Urban and Rural Areas

Urban and Rural areas in the world

 

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Urban areas (or urban agglomerations) are areas of continuous urban development within a metropolitan area (labor market area), and are the physical form of that constitutes the essence a city. Generally, urban areas can be identified by the lights one would see from an airplane at night or in a satellite photograph. Urban areas are not metropolitan areas, which represent the economic or functional form of a city. Urban areas are a component of metropolitan areas, the other component of which is non-urban or rural territory. A metropolitan area is the combination of the urban area(s) and rural areas, which together comprise the economic region or labor market (commute shed).

Over the last year, new census reports have become available in such nations as India, Indonesia, China, Canada, Bangladesh, the United States and South Korea. The new data has resulted in a number of ranking changes from before.

The Megacities: In 2012, 26 urban areas qualify as megacities (Rental Car Tours for 24 of the megacities are available), with populations of greater than 10 million people (Table). As has been the case for nearly six decades, Tokyo remains the largest urban area in the world, with approximately 37 million. New York, which Tokyo displaced in 1955, has fallen to seventh largest and has the lowest population density of any megacity, at 4600 per square mile or 1800 per square kilometer (Note 2). London, which New York displaced in the 1920s never became a megacity due to the imposition of its greenbelt. Instead urbanization leapfrogged into the exurbs of southeast England, where all of the London area's net population growth has occurred since World War II (London ranked third as late as 1960).

 

 

Jakarta (Jabotabek) has emerged as the world's second largest urban area, with a population of 26 million. This is a larger population than reported by the United Nations, since its estimates include little more than DKI Jakarta, the national capital district and beyond which urbanization stretches for a considerable distance. Continuing suburban growth in Seoul-Incheon secured that urban area a ranking of third, with approximately 22.5 million people. As was reported last year, new estimates indicate that Delhi has emerged as India's largest urban area, with a population of 22.2 million and a growth rate that should result in its passing Seoul-Inchon in a matter of a few years. Mumbai, which like Mexico City in the 1980s has often been promoted as being destined to become the largest urban area in the world, was passed by Delhi over the past decade and has become the second largest urban area in India.

Manila is ranked as the fifth largest urban area in the world, with 22.0 million people. In Manila, as in Jakarta, the population reported to the United Nations is far below that of the genuine urban area. The reported population is for the National Capital Region (popularly and misleadingly called "Metro Manila), which represents approximately one-half of the population of the urban area, which stretches into four additional provinces (Cavite, Laguna, Rizal and Batangas). If the population of the Washington urban area were reported in the same manner, it would be 600,000 – the population of the District of Columbia – rather than the 4.6 million indicated in the 2010 census for the entire urban area.

Los Angeles, until recent years one of the fastest growing urban areas in the world, has dropped to 17th largest in the world and seems destined to drop out of the top 20 in the next decade or two. Fast growing Karachi, Istanbul, Lagos and others could become larger than Los Angeles. Los Angeles reached its peak ranking of 6th largest in the world from 1965 through 1980 and entered the top ten by 1950.

Over the past decade, Paris became a megacity, reaching a population of 10.7 million. Paris has been Western Europe's fastest growing large urban area since World War II. All of its growth since 1921 has been in the suburbs, which stretch over more than 1,000 miles (2,600 square kilometers). This is more land area than Houston's suburbs, but more densely populated. Since 1921, the historical core municipality (the ville de Paris) has dropped in population from 2.9 million to 2.2 million.

By world standards, the Paris urban area has grown slowly, having fallen from being the world's third largest in 1965 to its current ranking of 23rd. However, over the past census period, Paris added 600,000 residents, compared to less than 200,000 in the previous period, indicating a decline in out-migration and a higher natural population rate increase.

Urban Area Densities: Dhaka, the capital of Bangladesh grew strongly between 2001 and 2011 and is by far the most densely populated urban area in the world. Dhaka's density is estimated at 115,000 per square mile or 44,000 per square kilometer, with slum (informal dwelling) densities reported report up 4,210 per acre, or 2.7 million per square mile (1 million per square kilometer). At this density, all of the world's 3.7 billion urban residents could be accommodated in an area approximately equal to that of the Washington (DC-MD-VA) urban area. All of Dhaka's urban population of 15.4 million fits into a land area equal to that of the city (municipality) of Portland (population less than 600,000). Nonetheless, analysts have referred to this example of the ultimate of urban density to be "sprawling."

