Overview

Population Growth Population Definitions The Demographic Transition The Demographic Equation World Population Distribution Population Density Population Data and Projections Population Controls Population Prospects

Population Geography vs. Demography

Population geography Focuses on the number, composition, and distribution

of humans in relation to variations in the conditions of earth space

Spatial analysis Demography

The statistical study of human population

Population Growth

World population is about 6.7 billion Annual increase of 74-75 million

Annual increases have been declining 2006 UN projections

9.2 billion in 2050 9.4-9.5 billion by 2100

Future growth will occur in developing countries

Population Definitions

Population measures are made more meaningful by rates and cohort measures Rates

Frequency of occurrence during a specified time period Cohort

Population group unified by a common characteristic, such as age

Birth Rates

Annual number of live births per 1000 population Influenced by age and sex structure, customs and

family size expectations, population policies High birth rates (≥ 30)

Characteristic of agricultural, rural countries in which a high proportion of the female population is young

Low birth rates (< 18) Characteristic of industrialized, urbanized countries

Transitional birth rates (18-30) Some developing and newly industrializing countries

Subject to change

Total Fertility Rates

Average number of children born to each woman Replacement level fertility: 2.1-2.3 Worldwide TFR in 2007: 2.7

More-developed countries: 1.6 Less-developed countries: 2.9

Fertility declines in recent decades Dramatic declines in many less-developed countries

Changing cultural values TFRs below replacement level

Populations may stabilize or grow due to migration

Death Rates

Annual number of deaths per 1000 population In the past, varied with levels of development

Dramatic reductions in in less-developed countries As a group, death rates now lower than in more-

developed countries

Also influenced by age structure Infant mortality rate

Ratio of deaths of infants aged 1 year or under per 1000 live births

Significant declines in modern times

Death Rates

Modern medicine and sanitation have increased life expectancy Regional variation in benefits

HIV/AIDS Sub-Saharan Africa has been hit hardest

Average life expectancy has been cut Food insecurity

Population Pyramids

Graphic depiction of the age and sex composition of a population

Types of population profiles Rapid growth Slow growth Decline Disrupted growth

Population profile influences demands on a country’s social and economic systems Dependency ratio

Number of economic dependents that each 100 persons in the productive years must support

Natural Increase and Doubling Time

Rate of natural increase Birth rate minus death rate expressed as a percentage Excludes migration

Doubling time Time it takes for a population to double if current

growth rate remains constant 72 divided by rate of natural increase

J-curve Depicts exponential (geometric) growth

Demographic Transition

Model of the effect of economic development on population growth Stage 1: High birth and death rates Stage 2: High birth rates and declining death rates Stage 3: Declining birth rates and low death rates Stage 4: Low birth and death rates Stage 5: Death rates exceed birth rates

Devised to describe the experience of northwest European countries

A Divided World Converging

The population history of Europe was not relevant to all developing countries Many remained in the second stage

Introduction of Western technologies of medicine and public health to developing countries Quickly lowered death rates

Birth rates are largely dependent on social acceptance of fewer children Have fallen in some developing countries but remain

high in others

Demographic Equation

Regional population change is a function of natural change and net migration

Population relocation Can relieve pressures of rapid growth

Immigration impacts Demographic equation Population structures of origin and destination

Emigrant groups are skewed in favor of young singles

World Population Distribution

Uneven population distribution Almost 90% live north of the equator

2/3 of total between 20° and 60° N A large majority occupies a small part of the land People congregate in lowland areas Continental margins have the densest settlement

Four clusters of population East Asia South Asia Europe NE United States/SE Canada

World Population Distribution

Ecumene Permanently inhabited areas of the earth Has been extended by technologies

Nonecumene Uninhabited or very sparsely occupied zone 35% to 40% of the land surface

Population Density

The relationship between number of inhabitants and the area they occupy

Crude (arithmetic) density Number of people per unit area of land

Physiological density Number of people per unit of arable land

Agricultural density Number of rural residents per unit of agriculturally

productive land

Overpopulation

Value judgment that the resources of an area are insufficient to sustain its present population Not the inevitable consequence of high density

A continuing imbalance between numbers of people and the carrying capacity of the land Number of people an area can support, given the

prevailing technology Related to level of economic development

Urbanization

Transformation from rural to urban status Rapid growth of cities in developing countries

Nearly all world population increase between 2000 and 2030 will be in urban areas of developing countries

Consumes a great deal of cropland Problems in densely populated cities in

developing countries Lack of housing, jobs, education, health and social

services

Population Data and Projections

Population data Sources: United Nations, World Bank, Population

Reference Bureau, national censuses May be inaccurate

Population projections Based on assumptions applied to current data Not predictions High, medium, and low projections may be given

Population Controls

Thomas Robert Malthus Unchecked population increases geometrically, food

production increases arithmetically Equilibrium must be achieved between numbers

and resources Overpopulation will result in a dieback

J-curve converted to S-curve Homeostatic plateau

Population that is equivalent to carrying capacity

Population Controls

Neo-Malthusianism Advocacy of population control programs to improve

prosperity and well-being Many countries have adopted family planning programs

E.g., China

Cornucopians Believe population growth is a stimulus to

development

Population Prospects

Population (demographic) momentum Numbers of births continue to grow as fertility rates

per woman decline High concentration of people in the childbearing years

Aging Result of transition from high to low levels of fertility

and mortality Pace is much faster in developing countries Increasing burdens on working-age populations

Potential support ratio is falling