check out the US Census Bureau's World Population Clock:
”The structure of the present controls the content of the future.”
“The size, characteristics, growth trends, and migrations of today’s population help shape the well-being of peoples yet unborn but whose numbers and distributions are now being determined. The numbers, age, and sex distribution of people; patterns and trends in their fertility and mortality; their density of settlement and rate of growth all affect and are affected by the social political, and economic organization of a society.
“Through population data we begin to understand how the people in a given area live, how they may interact with one another, how they use the land, and what pressure on resources exists, and what the future may bring.
“Population geography provides the background tools and understandings of those interests. It focuses on the number, composition, and distribution of human beings in relation to variations in the conditions of earth space. It differs from demography, the statistical study of human population, in its concern with spatial analysis—the relationship of numbers to area. Regional circumstances of resource base, type of economic development, level of living, food supply, and conditions of health and well-being are basic to geography’s population concerns. They are, as well fundamental expressions of the human-environment relationships that are the substance of all human geographic inquiry.” (Getis,9th, p. 186)
Late 2008, world population is estimated to be 6.7 billion people
Early 2003, world population reached 6.3 billion people.
2000 6.1 billion
1990 5.3 billion
1900 1.6 billion
Year Estimated Population Doubling Time (Years)
1 250 million
1650 500 million 1650
1804 1 billion 154
1927 2 billion 123
1974 4 billion 47
World Population may reach
2030 8 billion 56
The final estimate of doubling time reflects assumptions of decreasing and stabilizing fertility rates. No current projection contemplates a further doubling
Some Population Definitions
Rates: record the frequency of occurrence of an event during a given time frame for a designated population.
Cohort: refers to data of a population group unified by a specified common characteristic.
Crude birth rate (CBR) or simply birth rate: is the annual number of live births per 1000 population. “It is ‘crude” because it relates births to total population without regard to the age or sex composition of that population.
Early 21st century
High birth rates:
Mali and Niger have a birth rate of 50 per 1000 population.
Birth rates above 30 per 1000 are considered high. 1/6 of world’s population live in countries with high birth rates. Africa, Western and Southern Asia, and Latin America with a predominantly agricultural and rural population. Many young women of childbearing age. 40 million births are believed to take place, which are not registered.
Low birth rates:
Western European countries have a birth rate of 8 to 9 per 1000 population.
Birth rates of 18 or less per 1000 are considered low.
This includes all of Europe including Russia, Anglo America, Japan, Australia, and New Zealand. China, with family planning, has also reached this low number.
Transitional birth rates:
18 to 30 births per 1000 population.
This includes many smaller developing countries and India (since 1994)
Total Fertility Rate (TFR): is “the average number of children that would be born to each woman, if during her childbearing years, she bore children at the current year’s rate for women that age. The fertility rate minimizes the effects of fluctuation in the population structure and is thus a more reliable figure for regional comparative and predictive purposes than the crude birth rate.” (Getis, 190)
Crude birth rates may display such regional variability because of differences in age and sex composition or disparities in births among the reproductive-age, rather than total, population. TFR is a more accurate statement than the birth rate in showing the amount of reproduction in the population.
A total fertility rate of 2.1 is necessary to replace present population.
“On a worldwide basis, the TFR in 2002 was 2.8, down from 5.0 in 1965.
The more developed countries recorded a 1.6 rate at the start of the 21st century, down from 2.0 in 1985, while the less developed states (excluding China) had a collective TFR of 3.6, down from 5.0 in the mid 1980s.
Read section in Getis on p. 192.
Crude death rate (CDR) also called the mortality rate: is the annual number of deaths per 1000 of population.
Highest rates: over 20 per 1000 population are found in less developed countries of world (Africa, parts of Asia, and Latin America)
Lowest rates: less than 10 deaths per 1000 population are found in Europe and Anlo-America.
The correlation that death rates are linked to the level of development has become less valid “as dramatic reductions in death rat4s occurred in developing countries in the years following World War II. Infant mortality rates and life expectancies improved as antibiotics, vaccinations, and pesticides to treat diseases and control disease carriers were made available in almost all parts of the world and as increased attention was paid to funding improvements in urban and rural sanitary facilities and safe water supplies.” (Getis, 193)
Since 1994, death rates in developing countries are actually lower than in developed countries. BUT, “that reduction did not extend to maternal mortality rates.”
“Like crude birth rates, death rat4s are meaningful for comparative purposes only when we study identically structured populations. Countries with a high proportion of elderly people, such as Denmark and Sweden, would be expected to have higher death rates than those with a high proportion of young people, such as Iceland, assuming equality in other national conditions affecting health and longevity.” (Getis, 194)
To overcome that lack of comparability, death rates can be calculated for specific age groups.