Among the urban areas with more than 2.5 million population, the second-most dense is Mumbai, at 80,100 per square mile or 30,900 per square kilometer. The most dense high income world urban area is Hong Kong, at 67,000 persons per square mile or 25,900 per square kilometer. Of course, Hong Kong's density is the result of an accident of history, which resulted in huge migration to the former British colony following World War II. Hong Kong is more than twice as dense as the second most dense high income world urban area, Busan, Korea. The smaller nearby, yet historically similar enclave of Macau (560,000) has an even higher density than Hong Kong, at 70,000 per square mile (27,000 per square kilometer).

Seven of the densest urban areas with more than 2.5 million population are on the Asian subcontinent. These include Dhaka and Chittagong in Bangladesh, Mumbai, Ahmedabad, Surat and Jaipur in India and Karachi, in Pakistan. Colombia has two of the densest, Bogota and Medellin. Hong Kong is the only high income nation urban area among the 10 densest (Figures 1-2)

 

The least dense urban areas with more than 2.5 million population are all in the United States. The least dense is Atlanta, with 1800 people per square mile or 700 per square kilometer. The second least dense is, perhaps surprisingly, Boston, despite its reputation for high density. Boston's population density is 2200 per square mile or 800 per square kilometer. Also, perhaps surprisingly, Philadelphia is the least dense urban area in the world with more than 5 million population, while Chicago is the least dense urban area of more than 7.5 million. The lower density of US urban areas is illustrated by the fact that Portland, with its reputation for higher density and densification planning, would have ranked 11th least dense, if it had reached the 2.5 million threshold used in this ranking.

Most Extensive Urban Areas: New York covers the most land area of any urban area at nearly 4500 square miles or 11,000 square kilometers. Tokyo covers 3300 square miles or 8500 kilometers. Chicago is the third most expansive urban area, at 2,600 square miles (6,900 square kilometers). Los Angeles, which has long been perceived as the most sprawling of world urban areas, ranks fifth, covering 2400 square miles or 6,300 square kilometers. Atlanta and Boston, the world's least dense major urban areas, rank 4th and 6th, covering 2,600 and 2,100 square miles respectively (6,900 square kilometers and 5,400 square kilometers).

The Continuing Exodus from Rural Areas: Around the world, people continue to seek the promise of better economic outcomes in urban areas. United Nations forecasts indicate that another 2.5 billion people will be added to urban areas by 2050, while rural areas (which contain all population not urban) will be reduced in population by 300 million. The world's urban population is expected to rise from today's nearly 53 percent to 67 percent. More than 90 percent of the urban growth is expected to be in less developed nations.

Wendell Cox is a Visiting Professor, Conservatoire National des Arts et Metiers, Paris and the author of “War on the Dream: How Anti-Sprawl Policy Threatens the Quality of Life”.

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Note 1: Demographia World Urban Areas uses national census authority urban area population and land area data in the few nations designating urban areas on a basis generally consistent with that of the United States Census Bureau. Elsewhere, land area estimates are determined using satellite photography (Google Earth). Population estimates are also obtained from a variety of sources, such as United Nations data, where it is reflective of the urban area population (some data reported to the United Nations is for jurisdictions that are only a part of the urban area and in other cases, metropolitan area data is reported), estimates relying on a "build-up" of local authority data from national census authorities and other sources. Demographia combines some adjacent urban areas when they are contained within the same metropolitan area or consolidated area, such as in New York and Los Angeles (for a complete list see Demographia World Urban Areas). Also see: Urban Terms Defined.

Note 2: Exceptions: In some cases, continuous urbanization does not constitute a single urban area because they are not within a single labor market (metropolitan area). This can be the case within a nation, such as in the Pearl River Delta of China, where Shenzhen, Dongguan, Zhongshan, Jiangmen, Huizhou, Zhuhai, Guangzhou-Foshan and Hong Kong, which are separate labor markets. International borders (and the Hong Kong-Shenzhen border) also define separate urban areas if free movement of labor is not permitted. Thus Detroit and Windsor or San Diego and Tijuana are separate urban areas because free movement of labor is not permitted. On the other hand, treaties permit virtual free movement of labor between the French and Belgian sides of the Lille urban area and between the Swiss and French components of the Geneva urban area.

