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.