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Unformatted text preview: Global Population
We will ignore the very earliest stages of human development and arguments about when the species began. It is likely that human life began about 3 million years ago. Global Population
1 000 million = 1 billion 11 000 BP ~5-10 million ~5Birth of Christ 200 million 1650 AD 500 million 1850 AD 1000 million (1 billion) 1930 2 billion 1975 4 billion World Population Since A.D. 1
Source: Engelman, UN World Population Increase by Era 6 Billion People 4 2 0 0 400 800 1200 1600 2000 www.worldwatch.org Annual Growth Rate in World Population, 19502005
Source: U.S. Census Bureau Global Population
2005 6.59 billion 2050 9.1 billion People born since 1950 have seen more absolute population growth than occurred in the first 4 million years of human existence. 2.5 2.0 Percent 1.5 1.0 0.5 0.0 1950 1960 1970 1980 1990 2000 2010 www.worldwatch.org 1 Demography
The statistical study of populations. It does not include the notion of population movement (migration). When the latter is included we are dealing with population geography. Rates: the rate of anything simply refers to Rates: its frequency. In demography we usually use the base per 1000 (0/00). 0/00). Demography
Cohort Measures: a cohort refers to any Measures: specified group, e.g., children aged 1-5 1years old, all college freshmen in 2008. Crude Birth Rate (CBR): annual number of CBR): births per 1000 people. CBR >30 are high, e.g., Africa, S. Asia, Latin America. 50% of the world lives in countries with high CBRs. Demography
CBR <20 is low. Mainly developed world, e.g., Europe, Anglo-America, Japan, AngloRussia, Australia, etc. China (PRC) is very erratic.
1970 1986 2002 2005 CBR = 33 CBR = 18 CBR = 13 CBR = 12 Demography
China's CBR is government influenced. China' Japan's CBR dropped sharply after WW II Japan' simply as a result of family decisions. In general:
CBRs in developed world are ~11 CBRs in underdeveloped world are ~24-27 ~24- In general world population increase is overwhelmingly in the underdeveloped world at present. Demography
Crude Death Rate (CDR): also called the CDR): Mortality Rate. The annual number of Rate. deaths per 1000. CDR <10 = a low rate. The developed world, aging populations. CDR >20 = a high rate. Africa, the underdeveloped world. Sanitation, Medicine, & Death Rate 2 Projected Impact of AIDS in SubSubSaharan Africa Demography
Natural Growth is the simple relationship between the CBR and the CDR (input and output). If we consider natural growth plus migration we call it Overall Growth. Growth. Demography
A very widely used measure of the general healthiness of a population is its Infant Mortality Rate. Rate. deaths age < 1 year 1000 live births Demography
200 years ago IMRs often 200-300. 200- 300. Today:
More developed world ~7 Less developed world ~60 Africa ~86 (Sierra Leone ~153) ~153) Asia ~59 Russia ~16 USA 6.6, Canada 5.3, Nth & NW Europe 5. 6.6, 5.3, Demography
The CBR is not all that helpful because it varies with the nature of the population (old versus young populations). We need an adjusted value Total Fertility Rate (TFR). This measures tells us how many TFR). children a statistical woman will have in her lifetime (explain). A TFR of 2.1 is needed for replacement. replacement Demography
World = 2.7 More developed world = 1.6 Less developed world = 3.0
(without China = 3.5) 3.5) Africa = 5.1 China = 1.6 India = 3.0 3 The Shape of National Populations 1975 = pink; 2000 = blue Population Pyramid: Rapid Growth Population Pyramid: No/Slow Growth Negative Growth The Impact of Planning Policy in India Demography
Doubling Times: The amount of time it Times: takes for a population to double if you know its annual percentage change. (If negative these same percentages equal halving times). 1% annual increase, doubling time = 70 yr. yr. 2% annual increase, doubling time = 35 yr. yr. 4% annual increase, doubling time = 17 yr. yr. The planning policy was very aggressive, and successful, but there is still a long way to go before it looks like the developed world. 4 Demography
The relationship between annual percentage increase and doubling time is related to the natural logarithm. Divide the number 72 (you will see 70 used sometimes) by the annual percentage to sometimes) get the doubling time in years. E.g., 72/3% = 23.3 years. Demography
2005 world annual percentage increase was 1.2% Maximum was in 1963 when it was 2.2% Today: more developed world is 0.1% less developed world is 1.5% Sub-Saharan Africa 2.4% Sub- Demography
Globally or worldwide we are faced only by natural increase or decrease. But regionally or by country we are faced by overall growth. Obviously, some regions are losing people while others are gaining them from migration. We will look at this migration. issue next time. Demographic Transition Model
This model has been widely used to depict the stages of a country's population country' growth. It is based on the historic experience of European countries. It has four stages: First Stage: high birth rate + high Stage: fluctuating death rate give slow population growth. Probably characterized world until ~1750. No longer seen. Demographic Transition Model
Second Stage: Continued high birth rate + Stage: declining death rate create dramatic population increase and increase in life expectancy. Contemporary examples: S and SE Asia, Latin America. Pakistan CBR = 30 / CDR = 9, Bolivia CBR = 32 / CDR = 9. Demographic Transition Model
Third Stage: birth rate declines as families Stage: deliberately reduce it. E.g., Chile, CBR = 18 / CDR = 6; Thailand, CBR = 14 / CDR = 6. Fourth Stage: XCBR and CDR both very Stage: low. Population may even decline. E.g., Germany, CBR = 9 / CDR = 10; Denmark, CBR = 12 / CDR = 11, Hungary, CBR = 10 / CDR = 13. These are `old' countries. old' 5 Demographic Transition Model
For reasons that are not fully understood many underdeveloped countries have been stuck in Stage Two. Social issues Two. and attitudes appear to be the primary reasons that birth rates have not come down in these countries. The Demographic Transition Model 6 ...
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This note was uploaded on 04/07/2008 for the course GEOG 210 taught by Professor Thorn during the Spring '08 term at University of Illinois at Urbana–Champaign.
- Spring '08