 

What is ‘urban’ and what is ‘rural’? The implications of administrative definitions The difference between urban centres and rural areas may seem so obvious that definitions should not be an issue. However, there can be major variations in the ways in which different nations define what is an urban centre. The criteria used include population size and density, and availability of services such as secondary schools, hospitals and banks. However, the combination of criteria applied can vary greatly. Even the population thresholds used can be different: for many African nations it is 5,000 inhabitants, while for most Latin American and European nations it can be as low as 2,000 or 2,500 or even just a few hundred inhabitants. This wide fluctuation in definitions has three important implications. Official classifications should be treated with caution – for example, a large proportion of settlements classed as ‘rural’ in China and India would fall within the ‘urban’ category if they used the criteria and population thresholds adopted by many other countries. Given the size of the population of these two countries, this would significantly increase the overall proportion of urban residents in Asia and in the world. International comparisons are difficult, as they may look at settlements which, despite being classed in the same category, may be very different in both population size and infrastructure. In addition, the reliability of data on urbanization trends within one nation can be compromised by changes in the definition of urban centers over time. Public investment in services and infrastructure tends to concentrate on centers that are defined as urban. As a consequence, investment can bypass settlements not defined as urban even if these can, and often do, have an important ‘urban’ role in the development of the surrounding rural areas. Within national and regional urban systems, larger cities also tend to be favored with public investment over small and intermediate-sized urban centers, including those with important roles in supporting agricultural production, processing and marketing. Outside the city boundaries: the peri-urban interface The physical boundaries of urban built-up areas often do not coincide with their administrative boundaries. The areas surrounding urban centers generally have an important role in providing food for urban consumers, with proximity lowering the costs of transport and storage. It is difficult to make generalizations on the nature of peri-urban areas, which depends on the combination of a number of factors including the economic and infrastructural base of the urban center, the region and the nation; the historical, social and cultural characteristics of the area, and its ecological and geographical features. Peri-urban areas around one center are also not necessarily homogenous: high- and middle-income residential developments may dominate one section, while others may host industrial estates and others provide cheap accommodation to low-income migrants in informal settlements. The peri-urban interface around larger or more prosperous urban centres is also the location where processes of urbanisation are at their most intense and where some of the most obvious environmental impacts of urbanisation are located. They are often characterised by: Changes in land use: land markets are subject to competitive pressure as urban centres expand and speculation is frequent. Whether low-income groups such as small and marginal farmers or residents of informal settlements can benefit from these changes, or end up losing access to land, depends largely on land rights systems. Changing farming systems and patterns of labour force participation: because peri-urban agriculture can be highly profitable, small farmers may be squeezed out by larger farmers who can invest in agricultural intensification. As a consequence, wage agricultural labour often becomes more important than small-scale farming, attracting migrant workers. On the other hand, residents of peri-urban areas may benefit from employment opportunities in the city. Changing demands for infrastructure and pressure on natural resource systems, with many rural dwellers’ access to resources having to compete with urban demand (for example, for water, fuelwood and land for non-agricultural uses) or affected by urban-generated wastes. Variations in the characteristics of peri-urban areas can be important. For example, in the growing number of extended metropolitan regions in Southeast Asia, agriculture, small-scale industry, industrial estates and suburban residential developments co-exist side by side. Availability and affordability of transport are essential for the intense movement of goods and the extreme mobility of the population. In other contexts, and especially in less industry-based economies such as many countries in sub-Saharan Africa, agriculture still prevails in peri-urban areas although often with significant shifts in land ownership and use. This is especially the case where smallholder productivity is low because of the increasing costs of inputs and limited credit availability. Other problems include poor access to urban markets due to a lack of roads and physical infrastructure and the tight control over access to the urban market-places by middlemen and large traders. Thus, despite proximity to urban consumers, small farmers may be easily squeezed out, especially as the value of land in peri-urban areas increases with the expansion of the built-up center. Understanding rural-urban differences and rural-urban linkages  The figure emphasizes some of the most ‘rural’ characteristics of people’s livelihoods in the column on the left and some of the most ‘urban’ characteristics in the column on the right. These should be regarded as two ends of a continuum with most urban and rural areas falling somewhere between these extremes. The text noted earlier the importance of non-farm income sources for many rural households (including remittances from family members working in urban areas) and the importance of agriculture and/or of rural links for many urban households (including urban centers with many residents who work seasonally in rural areas). For all the contrasts between ‘rural’ and ‘urban’ highlighted in the figure, there are many exceptions. It is also useful to see in the middle of the continuum between ‘rural’ characteristics and ‘urban’ characteristics a ‘rural-urban’ interface in which there are complex mixes of ‘rural’ and ‘urban’ characteristics. For instance, many of the areas around prosperous cities or on corridors linking cities have a multiplicity of non-farm enterprises and a considerable proportion of the economically active population that commute daily to the city or find work seasonally or temporarily in urban areas. Many rural areas also have tourist industries that have fundamentally changed employment structures and environmental pressures.

