Human Population Issues

EVPP 111 Lecture

Spring 2004

Dr. Largen

Human Population Issues

• importance
• history
• current trends
• growth
• impacts on resources
• urbanization
• economic development

Human population issues - importance

• Importance
• Many human problems exacerbated by rapid increase in population, including
• hunger
• resource depletion
• environmental degradation
• underdevelopment
• poverty
• urban problems
• Human population growth is contributing factor in nearly every environmental problem
• including
• air pollution
• water pollution
• waste management and disposal
• environmental degradation
• extinction of species
• climate change

• history
• human population
• has increased over time
• rate of increase has increased with time
• been growing rapidly for centuries
• grown explosively over last 300 years

• less time between doubling time
• 1 A.D. = ~ 130 million
• 1000 A.D. = ~ 260 million
• 1650 A.D. = ~ 500 million
• 2000 A.D. = ~6,000 million (~6 billion)
• exponential growth in human population
• as human history progressed
• humans gained greater control over factors that influence growth rate
• through knowledge and technology

• improved control over
• food supply through agriculture
• development of weapons to ward off predators
• development of medicines to treat diseases

• enabled humans to expand the carrying capacity of their habitats
• escape confines of logistic growth
• re-enter exponential portion of sigmoid growth curve

Human population issues - current trends

• current trends
• human population growth
• continues, is rapid
• even though growth rate has declined
• not uniform over planet

• between 1963 - 2001
• growth rate has decreased 39%
• from 2.2% to 1.33%
• population based increased 91%
• from 3.2 billion to 6.1 billion

• growth not uniform over planet
• some countries = stable populations
• birth dates Å death rates
• example; Sweden
• some countries = burgeoning populations
• birth rates greatly exceed death rates
• example; many developing nations

• world
• current population
• ~6.3 billion
• 6 billion mark reached in October 1999
• natural rate of increase
• ~1.3%
• projected change
• 46% by 2050

• doubling time
• concept in understanding impact of "small" rates of increase on overall population size
• can be calculated
• 70/rate of increase

• = 70 years at rate of increase of 1%
• = 35 years at rate of increase of 2%
• = 54 years at rate of increase of 1.3 %
• current world rate of increase

• US
• current population
• ~287 million
• natural rate of increase
• ~0.6%
• projected change
• +44% by 2050

• population growth in various regions of world
• see textbook, figure 8.1: population growth in the world (2002)
• population characteristics of most populous countries
• see textbook, table 8.1: population characteristics of 20 most populous countries (2002)

Human Population Issues - Growth

• Growth rate
• populations grow (+) or decline (-)
• based on interplay of four factors factors
• births
• deaths
• immigration
• emigration
• population change=
• (births + immigration) - (deaths + emigration)
• zero
• when factors balance out
• a condition known as
• zero population growth (ZPG)
• based on
• birth rate=
• number of live births per 1000 people
• death rate
• number of deaths per 1000 people
• demographers use
• natural rate of increase =
• ((birth rate-death rate)/1000) x 100

• birth rate
• affected by fertility
• total fertility rate (TFR)
• # children per woman in her lifetime
• replacement fertility rate
• 2.1
• influenced by
• Age structure of a population
• proportion of individuals in different age groups
• can help predict future growth of population
• Age structure of a population
• illustrated graphically in a
• population pyramid
• bar graph, displays number of people in each age category by sex
• can predict demographic trends by "steepness" of pyramid

• population pyramid
• bar graph
• displays number of people in each age category by sex
• males to left, females to right of vertical axis
• usually uses percentage of population
• age categories can be; narrow, broad, tied to reproductive stages