Infant Mortality Rate: is the ratio of deaths of infants aged 1 year or under per 1000 live births.
200 years ago, infant mortality rates were as high as 200 to 300 deaths per 1000 live births
Even in 2000, for all of Africa, the infant mortality rate is near 90 deaths per 1000 births. Liberia, Mozambique, and Sierra Leone have rates above 130 per 1000 births.
The former Soviet Union has an overall rate of 23 per 1000 (1991), but in Central Asian region it was as high as 110/1000.
Western Europe and Anglo-America has an infant mortality rate of 4-7/1000.
Life Expectancy Rate: how long does the average person in that country live.
1950s five northern European countries had life expectancy rates above 70. By 2000, 60 countries outside of Europe and Anglo-America had life expectancies over 70 but none in sub-Saharan Africa.
Traditional diseases like:
Maleria, intestinal infections, typhoid, cholera, and, especially among children, malnutrition and dehydration from diarrhea
Have largely been overcome in the developed world.
World Health Organization estimates that 40 million people are HIV positive at beginning of 21st century.
95% of those infected are in developing world.
70% in sub-Saharan Africa.
“In the hardest hit region, as much as one-fourth of the adult population in some countries is HIV positive, average life expectancy has been cut by 15 years, and total population in 2015 is now projected to be 60 million less than it would have been in the absence of the disease. Economically, AIDS will cut an estimated 8% off national incomes in the worst-his sub-Saharan countries by 2010.” (Getis, 195)
“Nonetheless, because of their high fertility rates, populations in all sub-Saharan countries except South Africa are still expected to grow significantly between 2000 and 2050, adding nearly 1 billion to the total.
“Indeed, despite high mortality rates due to HIV/AIDS, the population of the world’s 48 least developed countries as a group will, according to UN projections, almost triple between 2000 and 2050, the consequence of their high fertility levels.
“However, warnings of the rapid spread of the AIDS epidemic in Russia, Ukraine, and South and East Asia—particularly China and India—raise new global demographic concerns even as more hopeful reports of declining infection and mortality rates in some African and Southeast Asian countries are appearing.” (Getis, 196-7)
Population Pyramids (Getis 197 – 200): “a graphic device that represents a population’s age and sex composition.”
“The population pyramid provides a quickly visualized demographic picture of immediate practical and predictive value.
Dependency ratio: is a simple measure of the number of dependents, old or young, that each 100 people in the productive years (usually, 15-64) must support. Population pyramids give quick visual evidence of that ratio.
Read p. 200 on China family planning consequences. Skewed male to female ratios.
Rate of Natural Increase of a population: is derived by subtracting the crude death rate from the crude birth rate. Natural means that increases, or decreases due to migration are not included. “If a country had a birth rate of 22 per 1000 and a death rate of 12 per 1000 for a given year, the rate of natural increase would be 10 per 1000. This rate is usually expressed as a percentage, that is, as a rate per 100 rather than per 1000. In the example given, the annual increase would be 1%.” (Getis, 200) Rate is given in percentages.
Doubling Time is the time it takes for a population to double. The rate of natural increase can be used to calculate the doubling time.
Population doubling time can be estimated by dividing the growth rate (rate of natural increase) into the number 70.
Annual % Rate of Natural Increase Doubling Time (Years)
Egypt and Peru in 2002 had a 2% rate of natural increase. If this continues, these countries will double their population in 35 years.
Since 1990, world rate of natural increase has declines and so has the doubling time. It is currently estimated to be 56 years since 1974.
Doubling times are based on geometric or exponential increases (1, 2, 4, 8, 16, 32 . . . n) rather than arithmetic growth (1,2,3,4,5 . . . n). Like compound interest.
J-Curve Growth projections are based on doubling times.
“Rounding the bend in the J-curve, which Figure 6.16 suggests world population did around 1900, fostered after 1950 dire predictions of inevitable unsupportable pressures on the planet’s population support capabilities.
“By 2000, however, it became apparent that few developed countries, particularly in Europe, are likely in the foreseeable future or ever to double their population size. Further, declining fertility rates in most of the developing world and the incidence of AIDS in sub-Saharan Africa and parts of populous Asia cast doubt on the utility or applicability of long-term doubling time projections even for present high growth rate countries. Although the United Nations estimates that the population of the 48 least developed countries will possibly almost triple between 2000 and 2050, we have learned that doubling time assumptions are inherently misleading and population increases are limited.” (Getis, 203)
Stages in Demographic Transition
Stage 1: Birth and death rates are both high. Slow population growth.
Stage 2: Death rate drops; birth rate remains high. Rapid population growth. Europe entered this stage about 1750 with the beginning of the Industrial Revolution.
Stage 3: Death rate drops; birth rate declines. Population growth slows.
Stage 4 Low death rate and low birth rate. Slow population growth or even slight decline.