Governing across and beyond the rural-urban boundary If well managed, the interactions between towns and countryside are the basis for a balanced regional development which is economically, socially and environmentally sustainable. Local development is increasingly associated with decentralisation processes, on the assumption that local government is ‘closer’ to citizens – meaning that it is both more accountable to them and that it has a better understanding of local needs and priorities. With regard to rural-urban linkages, local government can play an important role in facilitating positive interactions and limiting negative exchanges: It is best placed for decision-making on physical transport and communication infrastructure; however, expenditure for infrastructure can be significant and well beyond the means of local government. Wider alliances, which increase access to financial resources, are therefore necessary. The management of natural resources and wastes is an important area of local government intervention. However, it often includes much wider areas than those administered by local authorities, and requires alliances with other local, regional, national and sometimes cross-border governments. National level policies also have an important role, for example, with respect to access to land and land ownership and titling in both rural and urban areas. Clearly, this is not the responsibility of local authorities but is nevertheless crucial for local development planning and practice. In short, understanding rural-urban linkages matters because it provides the basis for measures that can improve both urban and rural livelihoods and environments. Ignoring them means that important opportunities will be lost, and in many cases it will also contribute to poor and marginal people’s hardship. There are urban initiatives that can reduce ecological damage to rural areas, and help support regional development. However, with a narrow urban-centric approach, such initiatives are unlikely to be given the priority they deserve.

 

 

 

In 1900, the Mexican population was 13.6 million. During the period of economic prosperity that was dubbed by economists as the "Mexican Miracle", the Mexican government invested in efficient social programs that reduced infant mortality rate and increased life expectancy which jointly led to an intense demographic increase between 1930 and 1980. The population's annual growth rate has been reduced from a 3.5% peak, in 1965 to 0.99% in 2005. While Mexico is now transitioning to the third phase of demographic transition, close to 50% of the population in 2009 was 25 and younger. Fertility rates have also decreased from 5.7 children per woman in 1976 to 2.2 in 2006. The average annual population growth rate of the capital, the Federal District, was the first in the country at 0.2%. The state with the lowest population growth rate over the same period was Michoacán (-0.1%), whereas the states with the highest population growth rates were Quintana Roo (4.7%) and Baja California Sur (3.4%),both of which are two of the least populous states and the last to be admitted to the Union in the 1970s. The average annual net migration rate of the Federal District over the same period was negative and the lowest of all political divisions of Mexico, whereas the states with the highest net migration rate were Quintana Roo (2.7), Baja California (1.8) and Baja California Sur (1.6). While the national annual growth rate is still positive (1.0%), the national net migration rate is negative (-4.75/1000 inhabitants), given the intense flow of immigrants to the United States; an estimated 5.3 million undocumented Mexicans lived in the United States in 2004 and 18.2 million American citizens in the 2000 Census declared having Mexican ancestry. Mexico itself constitutes the second country of total number of immigrants to the United States from 1830 to 2000, after Germany.
The Mexican government projects  that the Mexican population will grow to about 123 million by 2042 and then start declining slowly. Assumptions include fertility stabilizing at 1.85 children per woman and continued high net emigration (gently decreasing from 583,000 in 2005 to 393,000 in 2050).
The states and the Federal District that conform the Mexican federation are collectively called "federal entities". The five most populous federal entities in 2005 were the State of Mexico (14.4 million), the Federal District (8.7 million), Veracruz (7.1 million), Jalisco (6.7 million) and Puebla (5.4 million) which collectively contain 40.7% of the national population. Mexico City, being coextensive with the Federal District, is the most populous city in the country, whereas Greater Mexico City, that includes the adjacent municipalities that conform a metropolitan area, is estimated to be the second most popular in the world, by the UN Urbanization Report.
Intense population growth in the Northern states, especially in the US-Mexican border, changed the country's demographic profile in the second half of the 20th century since the 1967 US-Mexico maquiladora agreement through which all products manufactured in the border cities could be imported duty-free to the US. Since NAFTA, however, in which all products are allowed to be imported duty free regardless of their origin within Mexico, non-border maquiladora share of exports has increased while that of border cities has decreased, allowing for the growth of middle-size cities in different regions in Mexico. This has also led to decentralization and growth of other metropolitan areas that conform regional centers of economic growth, like Monterrey, Guadalajara, Puebla, San Luis Potosí, León and Torreón.

