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| World Environment Day 2005 |
Key Facts About Cities
Issues for the Urban Millennium
- In 1950 less than one person in three lived in a town or city.
Today nearly half the world’s population is urban. By 2030 the
proportion will be more than 60 per cent.
- Virtually all population growth in the next quarter-century
will be in urban areas in the less developed countries. The
fastest growth will not be in the bigger cities but in urban
centres with fewer than 500,000 people.
- In 2000 there were 402 cities with between 1 and 5 million
inhabitants; and 22 cities with between 5 and 10 million. In 1950
New York was the only city with more than 10 million people. By
2015, there will be 23 such cities, 19 of them in developing
countries.
- In the more developed countries, 75 per cent of the population
is urban. The proportion of urban dwellers in the Asian region is
less than 40 per cent, but its urban population is 1.5
billion—more than Europe, Latin America, Oceania and North America
combined. Africa is the least urbanized continent, but its urban
population is the fastest growing.
- Urbanization in the developed world has largely coincided with
economic growth and increases in welfare. This is not the case
with developing countries. For example, in Africa, more than 70
per cent of the urban population—over 160 million people—lives in
slums. Since 1990, Africa’s urban slum population has grown by
almost 5 per cent a year and is on course to double every 15
years.
- At least 1 billion people, mainly in Asia, Africa and Latin
America live in improvised slums and informal squatter
settlements, which are neither legally recognized nor serviced by
city authorities. By 2020 the figure could be more than 2 billion
people.
- One of the targets of Millennium Development Goal 7 (to ensure
environmental sustainability) is to significantly improve the
lives of at least 100 million slum dwellers by the year 2020.
Environmental factors are a major cause of death, disease and lost
productivity, all of which conspire to perpetuate poverty.
- Unsafe water and inadequate sanitation are typical hazards of
living in slums. Diarrhoea is the second most common cause of
child mortality, estimated to be responsible for 12 per cent of
deaths of children under five in developing countries—1.3 million
deaths every year.
- Slum dwellers generally also have to contend with poor air
quality. Approximately 2 million children under five die each year
from acute respiratory infections. The largest global killer of
young children, these infections are aggravated by environmental
factors such as indoor and outdoor air pollution.
- According to the World Health Organization, 1.5 billion urban
residents endure levels of outdoor air pollution that exceed
maximum recommended levels. As many as half a million deaths can
be attributed to particulate and sulphur dioxide air pollution
alone, mostly from vehicle exhaust emissions. One study estimates
that up to one in five lung cancer cases in the United States are
due to vehicle emissions.
- Burning refuse, especially plastics and other hazardous waste,
also affects air quality. The global health costs of air pollution
are estimated at US $1 billion. In developed countries air
pollution costs are close to 2 per cent of GDP; in developing
countries the figure is between 5 and 20 per cent.
- Power generation, industry and transport—currently mainly
associated with towns and cities in the developed world—are
responsible for the majority of emissions of carbon dioxide, the
main greenhouse gas that is causing climate change.
- Over the next quarter-century, it is estimated that carbon
dioxide emissions, mostly from cars, trucks and power stations,
will rise by 60 per cent. More than two-thirds of the increase
will come from developing countries as a consequence of fast
economic growth and a significant increase in car ownership.
- Climate change is a threat to low-lying and coastal towns and
cities due to sea level rise, and more frequent and severe storms.
Growing urban populations—especially those in slums—are more
vulnerable to natural disasters. Approximately 40 per cent of the
world’s population lives within 60 kilometres of the coast.
- Urbanization and economic development habitually goes
hand-in-hand with increased per capita resource consumption and
waste generation. Urban dwellers in the developed world generate
up to six times as much waste as in developing countries.
- Municipalities can spend as much as 30 per cent of their
budget on waste disposal, mostly on transportation. The costs are
often exacerbated by diminishing availability of suitable land as
urban areas spread and land prices rise.
- In developing countries, the cost of solid waste management
can be even higher, up to 50 percent of recurrent budgets. The
infrastructure for safe disposal of waste is also often lacking.
Between 30 and 60 per cent of urban solid waste is uncollected and
less than 50 per cent of the population is served.
- As towns and cities develop so does their reliance on
resources from further afield, as well as their environmental
impact—what is known as their ecological footprint.
- The ecological footprint of London, UK, is 120 times the
city’s area. An average North American city with a population of
650,000 requires 30,000 square kilometres of land to service its
needs. In contrast, a similar sized city but less affluent city in
India requires 2,800 square kilometres.
- Since 1950 global fossil fuel use has increased by 500 per
cent. Freshwater consumption has nearly doubled since 1960, and
the marine catch has quadrupled. A city of 10 million people—for
example Manila, Cairo or Rio de Janeiro—imports at least 6,000
tonnes of food every day.
- More than half of freshwater tapped for human use goes to
urban areas: for industry, for drinking and sanitation purposes,
or via irrigation for crops. Up to 65 per cent of water used for
irrigation is wasted.
- In many developing country cities between 40 and 60 per cent
of costly drinkable water is lost because of leaks in pipes and
illegal connections. Even in industrialized countries, as much as
a quarter of piped water is wasted.
- Urban air temperatures can be as much as 5 C hotter than the
surrounding countryside when natural land cover is replaced by
roads and buildings. This phenomenon, known as the ‘heat island
effect’, can be mitigated by preserving or creating green spaces
in cities.
- Green areas in urban settlements serve many other purposes.
Urban forests produce oxygen and absorb carbon dioxide, thus
enhancing air quality. They provide storm water control and
provide a home for urban wildlife.
- Managed well, urban settlements can support growing
concentrations of people, limiting their impact on the environment
and improving their health and living standards. National and
local laws and subsidies can discourage waste, encourage
conservation and promote sustainable solutions.
- Examples of good management include the use of so-called grey
water to flush toilets; low-polluting vehicles and efficient
public transport systems that solve gridlock problems and clean up
the atmosphere; low-energy lighting that saves energy; and waste
recycling schemes.
- There are many examples from around the globe of local
governments, citizens’ organizations, business and industry
devising and implementing innovative answers to the issues of the
urban millennium and creating Green Cities
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