• Age structure
• three kinds of age structure are characteristic of human populations
• expanding
• broad-based pyramid
• most of population is pre-reproductive
• population will continue to grow for some time as individuals in pre-reproductive stages enter reproductive stages of life
• example = Kenya
• stable
• more uniform, rectangular in shape
• sides roughly parallel
• age groups are nearly balanced
• will remain stable for some time since there will be little change in number of individuals in reproductive stages of life
• examples = US, Canada, Australia
• declining
• inverted pyramid
• narrow base, broad top
• fewer pre- and reproductive individuals than post-reproductive older individuals
• population will continue to decline
• no new ranks of individuals to replace reproductive individuals as they move into post-reproductive stage of life
• examples = Hungary, Germany
• Factors that affect growth rate
• three general categories
• cultural
• socioeconomic
• political
• cultural
• religious beliefs
• traditions
• cultural norms
• attitudes about birth control
• infant mortality rates
• importance of children as part of labor force
• average age at marriage

• religious beliefs, traditions, cultural norms, attitudes about birth control
• high TFRs traditional in many cultures
• motivations for having many children vary from culture to culture
• some cultures oppose use of birth control
• infant mortality rates
• major reason for high TFRs is to offset
• high infant and child mortality rates
• infant mortality rates
• to endure, a society must continue to produce enough children who survive to reproductive age
• if infant and child mortality rates are high
• total fertility rate must be high to compensate
• infant mortality rates
• though infant mortality rates have been decreasing worldwide
• there’s a lag time for culturally-imbedded fertility levels to decline
• parents must have sufficient confidence that the children they already have will survive before they stop having additional children
• importance of children in labor force
• in developing countries
• high TFRs help ensure that there are children to work in family enterprises, such as farming, commerce
• in developed nations, by contrast
• children have less value as a source of labor
• because; they attend school, society is more mechanized, care of elderly shared by society
• average age at marriage
• affects total fertility rate
• is determined by laws and customs of society
• varies from culture to culture
• there is always a correlation between marriage age and total fertility rate
• the older the average age of marriage, the lower the TFR
• it delays age at which first child is born
• lowers the number of children a woman can have in her lifetime
• example; in Sri Lanka
• average age of marriage is 25
• average number of children per women is 2.1
• population doubling time is 60 years
• example; in Bangladesh
• average age of marriage is 17
• average number of children per woman is 3.3
• population doubling time is 38 years

• socioeconomic
• socioeconomic status of women
• employment opportunities
• educational opportunities
• availability of family planning services
• socioeconomic status of women
• in most societies, women do not have same rights, privileges or opportunities as men
• evidence is accumulating that
• single most important factor affecting high TFRs is low status of women in many societies

• employment opportunities
• TFRs tend to be lower when women have access to paid employment outside the home
• employment opportunities brings
• financial independence
• tendency to marry later
• tendency to have fewer children
• educational opportunities
• in nearly all societies, women with more education tend to marry later and have fewer children
• providing women with education opportunities delays first childbirth
• thus reducing number of "active" childbearing years, increasing time between generations
• education opens door to greater career opportunities which often further delays first childbirth
• it has been said that single most important activity needed to reduce world population is to educate women
• example; in Botswana, women with
• secondary education have an average of 3.1 children
• primary education have an average of 5.1 children
• no formal education have an average of 5.9 children

• availability of family planning services
• greater contraceptive use among married women of reproductive age correlates with a lower fertility rate
• socioeconomic conditions and status of women affect availability of family planning services
• political
• family planning policies
• governments in ~ 78 developing countries have established policies to help help limit population growth, including
• public education efforts
• economics rewards and penalties
• laws
• China
• first program began in 1955
• launched wan xi shao campaign in 1971, meaning
• "later" marriages
• "longer" intervals between births
• "fewer" children

• China
• TRF has been reduced to 1.8 (from 5.9 in 1965)
• ~80% of couples use contraception
• 87% of women are literate (1990)
• projected population change by 2050 = +9%
• India
• has been less successful
• TRF has been reduced to 3.2 (from 5.8 in 1965)
• ~48% of couples use contraception
• 40% of women are literate (1990)
• projected population change by 2050 = +55%