 

Social and Economic Implications of Growth, Compsition and Distribution of Population in the World and Mexico

Social and Economic Implications of Growth, Compsition and Distribution of Population in the World and Mexico

Human Population Growth over Time

Since Prehistory population has grown even with wars, epidemics and catastrophes that have caused a lot of death. During several centuries growth was slow, but with the development of science and technology death became less and life expectancy  increased. The human population growth of the last century has been truly phenomenal. It required only 40 years after 1950 for the population to double from 2.5 billion to 5 billion. This doubling time is less than the average human lifetime. The world population passed 6 billion just before the end of the 20th century. Present estimates are for the population to reach 8-12 billion before the end of the 21st century. During each lecture hour, more than 10,000 new people enter the world, a rate of ~3 per second!

In October 1999, the human population of the world reached 6 billion. Governments, scientific societies, and other organizations reacted with celebrations, but also with concern. The population had doubled in only 40 years, with most of the growth occurring in developing countries. Experts predicted that at the current growth rate of 77 million new people a year, the population would swell to 9 billion by 2050, increasing requirements for food, water, and health care in countries where basic necessities were already scarce.

In Mexico the demographic politics were naturalist and it was favorable to have many kids, not thinking that population growth could be a problem since it is a big country. Soon it became evident that it was not possible to care for the needs in food, lands for agriculture, education, health, jobs, etc because the fast growth in population wasn´t relative to economical development of the country. In 1974 the General Population Law was created in order to regulate the population growth. The CONAPO (National Population Council) was created to reduce birth rates and death rates. And Family planning programs were introduced to educate and reduce the number of kids being born.

The demographic indicators that allow us to preview the characteristics of a population are fertility, mortality, and birth rates. The information is collected through census and indicators provided by them allow governments to identify the needs of the population in aspects like health, education, housing and services in general.

Of the 6 billion people in the world, about half live in poverty and at least one fifth are severely undernourished. The rest live out their lives in comparative comfort and health. The factors affecting global human population are very simple. They The current growth rate of ~1.3% per year is smaller than the peak which occurred a few decades ago (~2.1% per year in 1965-1970), but since this rate acts on a much larger population base, the absolute number of new people per year (~90 million) is at an all time high. The stabilization of population will require a reduction in fertility globally. In the most optimistic view, this will take some time.

Birth Rate

The birth rate is typically the rate of births in a population over time.^[1] The rate of births in a population is calculated in several ways: live births from a universal registration system for births, deaths, and marriages; population counts from a census, and estimation through specialized demographic techniques. The birth rate (along with mortality and migration rate) are used to calculate population growth.

The crude birth rate is the number of births per 1,000 people per year. Another term used interchangeably with birth rate is natality. When the crude death rate is subtracted from the crude birth rate, the result is the rate of natural increase (RNI). This is equal to the rate of population change (excluding migration).

The total (crude) birth rate (which includes all births)—typically indicated as births per 1,000 population—is distinguished from an age-specific rate (the number of births per 1,000 persons in an age group). The first known use of the term "birth rate" in English occurred in 1859.

In 2012 the average global birth rate was 19.15 births per 1,000 total population, compared to 20.09 per 1,000 total population in 2007.

