Current Human
Population Growth
and Implications
Human Population History
Factors Contributing to
Population Explosion
• Agricultural
advances
• Advances in
medicine
• Industrial
revolution
Reasons for exponential growth
of human population
• Increased food supply
• Improvements in medical and public health
and technology
• Improvements in sanitation and personal
hygiene
• Safer water supplies
Thomas Malthus
• Studied the decline of living conditions in
19th century England
• Blamed this decline on:
– Too many children
– Inability of resources to replenish at levels with
increased population
– Irresponsibility of lower class
• Proposed regulating family size of lower
class to limit it to a level they could support
Malthus continued
• He said “positive checks” like food
shortages and disease kept population at
appropriate levels
• He said population growth was exponential
but food production could not keep growing
exponentially.
• As of today, he was wrong due to GM
foods.
Current Stats
• World Population: 6.6 billion people
• U.S. Population: 295 million people
• Kentucky Population: 4.1 million
people
• Louisville Population: 500,000 people
• The U.S. is only 5% of the world’s
population, but we use ~ 1/3 of the
Earth’s natural resources!!!
Crude Birth Rate and CDR
• CBR= the number of live births per 1000
members of the population in one year.
• CDR= the number of deaths per 1000
members of the population in one year.
• When calculating population change you
must take into account total population size
when using CDR and CBR.
Population change=
(CBR+ immigration) – (CDR + emigration)
• Example: If the population is 50,000 and
the number of births is 14 per 1000 and the
number of deaths is 5 per 1000, what was
the population change assuming no net
immigration or emigration?
Alarming Facts…
• The human population
is currently growing at
a rate of 260,000
people per day!
• Every 3 years, the
global environment
must support another
285 million people
As a result of rapid
growth…
• 1.3 billion people are impoverished
• 841 million people are chronically
malnourished
• Supplies of water for irrigation are declining
• Nearly half of the Earth’s land mass has
been changed by human activity
• Ocean fish stocks are depleting
• Species are going extinct faster than ever
Earth’s Carrying
Capacity (2billion-30billion)
• Determined by
– Food production
– Living space
– Waste assimilation
– Resource availability
• Can be expanded through advances in
– Agriculture
– Industry
– Medicine
Accomodations
To accommodate greater populations,
many policies would have to be
implimented:
Massive recycling
Driving restrictions
Restrictions on the transport of food
Prohibitions against cutting trees on
one’s property
Limitations to burning of fossil fuels
Fertility rates
• Replacement level fertility (RLF)= having
enough kids to replace yourself
– Slightly higher than 2 (2.1) b/c some kids die
• Total fertility rate (TFR)= average number
of children a woman will have in her
lifetime
– Many factors affect like urbanization,
education, contraceptives and abortion
availability
Indicators of overall human
health:
• Life expectancy
• Infant mortality rate
Other factors that affect
population growth
•
•
•
•
Policies to encourage immigration
Environmental refugees
Religious persecution
Baby boom generation in US
– Why they are waiting to retire
– How their retirement will affect the rest of us
Demographic Transition
• Pre-industrial= little to no growth (African
nations)
• Transitional= rapid growth (Mexico,
Pakistan)
• Industrial= stable growth (china)
• Post-industrial= declining growth (Japan,
Russia, Germany)
Why are developing countries like
India not moving toward Industrial
stage?
• Most people are poor. Money is kept to few
in the country.
Age Structures and what they tell us
about future population growth:
• What would a stable population age
structure look like?
• What would a declining population age
structure look like?
Ways to lower population
growth:
• Provide economic incentives for having
fewer children
• Empower and educate women
• More education means more money for
work which mean less children are needed
to take care of parents
• More education usually means having
children later in life which usually means
having less children
Cont.
• Family planning including contraceptives,
legal abortions
• Improve prenatal and infant health care
(need less kids if they survive)
China and India as case studies
on family planning
• What do you think of these interventions?
What do you think?
• What is the US’s role (thus the taxpayers
role) in other country’s population control?