Human population issues - impacts on resources

• discrepancy between individual resource demands in developing vs.developed nations
• developing nations
• individual resource demands are small
• but rapidly increasing populations deplete natural resources
• developed nations
• individual resource demands are large
• and this demand depletes natural resources
• Effects of overpopulation on
• nonrenewable resources
• present in limited quantities, depleted by use
• used/depleted faster than they can be replenished
• slowing population growth would give more time to find substitutes for nonrenewable resources
• people in US and other developed nations consume majority of world’s nonrenewable resources
• renewable resources
• replaced by nature, fairly "rapidly"
• can be used forever as long as they are not exploited in short term
• rapid population growth can cause renewable resources to be overexploited
• renewable resources must be used in sustainable way that gives them time to replace or replenish themselves

• Effects of population growth on natural resources
• particularly critical in developing nations
• economic growth of developing nations is often tied to exploitation of their natural resources
• to provide for their expanding populations in short term

• Effects of population growth on natural resources
• resources issues are clearly related to population size
• more people use more resources
• resource consumption
• more important issue
• measure of human use of materials/ energy
• people in developed nations are extravagant consumers
• their use of resources is greatly out of proportion to their numbers
• people in developed nations are extravagant consumers
• their use of resources is greatly out of proportion to their numbers
• highly developed nations represent ~20% of world’s population
• yet they consume >50% of its resources
• Overpopulation
• a country is overpopulated if level of demand on its resource base results in damage to environment
• a country can be overpopulated in two ways
• people overpopulation
• consumption overpopulation
• people overpopulation
• occurs when environment is degraded from too many people
• even if those people consume few resources per person
• consumption overpopulation
• occurs when each individual in a population consumes too large a share of resources
• effects of both are same
• pollution and degradation of environment

• model of human impacts on the environment
• three factors most important in determining environmental impact (I)
• number of people (P)
• affluence per person (A)
• measure of consumption or amount of resources used per person
• environmental effects of technologies (T) used to obtain and consume the resources
• I = P x A x T
• model of human impacts on the environment
• I = P x A x T
• model expressed by this equation can be useful
• but must be interpreted with care
• because we often do not understand all the environmental impacts of certain actions of processes

Human population issues - urbanization

• Geographical distribution of people affects impact of population growth
• throughout recent history, people have increasingly migrated to cities
• urbanization
• process in which people increasingly move from rural areas to densely populated cities
• involves transformation of rural areas into urban areas
• Geographical distribution of people affects impact of population growth
• distinction between rural and urban areas
• not just how many people live in area
• but how people make their living
• rural areas
• most people have occupations that involve harvesting natural resources
• urban areas
• most people have occupations that are not directly connected with natural resources

Human population issues - economic development

• Demographic transition
• hypothesis of population change
• concept grew out of relationship between standard of living and population growth rate
• countries with
• highest standard of living have lowest growth rates
• lowest standard of living have highest growth rates
• based on examination of birth and death rates of North America and western European countries that industrialized during 19th century
• states that
• as countries become industrialized
• first their death rates and then their birth rates decline
• takes place in four distinct stages
• pre-industrial stage
• transitional stage
• industrial stage
• postindustrial stage
• pre-industrial stage
• little population growth
• harsh living conditions lead to both
• high birth rates
• to compensate for high infant mortality rates
• high death rates
• transitional stage
• population grows rapidly
• because with advent of industrialization
• food production increases
• health care improves
• death rate decreases
• birth rate remains unchanged
• culturally imbedded
• industrial stage
• population growth continues
• but at slower and more fluctuating rate depending on economic conditions
• birth rate drops and approaches death rate
• as industrialization and modernization become more widespread
• most developed nations are in this stage
• post-industrial stage
• total population size decreases slowly
• birth rate declines below death rate
• 35 countries, most in Europe, containing about 13% of world’s population have entered this stage
• will it be experienced by today’s less-developed nations?
• when today’s developed nations passed through transition, conditions included
• world population was lower
• energy, natural resources were still abundant
• access to large expanses of of unexploited lands
• industrialization occurred fast enough to impact population growth
• will it be experienced by today’s less-developed nations?
• necessary conditions for demographic transition to occur may not be available to today’s developing nations

The End.