Fertility

The current growth of population is driven by fertility. Figure 2 shows how total fertility rate is a strong function of region. It can be readily seen that the more developed countries ("the North") have lower fertility rates than the less developed countries ("the South"). The fertility rates in the developed world are close to replacement levels (i.e., the population is roughly stable), while the rates in the developing world are much higher. Thus, population growth and level of development are clearly linked.

Global Total Fertility Rates, 1990-1995

 

Fertility is largely controlled by economics and by human aspirations. The high fertility of the developing world can be partially explained by the large number of hands needed to perform low-technology agricultural tasks. In these areas, families with large numbers of children realize an enhanced economic status. As technology improves, parents realize that having more children decreases rather than increases their standard of living. A dramatic example of this effect occurred in Thailand, where, as soon as parents realized that future economic status was linked to the secondary schooling (which is expensive in Thailand), the fertility rate dropped from about 6 to 2 in a decade!

 

 

 

 

 

Population-Age Pyramids

While fertility rates are obviously useful, the demographics of the existing population are also important and can provide key information to predict future growth rates. An example of two such population-age pyramids is shown here:

Population/Age Pyramids of the Developed and Developing World

 

The top figure shows the population-age pyramid for the developed world and the bottom figure is for the developing world. The figure illustrates the pyramids for the years 1975 (pink) and 2000 (blue). The population/age structure of the developed world represents that of a stable (or nearly stable) population. Here, the pyramid is more rectangular than for a rapidly growing population (bottom) where there is a much larger number of young people. The bottom figure (typical for countries like Mexico, Malaysia, India, etc.) is more triangular and shows how a rapidly growing population is dominated by young people. The female side of the diagram is particularly important in understanding future growth. This is because fertility is largely controlled by the number of females in their reproductive years (roughly ages 15 - 40).

In the developing world, not only are there many females capable of reproduction, but there are many more young females who are of potential mothers. Thus, the shape of the population-age pyramid for the developing world indicates that the population will continue to grow aggressively for the near future as the cohort of fertile females gets larger each year, fed from the lower parts of the pyramid. It takes many tens (perhaps hundreds) of years to steepen the slopes of the population-age pyramid. Such a steepening is essential before populations can become stable. Intensive efforts to control population have been implemented in various countries. In China, aggressive population control via a one-child family policy is bringing remarkable change to age structure and population size.

 

Comparative Population Pyramids for India

Clearly, population control is a challenging task for which both persistence and patience will be needed.

 

Mortality

 

Mortality, or the death rate per individual, is another determining factor of population growth. In the developing world, the death rate has dropped, more or less continuously, since the start of the industrial revolution. The following figure shows the slow, hard won, reduction in death rate in various European countries. Personal hygiene and improved methods of sanitation have played a major role and preceded the impact of modern medicine and, in particular, the development of antibiotics capable of reducing death due to infection. The downward trend of the death rate is common to most countries, although there are some countries (for example, Russia) where the death rate remains high and refuses to move appreciably.

Death Rates per 1000 over Time

 

The combination of decreasing death rate due to the march of progress in sanitation and medicine, coupled with the decrease in birth rate due to changes in the economies, has led to a profound change in the population growth curve in the developed world. This change is called the Demographic Transition.

 

The Demographic Transition

This is the name given to the process that has occurred during the past century, leading to a stabilization of population growth in the more highly developed countries. The Demographic Transition is shown schematically in Figure 6. It is generally characterized as having four separate phases or stages.

 

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The Demographic Transition Model

The Demographic Transition Model attempts to show how population changes as a country develops.

The model is divided into four stages.

Stage 1
Birth rate and death rate are high - low natural increase - low total population

Stage 2
Birth rate is high - death rate is falling - high natural increase (population growth)

Stage 3

Falling birth rate - low death rate - high natural increase (population growth)

Stage 4
Birth rate and death rate is low - low natural increase - high total population

The Demographic Transition Model does not take into account migration.

Population Structure / Population Pyramids

The population structure for an area shows the number of males and females within different age groups in the population. This information is displayed as an age-sex or population pyramid. Population pyramids of LEDCs (Less Economically Developed Countries) typically have a wide base and a narrow top. This represents a high birth rate and high death rate. Population pyramids of MEDCs (More Economically Developed Countries) typically have a roughly equal distribution of population throughout the age groups. The top obviously gets narrower as a result of deaths. Population pyramids are used to show the structure of the population according to age and sex.

