice

for the past 22 years. A combination of high tides and winds forced waters over

the canal banks and into buildings and public areas (see figure 3). This type of flooding,

which has increased dramatically in the recent past, has seen up to 40 flooding

events a year. This has led to reduced tourist numbers as buildings and public

areas are flooded and transport is curtailed because boats cannot fit under

bridges.

How

will Venice reduce the impact of floods?

The MOSE (Modulo Sperimentale Elettromeccanico) or Experimental

Electromechanical Module Project has been proposed to reduce the impact of

floods on Venice. It consists of rows of mobile gates that are able to isolate

the lagoon and canals from high tides that are above a level of 110 centimetres

to a maximum of 3 metres.

The project has been criticised by

some who say that flushing of the canals would be reduced and the huge cost of

the project could not be justified as it may be effective for only a few years

if sea levels continue to rise. If this project is not to go ahead, then

clearly other management strategies need to be found or Venice will one day

sink into the sea.

6.7 What is the future of our Urban

Environment?

Glossary words:

· Ecological Footprint: The amount of productive land

required by each person in the world for food, water, transport, housing and

waste management.

· Medium – Density Housing: A form of residential

development such as detached, semi-attached and multi-unit housing that can

range from about 25 to 80 dwellings per hectare.

· Urbanisation: The social and economic processes whereby

cities increase in size largely due to population growth.

Cities

throughout human history have changed as new forms of technology have

developed. For instance, high-rise buildings such as skyscrapers could not

exist without modern cement-and-steel methods of construction and the

development of high-speed lifts.

How

is urbanisation being managed?

The United Nations (UN) has

established the Millennium Development Goals (MDGs) which have informed other

bodies that have an interest in urban development. These bodies include

UN-Habitat, ComHabitat (Commonwealth Habitat), the Cities Alliance and the

World Bank, and all are aiming to address the urban challenges of the

twenty-first century with a focus on social and economic management criteria.

The eight MDGs are:

1. Eradicate extreme poverty and

hunger.

2. Achieve universal primary

education.

3. Promote gender equality and empower

women.

4. Reduce child mortality.

5. Improve maternal health.

6. Combat HIV / AIDS, malaria and

other diseases.

7. Ensure environmental

sustainability.

8. Develop a global partnership for

development.

What

are the challenges for cities?

Many cities throughout the world

have extensive areas of slum housing and a general lack of infrastructure to

support what may be called a socially just and economically fair lifestyle.

Particularly in the poorest or least developed countries there are significant

environmental management issues associated with large cities.

Urban

Challenges:

How

can we plan for the future?

By promoting sustainable urban environments

at all levels of scale (local, regional, national and global), problems can be

overcome.

Some management strategies that

will foster sustainable urban environments include:

· Building energy-efficient houses based on materials and

energy sources that reduce the ecological footprint of cities

· Reducing waste by recycling and reusing material

· Improving public transport systems to reduce reliance on cars

· Redeveloping to include medium-density housing to reduce urban sprawl

Exchanging ideas between governments about planning and

building policies and best and successful practice in design.

New Page

pg 2