Stage 5??: Maybe population decline possibly due to new diseases (HIV-AIDS)
This model was developed for Europe.
“Many countries in southern Asia and Latin America display characteristics of this second stage in the population model.
Bhutan: 34/1000 birth rate; 9/1000 death rate.
Nicaragua: 34/1000 birth rate; 5/1000 death rate.
The original transition model was devised to describe the experience of northwest European countries as they went from rural-agrariansocieties to urban-industrial ones. It may not fully reflect the prospects of contemporary developing countries.
Epidemiologic transition or mortality revolution came first with improvements in dealing with epidemic diseases.
A Divided World Converging. The population history of Europe is not entirely relevant to the developing world. Many developing societies seemingly remained locked in the second stage of the model, unable to realize the economic gains and social changes necessary to progress to the third stage of falling birth rates.
European technologies reduced mortality rates with startling speed in developing countries after 1950s. What in Europe took centuries occurred elsewhere in decades.
World Population soared:
2.5 billion 1950
3.0 billion 1960
6.0 billion 2000
“Birth rate levels, of course, unlike life expectancy improvements depend less on supplied technology and assistance than they do on social acceptance of the idea of fewer children and smaller families.
“That acceptance began to grow broadly but unevenly worldwide even as regional and world population growth seemed uncontrollable. In 1984, only 18% of world population lived in countries with fertility rates at or below replacement levels (that is, countries that had achieved the demographic transition). By 2000, however, 44% lived in such countries, and early in the 21st century it is increasingly difficult to distinguish between developed and developing societies on the basis of their fertility rates. Those rates in many separate Indian states (Kerala and Tamil Nadu, for example) and in such countries as Sri Lanka, Thailand, South Korea, and Chinaare below those of the United States.” (Getis, 206)
“Despite this general substantial convergence in fertility, there still remains a significant minority share of the developing world with birth rates averaging 1.5 to 2 times or more above the replacement level. Indeed, early in the 21st century almost 1.4 billion persons live in countries or regions where total fertility is still 3.5 or greater. (Sub-Saharan Africa and Northern India)
“The established patterns of both high and low fertility regions tend to be self-reinforcing.
“Low growth permits the expansion of personal income and the accumulation of capital that enhance the quality and security of life to make large families less attractive or successful.
“In contrast, in high birth rate regions, population growth consumes in social services and assistance the investment capital that might promote economic expansion. Increasing populations place ever greater demands on limited soil, forest, water, grassland, and cropland resources. As the environmental base deteriorates, productivity declines and population-supporting capacities are so diminished as to make difficult or impossible the economic progress on which the demographic transition depends.” (Getis, 207)
The Cairo Plan. UN International Conference on Population and Development in Cairo in 1994 endorsed a strategy of stabilizing the world’s population at 7.27 billion by no later than 2015.
Conference proposed giving women a greater role in reproductive decisions. Better education for women.
Issue: contraception. Abortion. Sexual relations outside marriage.
Demographic Equation summarizes the contribution made to regional population change over time by the combination of natural change (difference between births and deaths) and net migration (difference between in-migration and out-migration).
On a global scale, of course, all population change is accounted for by natural change. The impact of migration on the demographic equation increases as the population size of the areal unit studied decreases.
World Population Distribution
Crude Density or arithmetic density: calculates the number of people per unit area of land. Figures become more meaningful when the unit area of land is specified: New Jersey vs. Wyoming as opposed to all of US. Agricultural land. Urban rural, etc.
Physiological density relates population to area of a country which can be cultivated, that is, arable land.
Agricultural density. It excludes city populations from the physiological density calculations.
Population Data and Projections
Population Data come primarily from the United Nations Statistical Office, the World Bank, the Population Reference Bureau, and ultimately, from national censuses and sample surveys.
Population Projections are imprecise. They are not as accurate as weather predictions.
High, low, medium projections based on various assumptions.
Carrying capacity. Sustainable development
Thomas Robert Malthus (1766 – 1834)
Population can increase geometrically
Food supply increases arithmetically.
Economics is the dismal science.
Demographic Momentum: Even if world fertility levels were to go to the replacement level of 2.1 births per woman that would not mean an immediate stabilization of world population due to the demographic or population momentum. A large fertile population will still increase even if they have less children per couple.
“The populations of developing countries are far younger than those of the established industrially developed regions, with about one-third (in Asia and Latin America) to almost about one-half (in Africa) below the age of 15. The consequences of the fertility of these young people are yet to be realized. A population with a greater number of young people tends to grow rapidly regardless of the level of child-bearing. The results will continue to be felt until the now youthful groups mature and work their way through the population pyramid."
To the social and economic implications of their present population momentum, developing countries must add the aging consequences of past patterns and rates of growth.