 

 

Calculating the Growth Rate

To calculate the natural growth rate of a country you subtract the coefficient of death from the birth one. Example:

 

birth rate                     18.5

death rate                   -4.3

                                   14.2

 

14.2 / 10 = 1.4    Growth rate = 1.4

 

Population Structure

The population structure of a country is how it is made up of people of different ages, and of males and females. The common method to show the structure is by a population pyramid. This diagram is made up by putting two bar graphs (one for male, one for female) side by side. From this you can read off what percentage of a population is of a certain gender and age range. In the example below 4% of the population are females aged between 25 and 29.

Population Structure - Developing Countries

This population pyramid is wide at the base, which means there are a large proportion of young people in the country. It tapers very quickly as you go up into the older age groups, and is narrow at the top. This shows that a very small proportion of people are elderly.

This shape of pyramid is typical of a developing country, such as Kenya or Vietnam.

Population Structure - Developed Countries

This shape is typical of a developed country. It is narrow at the base, wider in the middle, and stays quite wide until the very top, as there is a sizable percentage of older people. Note that there are more old women than men. Italy and Japan have population structures that are of this shape.

Population Distribution
Population distribution means the pattern of where people live. World population distribution is uneven. Places which are sparsely populated contain few people. Places which are densely populated contain many people. Sparsely populated places tend to be difficult places to live. These are usually places with hostile environments e.g. Antarctica. Places which are densely populated are habitable environments e.g. Europe.

Population Density
Population density is a measurement of the number of people in an area. It is an average number. Population density is calculated by dividing the number of people by area. Population density is usually shown as the number of people per square kilometer. The map below is a choropleth (shading) map and illustrates population density. The darker the colour the greater the population density.

Source: Columbia University's Center for International Earth Science Information Network
Page URL: http://sedac.ciesin.columbia.edu/plue/gpw/index.html?main.html&2

The map above shows that world population distribution is uneven. Some areas have a high population density while others have a low population density. Areas of high population density tend to be located between 20° and 60°N. This area contains a large land area and a relatively temperate climate.

Factors Affecting Population Density
There are a range of human and natural factors that affect population density. The tables below illustrate this.

Physical Factors	High Density	Low Density
Relief (shape and height of land)	Low land which is flat e.g. Ganges Valley in India	High land that is mountainous e.g. Himalayas
Resources	Areas rich in resources (e.g. coal, oil, wood, fishing etc.) tend to densely populated e.g. Western Europe	Areas with few resources tend to be sparsely populated e.g. The Sahel
Climate	Areas with temperate climates tend to be densely populated as there is enough rain and heat to grow crops e.g. UK	Areas with extreme climates of hot and cold tend to be sparsely populated e.g. the Sahara Desert

 

Human Factors	High Density	Low Density
Political	Countries with stable governments tend to have a high population density e.g. Singapore	Unstable countries tend to have lower population densities as people migrate e.g. Afghanistan.
Social	Groups of people want to live close to each other for security e.g. USA	Other groups of people prefer to be isolated e.g. Scandinavians
Economic	Good job opportunities encourage high population densities, particularly in large cities in MEDCs and LEDCs around the world.	Limited job opportunities cause some areas to be sparsely populated e.g. Amazon Rainforest

Population Change
The world's population is growing very rapidly. In 1820 the world's population reached one billion. In 1990 it reached 6 billion people.

This rapid growth in population has been called a population explosion.

The major reason for population changes, whether in an individual country or for the whole world, is the change in birth and death rates. The birth rate is the number of live babies born in a year for every 1000 people in the total population. Death rates are number of people dying per 1000 people. When birth rates are higher than death rates the population of an area will increase.

Over the past 150 years improvements in health care and sanitation around the world have led to a drop in the death rate. While birth rates have dropped in MEDCs, birth rates are still high in LEDCs. Therefore the number of people in the world has grown rapidly.

Life Expectancy
Life expectancy is the average age a person can expect to live to in a particular area. Life expectancy can be used as an indicator of the overall 'health' of a country. From this figure you can determine many features of a country e.g. standard of living. As a general rule the higher the life expectancy the more healthy (or developed) a country is.